rewrite how events are held

.clang-format

@@ -34,14 +34,14 @@ EmptyLineBeforeAccessModifier: Always
 FixNamespaceComments: false
 IncludeBlocks: Regroup
 IncludeCategories:
+    - Regex: '<[[:alnum:]._]+>'
+      Priority: -10
     - Regex: '^<fontconfig'
       Priority: -5
     - Regex: '^<SDL'
       Priority: -5
     - Regex: '^<basic_widgets/'
       Priority: 0
-    - Regex: '<[[:alnum:]._]+>'
-      Priority: -10
     - Regex: '^".*"$'
       Priority: 5
 IndentCaseLabels: true

README.md

@@ -1,125 +1,4 @@
 # sdl2_basic_widgets
 
-A (very) basic and incomplete widget library for SDL applications.
+A (very) basic widget library for SDL applications.
 
-## Build
-The build dependencies are SDL2, SDL_ttf and fontconfig dev libs
-and headers. Meson is used as build system, so you'll need it too.
-
-As the code use some C++20 features, you'll need a recent compiler
-which support that version of the standard.
-
-Then, inside the project root directory, run the following commands:
-
-```ShellSession
-$ meson build
-$ meson compile -C build -j0
-```
-
-After that you'll have in the build directory the static library and the
-example programs.
-
-## API overview
-
-The library API is divided in two main parts:
-- the core, which provides some basic wrapping of
-  SDL, SDL_ttf and fontconfig functionalities.
-- the widget API built on top of the core.
-
-### Core
-
-The main classes of the core are:
-
-- [Font](inc/basic_widgets/core/font.hpp):
-  wraps TTF_Font object with the most common operations
-  of SDL_ttf. Also provide a helper function to
-  search system fonts by using fontconfig.
-- [Renderer](inc/basic_widgets/core/renderer.hpp):
-  wraps SDL_Renderer object with common operation from
-  the SDL 2D accelerated rendering API.
-- [Texture](inc/basic_widgets/core/texture.hpp):
-  wraps SDL_Texture object with common operations
-  to manipulate it.
-
-Apart from the SDL API wrappers, some generic utility functions and
-data types are defined:
-
-- [Color](inc/basic_widgets/core/type/color.hpp):
-  wraps SDL_Color object and adds convenience operators
-  overloads to operate on all color channels and/or
-  alpha channel.
-- [draw.hpp](inc/basic_widgets/core/draw.hpp):
-  2D drawing utilities. Currently, provides a couple of basic utility
-  functions for software rendered textures: circle rendering
-  and an antialising algorithm.
-- [math.hpp](inc/basic_widgets/core/math.hpp): mostly provides
-  frequently used formulas to work with rectangles and points
-  on a 2D coordinate system.
-- [concepts.hpp](inc/basic_widgets/core/type/concepts.hpp):
-  a few concept definitions for used for generic programming.
-- [Size](inc/basic_widgets/core/type/size.hpp): representation
-  of a 2D size. There are also a few operator overloads to
-  operate on Size objects.
-
-## Widgets
-
-Widgets are classes that implements the common widget interface and
-optionally one or more "handler" interfaces. Handlers are interfaces
-for event or external resources handling.
-
-These interfaces are:
-
-- [Widget](inc/basic_widgets/w/base/widget.hpp): the common base
-  interface of every widget.
-- [EventHandler](inc/basic_widgets/w/feat/event_handler.hpp): base
-  interface for event handlers.
-- [FocusHandler](inc/basic_widgets/w/feat/focus_handler.hpp): base
-  interface for handler having a focus notion.
-- [KeyboardHandler](inc/basic_widgets/w/feat/keyboard_handler.hpp):
-  interface for key and text input events handling.
-- [MouseHandler](inc/basic_widgets/w/feat/mouse_handler.hpp):
-  interface for mouse events handling. Handle click and focus state
-  changes and also introduce a notion of "pushed" state.
-- [FontHandler](inc/basic_widgets/w/feat/font_handler.hpp): interface
-  for widgets using a font. Declares methods to set the widget font and
-  set background and text color used for text rendering.
-- [TextureHandler](inc/basic_widgets/w/feat/texture_handler.hpp): it exists
-  but I'm thinking now that it shouldn't.
-
-Based on these interfaces, there's implementation for a few basic widgets.
-Currently, the following ones are defined:
-
-- [Button](inc/basic_widgets/w/button.hpp): a push button.
-- [Caption](inc/basic_widgets/w/caption.hpp): a caption
-  that displays a rendered string. No multiline support.
-- [Input<T>](inc/basic_widgets/w/base/input.hpp): base
-  class for widgets using an input field.
-- [NumericInput<Numeric>](inc/basic_widgets/w/numeric_input.hpp) an
-  input widget for numeric values with two buttons to increase/decrease
-  the hold value.
-
-There are also "containers" widgets which are widget that hold a collection of
-widgets and manage their geometry:
-
-- [Layout](inc/basic_widgets/w/base/layout.hpp): abstract class for container widgets.
-- [AlignedLayout](inc/basic_widgets/w/aligned_layout.hpp): layout that is done by distributing
-  widgets on a horizontal or vertical row.
-
-To create widget objects, the corresponding function from [widget_factory.hpp](inc/basic_widgets/w/widget_factory.hpp)
-should be used. It's done this way for interface-implementation sake.
-
-## Source code organization overview
-
-The header and source directory hierarchies is organized in the following way:
-
-- core: C→C++ wrappers and commonly used generic functions.
-- core/type: basic data types and concepts.
-- w: the widget library
-- w/base: the abstract widget classes.
-- w/feat: handlers (optional widget features)
-
-Widget code intent to separate public API from implementation details. For that
-a Widget has two classes, a pure virtual one (Widget) which is the public API and another
-class (WidgetImpl) that implements the interface of the first one. Unless an access
-to implementation details is required, the interface (pure virtual) type should
-be used.

examples/button_example.cpp

@@ -1,19 +1,19 @@
 #include <iostream>
 
-#include <basic_widgets/w/widget_factory.hpp>
+#include <basic_widgets/w/button.hpp>
 
 #include "run.hpp"
 
+using bwidgets::Button;
+
 auto main() -> int
 {
-    run_example<bwidgets::Button>(
-      []() { return bwidgets::create_button(); },
-      [](auto w, auto f, auto x, auto y) {
-          w->click_handler([x, y](const SDL_MouseButtonEvent&) {
-              std::cout << "button(" << x << ',' << y << "):click!" << std::endl;
-          });
-          w->font(f);
-          w->text("click me");
-      });
+    run_example<Button>([](auto w, auto f, auto x, auto y) {
+        w->click_handler([x, y](const SDL_MouseButtonEvent&) {
+            std::cout << "button(" << x << ',' << y << "):click!" << std::endl;
+        });
+        w->font(f);
+        w->text("+");
+    });
     return 0;
 }

examples/caption_example.cpp

@@ -1,16 +1,17 @@
-#include <basic_widgets/w/widget_factory.hpp>
+#include <basic_widgets/w/caption.hpp>
 
 #include "run.hpp"
 
+using bwidgets::Caption;
+
 auto main() -> int
 {
-    run_example<bwidgets::Caption>([]() { return bwidgets::create_caption(); },
-                                   [](auto w, auto f, auto, auto) {
-                                       w->alignment =
-                                         bwidgets::Caption::Alignment::CENTER;
-                                       w->text("¡jello!");
-                                       w->font(f);
-                                   },
-                                   4, 8); // NOLINT(readability-magic-numbers)
+    run_example<Caption>(
+      [](auto w, auto f, auto, auto) {
+          w->alignment = Caption::Alignment::CENTER;
+          w->text("¡jello!");
+          w->font(f);
+      },
+      4, 8); // NOLINT(readability-magic-numbers)
     return 0;
 }

examples/example_example.cpp

@@ -3,11 +3,9 @@
 
 auto main() -> int
 {
-    run_example<Example>(
-      []() { return std::make_unique<Example>(); },
-      [](auto w, auto, auto x, auto y) {
-          w->cycle_r = (x + 1) * 3000;              // NOLINT(readability-magic-numbers)
-          w->cycle_b = (y + 1) * 3000;              // NOLINT(readability-magic-numbers)
-          w->cycle_b = (1 + x + y) * (y + 1) * 400; // NOLINT(readability-magic-numbers)
-      });
+    run_example<Example>([](auto w, auto, auto x, auto y) {
+        w->cycle_r = (x + 1) * 3000;              // NOLINT(readability-magic-numbers)
+        w->cycle_b = (y + 1) * 3000;              // NOLINT(readability-magic-numbers)
+        w->cycle_b = (1 + x + y) * (y + 1) * 400; // NOLINT(readability-magic-numbers)
+    });
 }

examples/example_widget.hpp

@@ -5,14 +5,14 @@
 
 #include <basic_widgets/core/math.hpp>
 #include <basic_widgets/core/renderer.hpp>
-#include <basic_widgets/w/base/widget_impl.hpp>
+#include <basic_widgets/w/base/widget.hpp>
 
 using bwidgets::Color;
 using bwidgets::rect_margin;
 using bwidgets::Size;
-using bwidgets::WidgetImpl;
+using bwidgets::Widget;
 
-class Example final : public WidgetImpl
+class Example final : public Widget
 {
     void _handle_geometry_change(const SDL_Rect& vp) noexcept override
     {
@@ -27,7 +27,8 @@ class Example final : public WidgetImpl
         const uint8_t r = 255 * (now % cycle_r / (float)cycle_r); // NOLINT
         const uint8_t g = 255 * (now % cycle_g / (float)cycle_g); // NOLINT
         const uint8_t b = 255 * (now % cycle_b / (float)cycle_b); // NOLINT
-        const Color   base_color {r, g, b, SDL_ALPHA_OPAQUE};
+        // NOLINTNEXTLINE(readability-magic-numbers)
+        const Color   base_color {r, g, b, 255};
 
         const int border = 10;
         for (auto i = 0; i < border; i += 3) {
@@ -49,7 +50,12 @@ public:
     unsigned int cycle_g {3500}; // NOLINT(readability-magic-numbers)
     unsigned int cycle_b {3500}; // NOLINT(readability-magic-numbers)
 
-    using WidgetImpl::WidgetImpl;
+    using Widget::Widget;
+    Example(Example&&)      = delete;
+    Example(const Example&) = delete;
+    auto operator=(Example&&) = delete;
+    auto operator=(const Example&) = delete;
+    ~Example() noexcept override   = default;
 
     [[nodiscard]] auto size() const noexcept -> Size override
     {

examples/input_example.cpp

@@ -1,15 +1,15 @@
-#include <basic_widgets/w/widget_factory.hpp>
+#include <basic_widgets/w/numeric_input.hpp>
 
 #include "run.hpp"
 
+using bwidgets::NumericInput;
+
 auto main() -> int
 {
-    run_example<bwidgets::NumericInput<float>>(
-      []() { return bwidgets::create_input_float(); },
-      [](auto w, auto f, auto, auto) {
-          w->font(f);
-          w->button_step = 0.5;       // NOLINT(readability-magic-numbers)
-          w->value_range(-3.14, 8.5); // NOLINT(readability-magic-numbers)
-      });
+    run_example<NumericInput<float>>([](auto w, auto f, auto, auto) {
+        w->font(f);
+        w->button_step = 0.5;       // NOLINT(readability-magic-numbers)
+        w->value_range(-3.14, 8.5); // NOLINT(readability-magic-numbers)
+    });
     return 0;
 }

examples/run.hpp

@@ -3,16 +3,23 @@
 
 #include <functional>
 #include <iostream>
+#include <memory>
+#include <stack>
 
-#include <basic_widgets/core/type/deleter.hpp>
-#include <basic_widgets/w/widget_factory.hpp>
+#include <SDL2/SDL.h>
+#include <SDL2/SDL_ttf.h>
+
+#include <basic_widgets/core/error_helper.hpp>
+#include <basic_widgets/core/font.hpp>
+#include <basic_widgets/core/renderer.hpp>
+#include <basic_widgets/w/aligned_layout.hpp>
+#include <basic_widgets/w/base/widget.hpp>
 
 template<typename T>
 concept WidgetType = std::derived_from<T, bwidgets::Widget>;
 
 template<WidgetType W>
 void run_example(
-  std::function<std::unique_ptr<W>()>                                      factory,
   std::function<void(W*, const std::shared_ptr<bwidgets::Font>, int, int)> setup,
   int w = 3, int h = 3)
 {
@@ -27,30 +34,31 @@ void run_example(
         auto                 font =
           std::make_shared<bwidgets::Font>(bwidgets::Font::find("Monospace"),
                                            16); // NOLINT(readability-magic-numbers)
-
-        auto win = std::unique_ptr<SDL_Window, bwidgets::Deleter>(
+        auto win = bwidgets::OpaqueStruct<SDL_Window>(
           bwidgets::ptr_or_throw<bwidgets::SDLError>(SDL_CreateWindow(
             "basic_widgets example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
             size_init.w, size_init.h,
-            SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE | SDL_WINDOW_UTILITY)));
-
+            SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE | SDL_WINDOW_UTILITY)),
+          [](auto ptr) noexcept { SDL_DestroyWindow(ptr); });
         auto renderer =
-          std::make_shared<bwidgets::Renderer>(win.get(), -1, SDL_RENDERER_ACCELERATED);
+          std::make_shared<bwidgets::Renderer>(win(), -1, SDL_RENDERER_ACCELERATED);
         renderer->blend_mode(SDL_BLENDMODE_BLEND);
 
-        auto layout = bwidgets::create_horizontal_layout();
+        bwidgets::AlignedLayout<bwidgets::LayoutAlignment::HORIZONTAL> layout;
+
         for (auto x = 0; x < w; x++) {
-            auto col = bwidgets::create_vertical_layout();
+            auto col = std::make_unique<
+              bwidgets::AlignedLayout<bwidgets::LayoutAlignment::VERTICAL>>();
             for (auto y = 0; y < h; y++) {
-                auto widget = factory();
+                auto widget = std::make_unique<W>();
                 setup(widget.get(), font, x, y);
                 col->add_widget(std::move(widget));
             }
-            layout->add_widget(std::move(col));
+            layout.add_widget(std::move(col));
         }
 
-        layout->renderer(renderer);
-        layout->viewport({0, 0, size_init.w, size_init.h});
+        layout.renderer(renderer);
+        layout.viewport({0, 0, size_init.w, size_init.h});
 
         bool quit {false};
         while (!quit) {
@@ -63,18 +71,18 @@ void run_example(
                     case SDL_WINDOWEVENT:
                         if (ev.window.event == SDL_WINDOWEVENT_SIZE_CHANGED) {
                             const auto size = renderer->output_size();
-                            layout->viewport({0, 0, size.w, size.h});
+                            layout.viewport({0, 0, size.w, size.h});
                         }
                         break;
                 }
-                layout->handle_event(ev);
+                layout.handle_event(ev);
             }
 
             // NOLINTNEXTLINE(readability-magic-numbers)
             renderer->draw_color({50, 60, 70, SDL_ALPHA_OPAQUE});
             renderer->clear();
 
-            layout->render();
+            layout.render();
             renderer->present();
         }
     } catch (const std::exception& e) {

inc/basic_widgets/core/draw.hpp

@@ -1,6 +1,7 @@
 #ifndef BWIDGETS_DRAW_HPP
 #define BWIDGETS_DRAW_HPP
 
+#include <cstdint>
 #include <functional>
 #include <memory>
 
@@ -13,21 +14,11 @@ namespace bwidgets
     class Renderer;
     class Texture;
 
-    // Add transparency to color base_color relative to the distance d from
-    // a limit to produce an AntiAliasing effect.
-    // d >= 0                → full transparency;
-    // −(aa_pixels) <= d < 0 → smoothsteped transparency gradient;
-    // d < −(aa_pixels)      → fully opaque.
-    [[nodiscard]] auto aa(Color base_color, int aa_pixels, float d) noexcept -> Color;
-    // Render a filled circle texture of color c and diameter resolution with
-    // aa_pixels used for antialiasing.
-    [[nodiscard]] auto filled_circle(Color c, int resolution, const Renderer&,
-                                     int aa_pixels = 3) -> std::shared_ptr<Texture>;
-    // Set the color of every pixels of a Texture using the passed function to compute
-    // pixel color.
-    void
-    set_pixels_color(Texture*,
-                     const std::function<uint32_t(SDL_Point, const SDL_PixelFormat&)>&);
+    [[nodiscard]] auto aa(Color, int, float) noexcept -> Color;
+    [[nodiscard]] auto filled_circle(Color, int resolution, Renderer*, int aa_pixels = 3)
+      -> std::shared_ptr<Texture>;
+    void set_pixels_color(Texture*,
+                          std::function<uint32_t(SDL_Point, const SDL_PixelFormat*)>);
 }
 
 #endif

inc/basic_widgets/core/error_helper.hpp

@@ -1,19 +1,13 @@
-#ifndef BWIDGETS_ERROR_HELPER_HPP
-#define BWIDGETS_ERROR_HELPER_HPP
-
-#include <functional>
+#ifndef BWIDGETS_ERROR_HELPER
+#define BWIDGETS_ERROR_HELPER
 
+#include <basic_widgets/core/type/exception.hpp>
 #include <basic_widgets/core/type/sdl_error.hpp>
 
-extern "C" {
-    auto SDL_GetError() -> const char*;
-}
-
 namespace bwidgets
 {
-    // Throw a E exception with message w if ptr is null. Otherwise return ptr.
     template<Exception E, typename T>
-    inline auto ptr_or_throw(T* const ptr, const std::string_view w = "unknown") -> T*
+    inline auto ptr_or_throw(T* ptr, const std::string& w = "unknown") -> T*
     {
         std::string what;
         if constexpr (std::is_same_v<E, SDLError>)
@@ -24,21 +18,16 @@ namespace bwidgets
         return ptr;
     }
 
-    // Check a return code with the success function passed. If success return false
-    // throw an E Exception with message w.
     template<Exception E, typename T>
     inline auto success_or_throw(
-      const T code, const std::string_view w = "unknown",
-      const std::function<bool(T)>& success = [](const T code) { return code == 0; })
-      -> T
+      T code, const std::string& w = "unknown",
+      std::function<bool(T)> success = [](T code) { return code == 0; }) -> T
     {
-        // If exception type is SDLError and no value or unknown was passed for w, get
-        // the last error message using SDL facilities.
         if constexpr (std::is_same_v<E, SDLError>) {
-            const std::string what {w == "unknown" ? SDL_GetError() : w};
+            std::string what {w == "unknown" ? SDL_GetError() : w};
             if (code < 0) throw E(what);
         }
-        else if (!success(code)) throw E(w.data());
+        else if (success(code)) throw E(w);
 
         return code;
     }

inc/basic_widgets/core/font.hpp

@@ -4,19 +4,16 @@
 #include <memory>
 #include <string>
 
-#include <SDL_ttf.h>
+#include <SDL2/SDL_ttf.h>
 
 #include <basic_widgets/core/type/color.hpp>
-#include <basic_widgets/core/type/deleter.hpp>
+#include <basic_widgets/core/type/opaque_struct.hpp>
 #include <basic_widgets/core/type/size.hpp>
 
 namespace bwidgets
 {
-    // Wrap TTF_Font from SDL_ttf and provide a font finding function.
-    class Font final
+    class Font final : OpaqueStruct<TTF_Font>::Wrapper
     {
-        const std::unique_ptr<TTF_Font, Deleter> _data;
-
     public:
         enum struct Hinting
         {
@@ -55,8 +52,7 @@ namespace bwidgets
         const std::string style_name;
 
         explicit Font(TTF_Font*);
-        // Load font at given path and with given size.
-        Font(std::string_view, int);
+        Font(const std::string&, int);
         Font(const Font&) = delete;
         Font(Font&&)      = delete;
         ~Font() noexcept  = default;
@@ -70,15 +66,13 @@ namespace bwidgets
         auto               kerning(bool) noexcept -> Font*;
         [[nodiscard]] auto outline() const noexcept -> int;
         auto               outline(int) noexcept -> Font*;
-        auto render(RenderMode, std::string_view, Color fg = default_color_fg,
-                    Color bg = default_color_bg)
-          -> std::unique_ptr<SDL_Surface, Deleter>;
+        auto render(RenderMode, const std::string&, Color fg = default_color_fg,
+                    Color bg = default_color_bg) -> SDL_Surface*;
         [[nodiscard]] auto style() const noexcept -> uint8_t;
         auto               style(uint8_t) noexcept -> Font*;
-        [[nodiscard]] auto text_size(std::string_view) const noexcept -> Size;
+        [[nodiscard]] auto text_size(const std::string&) const noexcept -> Size;
 
-        // Get file path of the font best matching a give fontconfig pattern.
-        [[nodiscard]] static auto find(std::string_view) -> std::string;
+        [[nodiscard]] static auto find(const std::string&) -> std::string;
     };
 }
 

inc/basic_widgets/core/math.hpp

@@ -4,39 +4,34 @@
 #include <algorithm>
 #include <cmath>
 
-#include <SDL_rect.h>
+#include <SDL2/SDL_rect.h>
 
 #include <basic_widgets/core/type/color.hpp>
+#include <basic_widgets/core/type/concepts.hpp>
 #include <basic_widgets/core/type/size.hpp>
 
 namespace bwidgets
 {
-    // Get the start coordinate offset required to center a ligne with a length used_len on another
-    // line with a length available_len.
-    [[nodiscard]] inline auto center_line(const int available_len, const int used_len) noexcept -> int
+    [[nodiscard]] inline auto center_line(int available_len, int used_len) noexcept -> int
     {
         return (available_len - used_len) / 2;
     }
 
-    // Get the squared distance of two points on a 2D plan. This avoid computing square root
-    // when for instance we need to compare two lenght but knowing the actual lenght is not
-    // needed.
-    [[nodiscard]] inline auto distance_sqrd(const SDL_Point a, const SDL_Point b) noexcept
+    [[nodiscard]] inline auto distance_sqrd(SDL_Point a, SDL_Point b) noexcept
       -> float
     {
-        return float(a.x - b.x) * float(a.x - b.x)
-             + float(a.y - b.y) * float(a.y - b.y);
+        // NOLINTNEXTLINE(bugprone-narrowing-conversions)
+        return (a.x - b.x) * (a.x - b.x)
+             + (a.y - b.y) * (a.y - b.y);
     }
 
-    // Get distance of two points on a 2D plan.
-    [[nodiscard]] inline auto distance(const SDL_Point a, const SDL_Point b) noexcept -> float
+    [[nodiscard]] inline auto distance(SDL_Point a, SDL_Point b) noexcept -> float
     {
         return std::sqrt(distance_sqrd(a, b));
     }
 
-    // Like std::lerp but for use with Color object. lerp function is applied only to enabled channels.
     template<FloatingPoint F>
-    [[nodiscard]] inline auto lerp(const Color a, const Color b, const F x, const bool op_alpha=false, const bool op_color=true) noexcept -> Color
+    [[nodiscard]] inline auto lerp(Color a, Color b, F x, bool op_alpha=false, bool op_color=true) noexcept -> Color
     {
         return {{
             op_color ? (uint8_t)std::lerp(a().r, b().r, x) : a().r,
@@ -46,48 +41,42 @@ namespace bwidgets
         }};
     }
 
-    // Reverse lerp.
     template<Numeric N>
-    [[nodiscard]] inline auto linear(const N x, const N a, const N b) noexcept -> float
+    [[nodiscard]] inline auto linear(N x, N a, N b) noexcept -> float
     {
         return (float)(x - a) / (float)(b - a);
     }
 
-    // Check if a rectangle is completly inside of another rectangle.
     [[nodiscard]] inline auto rect_in_rect(const SDL_Rect& outer, const SDL_Rect& inner) noexcept
       -> bool
     {
-        const SDL_Point top_left {inner.x, inner.y};
-        const SDL_Point bottom_right {inner.x + inner.w, inner.y + inner.h};
+        SDL_Point top_left {inner.x, inner.y};
+        SDL_Point bottom_right {inner.x + inner.w, inner.y + inner.h};
 
         return (SDL_PointInRect(&top_left, &outer) == SDL_TRUE)
             && (SDL_PointInRect(&bottom_right, &outer) == SDL_TRUE);
     }
 
-    // Get the rectangle inside r leaving margins of given size between inner and outer rectangle.
-    [[nodiscard]] inline auto rect_margin(const SDL_Rect& r, const Size margin) noexcept
+    [[nodiscard]] inline auto rect_margin(const SDL_Rect& r, Size margin) noexcept
       -> SDL_Rect
     {
         return {r.x + margin.w, r.y + margin.h, r.w - 2 * margin.w, r.h - 2 * margin.h};
     }
 
-    // Get the rectangle obtained from adding offset to its origin coordinate.
-    [[nodiscard]] inline auto rect_offset(const SDL_Rect& r, const SDL_Point offset) noexcept
+    [[nodiscard]] inline auto rect_offset(const SDL_Rect& r, SDL_Point offset) noexcept
       -> SDL_Rect
     {
         return {r.x + offset.x, r.y + offset.y, r.w, r.h};
     }
 
-    // Commodity function to use another rectangle as a size for the offset to be added to r.
     [[nodiscard]] inline auto rect_offset(const SDL_Rect& r, const SDL_Rect& offset) noexcept
       -> SDL_Rect
     {
         return rect_offset(r, SDL_Point {offset.x, offset.y});
     }
 
-    // Standard smoothstep algorithm.
     template<Numeric N>
-    [[nodiscard]] inline auto smoothstep(const N x, const N a, const N b) noexcept -> float
+    [[nodiscard]] inline auto smoothstep(N x, N a, N b) noexcept -> float
     {
         const float x_norm = linear(std::clamp<float>(x, a, b), a, b);
         return 3 * x_norm * x_norm - 2 * x_norm * x_norm * x_norm;

inc/basic_widgets/core/renderer.hpp

@@ -1,27 +1,27 @@
 #ifndef BWIDGETS_RENDERER_HPP
 #define BWIDGETS_RENDERER_HPP
 
+#include <cstdint>
 #include <memory>
 #include <span>
+#include <vector>
 
-#include <SDL_render.h>
+#include <SDL2/SDL_render.h>
 
 #include <basic_widgets/core/error_helper.hpp>
 #include <basic_widgets/core/type/color.hpp>
-#include <basic_widgets/core/type/deleter.hpp>
+#include <basic_widgets/core/type/opaque_struct.hpp>
+#include <basic_widgets/core/type/sdl_error.hpp>
 #include <basic_widgets/core/type/size.hpp>
 
 namespace bwidgets
 {
     class Texture;
 
-    // Wrap some of SDL's 2D accelerated rendering API.
-    class Renderer final
+    class Renderer final : OpaqueStruct<SDL_Renderer>::Wrapper
     {
         friend Texture;
 
-        const std::unique_ptr<SDL_Renderer, Deleter> _data;
-
         static auto _info(SDL_Renderer* r) -> SDL_RendererInfo
         {
             SDL_RendererInfo info;
@@ -45,7 +45,7 @@ namespace bwidgets
         [[nodiscard]] auto blend_mode() -> SDL_BlendMode;
         auto               blend_mode(SDL_BlendMode) -> Renderer*;
         auto               clear() -> Renderer*;
-        auto copy(const Texture&, const SDL_Rect*, const SDL_Rect*) -> Renderer*;
+        auto copy(const Texture*, const SDL_Rect*, const SDL_Rect*) -> Renderer*;
         [[nodiscard]] auto draw_color() -> Color;
         auto               draw_color(Color) -> Renderer*;
         auto               draw_line(SDL_Point, SDL_Point) -> Renderer*;
@@ -61,33 +61,33 @@ namespace bwidgets
         [[nodiscard]] auto viewport() noexcept -> SDL_Rect;
         auto               viewport(const SDL_Rect*) -> Renderer*;
 
-        auto copy(const Texture& t, const SDL_Rect* src, const SDL_Rect& dst)
+        auto copy(const Texture* t, const SDL_Rect* src, const SDL_Rect& dst)
         {
             const auto d = dst;
             return copy(t, src, &d);
         }
-        auto copy(const Texture& t, const SDL_Rect& src, const SDL_Rect* dst)
+        auto copy(const Texture* t, const SDL_Rect& src, const SDL_Rect* dst)
         {
             const auto s = src;
             return copy(t, &s, dst);
         }
-        auto copy(const Texture& t, const SDL_Rect& src, const SDL_Rect& dst)
+        auto copy(const Texture* t, const SDL_Rect& src, const SDL_Rect& dst)
         {
             const auto s = src;
             const auto d = dst;
             return copy(t, &s, &d);
         }
-        auto draw_rect(SDL_Rect&& r)
+        auto draw_rect(const SDL_Rect& r)
         {
             const auto rect = r;
             return draw_rect(&rect);
         }
-        auto fill_rect(SDL_Rect&& r)
+        auto fill_rect(const SDL_Rect& r)
         {
             const auto rect = r;
             return fill_rect(&rect);
         }
-        auto viewport(SDL_Rect&& vp)
+        auto viewport(const SDL_Rect& vp)
         {
             const auto v = vp;
             return viewport(&v);

inc/basic_widgets/core/texture.hpp

@@ -1,21 +1,22 @@
 #ifndef BWIDGETS_TEXTURE_HPP
 #define BWIDGETS_TEXTURE_HPP
 
+#include <cstdint>
 #include <memory>
 
-#include <SDL_pixels.h>
-#include <SDL_render.h>
+#include <SDL2/SDL_pixels.h>
+#include <SDL2/SDL_render.h>
 
 #include <basic_widgets/core/error_helper.hpp>
 #include <basic_widgets/core/type/color.hpp>
-#include <basic_widgets/core/type/deleter.hpp>
+#include <basic_widgets/core/type/opaque_struct.hpp>
+#include <basic_widgets/core/type/sdl_error.hpp>
 
 namespace bwidgets
 {
     class Renderer;
 
-    // Wrap most of the texture functions of SDL 2D rendering API.
-    class Texture final
+    class Texture final : OpaqueStruct<SDL_Texture>::Wrapper
     {
         friend Renderer;
 
@@ -25,15 +26,12 @@ namespace bwidgets
             SDL_PixelFormat*  format;
             SDL_TextureAccess access;
             int               w, h;
-        };
-
-        const Attr                                  _attributes;
-        const std::unique_ptr<SDL_Texture, Deleter> _data;
+        } _attributes {};
 
     public:
         explicit Texture(SDL_Texture*);
-        Texture(const Renderer&, SDL_PixelFormatEnum, SDL_TextureAccess, int, int);
-        Texture(const Renderer&, SDL_Surface*);
+        Texture(Renderer*, SDL_PixelFormatEnum, SDL_TextureAccess, int, int);
+        Texture(Renderer*, SDL_Surface*);
         Texture(const Texture&) = delete;
         Texture(Texture&&)      = delete;
         ~Texture() noexcept;
@@ -49,14 +47,14 @@ namespace bwidgets
         auto               color_mode(Color) -> Texture*;
         [[nodiscard]] auto scale_mode() -> SDL_ScaleMode;
         auto               scale_mode(SDL_ScaleMode) -> Texture*;
-        auto               update(const SDL_Rect*, const void*, int) -> Texture*;
+        auto               update(SDL_Rect*, const void*, int) -> Texture*;
 
         [[nodiscard]] const auto& attributes() const noexcept
         {
             return _attributes;
         }
 
-        auto update(SDL_Rect&& r, const void* pix, int pitch)
+        auto update(const SDL_Rect& r, const void* pix, int pitch)
         {
             SDL_Rect rect = r;
             update(&rect, pix, pitch);

inc/basic_widgets/core/type/color.hpp

@@ -2,16 +2,16 @@
 #define BWIDGETS_COLOR_HPP
 
 #include <cmath>
+#include <cstdint>
 #include <functional>
-#include <stdexcept>
 
-#include <SDL_pixels.h>
+#include <SDL2/SDL_assert.h>
+#include <SDL2/SDL_pixels.h>
 
 #include <basic_widgets/core/type/concepts.hpp>
 
 namespace bwidgets
 {
-    // Wrap SDL_Color to provide operator overloads.
     class Color final
     {
     public:
@@ -24,28 +24,23 @@ namespace bwidgets
             _operate_on_colors {op_on_colors}
         {}
         Color(SDL_Color c = {}, bool op_on_alpha = false,
-              bool op_on_colors = true) noexcept
+                     bool op_on_colors = true) noexcept
           : sdl_type(c), _operate_on_alpha(op_on_alpha), _operate_on_colors(op_on_colors)
         {}
         Color(const Color&) noexcept = default;
         Color(Color&&) noexcept      = default;
         ~Color()                     = default;
 
-        // Enable/disable operations on alpha channel. Disabled by default on
-        // construction.
-        [[nodiscard]] auto alpha(const bool state = true) const noexcept -> Color
+        [[nodiscard]] auto alpha() const noexcept -> Color
         {
-            return {sdl_type, _operate_on_colors, state};
+            return {sdl_type, _operate_on_colors, true};
         }
 
-        // Enable/disable operations on color channels.Enabled by default on
-        // construction.
-        [[nodiscard]] auto colors(const bool state = true) const noexcept -> Color
+        [[nodiscard]] auto colors() const noexcept -> Color
         {
-            return {sdl_type, state, _operate_on_alpha};
+            return {sdl_type, true, _operate_on_alpha};
         }
 
-        // Get reference to the wrapped SDL native object.
         [[nodiscard]] auto& operator()() noexcept
         {
             return sdl_type;
@@ -56,33 +51,28 @@ namespace bwidgets
             return sdl_type;
         }
 
-        // Add operand to enabled channels.
         template<Numeric N>
-        [[nodiscard]] auto operator+(const N operand) const noexcept
+        [[nodiscard]] auto operator+(N operand) const noexcept
         {
             return _operate(operand, [](N a, N b) { return a + b; });
         }
 
-        // Substract operand from enabled channels.
         template<Numeric N>
-        [[nodiscard]] auto operator-(const N operand) const noexcept
+        [[nodiscard]] auto operator-(N operand) const noexcept
         {
             return _operate(operand, [](N a, N b) { return a - b; });
         }
 
-        // Multiply enabled channel values by opererand.
         template<Numeric N>
-        [[nodiscard]] auto operator*(const N operand) const noexcept
+        [[nodiscard]] auto operator*(N operand) const noexcept
         {
             return _operate(operand, [](N a, N b) { return a * b; });
         }
 
-        // Divide enabled channel values by operand.
         template<Numeric N>
-        [[nodiscard]] auto operator/(const N operand) const
+        [[nodiscard]] auto operator/(N operand) const noexcept
         {
-            if (operand == 0) throw std::domain_error("division by zero.");
-
+            SDL_assert_release(operand != 0); // NOLINT
             return _operate<N>(operand, [](N a, N b) { return a / b; });
         }
 
@@ -95,18 +85,14 @@ namespace bwidgets
             return *this;
         }
 
-        // Compare for equality of the enabled channel values between two Color
-        // instances.
-        [[nodiscard]] auto operator==(const Color other) const noexcept
+        [[nodiscard]] auto operator==(Color other) const noexcept
         {
             return (_operate_on_colors && sdl_type.r == other().r
                     && sdl_type.g == other().g && sdl_type.b == other().b)
                 || (_operate_on_alpha && sdl_type.a == other().a);
         }
 
-        // Compare for inequality of the enabled channel values between two Color
-        // instances.
-        [[nodiscard]] auto operator!=(const Color other) const noexcept
+        [[nodiscard]] auto operator!=(Color other) const noexcept
         {
             return (sdl_type.r != other().r || sdl_type.g != other().g
                     || sdl_type.b != other().b)
@@ -119,25 +105,21 @@ namespace bwidgets
         bool _operate_on_colors;
 
         template<Numeric N>
-        auto _operate(const N operand, const std::function<N(N, N)>& operator_) const
+        auto _operate(N operand, std::function<N(N, N)> operator_) const noexcept
         {
-            const auto overunderflow_check = [](auto x) {
-                if (x > (uint8_t)x) throw std::overflow_error("uint8_t overflow.");
-                if (x < (uint8_t)x) throw std::underflow_error("uint8_t underflow.");
-            };
-
             Color c(sdl_type, _operate_on_alpha, _operate_on_colors);
             if (_operate_on_alpha) {
-                const auto a = std::round(operator_(c().a, operand));
-                overunderflow_check(a);
+                auto a = std::round(operator_(c().a, operand));
+                SDL_assert_release(a == (uint8_t)a); // NOLINT
                 c().a = (uint8_t)a;
             }
             if (_operate_on_colors) {
-                const auto r = std::round(operator_(c().r, operand));
-                const auto g = std::round(operator_(c().g, operand));
-                const auto b = std::round(operator_(c().b, operand));
-                for (const auto x : {r, g, b}) overunderflow_check(x);
-
+                auto r = std::round(operator_(c().r, operand));
+                auto g = std::round(operator_(c().g, operand));
+                auto b = std::round(operator_(c().b, operand));
+                // NOLINTNEXTLINE
+                SDL_assert_release(r == (uint8_t)r && g == (uint8_t)g
+                                   && b == (uint8_t)b);
                 c().r = (uint8_t)r;
                 c().g = (uint8_t)g;
                 c().b = (uint8_t)b;

inc/basic_widgets/core/type/concepts.hpp

@@ -1,27 +1,25 @@
-#ifndef BWIDGETS_CONCEPTS_HPP
-#define BWIDGETS_CONCEPTS_HPP
+#ifndef BWIDGETS_CONCEPTS_HPP_
+#define BWIDGETS_CONCEPTS_HPP_
 
+#include <ostream>
 #include <string>
+
 #include <type_traits>
 
 namespace bwidgets
 {
-    // T can be converted to string with to_string.
     template<typename T>
     concept CanToString = requires(T value)
     {
         std::to_string(value);
     };
 
-    // T is a floating point type.
     template<typename T>
     concept FloatingPoint = std::is_floating_point_v<T>;
 
-    // T can be any numeric type.
     template<typename T>
     concept Numeric = std::is_arithmetic_v<T>;
 
-    // T can be converted to string by using ostream.
     template<typename T>
     concept Printable = requires(T value)
     {

inc/basic_widgets/core/type/deleter.hpp

@@ -1,51 +0,0 @@
-#ifndef BWIDGETS_OPAQUE_STRUCT_HPP
-#define BWIDGETS_OPAQUE_STRUCT_HPP
-
-#include <fontconfig/fontconfig.h>
-#include <SDL_render.h>
-#include <SDL_surface.h>
-#include <SDL_ttf.h>
-
-namespace bwidgets
-{
-    // Deleter type for fancy pointers.
-    struct Deleter
-    {
-        void operator()(FcConfig* ptr)
-        {
-            FcConfigDestroy(ptr);
-        }
-
-        void operator()(FcPattern* ptr)
-        {
-            FcPatternDestroy(ptr);
-        }
-
-        void operator()(SDL_Renderer* ptr)
-        {
-            SDL_DestroyRenderer(ptr);
-        }
-
-        void operator()(SDL_Surface* ptr)
-        {
-            SDL_FreeSurface(ptr);
-        }
-
-        void operator()(SDL_Texture* ptr)
-        {
-            SDL_DestroyTexture(ptr);
-        }
-
-        void operator()(SDL_Window* ptr)
-        {
-            SDL_DestroyWindow(ptr);
-        }
-
-        void operator()(TTF_Font* ptr)
-        {
-            TTF_CloseFont(ptr);
-        }
-    };
-}
-
-#endif

inc/basic_widgets/core/type/exception.hpp

@@ -1,20 +1,20 @@
 #ifndef BWIDGETS_EXCEPTION_HPP
 #define BWIDGETS_EXCEPTION_HPP
 
+#include <any>
+#include <functional>
+#include <map>
 #include <stdexcept>
 
 #include <basic_widgets/core/type/concepts.hpp>
 
 namespace bwidgets
 {
-    // Base type for custom runtime errors.
-    class BaseException : std::runtime_error
+    struct BaseException : std::runtime_error
     {
-    protected:
         using runtime_error::runtime_error;
     };
 
-    // T derives from BaseException.
     template<typename T>
     concept Exception = std::derived_from<T, BaseException>;
 }

inc/basic_widgets/core/type/fc_error.hpp

@@ -5,7 +5,6 @@
 
 namespace bwidgets
 {
-    // Exception type for fontconfig errors
     struct FCError final : BaseException
     {
         using BaseException::BaseException;

inc/basic_widgets/core/type/opaque_struct.hpp

@@ -0,0 +1,50 @@
+#ifndef BWIDGETS_OPAQUE_STRUCT_HPP
+#define BWIDGETS_OPAQUE_STRUCT_HPP
+
+#include <functional>
+
+namespace bwidgets
+{
+    template<typename T>
+    class OpaqueStruct
+    {
+        using Deleter = std::function<void(T*)>;
+
+        const Deleter _deleter;
+
+        T* _c_pod;
+
+    public:
+        OpaqueStruct(T* ptr, Deleter d) : _deleter {std::move(d)}, _c_pod {ptr} {}
+
+        OpaqueStruct(const OpaqueStruct&) = delete;
+        OpaqueStruct(OpaqueStruct&&)      = delete;
+
+        virtual ~OpaqueStruct() noexcept
+        {
+            try {
+                _deleter(_c_pod);
+            } catch (...) {
+            }
+        };
+
+        [[nodiscard]] auto* operator()() const
+        {
+            return _c_pod;
+        }
+
+        auto operator=(const OpaqueStruct&) = delete;
+        auto operator=(OpaqueStruct&&) = delete;
+
+        class Wrapper
+        {
+        protected:
+            OpaqueStruct _data;
+
+        public:
+            Wrapper(T* ptr, Deleter d) : _data(ptr, std::move(d)) {}
+        };
+    };
+}
+
+#endif

inc/basic_widgets/core/type/sdl_error.hpp

@@ -3,9 +3,12 @@
 
 #include <basic_widgets/core/type/exception.hpp>
 
+extern "C" {
+    auto SDL_GetError() -> const char*;
+}
+
 namespace bwidgets
 {
-    // Custom exception type for SDL errors.
     struct SDLError final : BaseException
     {
         using BaseException::BaseException;

inc/basic_widgets/core/type/size.hpp

@@ -5,34 +5,30 @@
 
 namespace bwidgets
 {
-    // Represent size of a 2D surface.
     struct Size
     {
         int w;
         int h;
     };
 
-    // Addition the dimensions of two Size objects.
-    [[nodiscard]] inline auto operator+(const Size a, const Size b) noexcept -> Size
+    [[nodiscard]] inline auto operator+(Size a, Size b) noexcept -> Size
     {
         return {a.w + b.w, a.h + b.h};
     }
 
-    // Substract dimensions of a Size object from another.
-    [[nodiscard]] inline auto operator-(const Size a, const Size b) noexcept -> Size
+    [[nodiscard]] inline auto operator-(Size a, Size b) noexcept -> Size
     {
         return {a.w - b.w, a.h - b.h};
     }
 
-    // Multiply dimensions of a Size instance by a number.
     template<Numeric N>
-    [[nodiscard]] inline auto operator*(const Size a, const N b) noexcept -> Size
+    [[nodiscard]] inline auto operator*(Size a, N b) noexcept -> Size
     {
         return {a.w * b, a.h * b};
     }
 
     template<Numeric N>
-    [[nodiscard]] inline auto operator*(const N a, const Size b) noexcept -> Size
+    [[nodiscard]] inline auto operator*(N a, Size b) noexcept -> Size
     {
         return b * a;
     }

inc/basic_widgets/impl/mouse_handler_impl.hpp

@@ -0,0 +1,45 @@
+#ifndef BWIDGETS_MOUSE_HANDLER_IMPL_HPP
+#define BWIDGETS_MOUSE_HANDLER_IMPL_HPP
+
+#include <basic_widgets/w/feat/mouse_handler.hpp>
+
+namespace bwidgets
+{
+    class MouseHandlerImpl : public MouseHandler
+    {
+    private:
+        const SDL_Rect* _area {nullptr};
+        bool            _hovered {false};
+        bool            _pushed {false};
+
+        std::function<void(const SDL_MouseButtonEvent&)> _click_handler;
+        std::function<void(const SDL_MouseMotionEvent&)> _motion_handler;
+
+    protected:
+        MouseHandlerImpl() = default;
+
+    public:
+        void
+        click_handler(std::function<void(const SDL_MouseButtonEvent&)> handler) override
+        {
+            _click_handler = std::move(handler);
+        }
+        void               disable_mouse_handler() override;
+        void               enable_mouse_handler(const SDL_Rect*) override;
+        [[nodiscard]] bool hovered() const override
+        {
+            return _hovered;
+        }
+        void mouse_motion_handler(
+          std::function<void(const SDL_MouseMotionEvent&)> handler) override
+        {
+            _motion_handler = std::move(handler);
+        }
+        [[nodiscard]] bool pushed() const override
+        {
+            return _pushed;
+        }
+    };
+}
+
+#endif

inc/basic_widgets/w/aligned_layout.hpp

@@ -1,6 +1,7 @@
 #ifndef BWIDGETS_ALIGNED_LAYOUT_HPP
 #define BWIDGETS_ALIGNED_LAYOUT_HPP
 
+#include <basic_widgets/core/math.hpp>
 #include <basic_widgets/w/base/layout.hpp>
 
 namespace bwidgets
@@ -11,11 +12,71 @@ namespace bwidgets
         VERTICAL
     };
 
-    // Align vertically or horizontally widgets.
-    class AlignedLayout : public virtual Layout
+    template<LayoutAlignment alignment>
+    class AlignedLayout final : public Layout
     {
+    private:
+        void _update_layout(const SDL_Rect& vp) override
+        {
+            if constexpr (alignment == LayoutAlignment::HORIZONTAL) {
+                int widget_width =
+                  (vp.w - ((int)_widgets.size() + 1) * margins.w) / (int)_widgets.size();
+
+                for (std::vector<Widget*>::size_type i = 0; i < _widgets.size(); i++) {
+                    const auto& w {_widgets[i]};
+                    w->viewport({vp.x + margins.w + (int)i * (widget_width + margins.w),
+                                 vp.y + center_line(vp.h, w->size().h), widget_width,
+                                 w->size().h});
+                }
+            }
+            else {
+                int offset = 0;
+                for (std::vector<Widget*>::size_type i = 0; i < _widgets.size(); i++) {
+                    const auto& w {_widgets[i]};
+                    w->viewport({
+                      vp.x,
+                      vp.y + ((int)i + 1) * margins.h + offset,
+                      vp.w,
+                      w->size().h,
+                    });
+                    offset += w->size().h;
+                }
+            }
+        }
+
     public:
-        using Layout::Layout;
+        AlignedLayout(Widget* p = nullptr) noexcept : Layout(p) {}
+
+        AlignedLayout(const AlignedLayout&) = delete;
+        AlignedLayout(AlignedLayout&&)      = delete;
+        ~AlignedLayout() override           = default;
+        auto operator=(const AlignedLayout&) = delete;
+        auto operator=(AlignedLayout&&) = delete;
+
+        [[nodiscard]] auto size() const noexcept -> Size override
+        {
+            Size min_size {0, 0};
+
+            if constexpr (alignment == LayoutAlignment::HORIZONTAL) {
+                for (const auto& w : _widgets) {
+                    if (w->size().w > min_size.w) min_size.w = w->size().w;
+                    if (w->size().h > min_size.h) min_size.h = w->size().h;
+                }
+
+                return {(int)_widgets.size() * min_size.w
+                          + ((int)_widgets.size() + 1) * margins.w,
+                        min_size.h + 2 * margins.h};
+            }
+
+            for (const auto& w : _widgets) {
+                if (w->size().w > min_size.w) min_size.w = w->size().w;
+
+                min_size.h += w->size().h;
+            }
+
+            return {min_size.w + 2 * margins.w,
+                    min_size.h + ((int)_widgets.size() + 1) * margins.h};
+        }
     };
 }
 

inc/basic_widgets/w/aligned_layout_impl.hpp

@@ -1,77 +0,0 @@
-#ifndef BWIDGETS_ALIGNED_LAYOUT_IMPL_HPP
-#define BWIDGETS_ALIGNED_LAYOUT_IMPL_HPP
-
-#include <basic_widgets/core/math.hpp>
-#include <basic_widgets/w/aligned_layout.hpp>
-#include <basic_widgets/w/base/layout_impl.hpp>
-#include <basic_widgets/w/base/widget_impl.hpp>
-
-namespace bwidgets
-{
-    template<LayoutAlignment alignment>
-    class AlignedLayoutImpl final : public virtual AlignedLayout,
-                                    public virtual LayoutImpl,
-                                    public virtual WidgetImpl
-    {
-    public:
-        using LayoutImpl::LayoutImpl;
-
-        // Return smallest usable size.
-        [[nodiscard]] auto size() const noexcept -> Size override
-        {
-            Size min_size {0, 0};
-
-            if constexpr (alignment == LayoutAlignment::HORIZONTAL) {
-                for (const auto& w : _widgets) {
-                    if (w->size().w > min_size.w) min_size.w = w->size().w;
-                    if (w->size().h > min_size.h) min_size.h = w->size().h;
-                }
-
-                return {(int)_widgets.size() * min_size.w
-                          + ((int)_widgets.size() + 1) * margins.w,
-                        min_size.h + 2 * margins.h};
-            }
-
-            // Vertical
-            for (const auto& w : _widgets) {
-                if (w->size().w > min_size.w) min_size.w = w->size().w;
-
-                min_size.h += w->size().h;
-            }
-
-            return {min_size.w + 2 * margins.w,
-                    min_size.h + ((int)_widgets.size() + 1) * margins.h};
-        }
-
-    private:
-        void _update_layout(const SDL_Rect& vp) override
-        {
-            if constexpr (alignment == LayoutAlignment::HORIZONTAL) {
-                const int widget_width =
-                  (vp.w - ((int)_widgets.size() + 1) * margins.w) / (int)_widgets.size();
-
-                for (std::vector<Widget*>::size_type i = 0; i < _widgets.size(); i++) {
-                    const auto& w {_widgets[i]};
-                    w->viewport({vp.x + margins.w + (int)i * (widget_width + margins.w),
-                                 vp.y + center_line(vp.h, w->size().h), widget_width,
-                                 w->size().h});
-                }
-            }
-            else { // Vertical
-                int offset = 0;
-                for (std::vector<Widget*>::size_type i = 0; i < _widgets.size(); i++) {
-                    const auto& w {_widgets[i]};
-                    w->viewport({
-                      vp.x,
-                      vp.y + ((int)i + 1) * margins.h + offset,
-                      vp.w,
-                      w->size().h,
-                    });
-                    offset += w->size().h;
-                }
-            }
-        }
-    };
-}
-
-#endif

inc/basic_widgets/w/base/input.hpp

@@ -1,23 +1,122 @@
 #ifndef BWIDGETS_INPUT_HPP
 #define BWIDGETS_INPUT_HPP
 
+#include <cmath>
+#include <exception>
+#include <iomanip>
+#include <sstream>
+
+#include <SDL2/SDL_events.h>
+#include <SDL2/SDL_keyboard.h>
+#include <SDL2/SDL_render.h>
+
+#include <basic_widgets/core/math.hpp>
 #include <basic_widgets/core/type/concepts.hpp>
-#include <basic_widgets/w/base/widget.hpp>
-#include <basic_widgets/w/feat/font_handler.hpp>
-#include <basic_widgets/w/feat/keyboard_handler.hpp>
-#include <basic_widgets/w/feat/mouse_handler.hpp>
+#include <basic_widgets/w/caption.hpp>
+#include <basic_widgets/w/feat/keyboard_handler_impl.hpp>
+#include <basic_widgets/w/feat/mouse_handler_impl.hpp>
 
 namespace bwidgets
 {
 
     template<typename T>
-    class Input : public virtual Widget,
-                  public virtual FontHandler,
-                  public virtual KeyboardHandler,
-                  public virtual MouseHandler
+    class Input : public Widget,
+                  public FontHandler,
+                  public KeyboardHandlerImpl,
+                  public MouseHandlerImpl
     {
     protected:
-        using Widget::Widget;
+        Caption _input_caption;
+
+        Input(Widget* parent = nullptr) : Widget {parent}, _input_caption {this}
+        {
+            FocusHandlerImpl::focus_handler([this](bool focus) {
+                if (focus) {
+                    SDL_StartTextInput();
+                }
+                // focus loss.
+                else if (FocusHandlerImpl::focus()) {
+                    value = value_from_string(input_text());
+                    input_text(value_to_string(value));
+                    SDL_StopTextInput();
+                    _input_caption.text(value_to_string(value));
+                }
+            });
+
+            KeyboardHandlerImpl::key_handler([this](const SDL_KeyboardEvent& key) {
+                if (key.type == SDL_KEYDOWN) {
+                    switch (key.keysym.sym) {
+                        case SDLK_BACKSPACE: {
+                            std::string txt = input_text();
+                            if (txt.length() > 0) {
+                                txt.pop_back();
+                                input_text(txt);
+                            }
+                            break;
+                        }
+                        case SDLK_RETURN:
+                        case SDLK_RETURN2: // what is return2 btw?
+                        case SDLK_KP_ENTER:
+                            value = value_from_string(input_text());
+                            FocusHandlerImpl::focus(false);
+                            break;
+                    }
+                }
+            });
+            KeyboardHandlerImpl::text_input_handler(
+              [this](const SDL_TextInputEvent& input) {
+                  if (is_valid_input(input.text)) {
+                      input_text(input_text() + input.text);
+                  }
+              });
+            KeyboardHandlerImpl::enable_keyboard_handler();
+
+            MouseHandlerImpl::enable_mouse_handler(&(Input::_widget_area),
+                                                   &(Input::_viewport));
+        }
+
+        void _handle_font_change(const std::shared_ptr<Font>& f) override
+        {
+            _input_caption.font(f);
+            _handle_geometry_change(_viewport);
+        }
+
+        void _handle_font_color_change(Color fg, Color bg) override
+        {
+            _input_caption.font_color_bg(bg)->font_color_fg(fg);
+        }
+
+        void _handle_geometry_change(const SDL_Rect& vp) override
+        {
+            const auto input_h = _input_caption.size().h + 2 * border_width;
+            _widget_area       = {0, center_line(vp.h, input_h), vp.w, input_h};
+
+            _input_caption.viewport(rect_offset(
+              {rect_margin(_widget_area, {border_width, border_width})}, vp));
+        }
+
+        void _handle_renderer_change(const std::shared_ptr<Renderer>& r) override
+        {
+            _input_caption.renderer(r);
+        }
+
+        void _handle_rendering() override
+        {
+            for (int i = border_width - 1; i >= 0; i--) {
+                const auto  factor = linear(i, 0, border_width);
+                const auto& color_end =
+                  FocusHandlerImpl::focus() ? color_bg_focused : color_bg;
+                const auto color_start = color_end / 2;
+                _renderer->draw_color(lerp(color_start, color_end, factor))
+                  ->draw_rect(rect_margin(_widget_area, {i, i}));
+            }
+
+            if (hovered() || FocusHandlerImpl::focus())
+                _input_caption.font_color_bg(color_bg_focused);
+            else _input_caption.font_color_bg(color_bg);
+
+            _input_caption.render();
+        }
 
     public:
         static const int          default_border_width = 3;
@@ -28,30 +127,102 @@ namespace bwidgets
         static const int          default_min_width        = 1;
 
         int   border_width     = default_border_width;
-        Color color_bg_default = default_color_bg;
+        Color color_bg         = default_color_bg;
         Color color_bg_focused = default_color_bg_focused;
         int   float_precision  = default_float_precision;
         int   input_min_width  = default_min_width;
-        char  input_width_unit = 'W'; // char used as unit for text length computation.
+        char  input_width_unit = 'W';
         T     value {};
 
-        // Get the current displayed string.
-        [[nodiscard]] virtual auto input_text() const -> std::string_view = 0;
-        // Set displayed string
-        virtual void               input_text(std::string)                = 0;
-        virtual void               input_text_color(Color)                = 0;
-        // Check if a character is allowed to be inputted. String are used because we
-        // could have multibytes characters to represent using 8bits chars.
-        [[nodiscard]] virtual auto is_valid_input(std::string_view) const noexcept
-          -> bool = 0;
+        Input(const Input&) = delete;
+        Input(Input&&)      = delete;
+        ~Input() override   = default;
+        auto operator=(const Input&) = delete;
+        auto operator=(Input&&) = delete;
 
-        // Process a value for instance to modify it before saving it.
-        [[nodiscard]] virtual auto process_value(T) const noexcept -> T = 0;
-        // Get string representation to be shown of the stored value.
-        [[nodiscard]] virtual auto value_from_string(std::string_view) const noexcept
-          -> T                                                                      = 0;
-        // Parse a string to get its representation in T type of input value memory.
-        [[nodiscard]] virtual auto value_to_string(T) const noexcept -> std::string = 0;
+        virtual auto color_fg(Color c) -> Input<T>*
+        {
+            _input_caption.font_color_fg(c);
+            return this;
+        }
+
+        [[nodiscard]] virtual auto input_text() const -> const std::string&
+        {
+            return _input_caption.text();
+        }
+
+        virtual auto input_text(const std::string& txt) -> Input<T>*
+        {
+            _input_caption.text(txt);
+            return this;
+        }
+
+        [[nodiscard]] virtual auto is_valid_input(const std::string&) const noexcept
+          -> bool
+        {
+            return true;
+        }
+
+        [[nodiscard]] virtual auto process_value(T x) const noexcept -> T
+        {
+            return x;
+        }
+
+        [[nodiscard]] auto size() const noexcept -> Size override
+        {
+            if (_font == nullptr) return {0, 0};
+
+            return {
+              _font->text_size(std::string(input_min_width, input_width_unit)).w
+                + 2 * border_width,
+              _font->line_skip + 4 * border_width // _why_ 4 and not 2?…
+            };
+        }
+
+        [[nodiscard]] auto value_from_string(std::string s) noexcept
+        {
+            T v;
+
+            if constexpr (std::is_arithmetic_v<T>) {
+                s = s.length() > 0 ? s : "0";
+                if constexpr (std::is_floating_point_v<T>) v = (T)std::stold(s);
+                else if constexpr (std::is_integral_v<T>) v = (T)std::stoll(s);
+            }
+            else if constexpr (std::is_same_v<
+                                 T, std::string> || std::convertible_to<std::string, T>)
+                v = s;
+            else
+                // NOLINTNEXTLINE(readability-simplify-boolean-expr)
+                static_assert((bool)sizeof(T) && false,
+                              "string cannot be converted to type T.");
+
+            return process_value(v);
+        }
+
+        [[nodiscard]] auto value_to_string(T value) noexcept
+        {
+            std::string s;
+
+            if constexpr (std::is_same_v<std::string,
+                                         T> || std::convertible_to<T, std::string>)
+                s = std::move(value);
+            else if constexpr (CanToString<T>) {
+                std::stringstream ss;
+                ss << std::fixed << std::setprecision(float_precision) << value;
+                s = std::move(ss).str();
+            }
+            else if constexpr (Printable<T>) {
+                std::stringstream ss;
+                ss << value;
+                s = std::move(ss).str();
+            }
+            else
+                // NOLINTNEXTLINE(readability-simplify-boolean-expr)
+                static_assert((bool)sizeof(T) && false,
+                              "value cannot be converted to string.");
+
+            return s;
+        }
     };
 }
 

inc/basic_widgets/w/base/input_impl.hpp

@@ -1,231 +0,0 @@
-#ifndef BWIDGETS_INPUT_IMPL_HPP
-#define BWIDGETS_INPUT_IMPL_HPP
-
-#include <iomanip>
-#include <sstream>
-
-#include <basic_widgets/core/math.hpp>
-#include <basic_widgets/w/base/input.hpp>
-#include <basic_widgets/w/base/widget_impl.hpp>
-#include <basic_widgets/w/caption.hpp>
-#include <basic_widgets/w/feat/font_handler_impl.hpp>
-#include <basic_widgets/w/feat/keyboard_handler_impl.hpp>
-#include <basic_widgets/w/feat/mouse_handler_impl.hpp>
-#include <basic_widgets/w/widget_factory.hpp>
-
-namespace bwidgets
-{
-    template<typename T>
-    class InputImpl : public virtual Input<T>,
-                      public virtual FontHandlerImpl,
-                      public virtual KeyboardHandlerImpl,
-                      public virtual MouseHandlerImpl,
-                      public virtual WidgetImpl
-    {
-    public:
-        [[nodiscard]] auto input_text() const -> std::string_view override
-        {
-            return _input_caption->text();
-        }
-
-        void input_text(std::string txt) override
-        {
-            _input_caption->text(std::move(txt));
-        }
-
-        void input_text_color(const Color c) override
-        {
-            _input_caption->font_color_fg(c);
-        }
-
-        [[nodiscard]] auto is_valid_input(const std::string_view) const noexcept
-          -> bool override
-        {
-            return true;
-        }
-
-        [[nodiscard]] auto process_value(const T x) const noexcept -> T override
-        {
-            return x;
-        }
-
-        [[nodiscard]] auto size() const noexcept -> Size override
-        {
-            if (!_font) return {0, 0};
-
-            return {
-              _font
-                  ->text_size(
-                    std::string(InputImpl::input_min_width, InputImpl::input_width_unit))
-                  .w
-                + 2 * InputImpl::border_width,
-              _font->line_skip + 4 * InputImpl::border_width // _why_ 4 and not 2?…
-            };
-        }
-
-        [[nodiscard]] auto value_from_string(const std::string_view s) const noexcept
-          -> T override
-        {
-            const T v = [s]() {
-                if constexpr (std::is_arithmetic_v<T>) {
-                    const auto _s = s.length() > 0 ? s : "0";
-                    if constexpr (std::is_floating_point_v<T>)
-                        return (T)std::stold(_s.data());
-                    else if constexpr (std::is_integral_v<T>)
-                        return (T)std::stoll(_s.data());
-                }
-                else if constexpr (std::is_same_v<
-                                     T,
-                                     std::string> || std::convertible_to<std::string, T>)
-                    return std::string(s);
-                else
-                    // NOLINTNEXTLINE(readability-simplify-boolean-expr)
-                    static_assert((bool)sizeof(T) && false,
-                                  "string cannot be converted to type T.");
-            }();
-
-            return process_value(v);
-        }
-
-        [[nodiscard]] auto value_to_string(const T value) const noexcept
-          -> std::string override
-        {
-            std::string s = [value, this]() {
-                if constexpr (std::is_same_v<std::string,
-                                             T> || std::convertible_to<T, std::string>)
-                    return std::move(value);
-                else if constexpr (CanToString<T>) {
-                    std::stringstream ss;
-                    ss << std::fixed << std::setprecision(InputImpl::float_precision)
-                       << value;
-                    return std::move(ss).str();
-                }
-                else if constexpr (Printable<T>) {
-                    std::stringstream ss;
-                    ss << value;
-                    return std::move(ss).str();
-                }
-                else
-                    // NOLINTNEXTLINE(readability-simplify-boolean-expr)
-                    static_assert((bool)sizeof(T) && false,
-                                  "value cannot be converted to string.");
-            }();
-
-            return s;
-        }
-
-    protected:
-        std::unique_ptr<Caption> _input_caption;
-
-        InputImpl(Widget* parent = nullptr)
-          : WidgetImpl {parent}, _input_caption {create_caption(this)}
-        {
-            // Start text input on focus. Stop it on focus loss and save the inputted
-            // value.
-            focus_handler([this](const bool focus) {
-                if (focus) {
-                    _input_caption->font_color_bg(InputImpl::color_bg_focused);
-                    SDL_StartTextInput();
-                    return;
-                }
-                SDL_StopTextInput();
-                _input_caption->font_color_bg(InputImpl::color_bg_default);
-
-                InputImpl::value = value_from_string(input_text());
-                input_text(value_to_string(InputImpl::value));
-                _input_caption->text(value_to_string(InputImpl::value));
-            });
-
-            key_handler([this](const SDL_KeyboardEvent& key) {
-                if (key.type == SDL_KEYDOWN) {
-                    switch (key.keysym.sym) {
-                        // Discard inputted value on escape key.
-                        case SDLK_ESCAPE: {
-                            focus(false);
-                            input_text(value_to_string(InputImpl::value));
-                            break;
-                        }
-                        case SDLK_BACKSPACE: {
-                            const auto& txt = input_text();
-                            if (const auto len = txt.length(); len > 0) {
-                                input_text(std::string(txt.substr(0, len - 1)));
-                            }
-                            break;
-                        }
-                        // Save inputted value and unfocus the widget on enter key.
-                        case SDLK_RETURN:
-                        case SDLK_RETURN2: // what is return2 btw?
-                        case SDLK_KP_ENTER:
-                            focus(false);
-                            InputImpl::value = value_from_string(input_text());
-                            break;
-                    }
-                }
-            });
-            // Just keep the string representation of input in the input field caption
-            // text but don't save the parsed value until some other event
-            // (Esc/Enter/focus loss)
-            text_input_handler([this](const SDL_TextInputEvent& input) {
-                if (is_valid_input(input.text)) {
-                    input_text(std::string(input_text()) + input.text);
-                }
-            });
-            enable_keyboard_handler();
-
-            // Highlight input field on mouse hover.
-            hover_handler([this](const bool _hover) {
-                if (_hover) _input_caption->font_color_bg(InputImpl::color_bg_focused);
-                else _input_caption->font_color_bg(InputImpl::color_bg_default);
-            });
-            enable_mouse_handler(_widget_area, _viewport);
-
-            _input_caption->font_color_bg(InputImpl::color_bg_default);
-        }
-
-        void _handle_font_change(const std::shared_ptr<Font>& f) override
-        {
-            _input_caption->font(f);
-            _handle_geometry_change(_viewport);
-        }
-
-        void _handle_font_color_change(const Color fg, const Color bg) override
-        {
-            _input_caption->font_color_bg(bg);
-            _input_caption->font_color_fg(fg);
-        }
-
-        void _handle_geometry_change(const SDL_Rect& vp) override
-        {
-            const auto input_h = _input_caption->size().h + 2 * InputImpl::border_width;
-            _widget_area       = {0, center_line(vp.h, input_h), vp.w, input_h};
-
-            _input_caption->viewport(
-              rect_offset({rect_margin(_widget_area, {InputImpl::border_width,
-                                                      InputImpl::border_width})},
-                          vp));
-        }
-
-        void _handle_renderer_change(const std::shared_ptr<Renderer>& r) override
-        {
-            _input_caption->renderer(r);
-        }
-
-        void _handle_rendering() override
-        {
-            const auto& color_end =
-              focus() ? InputImpl::color_bg_focused : InputImpl::color_bg_default;
-
-            const auto color_start = color_end / 2;
-            // Render input borders.
-            for (int i = InputImpl::border_width - 1; i >= 0; i--) {
-                const auto factor = linear(i, 0, InputImpl::border_width);
-                _renderer->draw_color(lerp(color_start, color_end, factor))
-                  ->draw_rect(rect_margin(_widget_area, {i, i}));
-            }
-
-            _input_caption->render();
-        }
-    };
-}
-
-#endif

inc/basic_widgets/w/base/layout.hpp

@@ -1,26 +1,48 @@
 #ifndef BWIDGETS_LAYOUT_HPP
 #define BWIDGETS_LAYOUT_HPP
 
+#include <functional>
+#include <vector>
+
 #include <basic_widgets/core/type/size.hpp>
 #include <basic_widgets/w/base/widget.hpp>
 
 namespace bwidgets
 {
-    class Layout : public virtual Widget
+    class Renderer;
+}
+
+namespace bwidgets
+{
+    class Layout : public Widget
     {
     protected:
-        using Widget::Widget;
+        std::vector<std::unique_ptr<Widget>> _widgets;
+
+        void _handle_geometry_change(const SDL_Rect&) override;
+        void _handle_renderer_change(const std::shared_ptr<Renderer>&) override;
+        void _handle_rendering() override;
+
+        virtual void _update_layout(const SDL_Rect&) = 0;
 
     public:
-        static inline const Size default_margins {8, 8};
+        static const Size default_margins;
 
-        // Margins between layout widgets.
         Size margins = default_margins;
 
-        // Add widget to the layout
-        virtual void add_widget(std::unique_ptr<Widget>)              = 0;
-        // Apply a function to every layout widget.
-        virtual void for_widgets(const std::function<void(Widget*)>&) = 0;
+        using Widget::Widget;
+
+        Layout(const Layout&) = delete;
+        Layout(Layout&&)      = delete;
+        ~Layout() override    = default;
+        auto operator=(const Layout&) = delete;
+        auto operator=(Layout&&) = delete;
+
+        void               handle_event(const SDL_Event&) override;
+        [[nodiscard]] auto size() const noexcept -> Size override = 0;
+
+        virtual auto add_widget(std::unique_ptr<Widget>) -> Layout*;
+        virtual void for_widgets(const std::function<void(Widget*)>&);
     };
 }
 

inc/basic_widgets/w/base/layout_impl.hpp

@@ -1,38 +0,0 @@
-#ifndef BWIDGETS_LAYOUT_IMPL_HPP
-#define BWIDGETS_LAYOUT_IMPL_HPP
-
-#include <vector>
-
-#include <basic_widgets/w/base/layout.hpp>
-#include <basic_widgets/w/base/widget_impl.hpp>
-
-namespace bwidgets
-{
-    class Renderer;
-}
-
-namespace bwidgets
-{
-    class LayoutImpl : public virtual Layout,
-                       public virtual WidgetImpl
-    {
-    public:
-        using WidgetImpl::WidgetImpl;
-
-        void add_widget(std::unique_ptr<Widget>) override;
-        void for_widgets(const std::function<void(Widget*)>&) override;
-        void handle_event(const SDL_Event&) override;
-
-    protected:
-        std::vector<std::unique_ptr<Widget>> _widgets;
-
-        void _handle_geometry_change(const SDL_Rect&) override;
-        void _handle_renderer_change(const std::shared_ptr<Renderer>&) override;
-        void _handle_rendering() override;
-
-        // Compute and set widget geometry.
-        virtual void _update_layout(const SDL_Rect&) = 0;
-    };
-}
-
-#endif

inc/basic_widgets/w/base/widget.hpp

@@ -5,7 +5,7 @@
 
 #include <basic_widgets/core/renderer.hpp>
 #include <basic_widgets/core/type/size.hpp>
-#include <basic_widgets/w/feat/event_handler.hpp>
+#include <basic_widgets/w/feat/event_handler_impl.hpp>
 
 union SDL_Event;
 
@@ -13,26 +13,28 @@ struct SDL_Renderer;
 
 namespace bwidgets
 {
-    class Widget : public virtual EventHandler
+    class Widget : public virtual EventHandlerImpl
     {
+    protected:
+        std::shared_ptr<Renderer> _renderer;
+        SDL_Rect                  _viewport {0, 0, 0, 0};
+        SDL_Rect                  _widget_area {0, 0, 0, 0};
+
+        virtual void _handle_geometry_change(const SDL_Rect&) = 0;
+        virtual void _handle_renderer_change(const std::shared_ptr<Renderer>&) {}
+        virtual void _handle_rendering() = 0;
+
     public:
-        // Parent widget for bidirectional message passing between widgets.
-        // Currently not used by this lib.
         Widget* parent;
 
         explicit Widget(Widget* p = nullptr) noexcept : parent {p} {}
 
-        // Render widget on current renderer target.
-        virtual void               render()                            = 0;
-        // Set widget renderer.
-        virtual void               renderer(std::shared_ptr<Renderer>) = 0;
-        // Get prefered or minimal widget size.
-        [[nodiscard]] virtual auto size() const noexcept -> Size       = 0;
-        // Set the viewport delimiting the widget rendering area and the origin
-        // for relative coordinates.
-        virtual void               viewport(const SDL_Rect&)           = 0;
-        // Get current viewport.
-        [[nodiscard]] virtual auto viewport() const -> const SDL_Rect& = 0;
+        [[nodiscard]] virtual auto size() const noexcept -> Size = 0;
+
+        virtual auto               render() -> Widget* final;
+        virtual auto               renderer(std::shared_ptr<Renderer>) -> Widget* final;
+        virtual auto               viewport(const SDL_Rect&) -> Widget* final;
+        [[nodiscard]] virtual auto viewport() const -> const SDL_Rect& final;
     };
 }
 

inc/basic_widgets/w/base/widget_impl.hpp

@@ -1,35 +0,0 @@
-#ifndef BWIDGETS_WIDGET_IMPL_HPP
-#define BWIDGETS_WIDGET_IMPL_HPP
-
-#include <basic_widgets/w/base/widget.hpp>
-#include <basic_widgets/w/feat/event_handler_impl.hpp>
-
-namespace bwidgets
-{
-    class WidgetImpl : public virtual Widget,
-                       public virtual EventHandlerImpl
-    {
-    public:
-        void               render() override;
-        void               renderer(std::shared_ptr<Renderer>) override;
-        void               viewport(const SDL_Rect&) override;
-        [[nodiscard]] auto viewport() const -> const SDL_Rect& override;
-
-    protected:
-        std::shared_ptr<Renderer> _renderer;
-        SDL_Rect                  _viewport {0, 0, 0, 0};
-        // Area actually used by the widget.
-        SDL_Rect                  _widget_area {0, 0, 0, 0};
-
-        using Widget::Widget;
-
-        // Called on viewport change.
-        virtual void _handle_geometry_change(const SDL_Rect&) = 0;
-        // Called on renderer change.
-        virtual void _handle_renderer_change(const std::shared_ptr<Renderer>&) {}
-        // Called on rendering.
-        virtual void _handle_rendering() = 0;
-    };
-}
-
-#endif

inc/basic_widgets/w/button.hpp

@@ -1,36 +1,57 @@
 #ifndef BWIDGETS_BUTTON_HPP
 #define BWIDGETS_BUTTON_HPP
 
+#include <functional>
 #include <string>
 
 #include <basic_widgets/core/type/color.hpp>
-#include <basic_widgets/w/base/widget.hpp>
-#include <basic_widgets/w/feat/font_handler.hpp>
-#include <basic_widgets/w/feat/mouse_handler.hpp>
+#include <basic_widgets/w/caption.hpp>
+#include <basic_widgets/w/feat/mouse_handler_impl.hpp>
 
 namespace bwidgets
 {
     class Button : public virtual Widget,
                    public virtual FontHandler,
-                   public virtual MouseHandler
+                   public virtual MouseHandlerImpl
     {
+    protected:
+        Caption  _caption;
+        SDL_Rect _caption_area {};
+        Color    _color_foreground = default_color_fg;
+
+        void _handle_font_change(const std::shared_ptr<Font>&) override;
+        void _handle_font_color_change(Color, Color)
+        override;
+        void _handle_geometry_change(const SDL_Rect&) override;
+        void _handle_renderer_change(const std::shared_ptr<Renderer>&) override;
+        void _handle_rendering() override;
+        void _on_push(bool) override;
+
     public:
-        static inline const Color default_color_bg {150, 150, 150, SDL_ALPHA_OPAQUE};
-        static inline const Color default_color_bg_hover {175, 175, 175,
-                                                          SDL_ALPHA_OPAQUE};
-        static inline const Color default_color_fg {0, 0, 0, SDL_ALPHA_OPAQUE};
+        static const Color default_color_bg;
+        static const Color default_color_bg_hover;
+        static const Color default_color_fg;
 
         std::function<Color(int, int, float)> border_gradient;
         Size                                  border_size {3, 3};
         Color                                 color_bg       = default_color_bg;
         Color                                 color_bg_hover = default_color_bg_hover;
 
-        using Widget::Widget;
+        using EventHandlerImpl::handle_event;
+        using FocusHandlerImpl::focus;
+        using FocusHandlerImpl::focus_handler;
 
-        // Get button text (label).
-        [[nodiscard]] virtual auto text() const noexcept -> std::string_view = 0;
-        // Set button text
-        virtual void               text(std::string)                         = 0;
+        Button(Widget* parent = nullptr) noexcept;
+        Button(const Button&) = delete;
+        Button(Button&&)      = delete;
+        ~Button() override    = default;
+        auto operator=(const Button&) = delete;
+        auto operator=(Button&&) = delete;
+
+        [[nodiscard]] auto size() const noexcept -> Size override;
+
+        [[nodiscard]] virtual auto text() const noexcept -> const std::string&;
+        virtual auto               text(const std::string&) -> Button*;
     };
 }
 

inc/basic_widgets/w/button_impl.hpp

@@ -1,40 +0,0 @@
-#ifndef BWIDGETS_BUTTON_IMPL_HPP
-#define BWIDGETS_BUTTON_IMPL_HPP
-
-#include <basic_widgets/w/base/widget_impl.hpp>
-#include <basic_widgets/w/button.hpp>
-#include <basic_widgets/w/caption.hpp>
-#include <basic_widgets/w/feat/font_handler_impl.hpp>
-#include <basic_widgets/w/feat/mouse_handler_impl.hpp>
-
-namespace bwidgets
-{
-    class ButtonImpl : public virtual Button,
-                       public virtual FontHandlerImpl,
-                       public virtual MouseHandlerImpl,
-                       public virtual WidgetImpl
-    {
-    public:
-        ButtonImpl(Widget* parent = nullptr) noexcept;
-
-        // Smallest valid button size.
-        [[nodiscard]] auto size() const noexcept -> Size override;
-        [[nodiscard]] auto text() const noexcept -> std::string_view override;
-        void               text(std::string) override;
-
-    protected:
-        std::unique_ptr<Caption> _caption;
-        SDL_Rect                 _caption_area {};
-        Color                    _color_foreground = default_color_fg;
-
-        void _handle_font_change(const std::shared_ptr<Font>&) override;
-        void _handle_font_color_change(Color, Color)
-        override;
-        void _handle_geometry_change(const SDL_Rect&) override;
-        void _handle_renderer_change(const std::shared_ptr<Renderer>&) override;
-        void _handle_rendering() override;
-        void _on_push(bool) override;
-    };
-}
-
-#endif

inc/basic_widgets/w/caption.hpp

@@ -1,6 +1,8 @@
 #ifndef BWIDGETS_CAPTION_HPP
 #define BWIDGETS_CAPTION_HPP
 
+#include <basic_widgets/core/texture.hpp>
+#include <basic_widgets/core/type/size.hpp>
 #include <basic_widgets/w/base/widget.hpp>
 #include <basic_widgets/w/feat/font_handler.hpp>
 #include <basic_widgets/w/feat/texture_handler.hpp>
@@ -9,10 +11,23 @@ struct SDL_Surface;
 
 namespace bwidgets
 {
-    class Caption : public virtual Widget,
-                    public virtual FontHandler,
-                    public virtual TextureHandler
+    class Caption : public Widget,
+                    public FontHandler,
+                    public TextureHandler
     {
+    protected:
+        Font::RenderMode         _render_mode {Font::RenderMode::SHADED};
+        std::string              _text;
+        std::shared_ptr<Texture> _text_texture {nullptr};
+
+        void _handle_font_change(const std::shared_ptr<Font>&) override;
+        void _handle_font_color_change(Color, Color)
+        override;
+        void _handle_geometry_change(const SDL_Rect&) override;
+        void _handle_renderer_change(const std::shared_ptr<Renderer>&) override;
+        void _handle_rendering() override;
+        void _handle_texture_update() override;
+
     public:
         enum struct Alignment
         {
@@ -20,22 +35,26 @@ namespace bwidgets
             LEFT,
             RIGHT
         };
+
         inline static const Color default_color_bg = {255, 255, 255, SDL_ALPHA_OPAQUE};
         inline static const Color default_color_fg = {0, 0, 0, SDL_ALPHA_OPAQUE};
         inline static const Size  default_margins  = {3, 3};
 
-        // Text horizontal alignment on the caption viewport.
         Alignment alignment {Alignment::LEFT};
-        Size      margins {default_margins};
+        Size      margins {3, 3};
 
-        using Widget::Widget;
+        Caption(Widget* parent = nullptr) noexcept;
+        Caption(const Caption&) = delete;
+        Caption(Caption&&)      = delete;
+        ~Caption() override     = default;
+        auto operator=(const Caption&) = delete;
+        auto operator=(Caption&&) = delete;
 
-        // Set caption text rendering mode.
-        virtual void               render_mode(Font::RenderMode)             = 0;
-        // Get caption text.
-        [[nodiscard]] virtual auto text() const noexcept -> std::string_view = 0;
-        // Set caption text.
-        virtual void               text(std::string)                         = 0;
+        virtual auto               render_mode(Font::RenderMode) -> Caption*;
+        [[nodiscard]] virtual auto text() const noexcept -> const std::string&;
+        virtual auto               text(const std::string&) -> Caption*;
+
+        [[nodiscard]] auto size() const noexcept -> Size override;
     };
 }
 

inc/basic_widgets/w/caption_impl.hpp

@@ -1,37 +0,0 @@
-#ifndef BWIDGETS_CAPTION_IMPL_HPP
-#define BWIDGETS_CAPTION_IMPL_HPP
-
-#include <basic_widgets/w/base/widget_impl.hpp>
-#include <basic_widgets/w/caption.hpp>
-#include <basic_widgets/w/feat/font_handler_impl.hpp>
-
-namespace bwidgets
-{
-    class CaptionImpl : public virtual Caption,
-                        public virtual FontHandlerImpl,
-                        public virtual WidgetImpl
-    {
-    public:
-        CaptionImpl(Widget* p = nullptr) noexcept;
-
-        void               render_mode(Font::RenderMode) override;
-        [[nodiscard]] auto size() const noexcept -> Size override;
-        [[nodiscard]] auto text() const noexcept -> std::string_view override;
-        void               text(std::string) override;
-
-    protected:
-        Font::RenderMode         _render_mode {Font::RenderMode::SHADED};
-        std::string              _text;
-        std::shared_ptr<Texture> _text_texture {nullptr};
-
-        void _handle_font_change(const std::shared_ptr<Font>&) override;
-        void _handle_font_color_change(Color, Color)
-        override;
-        void _handle_geometry_change(const SDL_Rect&) override;
-        void _handle_renderer_change(const std::shared_ptr<Renderer>&) override;
-        void _handle_rendering() override;
-        void _handle_texture_update() override;
-    };
-}
-
-#endif

inc/basic_widgets/w/feat/event_handler.hpp

@@ -2,6 +2,7 @@
 #define BWIDGETS_EVENT_HANDLER_HPP
 
 #include <functional>
+#include <utility>
 
 #include <SDL_events.h>
 
@@ -9,13 +10,14 @@ namespace bwidgets
 {
     class EventHandler
     {
-    protected:
-        EventHandler() = default;
-
     public:
         using handler_t =
           std::pair<SDL_EventType, std::function<void(const SDL_Event&)>>;
 
+    protected:
+        EventHandler() = default;
+
+    public:
         EventHandler(const EventHandler&) = delete;
         EventHandler(EventHandler&&)      = delete;
         auto operator=(const EventHandler&) -> EventHandler& = delete;
@@ -23,7 +25,6 @@ namespace bwidgets
 
         virtual ~EventHandler() = default;
 
-        // Pass the event to be handled.
         virtual void handle_event(const SDL_Event&) = 0;
     };
 }

inc/basic_widgets/w/feat/event_handler_impl.hpp

@@ -12,18 +12,12 @@ namespace bwidgets
         std::unordered_map<SDL_EventType, std::function<void(const SDL_Event&)>>
           _event_handlers {};
 
+    protected:
+        auto _add_event_handler(handler_t) -> bool;
+        auto _remove_event_handler(SDL_EventType) -> std::pair<handler_t, bool>;
+
     public:
         void handle_event(const SDL_Event&) override;
-
-    protected:
-        // Add an handler for a given event type. There can be only one handler by
-        // event type. Return true if handler is added successfuly. Return false
-        // if handler cannot be added because there's already an handler for that
-        // event type.
-        auto _add_event_handler(handler_t) -> bool;
-        // Remove the handler of a given event type. Return true with the removed
-        // handler on success, false otherwise.
-        auto _remove_event_handler(SDL_EventType) -> std::pair<handler_t, bool>;
     };
 }
 

inc/basic_widgets/w/feat/focus_handler.hpp

@@ -17,11 +17,8 @@ namespace bwidgets
         auto operator=(const FocusHandler&) = delete;
 
         virtual ~FocusHandler()                               = default;
-        // set focus state.
         virtual void focus(bool focus)                        = 0;
-        // get focus state.
         virtual bool focus()                                  = 0;
-        // set an handler for focus states changes.
         virtual void focus_handler(std::function<void(bool)>) = 0;
     };
 }

inc/basic_widgets/w/feat/focus_handler_impl.hpp

@@ -11,9 +11,10 @@ namespace bwidgets
         std::function<void(bool)> _focus_handler {[](auto) {}};
 
     public:
-        void focus(const bool _focus) override
+        void focus(bool focus_) override
         {
-            if (_has_focus != _focus) _focus_handler(_has_focus = _focus);
+            _focus_handler(focus_);
+            _has_focus = focus_;
         }
 
         bool focus() override

inc/basic_widgets/w/feat/font_handler.hpp

@@ -1,33 +1,67 @@
 #ifndef BWIDGETS_FONT_HANDLER_HPP
 #define BWIDGETS_FONT_HANDLER_HPP
 
+#include <memory>
+
 #include <basic_widgets/core/font.hpp>
 
 namespace bwidgets
 {
     class FontHandler
     {
+    protected:
+        std::shared_ptr<Font> _font;
+        Color                 _font_color_bg = default_font_color_bg;
+        Color                 _font_color_fg = default_font_color_fg;
+        Font::RenderMode      _font_render_mode {Font::RenderMode::SHADED};
+
+        virtual void _handle_font_change(const std::shared_ptr<Font>&) = 0;
+        virtual void _handle_font_color_change(Color, Color)           = 0;
+
     public:
         inline static const Color default_font_color_bg {255, 255, 255,
                                                          SDL_ALPHA_OPAQUE};
         inline static const Color default_font_color_fg {0, 0, 0, SDL_ALPHA_OPAQUE};
 
+        FontHandler() noexcept          = default;
         FontHandler(const FontHandler&) = delete;
         FontHandler(FontHandler&&)      = delete;
         auto operator=(const FontHandler&) = delete;
         auto operator=(FontHandler&&)   = delete;
         virtual ~FontHandler() noexcept = default;
 
-        // Set the used font.
-        virtual void font(std::shared_ptr<Font> f) = 0;
-        // Set background color used for shaded text rendering
-        // mode.
-        virtual void font_color_bg(Color c)        = 0;
-        // Set foreground (glyphs) color.
-        virtual void font_color_fg(Color c)        = 0;
+        virtual auto font(std::shared_ptr<Font> f) -> FontHandler* final
+        {
+            if (f != nullptr
+                && (f != _font || f->family_name != _font->family_name
+                    || f->height != _font->height || f->hinting() != _font->hinting()
+                    || f->kerning() != _font->kerning()
+                    || f->outline() != _font->outline()
+                    || f->style_name != _font->style_name))
+            {
+                _handle_font_change(f);
+                _font = f;
+            }
+            return this;
+        }
 
-    protected:
-        FontHandler() noexcept = default;
+        virtual auto font_color_bg(Color c) -> FontHandler* final
+        {
+            if (c != _font_color_bg) {
+                _handle_font_color_change(_font_color_bg, c);
+                _font_color_bg = c;
+            }
+            return this;
+        }
+
+        virtual auto font_color_fg(Color c) -> FontHandler* final
+        {
+            if (c != _font_color_fg) {
+                _handle_font_color_change(c, _font_color_fg);
+                _font_color_fg = c;
+            }
+            return this;
+        }
     };
 }
 

inc/basic_widgets/w/feat/font_handler_impl.hpp

@@ -1,54 +0,0 @@
-#ifndef BWIDGETS_FONT_HANDLER_IMPL_HPP
-#define BWIDGETS_FONT_HANDLER_IMPL_HPP
-
-#include <basic_widgets/w/feat/font_handler.hpp>
-
-namespace bwidgets
-{
-    class FontHandlerImpl : public virtual FontHandler
-    {
-    public:
-        void font(const std::shared_ptr<Font> f) final
-        {
-            if (f
-                && (f != _font || f->family_name != _font->family_name
-                    || f->height != _font->height || f->hinting() != _font->hinting()
-                    || f->kerning() != _font->kerning()
-                    || f->outline() != _font->outline()
-                    || f->style_name != _font->style_name))
-            {
-                _handle_font_change(f);
-                _font = f;
-            }
-        }
-
-        void font_color_bg(const Color c) final
-        {
-            if (c != _font_color_bg) {
-                _handle_font_color_change(_font_color_fg, c);
-                _font_color_bg = c;
-            }
-        }
-
-        void font_color_fg(const Color c) final
-        {
-            if (c != _font_color_fg) {
-                _handle_font_color_change(c, _font_color_fg);
-                _font_color_fg = c;
-            }
-        }
-
-    protected:
-        std::shared_ptr<Font> _font;
-        Color                 _font_color_bg = default_font_color_bg;
-        Color                 _font_color_fg = default_font_color_fg;
-        Font::RenderMode      _font_render_mode {Font::RenderMode::SHADED};
-
-        // Called on font changes.
-        virtual void _handle_font_change(const std::shared_ptr<Font>&) = 0;
-        // Called on font color changes.
-        virtual void _handle_font_color_change(Color, Color)           = 0;
-    };
-}
-
-#endif

inc/basic_widgets/w/feat/keyboard_handler.hpp

@@ -16,13 +16,9 @@ namespace bwidgets
         using EventHandler::EventHandler;
 
     public:
-        // Disable keyboard event handling.
         virtual void disable_keyboard_handler()                                 = 0;
-        // Enable keyboard event handling.
         virtual void enable_keyboard_handler()                                  = 0;
-        // Set the handler for key press events.
         virtual void key_handler(std::function<void(const SDL_KeyboardEvent&)>) = 0;
-        // Set the handler for text input events.
         virtual void
         text_input_handler(std::function<void(const SDL_TextInputEvent&)>) = 0;
     };

inc/basic_widgets/w/feat/keyboard_handler_impl.hpp

@@ -7,9 +7,9 @@
 
 namespace bwidgets
 {
-    class KeyboardHandlerImpl : public virtual KeyboardHandler,
-                                public virtual EventHandlerImpl,
-                                public virtual FocusHandlerImpl
+    class KeyboardHandlerImpl : public KeyboardHandler,
+                                virtual public EventHandlerImpl,
+                                virtual public FocusHandlerImpl
     {
         std::function<void(const SDL_KeyboardEvent&)>  _key_handler {[](auto) {}};
         std::function<void(const SDL_TextInputEvent&)> _input_handler {[](auto) {}};

inc/basic_widgets/w/feat/mouse_handler.hpp

@@ -9,27 +9,21 @@ struct SDL_MouseMotionEvent;
 
 namespace bwidgets
 {
-    class MouseHandler : public virtual FocusHandler,
-                         public virtual EventHandler
+    class MouseHandler : virtual public FocusHandler,
+                         virtual public EventHandler
     {
     protected:
         using EventHandler::EventHandler;
 
+        virtual void _on_push(bool) = 0;
+
     public:
-        // Set click handler.
         virtual void click_handler(std::function<void(const SDL_MouseButtonEvent&)>) = 0;
-        // Disable mouse event handling.
         virtual void disable_mouse_handler()                                         = 0;
-        // Enable mouse event handling.
-        virtual void enable_mouse_handler(const SDL_Rect&, const SDL_Rect&)          = 0;
-        // Called on hover state changes.
-        virtual void hover_handler(std::function<void(bool)>)                        = 0;
-        // Get current hover state.
+        virtual void enable_mouse_handler(const SDL_Rect*, const SDL_Rect*)          = 0;
         [[nodiscard]] virtual bool hovered() const                                   = 0;
-        // Set mouse motion handler.
         virtual void
         mouse_motion_handler(std::function<void(const SDL_MouseMotionEvent&)>) = 0;
-        // Get current push state (mouse button down)
         [[nodiscard]] virtual bool pushed() const                              = 0;
     };
 }

inc/basic_widgets/w/feat/mouse_handler_impl.hpp

@@ -7,38 +7,39 @@
 
 namespace bwidgets
 {
-    class MouseHandlerImpl : public virtual MouseHandler,
-                             public virtual EventHandlerImpl,
-                             public virtual FocusHandlerImpl
+    class MouseHandlerImpl : public MouseHandler,
+                             virtual public EventHandlerImpl,
+                             virtual public FocusHandlerImpl
     {
+    private:
         bool _hovered {false};
         bool _pushed {false};
 
         std::function<void(const SDL_MouseButtonEvent&)> _click_handler {[](auto) {}};
-        std::function<void(bool)>                        _hover_handler {[](auto) {}};
         std::function<void(const SDL_MouseMotionEvent&)> _motion_handler {[](auto) {}};
 
+    protected:
+        using MouseHandler::MouseHandler;
+
+        void _on_push(bool) override {}
+
     public:
-        void click_handler(decltype(_click_handler) handler) override
+        void
+        click_handler(std::function<void(const SDL_MouseButtonEvent&)> handler) override
         {
             _click_handler = std::move(handler);
         }
 
         void disable_mouse_handler() override;
 
-        void enable_mouse_handler(const SDL_Rect&, const SDL_Rect&) override;
-
+        void enable_mouse_handler(const SDL_Rect*, const SDL_Rect*) override;
         [[nodiscard]] bool hovered() const override
         {
             return _hovered;
         }
 
-        void hover_handler(decltype(_hover_handler) handler) override
-        {
-            _hover_handler = std::move(handler);
-        }
-
-        void mouse_motion_handler(decltype(_motion_handler) handler) override
+        void mouse_motion_handler(
+          std::function<void(const SDL_MouseMotionEvent&)> handler) override
         {
             _motion_handler = std::move(handler);
         }
@@ -47,12 +48,6 @@ namespace bwidgets
         {
             return _pushed;
         }
-
-    protected:
-        using MouseHandler::MouseHandler;
-
-        // Called on push state changes.
-        virtual void _on_push(bool) {}
     };
 }
 

inc/basic_widgets/w/feat/texture_handler.hpp

@@ -1,5 +1,5 @@
-#ifndef BWIDGETS_TEXTURE_HANDLER_HPP
-#define BWIDGETS_TEXTURE_HANDLER_HPP
+#ifndef BWIDGETS_TEXTURE_HANDLER
+#define BWIDGETS_TEXTURE_HANDLER
 
 namespace bwidgets
 {
@@ -11,11 +11,10 @@ namespace bwidgets
     class TextureHandler
     {
     protected:
-        TextureHandler() noexcept             = default;
-        // (Re)render textures.
         virtual void _handle_texture_update() = 0;
 
     public:
+        TextureHandler() noexcept             = default;
         TextureHandler(const TextureHandler&) = delete;
         TextureHandler(TextureHandler&&)      = delete;
         virtual ~TextureHandler() noexcept    = default;

inc/basic_widgets/w/numeric_input.hpp

@@ -1,26 +1,178 @@
 #ifndef BWIDGETS_NUMERIC_INPUT_HPP
 #define BWIDGETS_NUMERIC_INPUT_HPP
 
+#include <limits>
+#include <type_traits>
+
+#include <basic_widgets/core/math.hpp>
 #include <basic_widgets/core/type/concepts.hpp>
 #include <basic_widgets/w/base/input.hpp>
+#include <basic_widgets/w/button.hpp>
 
 namespace bwidgets
 {
     template<Numeric T>
-    class NumericInput : public virtual Input<T>
+    class NumericInput : public Input<T>
     {
     protected:
-        using Input<T>::Input;
+        Button          _increment_button;
+        SDL_Rect        _increment_button_area {};
+        Button          _decrement_button;
+        SDL_Rect        _decrement_button_area {};
+        std::pair<T, T> _value_range {std::numeric_limits<T>::lowest(),
+                                      std::numeric_limits<T>::max()};
+
+        void _handle_font_change(const std::shared_ptr<Font>& f) override
+        {
+            _decrement_button.font(f);
+            _increment_button.font(f);
+            Input<T>::_handle_font_change(f);
+        }
+
+        void _handle_font_color_change(Color fg, Color bg) override
+        {
+            Input<T>::_handle_font_color_change(fg, bg);
+            _decrement_button.font_color_bg(bg)->font_color_fg(fg);
+            _increment_button.font_color_bg(bg)->font_color_fg(fg);
+        }
+
+        void _handle_geometry_change(const SDL_Rect& vp) override
+        {
+            Input<T>::_handle_geometry_change(vp);
+
+            const int widest_button     = _increment_button.size().w != 0
+                                          ? _increment_button.size().w
+                                          : _decrement_button.size().w;
+            const int button_area_width = 2 * widest_button;
+            const int spacing           = center_line(button_area_width, widest_button);
+            const int field_width       = vp.w - 2 * button_area_width;
+
+            Widget::_widget_area.x = Widget::_widget_area.x + button_area_width;
+            Widget::_widget_area.w = field_width;
+
+            Input<T>::_input_caption.viewport(
+              rect_offset(rect_margin(Widget::_widget_area,
+                                      {Input<T>::border_width, Input<T>::border_width}),
+                          vp));
+            _decrement_button_area = {spacing, Widget::_widget_area.y,
+                                      _decrement_button.size().w,
+                                      _decrement_button.size().h};
+
+            _increment_button_area = {vp.w - spacing - _increment_button.size().w,
+                                      Widget::_widget_area.y, _increment_button.size().w,
+                                      _increment_button.size().h};
+
+            _increment_button.viewport(rect_offset(_increment_button_area, vp));
+            _decrement_button.viewport(rect_offset(_decrement_button_area, vp));
+        }
+
+        void _handle_renderer_change(const std::shared_ptr<Renderer>& r) override
+        {
+            Input<T>::_handle_renderer_change(r);
+            _decrement_button.renderer(r);
+            _increment_button.renderer(r);
+        }
+
+        void _handle_rendering() override
+        {
+            Input<T>::_handle_rendering();
+            _increment_button.render();
+            _decrement_button.render();
+        }
 
     public:
-        // Button increment/decrement step.
         T button_step = 1;
 
-        // Get allowed value range.
-        [[nodiscard]] virtual auto value_range() const noexcept
-          -> const std::pair<T, T>&            = 0;
-        // Set allowed value range.
-        virtual void value_range(T min, T max) = 0;
+        NumericInput(Widget* parent = nullptr)
+          : Input<T>(parent), _increment_button(this), _decrement_button(this)
+        {
+            Input<T>::_input_caption.alignment = Caption::Alignment::RIGHT;
+
+            Input<T>::input_min_width  = 10; // NOLINT(readability-magic-numbers)
+            Input<T>::input_width_unit = '0';
+
+            _increment_button.text("+");
+
+            _increment_button.click_handler([this](const SDL_MouseButtonEvent&) {
+                T new_value = this->value + button_step;
+                if (_value_range.second - this->value < button_step)
+                    new_value = _value_range.second;
+
+                this->value = new_value;
+                this->input_text(this->value_to_string(new_value));
+            });
+
+            _decrement_button.text("-");
+
+            _decrement_button.click_handler([this](const SDL_MouseButtonEvent&) {
+                T new_value = this->value - button_step;
+                if (this->value - _value_range.first < button_step)
+                    new_value = _value_range.first;
+
+                this->value = new_value;
+                this->input_text(this->value_to_string(new_value));
+            });
+        }
+
+        NumericInput(const NumericInput&) = delete;
+        NumericInput(NumericInput&&)      = delete;
+        ~NumericInput() override          = default;
+        auto operator=(const NumericInput&) = delete;
+        auto operator=(NumericInput&&) = delete;
+
+        void handle_event(const SDL_Event& ev) override
+        {
+            Input<T>::handle_event(ev);
+            _increment_button.handle_event(ev);
+            _decrement_button.handle_event(ev);
+        }
+
+        [[nodiscard]] auto is_valid_input(const std::string& input) const noexcept
+          -> bool override
+        {
+            bool valid = false;
+
+            if (input[0] >= '0' && input[0] <= '9') valid = true;
+            if constexpr (std::is_floating_point_v<T>)
+                if (input[0] == '.'
+                    && Input<T>::input_text().find('.') == std::string::npos)
+                    valid = true;
+            if constexpr (std::is_signed_v<T>) {
+                std::string displayed_value = Input<T>::input_text();
+                if (input[0] == '-' && displayed_value.empty()) valid = true;
+            }
+            return valid;
+        }
+
+        [[nodiscard]] auto process_value(T x) const noexcept -> T override
+        {
+            T value = x;
+            if (x < _value_range.first) value = _value_range.first;
+            else if (x > _value_range.second) value = _value_range.second;
+
+            return value;
+        }
+
+        [[nodiscard]] auto size() const noexcept -> Size override
+        {
+            const auto base       = Input<T>::size();
+            const auto btns_width = 4 * _increment_button.size().w;
+            return {base.w + btns_width, base.h};
+        }
+
+        [[nodiscard]] virtual auto value_range() const noexcept -> const std::pair<T, T>&
+        {
+            return _value_range;
+        }
+
+        virtual auto value_range(T min, T max) -> NumericInput<T>*
+        {
+            if (min > max) throw std::invalid_argument("min cannot be greater than max");
+            _value_range    = {min, max};
+            Input<T>::value = process_value(Input<T>::value);
+            Input<T>::input_text(Input<T>::value_to_string(Input<T>::value));
+            return this;
+        }
     };
 }
 

inc/basic_widgets/w/numeric_input_impl.hpp

@@ -1,196 +0,0 @@
-#ifndef BWIDGETS_NUMERIC_INPUT_IMPL_HPP
-#define BWIDGETS_NUMERIC_INPUT_IMPL_HPP
-
-#include <basic_widgets/w/base/input_impl.hpp>
-#include <basic_widgets/w/numeric_input.hpp>
-
-namespace bwidgets
-{
-    template<Numeric T>
-    class NumericInputImpl : public virtual NumericInput<T>,
-                             public virtual InputImpl<T>
-    {
-        using Self = NumericInputImpl;
-
-    public:
-        NumericInputImpl(Widget* parent = nullptr)
-          : InputImpl<T>(parent),
-            _increment_button(create_button(this)),
-            _decrement_button(create_button(this))
-        {
-            Self::_input_caption->alignment = Caption::Alignment::RIGHT;
-
-            Self::input_min_width  = 10; // NOLINT(readability-magic-numbers)
-            Self::input_width_unit = '0';
-
-            // +/- buttons click handler. op is the operation (+/-) to apply on current
-            // value.
-            const auto button_action = [this](const std::function<T(T, T)> op) {
-                const T new_value = [this, &op]() {
-                    auto _new_value = op(this->value, NumericInput<T>::button_step);
-                    if (_new_value < this->value) {
-                        // if value - button_step is out of allowed range
-                        // set value to the smallest allowed value.
-                        if (std::abs(_value_range.first - this->value)
-                            < std::abs(NumericInput<T>::button_step))
-                            return _value_range.first;
-                        return _new_value;
-                    }
-                    // if value + button_step exceeds maximal allowed value
-                    // set value to max allowed value.
-                    if (std::abs(_value_range.second - this->value)
-                        < std::abs(NumericInput<T>::button_step))
-                        return _value_range.second;
-                    return _new_value;
-                }();
-
-                this->value = new_value;
-                this->input_text(this->value_to_string(new_value));
-            };
-
-            _increment_button->text("+");
-            _increment_button->click_handler(
-              [button_action](const SDL_MouseButtonEvent&) {
-                  button_action([](const T a, const T b) { return a + b; });
-              });
-
-            _decrement_button->text("-");
-
-            _decrement_button->click_handler(
-              [button_action](const SDL_MouseButtonEvent&) {
-                  button_action([](const T a, const T b) { return a - b; });
-              });
-        }
-
-        void handle_event(const SDL_Event& ev) override
-        {
-            InputImpl<T>::handle_event(ev);
-            _increment_button->handle_event(ev);
-            _decrement_button->handle_event(ev);
-        }
-
-        [[nodiscard]] auto is_valid_input(const std::string_view input) const noexcept
-          -> bool override
-        {
-            bool valid = [input, this]() {
-                // Allow 0-9 chars.
-                if (input[0] >= '0' && input[0] <= '9') return true;
-                // Allow one point for float types.
-                if constexpr (std::is_floating_point_v<T>)
-                    if (input[0] == '.'
-                        && Self::input_text().find('.') == std::string::npos)
-                        return true;
-                // Allow "-" as first input char for signed types.
-                if constexpr (std::is_signed_v<T>) {
-                    std::string_view displayed_value = Self::input_text();
-                    if (input[0] == '-' && displayed_value.empty()) return true;
-                }
-                return false;
-            }();
-            return valid;
-        }
-
-        [[nodiscard]] auto process_value(const T x) const noexcept -> T override
-        {
-            // If value is out of allowed range return either min or max allowed
-            // value.
-            T value = [x, this]() {
-                if (x < _value_range.first) return _value_range.first;
-                if (x > _value_range.second) return _value_range.second;
-                return x;
-            }();
-
-            return value;
-        }
-
-        [[nodiscard]] auto size() const noexcept -> Size override
-        {
-            const auto base       = InputImpl<T>::size();
-            const auto btns_width = 4 * _increment_button->size().w;
-            return {base.w + btns_width, base.h};
-        }
-
-        [[nodiscard]] auto value_range() const noexcept
-          -> const std::pair<T, T>& override
-        {
-            return _value_range;
-        }
-
-        void value_range(const T min, const T max) override
-        {
-            if (min > max) throw std::invalid_argument("min cannot be greater than max");
-            _value_range = {min, max};
-            Self::value  = process_value(Self::value);
-            Self::input_text(Self::value_to_string(Self::value));
-        }
-
-    protected:
-        std::unique_ptr<Button> _increment_button;
-        SDL_Rect                _increment_button_area {};
-        std::unique_ptr<Button> _decrement_button;
-        SDL_Rect                _decrement_button_area {};
-        std::pair<T, T>         _value_range {std::numeric_limits<T>::lowest(),
-                                      std::numeric_limits<T>::max()};
-
-        void _handle_font_change(const std::shared_ptr<Font>& f) override
-        {
-            _decrement_button->font(f);
-            _increment_button->font(f);
-            InputImpl<T>::_handle_font_change(f);
-        }
-
-        void _handle_font_color_change(const Color fg, const Color bg) override
-        {
-            InputImpl<T>::_handle_font_color_change(fg, bg);
-            _decrement_button->font_color_bg(bg);
-            _decrement_button->font_color_fg(fg);
-            _increment_button->font_color_bg(bg);
-            _increment_button->font_color_fg(fg);
-        }
-
-        void _handle_geometry_change(const SDL_Rect& vp) override
-        {
-            InputImpl<T>::_handle_geometry_change(vp);
-
-            const int widest_button     = _increment_button->size().w != 0
-                                          ? _increment_button->size().w
-                                          : _decrement_button->size().w;
-            const int button_area_width = 2 * widest_button;
-            const int spacing           = center_line(button_area_width, widest_button);
-            const int field_width       = vp.w - 2 * button_area_width;
-
-            Self::_widget_area.x = Self::_widget_area.x + button_area_width;
-            Self::_widget_area.w = field_width;
-
-            Self::_input_caption->viewport(rect_offset(
-              rect_margin(Self::_widget_area, {Self::border_width, Self::border_width}),
-              vp));
-            _decrement_button_area = {spacing, Self::_widget_area.y,
-                                      _decrement_button->size().w,
-                                      _decrement_button->size().h};
-
-            _increment_button_area = {vp.w - spacing - _increment_button->size().w,
-                                      Self::_widget_area.y, _increment_button->size().w,
-                                      _increment_button->size().h};
-
-            _increment_button->viewport(rect_offset(_increment_button_area, vp));
-            _decrement_button->viewport(rect_offset(_decrement_button_area, vp));
-        }
-
-        void _handle_renderer_change(const std::shared_ptr<Renderer>& r) override
-        {
-            InputImpl<T>::_handle_renderer_change(r);
-            _decrement_button->renderer(r);
-            _increment_button->renderer(r);
-        }
-
-        void _handle_rendering() override
-        {
-            InputImpl<T>::_handle_rendering();
-            _increment_button->render();
-            _decrement_button->render();
-        }
-    };
-}
-
-#endif

inc/basic_widgets/w/widget_factory.hpp

@@ -1,19 +0,0 @@
-#ifndef BWIDGETS_WIDGET_FACTORY_HPP
-#define BWIDGETS_WIDGET_FACTORY_HPP
-
-#include <basic_widgets/w/aligned_layout.hpp>
-#include <basic_widgets/w/button.hpp>
-#include <basic_widgets/w/caption.hpp>
-#include <basic_widgets/w/numeric_input.hpp>
-
-namespace bwidgets
-{
-    auto create_button(Widget* p = nullptr) -> std::unique_ptr<Button>;
-    auto create_caption(Widget* p = nullptr) -> std::unique_ptr<Caption>;
-    auto create_horizontal_layout(Widget* p = nullptr) -> std::unique_ptr<AlignedLayout>;
-    auto create_input_float(Widget* p = nullptr) -> std::unique_ptr<NumericInput<float>>;
-    auto create_input_int(Widget* p = nullptr) -> std::unique_ptr<NumericInput<int>>;
-    auto create_vertical_layout(Widget* p = nullptr) -> std::unique_ptr<AlignedLayout>;
-}
-
-#endif

meson.build

@@ -1,15 +1,15 @@
 project('sdl2_basic_widgets', 'cpp',
-    version : '0.9.0',
+    version : '0.1pre',
     default_options : [
-        'b_lundef=false',
-        'b_sanitize=undefined',
+        # 'b_lundef=false',
+        # 'b_sanitize=address,undefined',
         'cpp_std=c++20',
         'optimization=g',
         'warning_level=3',
     ],
     license: 'EUPL-1.2')
 
-add_project_arguments('-Wconversion', '-pedantic', language: 'cpp')
+add_project_arguments('-pedantic', language: 'cpp')
 
 if (get_option('buildtype').startswith('debug'))
     add_project_arguments('-DBWIDGETS_DEBUG', language: 'cpp')
@@ -28,14 +28,13 @@ libbasic_widgets = static_library('basic_widgets',
     'src/core/font.cpp',
     'src/core/renderer.cpp',
     'src/core/texture.cpp',
-    'src/w/base/layout_impl.cpp',
-    'src/w/base/widget_impl.cpp',
-    'src/w/button_impl.cpp',
-    'src/w/caption_impl.cpp',
+    'src/w/base/layout.cpp',
+    'src/w/base/widget.cpp',
+    'src/w/button.cpp',
+    'src/w/caption.cpp',
     'src/w/feat/event_handler_impl.cpp',
     'src/w/feat/keyboard_handler_impl.cpp',
     'src/w/feat/mouse_handler_impl.cpp',
-    'src/w/widget_factory.cpp',
     dependencies : [sdl, fontconfig],
     include_directories : pub_api,
     install : true)

src/core/draw.cpp

@@ -2,7 +2,7 @@
 #include <cmath>
 #include <vector>
 
-#include <SDL_render.h>
+#include <SDL2/SDL_render.h>
 
 #include <basic_widgets/core/draw.hpp>
 #include <basic_widgets/core/math.hpp>
@@ -10,24 +10,22 @@
 
 namespace bwidgets
 {
-    auto aa(const Color base_color, const int aa_pixels, const float d) noexcept -> Color
+    auto aa(Color base_color, const int aa_pixels, const float d) noexcept -> Color
     {
-        Color c = [aa_pixels, base_color, d]() -> Color {
-            const auto [r, g, b, a] = base_color();
-            // AA disabled, returns fully opaque or fully transparent colors
-            if (aa_pixels == 0) {
-                if (d > 0) return {r, g, b, 0};
-                return {r, g, b, a};
-            }
+        Color c(base_color);
+        if (aa_pixels == 0) {
+            if (d > 0) c().a = 0;
+        }
+        else {
             const auto factor = 1.0 - smoothstep<float>(d, (float)-aa_pixels, 0.);
-            return {r, g, b, (uint8_t)((float)base_color().a * factor)};
-        }();
+            c().a             = (uint8_t)((float)c().a * factor);
+        }
 
         return c;
     }
 
-    auto filled_circle(const Color c, const int resolution, const Renderer& r,
-                       const int aa_pixels) -> std::shared_ptr<Texture>
+    auto filled_circle(Color c, const int resolution, Renderer* r, const int aa_pixels)
+      -> std::shared_ptr<Texture>
     {
         // clang-format off
         auto           texture {std::make_shared<Texture>(
@@ -42,11 +40,11 @@ namespace bwidgets
 
         set_pixels_color(texture.get(),
                          [aa_pixels, c, center, radius](
-                           SDL_Point p, const SDL_PixelFormat& format) -> uint32_t {
+                           SDL_Point p, const SDL_PixelFormat* format) -> uint32_t {
                              const auto d_delta  = distance(center, p) - (float)radius;
                              const auto aa_color = aa(c, aa_pixels, d_delta);
 
-                             return SDL_MapRGBA(&format, aa_color().r, aa_color().g,
+                             return SDL_MapRGBA(format, aa_color().r, aa_color().g,
                                                 aa_color().b, aa_color().a);
                          });
         texture->blend_mode(SDL_BLENDMODE_BLEND);
@@ -56,21 +54,19 @@ namespace bwidgets
     }
 
     void set_pixels_color(
-      Texture&                                                          t,
-      const std::function<uint32_t(SDL_Point, const SDL_PixelFormat&)>& pixel_color)
+      Texture* t, std::function<uint32_t(SDL_Point, const SDL_PixelFormat*)> pixel_color)
     {
-        auto attr  = t.attributes();
+        auto attr  = t->attributes();
         auto pitch = attr.w * attr.format->BytesPerPixel;
 
         std::vector<uint32_t> pixels;
         pixels.reserve(attr.h * (std::vector<uint32_t>::size_type)pitch);
-        // TODO parallel algo
         for (auto y = 0; y < attr.h; y++) {
             for (auto x = 0; x < attr.w; x++) {
-                pixels.emplace_back(pixel_color({x, y}, *attr.format));
+                pixels.emplace_back(pixel_color({x, y}, attr.format));
             }
         }
 
-        t.update(nullptr, (const void*)pixels.data(), pitch);
+        t->update(nullptr, (const void*)pixels.data(), pitch);
     }
 }

src/core/font.cpp

@@ -1,13 +1,12 @@
 #include <functional>
-#include <memory>
 #include <stack>
-#include <stdexcept>
 
 #include <fontconfig/fontconfig.h>
 
 #include <basic_widgets/core/error_helper.hpp>
 #include <basic_widgets/core/font.hpp>
 #include <basic_widgets/core/type/fc_error.hpp>
+#include <basic_widgets/core/type/sdl_error.hpp>
 
 using namespace bwidgets;
 
@@ -15,7 +14,7 @@ const Color Font::default_color_bg {255, 255, 255, SDL_ALPHA_OPAQUE};
 const Color Font::default_color_fg {0, 0, 0, SDL_ALPHA_OPAQUE};
 
 Font::Font(TTF_Font* f)
-  : _data {ptr_or_throw<SDLError>(f)},
+  : Wrapper {ptr_or_throw<SDLError>(f), [f](TTF_Font*) noexcept { TTF_CloseFont(f); }},
     ascent {TTF_FontAscent(f)},
     descent {TTF_FontDescent(f)},
     faces {TTF_FontFaces(f)},
@@ -26,120 +25,134 @@ Font::Font(TTF_Font* f)
     style_name {TTF_FontFaceStyleName(f)}
 {}
 
-Font::Font(const std::string_view file, const int size)
-  : Font {TTF_OpenFont(file.data(), size)}
+Font::Font(const std::string& file, int size) : Font {TTF_OpenFont(file.c_str(), size)}
 {}
 
 auto Font::hinting() const noexcept -> Font::Hinting
 {
-    return static_cast<Hinting>(TTF_GetFontHinting(_data.get()));
+    return (Hinting)TTF_GetFontHinting(_data());
 }
 
 auto Font::hinting(const Font::Hinting h) noexcept -> Font*
 {
-    TTF_SetFontHinting(_data.get(), static_cast<int>(h));
+    TTF_SetFontHinting(_data(), (int)h);
     return this;
 }
 
 auto Font::kerning() const noexcept -> bool
 {
-    return TTF_GetFontKerning(_data.get()) != 0;
+    return TTF_GetFontKerning(_data()) != 0;
 }
 
 auto Font::kerning(const bool allowed) noexcept -> Font*
 {
-    TTF_SetFontKerning(_data.get(), static_cast<int>(allowed));
+    TTF_SetFontKerning(_data(), static_cast<int>(allowed));
     return this;
 }
 
 auto Font::outline() const noexcept -> int
 {
-    return TTF_GetFontOutline(_data.get());
+    return TTF_GetFontOutline(_data());
 }
 
 auto Font::outline(const int size) noexcept -> Font*
 {
-    TTF_SetFontOutline(_data.get(), size);
+    TTF_SetFontOutline(_data(), size);
     return this;
 }
 
-auto Font::render(const RenderMode m, const std::string_view str, const Color fg,
-                  const Color bg) -> std::unique_ptr<SDL_Surface, Deleter>
+auto Font::render(const RenderMode m, const std::string& str, Color fg, Color bg)
+  -> SDL_Surface*
 {
-    const char* const c_str = str.empty() ? " " : str.data();
-    auto renderer = [bg, c_str, fg, m, this]() -> std::function<SDL_Surface*()> {
-        switch (m) {
-            case RenderMode::BLENDED:
-                return [fg, c_str, this]() {
-                    return TTF_RenderUTF8_Blended(_data.get(), c_str, fg());
-                };
-            case RenderMode::SHADED:
-                return [bg, fg, c_str, this]() {
-                    return TTF_RenderUTF8_Shaded(_data.get(), c_str, fg(), bg());
-                };
-            case RenderMode::SOLID:
-                return [fg, c_str, this]() {
-                    return TTF_RenderUTF8_Solid(_data.get(), c_str, fg());
-                };
-            default:
-                throw std::logic_error("missing switch case.");
-        }
-    }();
+    std::function<SDL_Surface*()> renderer;
+    const char*                   c_str = str.empty() ? " " : str.c_str();
 
-    return std::unique_ptr<SDL_Surface, Deleter>(ptr_or_throw<SDLError>(renderer()));
+    switch (m) {
+        case RenderMode::BLENDED:
+            renderer = [&fg, c_str, this]() {
+                return TTF_RenderUTF8_Blended(_data(), c_str, fg());
+            };
+            break;
+        case RenderMode::SHADED:
+            renderer = [&bg, &fg, c_str, this]() {
+                return TTF_RenderUTF8_Shaded(_data(), c_str, fg(), bg());
+            };
+            break;
+        case RenderMode::SOLID:
+            renderer = [&fg, c_str, this]() {
+                return TTF_RenderUTF8_Solid(_data(), c_str, fg());
+            };
+            break;
+    }
+
+    return ptr_or_throw<SDLError>(renderer());
 }
 
 auto Font::style() const noexcept -> uint8_t
 {
-    return TTF_GetFontStyle(_data.get());
+    return TTF_GetFontStyle(_data());
 }
 
 auto Font::style(const uint8_t s) noexcept -> Font*
 {
-    TTF_SetFontStyle(_data.get(), s);
+    TTF_SetFontStyle(_data(), s);
     return this;
 }
 
-auto Font::text_size(const std::string_view str) const noexcept -> Size
+auto Font::text_size(const std::string& str) const noexcept -> Size
 {
     Size s {};
-    TTF_SizeUTF8(_data.get(), str.data(), &s.w, &s.h);
+    TTF_SizeUTF8(_data(), str.c_str(), &s.w, &s.h);
     return s;
 }
 
-auto Font::find(const std::string_view pat) -> std::string
+auto Font::find(const std::string& pat) -> std::string
 {
-    const auto conf = std::unique_ptr<FcConfig, Deleter>(
-      ptr_or_throw<FCError>(FcInitLoadConfigAndFonts(), "fontconfig init failed."));
+    std::stack<std::function<void()>> cleaners;
 
-    const auto pattern = [&conf, pat]() {
-        auto pattern = std::unique_ptr<FcPattern, Deleter>(ptr_or_throw<FCError>(
-          FcNameParse(reinterpret_cast<const FcChar8*>(pat.data())),
-          "pattern parsing failed"));
+    FcConfig* conf = ptr_or_throw<FCError>(FcInitLoadConfigAndFonts(), "init failed");
+    cleaners.emplace([conf]() { FcConfigDestroy(conf); });
 
-        success_or_throw<FCError, FcBool>(
-          FcConfigSubstitute(conf.get(), pattern.get(), FcMatchPattern),
-          "FcConfigSubstitute failed", [](auto code) { return code == FcTrue; });
-        return pattern;
-    }();
+    FcPattern* pattern = nullptr;
+    try {
+        pattern = ptr_or_throw<FCError>(FcNameParse((FcChar8*)pat.c_str()),
+                                        "pattern parsing failed");
+        cleaners.emplace([pattern]() { FcPatternDestroy(pattern); });
 
-    FcDefaultSubstitute(pattern.get());
-
-    std::string file_path = [&conf, &pattern]() {
-        FcResult   res {};
-        const auto font = std::unique_ptr<FcPattern, Deleter>(ptr_or_throw<FCError>(
-          FcFontMatch(conf.get(), pattern.get(), &res), "no font found."));
-
-        if (FcChar8* file = nullptr;
-            FcPatternGetString(font.get(), FC_FILE, 0, &file) == FcResultMatch)
-        {
-            // "I know what I'm doing"
-            // NOLINTNEXTLINE
-            std::string _file_path {reinterpret_cast<char*>(file)};
-            return _file_path;
+        // Don't check for error because it looks like it returns an error code when used
+        // as the actual code is. But neverless things doesn't work well without calling
+        // it.
+        /* success_or_throw<FCError, FcBool>( */
+        FcConfigSubstitute(conf, pattern,
+                           FcMatchPattern); //, "FcConfigSubstitute failed",
+        /* [](auto code) { return code == FcFalse; }); */
+    } catch (const FCError& e) {
+        while (!cleaners.empty()) {
+            cleaners.top()();
+            cleaners.pop();
         }
-        throw FCError("no font found.");
-    }();
+        throw e;
+    }
+
+    FcDefaultSubstitute(pattern);
+
+    std::string file_path;
+    FcResult    res {};
+    FcPattern*  font = FcFontMatch(conf, pattern, &res);
+    if (font != nullptr) {
+        FcChar8* file = nullptr;
+        if (FcPatternGetString(font, FC_FILE, 0, &file) == FcResultMatch) {
+            file_path = (char*)file;
+        }
+        FcPatternDestroy(font);
+    }
+
+    while (!cleaners.empty()) {
+        cleaners.top()();
+        cleaners.pop();
+    }
+
+    if (file_path.empty()) throw FCError {"no font found"};
 
     return file_path;
 }

src/core/renderer.cpp

@@ -3,39 +3,42 @@
 
 using namespace bwidgets;
 
-Renderer::Renderer(SDL_Renderer* r) : _data {ptr_or_throw<SDLError>(r)}, info {_info(r)}
+Renderer::Renderer(SDL_Renderer* r)
+  : Wrapper {ptr_or_throw<SDLError>(r),
+             [r](SDL_Renderer*) noexcept { SDL_DestroyRenderer(r); }},
+    info {_info(r)}
 {}
 
 Renderer::Renderer(SDL_Window* w, const int index, const uint32_t flags = 0)
-  : Renderer {SDL_CreateRenderer(w, index, flags)}
+  : Renderer {ptr_or_throw<SDLError>(SDL_CreateRenderer(w, index, flags))}
 {}
 
 auto Renderer::blend_mode() -> SDL_BlendMode
 {
     SDL_BlendMode mode {};
-    success_or_throw<SDLError>(SDL_GetRenderDrawBlendMode(_data.get(), &mode));
+    success_or_throw<SDLError>(SDL_GetRenderDrawBlendMode(_data(), &mode));
 
     return mode;
 }
 
 auto Renderer::blend_mode(const SDL_BlendMode mode) -> Renderer*
 {
-    success_or_throw<SDLError>(SDL_SetRenderDrawBlendMode(_data.get(), mode));
+    success_or_throw<SDLError>(SDL_SetRenderDrawBlendMode(_data(), mode));
 
     return this;
 }
 
 auto Renderer::clear() -> Renderer*
 {
-    success_or_throw<SDLError>(SDL_RenderClear(_data.get()));
+    success_or_throw<SDLError>(SDL_RenderClear(_data()));
 
     return this;
 }
 
-auto Renderer::copy(const Texture& t, const SDL_Rect* const src,
-                    const SDL_Rect* const dst) -> Renderer*
+auto Renderer::copy(const Texture* t, const SDL_Rect* src, const SDL_Rect* dst)
+  -> Renderer*
 {
-    success_or_throw<SDLError>(SDL_RenderCopy(_data.get(), t._data.get(), src, dst));
+    success_or_throw<SDLError>(SDL_RenderCopy(_data(), t->_data(), src, dst));
 
     return this;
 }
@@ -44,50 +47,50 @@ auto Renderer::draw_color() -> Color
 {
     Color c;
     success_or_throw<SDLError>(
-      SDL_GetRenderDrawColor(_data.get(), &c().r, &c().g, &c().b, &c().a));
+      SDL_GetRenderDrawColor(_data(), &c().r, &c().g, &c().b, &c().a));
 
     return c;
 }
 
-auto Renderer::draw_color(const Color c) -> Renderer*
+auto Renderer::draw_color(Color c) -> Renderer*
 {
     success_or_throw<SDLError>(
-      SDL_SetRenderDrawColor(_data.get(), c().r, c().g, c().b, c().a));
+      SDL_SetRenderDrawColor(_data(), c().r, c().g, c().b, c().a));
 
     return this;
 }
 
-auto Renderer::draw_line(const SDL_Point a, const SDL_Point b) -> Renderer*
+auto Renderer::draw_line(SDL_Point a, SDL_Point b) -> Renderer*
 {
-    success_or_throw<SDLError>(SDL_RenderDrawLine(_data.get(), a.x, a.y, b.x, b.y));
+    success_or_throw<SDLError>(SDL_RenderDrawLine(_data(), a.x, a.y, b.x, b.y));
 
     return this;
 }
 
-auto Renderer::draw_lines(const std::span<SDL_Point> pts) -> Renderer*
+auto Renderer::draw_lines(std::span<SDL_Point> pts) -> Renderer*
 {
     success_or_throw<SDLError>(
-      SDL_RenderDrawLines(_data.get(), pts.data(), (int)pts.size()));
+      SDL_RenderDrawLines(_data(), pts.data(), (int)pts.size()));
 
     return this;
 }
 
-auto Renderer::draw_point(const SDL_Point p) -> Renderer*
+auto Renderer::draw_point(SDL_Point p) -> Renderer*
 {
-    success_or_throw<SDLError>(SDL_RenderDrawPoint(_data.get(), p.x, p.y));
+    success_or_throw<SDLError>(SDL_RenderDrawPoint(_data(), p.x, p.y));
 
     return this;
 }
 
-auto Renderer::draw_points(const std::span<SDL_Point> pts) -> Renderer*
+auto Renderer::draw_points(std::span<SDL_Point> pts) -> Renderer*
 {
     success_or_throw<SDLError>(
-      SDL_RenderDrawPoints(_data.get(), pts.data(), (int)pts.size()));
+      SDL_RenderDrawPoints(_data(), pts.data(), (int)pts.size()));
 
     return this;
 }
 
-auto Renderer::draw_rect(const SDL_Rect* const r) -> Renderer*
+auto Renderer::draw_rect(const SDL_Rect* r) -> Renderer*
 {
     auto vp = viewport();
     // Has glitch at top-left and bottom-right corner.
@@ -95,35 +98,33 @@ auto Renderer::draw_rect(const SDL_Rect* const r) -> Renderer*
     // The second corner is missing a pixel.
     if (r != nullptr)
         viewport({vp.x + r->x, vp.y + r->y, r->w - 1, r->h - 1}); // crop extra pixel
-    success_or_throw<SDLError>(SDL_RenderDrawRect(_data.get(), nullptr));
+    success_or_throw<SDLError>(SDL_RenderDrawRect(_data(), nullptr));
     // add missing pixel. works sometimes…
     if (r != nullptr) draw_point({r->w - 1, r->h - 1});
     else draw_point({vp.w - 1, vp.h - 1});
 
-    viewport(&vp);
+    viewport(vp);
 
     return this;
 }
 
-auto Renderer::draw_rects(const std::span<SDL_Rect> rs) -> Renderer*
+auto Renderer::draw_rects(std::span<SDL_Rect> rs) -> Renderer*
 {
-    success_or_throw<SDLError>(
-      SDL_RenderDrawRects(_data.get(), rs.data(), (int)rs.size()));
+    success_or_throw<SDLError>(SDL_RenderDrawRects(_data(), rs.data(), (int)rs.size()));
 
     return this;
 }
 
-auto Renderer::fill_rect(const SDL_Rect* const r) -> Renderer*
+auto Renderer::fill_rect(const SDL_Rect* r) -> Renderer*
 {
-    success_or_throw<SDLError>(SDL_RenderFillRect(_data.get(), r));
+    success_or_throw<SDLError>(SDL_RenderFillRect(_data(), r));
 
     return this;
 }
 
-auto Renderer::fill_rects(const std::span<SDL_Rect> rs) -> Renderer*
+auto Renderer::fill_rects(std::span<SDL_Rect> rs) -> Renderer*
 {
-    success_or_throw<SDLError>(
-      SDL_RenderFillRects(_data.get(), rs.data(), (int)rs.size()));
+    success_or_throw<SDLError>(SDL_RenderFillRects(_data(), rs.data(), (int)rs.size()));
 
     return this;
 }
@@ -131,27 +132,27 @@ auto Renderer::fill_rects(const std::span<SDL_Rect> rs) -> Renderer*
 auto Renderer::output_size() -> Size
 {
     Size s {};
-    success_or_throw<SDLError>(SDL_GetRendererOutputSize(_data.get(), &s.w, &s.h));
+    success_or_throw<SDLError>(SDL_GetRendererOutputSize(_data(), &s.w, &s.h));
 
     return s;
 }
 
 void Renderer::present() noexcept
 {
-    SDL_RenderPresent(_data.get());
+    SDL_RenderPresent(_data());
 }
 
 auto Renderer::viewport() noexcept -> SDL_Rect
 {
     SDL_Rect vp;
-    SDL_RenderGetViewport(_data.get(), &vp);
+    SDL_RenderGetViewport(_data(), &vp);
 
     return vp;
 }
 
-auto Renderer::viewport(const SDL_Rect* const vp) -> Renderer*
+auto Renderer::viewport(const SDL_Rect* vp) -> Renderer*
 {
-    success_or_throw<SDLError>(SDL_RenderSetViewport(_data.get(), vp));
+    success_or_throw<SDLError>(SDL_RenderSetViewport(_data(), vp));
 
     return this;
 }

src/core/texture.cpp

@@ -4,17 +4,22 @@
 using namespace bwidgets;
 
 Texture::Texture(SDL_Texture* t)
-  : _attributes(attributes(t)), _data {ptr_or_throw<SDLError>(t)}
+  : Wrapper {ptr_or_throw<SDLError>(t),
+             [t](SDL_Texture*) noexcept { SDL_DestroyTexture(t); }}
+{
+    _attributes = attributes(t);
+}
+
+Texture::Texture(Renderer* r, const SDL_PixelFormatEnum f, const SDL_TextureAccess a,
+                 int w, int h)
+  : Texture {SDL_CreateTexture(r->_data(), f, a, w, h)}
 {}
 
-Texture::Texture(const Renderer& r, const SDL_PixelFormatEnum f,
-                 const SDL_TextureAccess a, int w, int h)
-  : Texture {SDL_CreateTexture(r._data.get(), f, a, w, h)}
-{}
-
-Texture::Texture(const Renderer& r, SDL_Surface* const s)
-  : Texture {SDL_CreateTextureFromSurface(r._data.get(), s)}
-{}
+Texture::Texture(Renderer* r, SDL_Surface* s)
+  : Texture {SDL_CreateTextureFromSurface(r->_data(), s)}
+{
+    _attributes = attributes(_data());
+}
 
 Texture::~Texture() noexcept
 {
@@ -25,14 +30,14 @@ Texture::~Texture() noexcept
 auto Texture::alpha_mode() -> uint8_t
 {
     uint8_t mode = 0;
-    success_or_throw<SDLError>(SDL_GetTextureAlphaMod(_data.get(), &mode));
+    success_or_throw<SDLError>(SDL_GetTextureAlphaMod(_data(), &mode));
 
     return mode;
 }
 
 auto Texture::alpha_mode(const uint8_t m) -> Texture*
 {
-    success_or_throw<SDLError>(SDL_SetTextureAlphaMod(_data.get(), m));
+    success_or_throw<SDLError>(SDL_SetTextureAlphaMod(_data(), m));
 
     return this;
 }
@@ -40,14 +45,14 @@ auto Texture::alpha_mode(const uint8_t m) -> Texture*
 auto Texture::blend_mode() -> SDL_BlendMode
 {
     SDL_BlendMode mode {};
-    success_or_throw<SDLError>(SDL_GetTextureBlendMode(_data.get(), &mode));
+    success_or_throw<SDLError>(SDL_GetTextureBlendMode(_data(), &mode));
 
     return mode;
 }
 
 auto Texture::blend_mode(const SDL_BlendMode m) -> Texture*
 {
-    success_or_throw<SDLError>(SDL_SetTextureBlendMode(_data.get(), m));
+    success_or_throw<SDLError>(SDL_SetTextureBlendMode(_data(), m));
 
     return this;
 }
@@ -56,14 +61,14 @@ auto Texture::color_mode() -> Color
 {
     Color mode;
     success_or_throw<SDLError>(
-      SDL_GetTextureColorMod(_data.get(), &mode().r, &mode().g, &mode().b));
+      SDL_GetTextureColorMod(_data(), &mode().r, &mode().g, &mode().b));
 
     return mode;
 }
 
 auto Texture::color_mode(Color m) -> Texture*
 {
-    success_or_throw<SDLError>(SDL_SetTextureColorMod(_data.get(), m().r, m().g, m().b));
+    success_or_throw<SDLError>(SDL_SetTextureColorMod(_data(), m().r, m().g, m().b));
 
     return this;
 }
@@ -71,22 +76,21 @@ auto Texture::color_mode(Color m) -> Texture*
 auto Texture::scale_mode() -> SDL_ScaleMode
 {
     SDL_ScaleMode mode {};
-    success_or_throw<SDLError>(SDL_GetTextureScaleMode(_data.get(), &mode));
+    success_or_throw<SDLError>(SDL_GetTextureScaleMode(_data(), &mode));
 
     return mode;
 }
 
 auto Texture::scale_mode(const SDL_ScaleMode m) -> Texture*
 {
-    success_or_throw<SDLError>(SDL_SetTextureScaleMode(_data.get(), m));
+    success_or_throw<SDLError>(SDL_SetTextureScaleMode(_data(), m));
 
     return this;
 }
 
-auto Texture::update(const SDL_Rect* const r, const void* const pixels, const int pitch)
-  -> Texture*
+auto Texture::update(SDL_Rect* r, const void* pixels, const int pitch) -> Texture*
 {
-    success_or_throw<SDLError>(SDL_UpdateTexture(_data.get(), r, pixels, pitch));
+    success_or_throw<SDLError>(SDL_UpdateTexture(_data(), r, pixels, pitch));
 
     return this;
 }

src/w/base/layout.cpp

@@ -0,0 +1,39 @@
+#include <basic_widgets/w/base/layout.hpp>
+
+using namespace bwidgets;
+
+const Size Layout::default_margins {8, 8};
+
+auto Layout::add_widget(std::unique_ptr<Widget> widget_ptr) -> Layout*
+{
+    widget_ptr->renderer(_renderer);
+    _widgets.emplace_back(std::move(widget_ptr));
+    _update_layout(_viewport);
+    return this;
+}
+
+void Layout::for_widgets(const std::function<void(Widget*)>& f)
+{
+    for (const auto& w : _widgets) f(w.get());
+}
+
+void Layout::handle_event(const SDL_Event& ev)
+{
+    EventHandlerImpl::handle_event(ev);
+    for (const auto& w : _widgets) w->handle_event(ev);
+}
+
+void Layout::_handle_geometry_change(const SDL_Rect& vp)
+{
+    _update_layout(vp);
+}
+
+void Layout::_handle_renderer_change(const std::shared_ptr<Renderer>& r)
+{
+    for (const auto& w : _widgets) w->renderer(r);
+}
+
+void Layout::_handle_rendering()
+{
+    for (const auto& w : _widgets) w->render();
+}

src/w/base/layout_impl.cpp

@@ -1,36 +0,0 @@
-#include <basic_widgets/w/base/layout_impl.hpp>
-
-using namespace bwidgets;
-
-void LayoutImpl::add_widget(std::unique_ptr<Widget> widget_ptr)
-{
-    if (_renderer) widget_ptr->renderer(_renderer);
-    _widgets.emplace_back(std::move(widget_ptr));
-    _update_layout(_viewport);
-}
-
-void LayoutImpl::for_widgets(const std::function<void(Widget*)>& f)
-{
-    for (const auto& w : _widgets) f(w.get());
-}
-
-void LayoutImpl::handle_event(const SDL_Event& ev)
-{
-    EventHandlerImpl::handle_event(ev);
-    for (const auto& w : _widgets) w->handle_event(ev);
-}
-
-void LayoutImpl::_handle_geometry_change(const SDL_Rect& vp)
-{
-    _update_layout(vp);
-}
-
-void LayoutImpl::_handle_renderer_change(const std::shared_ptr<Renderer>& r)
-{
-    for (const auto& w : _widgets) w->renderer(r);
-}
-
-void LayoutImpl::_handle_rendering()
-{
-    for (const auto& w : _widgets) w->render();
-}

src/w/base/widget.cpp

@@ -1,13 +1,12 @@
-#include <basic_widgets/w/base/widget_impl.hpp>
+#include <basic_widgets/w/base/widget.hpp>
 
 using namespace bwidgets;
 
-void WidgetImpl::render()
+auto Widget::render() -> Widget*
 {
-    if (!_renderer) return;
+    if (_renderer == nullptr) return this;
 
 #ifdef BWIDGETS_DEBUG
-    // Render a debug outline of widget viewport.
     _renderer
       ->draw_color({
   // NOLINTNEXTLINE(readability-magic-numbers)
@@ -16,25 +15,29 @@ void WidgetImpl::render()
       ->draw_rect(nullptr);
 #endif
 
-    _renderer->viewport(&_viewport);
+    _renderer->viewport(_viewport);
     _handle_rendering();
+
+    return this;
 }
 
-void WidgetImpl::renderer(std::shared_ptr<Renderer> r)
+auto Widget::renderer(std::shared_ptr<Renderer> r) -> Widget*
 {
     if (r != _renderer) {
         _handle_renderer_change(r);
-        _renderer = std::move(r);
+        _renderer = r;
     }
+    return this;
 }
 
-void WidgetImpl::viewport(const SDL_Rect& vp)
+auto Widget::viewport(const SDL_Rect& vp) -> Widget*
 {
     _handle_geometry_change(vp);
     _viewport = vp;
+    return this;
 }
 
-auto WidgetImpl::viewport() const -> const SDL_Rect&
+auto Widget::viewport() const -> const SDL_Rect&
 {
     return _viewport;
 }

src/w/button.cpp

@@ -0,0 +1,105 @@
+#include <cmath>
+
+#include <SDL2/SDL_render.h>
+
+#include <basic_widgets/core/math.hpp>
+#include <basic_widgets/w/button.hpp>
+
+using namespace bwidgets;
+
+const Color Button::default_color_bg {150, 150, 150, SDL_ALPHA_OPAQUE};
+const Color Button::default_color_bg_hover {175, 175, 175, SDL_ALPHA_OPAQUE};
+const Color Button::default_color_fg {0, 0, 0, SDL_ALPHA_OPAQUE};
+
+Button::Button(Widget* parent) noexcept : Widget {parent}, _caption {this}
+{
+    enable_mouse_handler(&_widget_area, &_viewport);
+    _caption.alignment = Caption::Alignment::CENTER;
+
+    _caption.render_mode(Font::RenderMode::BLENDED);
+
+    border_gradient = [this](int len, int pos, float divider) -> Color {
+        const auto& end_color   = hovered() ? color_bg_hover : color_bg;
+        const auto  start_color = end_color / divider;
+        const auto  factor      = linear(pos, 0, len);
+        return lerp(start_color, end_color, factor);
+    };
+}
+
+auto Button::size() const noexcept -> Size
+{
+    return _caption.size() + border_size * 2;
+}
+
+auto Button::text() const noexcept -> const std::string&
+{
+    return _caption.text();
+}
+
+auto Button::text(const std::string& txt) -> Button*
+{
+    _caption.text(txt);
+    _handle_geometry_change(_viewport);
+    return this;
+}
+
+void Button::_handle_font_change(const std::shared_ptr<Font>& f)
+{
+    _caption.font(f);
+    _handle_geometry_change(_viewport);
+}
+
+void Button::_handle_font_color_change(Color fg, Color)
+{
+    _caption.font_color_fg(fg);
+}
+
+void Button::_handle_geometry_change(const SDL_Rect& vp)
+{
+    const auto h = _caption.size().h + 2 * border_size.h;
+
+    _widget_area = {0, center_line(vp.h, _caption.size().h) - border_size.h, vp.w, h};
+
+    const auto txt_size = _caption.size();
+
+    _caption_area = {center_line(vp.w, txt_size.w), center_line(vp.h, txt_size.h),
+                     txt_size.w, txt_size.h};
+    _caption.viewport(rect_offset(_caption_area, vp));
+}
+
+void Button::_handle_renderer_change(const std::shared_ptr<Renderer>& r)
+{
+    _caption.renderer(r);
+}
+
+void Button::_handle_rendering()
+{
+    Color      c       = hovered() ? color_bg_hover : color_bg;
+    const auto divider = pushed() ? 1.5 : 2;
+    auto       x       = 0;
+    auto       y       = 0;
+    const auto biggest = border_size.w > border_size.h ? border_size.w : border_size.h;
+    while (x < border_size.w || y < border_size.h) {
+        const auto max    = x > y ? x : y;
+        const auto margin = Size({x, y});
+        _renderer->draw_color(border_gradient(biggest, max, divider))
+          ->draw_rect(rect_margin(_widget_area, margin));
+        if (x < border_size.w) x++;
+        if (y < border_size.h) y++;
+    }
+
+    _renderer->draw_color(c)->fill_rect(rect_margin(_widget_area, border_size));
+    _caption.font_color_bg(c);
+    _caption.render();
+}
+
+void Button::_on_push(bool state)
+{
+    SDL_Point offset {_viewport.x, _viewport.y};
+    if (state) {
+        offset.x += 1;
+        offset.y += 1;
+    }
+
+    _caption.viewport(rect_offset(_caption_area, offset));
+}

src/w/button_impl.cpp

@@ -1,102 +0,0 @@
-#include <cmath>
-
-#include <basic_widgets/core/math.hpp>
-#include <basic_widgets/w/button_impl.hpp>
-#include <basic_widgets/w/widget_factory.hpp>
-
-using namespace bwidgets;
-
-ButtonImpl::ButtonImpl(Widget* parent) noexcept
-  : WidgetImpl {parent}, _caption {create_caption(this)}
-{
-    enable_mouse_handler(_widget_area, _viewport);
-
-    _caption->alignment = Caption::Alignment::CENTER;
-    _caption->render_mode(Font::RenderMode::BLENDED);
-
-    border_gradient = [this](const int len, const int pos,
-                             const float divider) -> Color {
-        const auto& end_color = hovered() ? color_bg_hover : color_bg;
-        return lerp(end_color / divider, end_color, linear(pos, 0, len));
-    };
-}
-
-auto ButtonImpl::size() const noexcept -> Size
-{
-    return _caption->size() + border_size * 2;
-}
-
-auto ButtonImpl::text() const noexcept -> std::string_view
-{
-    return _caption->text();
-}
-
-void ButtonImpl::text(std::string txt)
-{
-    _caption->text(std::move(txt));
-    _handle_geometry_change(_viewport);
-}
-
-void ButtonImpl::_handle_font_change(const std::shared_ptr<Font>& f)
-{
-    _caption->font(f);
-    _handle_geometry_change(_viewport);
-}
-
-void ButtonImpl::_handle_font_color_change(const Color fg, Color)
-{
-    _caption->font_color_fg(fg);
-}
-
-void ButtonImpl::_handle_geometry_change(const SDL_Rect& vp)
-{
-    const auto h = _caption->size().h + 2 * border_size.h;
-    _widget_area = {0, center_line(vp.h, _caption->size().h) - border_size.h, vp.w, h};
-
-    const auto txt_size = _caption->size();
-    _caption_area       = {center_line(vp.w, txt_size.w), center_line(vp.h, txt_size.h),
-                     txt_size.w, txt_size.h};
-
-    _caption->viewport(rect_offset(_caption_area, vp));
-}
-
-void ButtonImpl::_handle_renderer_change(const std::shared_ptr<Renderer>& r)
-{
-    _caption->renderer(r);
-}
-
-void ButtonImpl::_handle_rendering()
-{
-    const Color& c       = hovered() ? color_bg_hover : color_bg;
-    const auto   divider = pushed() ? 1.5F : 2.F;
-    auto         x       = 0;
-    auto         y       = 0;
-    const auto   biggest_dimension =
-      border_size.w > border_size.h ? border_size.w : border_size.h;
-    const auto& max_xy = border_size.w > border_size.h ? x : y;
-
-    // Render button borders.
-    while (x < border_size.w || y < border_size.h) {
-        _renderer->draw_color(border_gradient(biggest_dimension, max_xy, divider))
-          ->draw_rect(rect_margin(_widget_area, {x, y}));
-        if (x < border_size.w) x++;
-        if (y < border_size.h) y++;
-    }
-
-    _renderer->draw_color(c)->fill_rect(rect_margin(_widget_area, border_size));
-    _caption->font_color_bg(c);
-    _caption->render();
-}
-
-void ButtonImpl::_on_push(const bool state)
-{
-    // Move slightly the caption position to give a push effect.
-    const auto offset = [state, this]() -> SDL_Point {
-        if (state) {
-            return {_viewport.x + 1, _viewport.y + 1};
-        }
-        return {_viewport.x, _viewport.y};
-    }();
-
-    _caption->viewport(rect_offset(_caption_area, offset));
-}

src/w/caption.cpp

@@ -0,0 +1,116 @@
+#include <SDL2/SDL_assert.h>
+
+#include <basic_widgets/core/math.hpp>
+#include <basic_widgets/core/texture.hpp>
+#include <basic_widgets/w/caption.hpp>
+#include <basic_widgets/w/numeric_input.hpp>
+
+using namespace bwidgets;
+
+Caption::Caption(Widget* parent) noexcept : Widget {parent}
+{
+    _font_color_bg = default_font_color_bg;
+    _font_color_fg = default_font_color_fg;
+}
+
+auto Caption::render_mode(Font::RenderMode m) -> Caption*
+{
+    if (m != _render_mode) {
+        _text_texture.reset();
+        _render_mode = m;
+    }
+    return this;
+}
+
+auto Caption::size() const noexcept -> Size
+{
+    if (_font == nullptr) return {0, 0};
+
+    const Size size = _font->text_size(_text);
+
+    return {size.w + 2 * margins.w, size.h + 2 * margins.h};
+}
+
+auto Caption::text() const noexcept -> const std::string&
+{
+    return _text;
+}
+
+auto Caption::text(const std::string& t) -> Caption*
+{
+    if (t != _text) {
+        _text_texture.reset();
+        _text = t;
+    }
+    return this;
+}
+
+void Caption::_handle_font_change(const std::shared_ptr<Font>&)
+{
+    _text_texture.reset();
+}
+
+void Caption::_handle_font_color_change(Color fg, Color bg)
+{
+    if (fg != _font_color_fg
+        || (bg != _font_color_bg && _font_render_mode == Font::RenderMode::SHADED))
+    {
+        _text_texture.reset();
+        _font_color_bg = bg;
+    }
+}
+
+void Caption::_handle_geometry_change(const SDL_Rect& vp)
+{
+    if (vp.w != _viewport.w || vp.h != _viewport.h) {
+        _widget_area = rect_margin({0, 0, vp.w, vp.h}, margins);
+    }
+}
+
+void Caption::_handle_renderer_change(const std::shared_ptr<Renderer>&)
+{
+    _text_texture.reset();
+}
+
+void Caption::_handle_rendering()
+{
+    if (_text_texture == nullptr) _handle_texture_update();
+
+    if (_render_mode == Font::RenderMode::SHADED) {
+        _renderer->draw_color(_font_color_bg)
+          ->fill_rect({0, 0, _viewport.w, _viewport.h});
+    }
+
+    const Size size_dst {
+      (int)((float)_text_texture->attributes().w / (float)_text_texture->attributes().h
+            * (float)_widget_area.h),
+      _widget_area.h};
+    SDL_Rect texture_dst {margins.w, margins.h, size_dst.w, size_dst.h};
+    switch (alignment) {
+        case Alignment::CENTER:
+            texture_dst.x = center_line(_widget_area.w, texture_dst.w) + _widget_area.x;
+            break;
+        case Alignment::LEFT:
+            break;
+        case Alignment::RIGHT:
+            texture_dst.x = _widget_area.w - texture_dst.w - margins.w + _widget_area.x;
+            break;
+    }
+    _renderer->copy(_text_texture.get(), nullptr, texture_dst);
+}
+
+void Caption::_handle_texture_update()
+{
+    SDL_assert_release(_font != nullptr && _text_texture == nullptr); // NOLINT
+    SDL_Surface* s {nullptr};
+    switch (_render_mode) {
+        case Font::RenderMode::SHADED:
+            s = _font->render(_render_mode, _text, _font_color_fg, _font_color_bg);
+            break;
+        default:
+            s = _font->render(_render_mode, _text, _font_color_fg);
+            break;
+    }
+    _text_texture = std::make_shared<Texture>(_renderer.get(), s);
+    SDL_FreeSurface(s);
+}

src/w/caption_impl.cpp

@@ -1,124 +0,0 @@
-#include <basic_widgets/core/math.hpp>
-#include <basic_widgets/core/texture.hpp>
-#include <basic_widgets/w/caption_impl.hpp>
-#include <basic_widgets/w/numeric_input.hpp>
-
-using namespace bwidgets;
-
-CaptionImpl::CaptionImpl(Widget* parent) noexcept : WidgetImpl {parent}
-{
-    _font_color_bg = default_font_color_bg;
-    _font_color_fg = default_font_color_fg;
-}
-
-void CaptionImpl::render_mode(const Font::RenderMode m)
-{
-    if (m != _render_mode) {
-        _text_texture.reset();
-        _render_mode = m;
-    }
-}
-
-auto CaptionImpl::size() const noexcept -> Size
-{
-    if (!_font) return {0, 0};
-
-    const auto [w, h] = _font->text_size(_text);
-    return {w + 2 * margins.w, h + 2 * margins.h};
-}
-
-auto CaptionImpl::text() const noexcept -> std::string_view
-{
-    return _text;
-}
-
-void CaptionImpl::text(std::string t)
-{
-    if (t != _text) {
-        _text_texture.reset();
-        _text = std::move(t);
-    }
-}
-
-void CaptionImpl::_handle_font_change(const std::shared_ptr<Font>&)
-{
-    _text_texture.reset();
-}
-
-void CaptionImpl::_handle_font_color_change(const Color fg, const Color bg)
-{
-    if (fg != _font_color_fg) {
-        _text_texture.reset();
-        _font_color_fg = fg;
-    }
-    if (bg != _font_color_bg && _font_render_mode == Font::RenderMode::SHADED) {
-        _text_texture.reset();
-        _font_color_bg = fg;
-    }
-}
-
-void CaptionImpl::_handle_geometry_change(const SDL_Rect& vp)
-{
-    if (vp.w != _viewport.w) {
-        _widget_area = rect_margin({0, 0, vp.w, vp.h}, margins);
-    }
-    else if (vp.h != _viewport.h) {
-        _widget_area = rect_margin({0, 0, vp.w, vp.h}, margins);
-        _text_texture.reset();
-    }
-}
-
-void CaptionImpl::_handle_renderer_change(const std::shared_ptr<Renderer>&)
-{
-    _text_texture.reset();
-}
-
-void CaptionImpl::_handle_rendering()
-{
-    if (!_text_texture) _handle_texture_update();
-
-    // fill caption viewport with background color when using
-    // shaded text rendering mode.
-    if (_render_mode == Font::RenderMode::SHADED) {
-        _renderer->draw_color(_font_color_bg)
-          ->fill_rect({0, 0, _viewport.w, _viewport.h});
-    }
-
-    const Size size_dst {
-      (int)((float)_text_texture->attributes().w / (float)_text_texture->attributes().h
-            * (float)_widget_area.h),
-      _widget_area.h};
-
-    const auto texture_dst = [size_dst, this]() -> SDL_Rect {
-        switch (alignment) {
-            case Alignment::CENTER:
-                return {center_line(_widget_area.w, size_dst.w) + _widget_area.x,
-                        margins.h, size_dst.w, size_dst.h};
-            case Alignment::LEFT:
-                return {margins.w, margins.h, size_dst.w, size_dst.h};
-            case Alignment::RIGHT:
-                return {_widget_area.w - size_dst.w - margins.w + _widget_area.x,
-                        margins.h, size_dst.w, size_dst.h};
-            default:
-                throw std::logic_error("missing switch case.");
-        }
-    }();
-    _renderer->copy(*_text_texture, nullptr, texture_dst);
-}
-
-void CaptionImpl::_handle_texture_update()
-{
-    if (!_font) return;
-    _text_texture.reset();
-
-    auto s = [this]() {
-        switch (_render_mode) {
-            case Font::RenderMode::SHADED:
-                return _font->render(_render_mode, _text, _font_color_fg,
-                                     _font_color_bg);
-            default:
-                return _font->render(_render_mode, _text, _font_color_fg);
-        }
-    }();
-    _text_texture = std::make_shared<Texture>(*_renderer, s.get());
-}

src/w/feat/event_handler_impl.cpp

@@ -14,11 +14,11 @@ auto EventHandlerImpl::_add_event_handler(handler_t event_handler) -> bool
 {
     if (_event_handlers.contains(event_handler.first)) return false;
 
-    _event_handlers.emplace(std::move(event_handler));
+    _event_handlers.emplace(event_handler);
     return true;
 }
 
-auto EventHandlerImpl::_remove_event_handler(const SDL_EventType ev_type)
+auto EventHandlerImpl::_remove_event_handler(SDL_EventType ev_type)
   -> std::pair<handler_t, bool>
 {
     handler_t handler;

src/w/feat/keyboard_handler_impl.cpp

@@ -12,12 +12,12 @@ void KeyboardHandlerImpl::disable_keyboard_handler()
 void KeyboardHandlerImpl::enable_keyboard_handler()
 {
     const auto keyboard_handler = [this](const SDL_Event& ev) {
-        if (focus()) _key_handler(ev.key);
+        if (FocusHandlerImpl::focus()) _key_handler(ev.key);
     };
 
     _add_event_handler({SDL_KEYDOWN, keyboard_handler});
     _add_event_handler({SDL_KEYUP, keyboard_handler});
     _add_event_handler({SDL_TEXTINPUT, [this](const SDL_Event& ev) {
-                            if (focus()) _input_handler(ev.text);
+                            if (FocusHandlerImpl::focus()) _input_handler(ev.text);
                         }});
 }

src/w/feat/mouse_handler_impl.cpp

@@ -5,44 +5,46 @@ using namespace bwidgets;
 
 void MouseHandlerImpl::disable_mouse_handler()
 {
-    _remove_event_handler(SDL_MOUSEBUTTONDOWN);
-    _remove_event_handler(SDL_MOUSEBUTTONUP);
+    EventHandlerImpl::_remove_event_handler(SDL_MOUSEBUTTONDOWN);
+    EventHandlerImpl::_remove_event_handler(SDL_MOUSEBUTTONUP);
     _remove_event_handler(SDL_MOUSEMOTION);
 }
 
 // NOLINTNEXTLINE(readability-function-cognitive-complexity)
-void MouseHandlerImpl::enable_mouse_handler(const SDL_Rect& rel_area,
-                                            const SDL_Rect& origin)
+void MouseHandlerImpl::enable_mouse_handler(const SDL_Rect* area, const SDL_Rect* vp)
 {
-    const auto mouse_in_rect = [&rel_area, &origin](const SDL_Point p) {
-        const auto area = rect_offset(rel_area, origin);
-        return SDL_PointInRect(&p, &area) == SDL_TRUE;
-    };
+    if (!area || !vp) throw std::logic_error("ptr parameters cannot be null.");
 
-    _add_event_handler({SDL_MOUSEBUTTONDOWN, [this, mouse_in_rect](const SDL_Event& ev) {
-                            if (!mouse_in_rect({ev.button.x, ev.button.y})) {
-                                focus(false);
+    _add_event_handler({SDL_MOUSEBUTTONDOWN, [this, area, vp](const SDL_Event& ev) {
+                            auto      absolute_area = rect_offset(*area, *vp);
+                            SDL_Point p             = {ev.button.x, ev.button.y};
+                            if (SDL_PointInRect(&p, &absolute_area) == SDL_FALSE) {
+                                FocusHandlerImpl::focus(false);
                                 return;
                             }
-                            _on_push(_pushed = true);
+                            _on_push(true);
+                            _pushed = true;
                         }});
-    _add_event_handler({SDL_MOUSEBUTTONUP, [this, mouse_in_rect](const SDL_Event& ev) {
+    _add_event_handler({SDL_MOUSEBUTTONUP, [this, area, vp](const SDL_Event& ev) {
+                            auto      absolute_area = rect_offset(*area, *vp);
+                            SDL_Point p             = {ev.button.x, ev.button.y};
                             if (_pushed) {
-                                _on_push(_pushed = false);
-                                // Only execute handler and give focus if mouse button
-                                // has been pushed and released over the widget.
-                                if (mouse_in_rect({ev.button.x, ev.button.y})) {
-                                    focus(true);
-                                    _click_handler(ev.button);
-                                }
+                                _on_push(false);
+                                _pushed = false;
                             }
+                            if (SDL_PointInRect(&p, &absolute_area) == SDL_FALSE) return;
+
+                            FocusHandlerImpl::focus(true);
+                            _click_handler(ev.button);
                         }});
-    _add_event_handler({SDL_MOUSEMOTION, [this, mouse_in_rect](const SDL_Event& ev) {
-                            if (!mouse_in_rect({ev.motion.x, ev.motion.y})) {
-                                if (_hovered) _hover_handler(_hovered = false);
+    _add_event_handler({SDL_MOUSEMOTION, [this, area, vp](const SDL_Event& ev) {
+                            auto      absolute_area = rect_offset(*area, *vp);
+                            SDL_Point p             = {ev.motion.x, ev.motion.y};
+                            if (SDL_PointInRect(&p, &absolute_area) == SDL_FALSE) {
+                                _hovered = false;
                                 return;
                             }
-                            if (!_hovered) _hover_handler(_hovered = true);
+                            _hovered = true;
                             _motion_handler(ev.motion);
                         }});
 }

src/w/widget_factory.cpp

@@ -1,37 +0,0 @@
-#include <basic_widgets/w/aligned_layout_impl.hpp>
-#include <basic_widgets/w/button_impl.hpp>
-#include <basic_widgets/w/caption_impl.hpp>
-#include <basic_widgets/w/numeric_input_impl.hpp>
-#include <basic_widgets/w/widget_factory.hpp>
-
-auto bwidgets::create_horizontal_layout(Widget* parent) -> std::unique_ptr<AlignedLayout>
-{
-    return std::unique_ptr<AlignedLayout>(
-      new AlignedLayoutImpl<LayoutAlignment::HORIZONTAL>(parent));
-}
-
-auto bwidgets::create_vertical_layout(Widget* parent) -> std::unique_ptr<AlignedLayout>
-{
-    return std::unique_ptr<AlignedLayout>(
-      new AlignedLayoutImpl<LayoutAlignment::VERTICAL>(parent));
-}
-
-auto bwidgets::create_button(Widget* parent) -> std::unique_ptr<Button>
-{
-    return std::unique_ptr<Button>(new ButtonImpl(parent));
-}
-
-auto bwidgets::create_caption(Widget* parent) -> std::unique_ptr<Caption>
-{
-    return std::unique_ptr<Caption>(new CaptionImpl(parent));
-}
-
-auto bwidgets::create_input_float(Widget* parent) -> std::unique_ptr<NumericInput<float>>
-{
-    return std::unique_ptr<NumericInput<float>>(new NumericInputImpl<float>(parent));
-}
-
-auto bwidgets::create_input_int(Widget* parent) -> std::unique_ptr<NumericInput<int>>
-{
-    return std::unique_ptr<NumericInput<int>>(new NumericInputImpl<int>(parent));
-}