From 3f15d1d857c28531309fe214cd5c2ee1e46d6761 Mon Sep 17 00:00:00 2001
From: Andrea Blankenstijn <a.b@kaze.ch>
Date: Wed, 26 Jan 2022 22:49:41 +0100
Subject: [PATCH] scrollable (texture) area works

---
 examples/button_example.cpp            |  2 +-
 examples/caption_example.cpp           |  2 +-
 examples/example_example.cpp           |  2 +-
 examples/input_example.cpp             |  2 +-
 examples/run.hpp                       | 11 ++++---
 examples/scrollable_area_example.cpp   |  6 +++-
 examples/scrollbar_example.cpp         | 14 ++++++--
 inc/basic_widgets/w/scrollbar.hpp      | 12 ++++---
 inc/basic_widgets/w/scrollbar_impl.hpp | 23 +++++++------
 src/w/scrollable_area_impl.cpp         | 25 ++++++++++++++
 src/w/scrollbar_impl.cpp               | 45 ++++++++++++++++----------
 11 files changed, 99 insertions(+), 45 deletions(-)

diff --git a/examples/button_example.cpp b/examples/button_example.cpp
index 56f70e9..0a23c86 100644
--- a/examples/button_example.cpp
+++ b/examples/button_example.cpp
@@ -8,7 +8,7 @@ auto main() -> int
 {
     run_example<bwidgets::Button>(
       []() { return bwidgets::create_button(); },
-      [](auto w, auto f, auto x, auto y) {
+      [](auto w, auto f, auto x, auto y, auto) {
           w->click_handler([x, y](const SDL_MouseButtonEvent&) {
               std::cout << "button(" << x << ',' << y << "):click!" << std::endl;
           });
diff --git a/examples/caption_example.cpp b/examples/caption_example.cpp
index 1842afb..7033f39 100644
--- a/examples/caption_example.cpp
+++ b/examples/caption_example.cpp
@@ -5,7 +5,7 @@
 auto main() -> int
 {
     run_example<bwidgets::Caption>([]() { return bwidgets::create_caption(); },
-                                   [](auto w, auto f, auto, auto) {
+                                   [](auto w, auto f, auto, auto, auto) {
                                        w->alignment(
                                          bwidgets::Caption::Alignment::CENTER);
                                        w->text("¡jello!");
diff --git a/examples/example_example.cpp b/examples/example_example.cpp
index 28f54e0..e82bbcb 100644
--- a/examples/example_example.cpp
+++ b/examples/example_example.cpp
@@ -5,7 +5,7 @@ auto main() -> int
 {
     run_example<Example>(
       []() { return std::make_unique<Example>(); },
-      [](auto w, auto, auto x, auto y) {
+      [](auto w, auto, auto x, auto y, auto) {
           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)
diff --git a/examples/input_example.cpp b/examples/input_example.cpp
index 594bd54..07f0a3b 100644
--- a/examples/input_example.cpp
+++ b/examples/input_example.cpp
@@ -6,7 +6,7 @@ auto main() -> int
 {
     run_example<bwidgets::NumericInput<float>>(
       []() { return bwidgets::create_input_float(); },
-      [](auto w, auto f, auto, auto) {
+      [](auto w, auto f, auto, 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)
diff --git a/examples/run.hpp b/examples/run.hpp
index 810401f..f89d32a 100644
--- a/examples/run.hpp
+++ b/examples/run.hpp
@@ -11,10 +11,11 @@ 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)
+void run_example(std::function<std::unique_ptr<W>()> factory,
+                 std::function<void(W*, const std::shared_ptr<bwidgets::Font>&, int, int,
+                                    const std::shared_ptr<bwidgets::Renderer>)>
+                     setup,
+                 int w = 3, int h = 3)
 {
     std::atexit([]() {
         TTF_Quit();
@@ -43,7 +44,7 @@ void run_example(
             auto col = bwidgets::create_vertical_layout();
             for (auto y = 0; y < h; y++) {
                 auto widget = factory();
-                setup(widget.get(), font, x, y);
+                setup(widget.get(), font, x, y, renderer);
                 col->add_widget(std::move(widget));
             }
             layout->add_widget(std::move(col));
diff --git a/examples/scrollable_area_example.cpp b/examples/scrollable_area_example.cpp
index b58bf6d..19bda1d 100644
--- a/examples/scrollable_area_example.cpp
+++ b/examples/scrollable_area_example.cpp
@@ -1,3 +1,4 @@
+#include <basic_widgets/core/draw.hpp>
 #include <basic_widgets/w/widget_factory.hpp>
 
 #include "run.hpp"
@@ -6,6 +7,9 @@ auto main() -> int
 {
     run_example<bwidgets::ScrollableArea>(
       []() { return bwidgets::create_scrollable_area(); },
-      [](auto w, auto f, auto x, auto y) { w->font(f); });
+      [](auto w, auto f, auto x, auto y, auto r) {
+          w->font(f);
+          w->texture(bwidgets::filled_circle({255, 0, 0, 255}, 300, *r));
+      });
     return 0;
 }
diff --git a/examples/scrollbar_example.cpp b/examples/scrollbar_example.cpp
index 0adb1e4..eacce47 100644
--- a/examples/scrollbar_example.cpp
+++ b/examples/scrollbar_example.cpp
@@ -1,11 +1,19 @@
+#include <iostream>
+
 #include <basic_widgets/w/widget_factory.hpp>
 
 #include "run.hpp"
 
 auto main() -> int
 {
-    run_example<bwidgets::ScrollableArea>(
-      []() { return bwidgets::create_scrollable_area(); },
-      [](auto w, auto f, auto x, auto y) {});
+    run_example<bwidgets::ScrollBar>([]() { return bwidgets::create_scrollbar(); },
+                                     [](auto w, auto f, auto x, auto y, auto) {
+                                         w->font(f);
+                                         w->on_scroll([x, y](const float v) {
+                                             std::cout << "Scroll(" << x << "," << y
+                                                       << "): " << v * 100 << "%"
+                                                       << std::endl;
+                                         });
+                                     });
     return 0;
 }
diff --git a/inc/basic_widgets/w/scrollbar.hpp b/inc/basic_widgets/w/scrollbar.hpp
index ff5b7eb..fb09c72 100644
--- a/inc/basic_widgets/w/scrollbar.hpp
+++ b/inc/basic_widgets/w/scrollbar.hpp
@@ -20,11 +20,13 @@ namespace bwidgets
             VERTICAL
         };
 
-        virtual void               on_scroll(std::function<void(int)>) = 0;
-        [[nodiscard]] virtual auto orientation() const -> Orientation  = 0;
-        virtual void               orientation(Orientation)            = 0;
-        [[nodiscard]] virtual auto value() const -> int                = 0;
-        virtual void               value(int)                          = 0;
+        virtual void               on_scroll(std::function<void(float)>) = 0;
+        [[nodiscard]] virtual auto orientation() const -> Orientation    = 0;
+        virtual void               orientation(Orientation)              = 0;
+        [[nodiscard]] virtual auto step() const -> float                 = 0;
+        virtual void               step(float)                           = 0;
+        [[nodiscard]] virtual auto value() const -> float                = 0;
+        virtual void               value(float)                          = 0;
     };
 }
 
diff --git a/inc/basic_widgets/w/scrollbar_impl.hpp b/inc/basic_widgets/w/scrollbar_impl.hpp
index 9447d66..cf1d8c3 100644
--- a/inc/basic_widgets/w/scrollbar_impl.hpp
+++ b/inc/basic_widgets/w/scrollbar_impl.hpp
@@ -22,22 +22,25 @@ namespace bwidgets
 
         auto               cursor_area() const -> SDL_Rect;
         void               handle_event(const SDL_Event&) override;
-        void               on_scroll(std::function<void(int)>) override;
+        void               on_scroll(std::function<void(float)>) override;
         [[nodiscard]] auto orientation() const -> Orientation override;
         void               orientation(Orientation) override;
         [[nodiscard]] auto size() const noexcept -> Size override;
-        [[nodiscard]] auto value() const -> int override;
-        void               value(int) override;
+        [[nodiscard]] auto step() const -> float override;
+        void               step(float) override;
+        [[nodiscard]] auto value() const -> float override;
+        void               value(float) override;
 
     protected:
-        SDL_Rect                 _bar_area;
-        std::unique_ptr<Button>  _button_minus;
-        std::unique_ptr<Button>  _button_plus;
-        const Size               _cursor_size {16, 16};
+        SDL_Rect                   _bar_area;
+        std::unique_ptr<Button>    _button_minus;
+        std::unique_ptr<Button>    _button_plus;
+        const Size                 _cursor_size {16, 16};
         // TODO: cursor_area
-        std::function<void(int)> _on_scroll;
-        Orientation              _orientation;
-        int                      _value {0};
+        std::function<void(float)> _on_scroll;
+        Orientation                _orientation;
+        float                      _step;
+        float                      _value {0};
 
         void _handle_font_change(const std::shared_ptr<Font>&) override;
         void _handle_font_color_change(Color, Color) override;
diff --git a/src/w/scrollable_area_impl.cpp b/src/w/scrollable_area_impl.cpp
index dc4948c..3c3fee1 100644
--- a/src/w/scrollable_area_impl.cpp
+++ b/src/w/scrollable_area_impl.cpp
@@ -1,6 +1,7 @@
 #include <utility>
 
 #include <basic_widgets/core/draw.hpp>
+#include <basic_widgets/core/math.hpp>
 #include <basic_widgets/w/scrollable_area_impl.hpp>
 #include <basic_widgets/w/widget_factory.hpp>
 
@@ -68,6 +69,30 @@ void ScrollableAreaImpl::_handle_rendering()
 {
     fill_rect_gradient(*renderer(), _texture_area, theme()->color_widget_border(),
                        theme()->color_widget_bg(), theme()->size_widget_border());
+
+    const auto texture_attr = _texture->attributes();
+    const auto copy_dst     = [this, &texture_attr]() {
+        auto dst = rect_margin(
+              _texture_area, {theme()->size_widget_border(), theme()->size_widget_border()});
+        if (dst.w > texture_attr.w) {
+            dst.x += center_line(dst.w, texture_attr.w);
+            dst.w = texture_attr.w;
+        }
+        if (dst.h > texture_attr.h) {
+            dst.y += center_line(dst.h, texture_attr.h);
+            dst.h = texture_attr.h;
+        }
+        return dst;
+    }();
+    renderer()->copy(
+      *_texture,
+      {static_cast<int>(_scrollbar_h->value()
+                        * std::clamp(texture_attr.w - copy_dst.w, 0, texture_attr.w)),
+       static_cast<int>(_scrollbar_v->value()
+                        * std::clamp(texture_attr.h - copy_dst.h, 0, texture_attr.h)),
+       copy_dst.w, copy_dst.h},
+      copy_dst);
+
     _scrollbar_h->render();
     _scrollbar_v->render();
 }
diff --git a/src/w/scrollbar_impl.cpp b/src/w/scrollbar_impl.cpp
index 707e04e..4a5630d 100644
--- a/src/w/scrollbar_impl.cpp
+++ b/src/w/scrollbar_impl.cpp
@@ -30,21 +30,22 @@ ScrollBarImpl::ScrollBarImpl(Widget* parent)
   : WidgetImpl {parent},
     _button_minus {create_button(this)},
     _button_plus {create_button(this)},
-    _orientation {Orientation::VERTICAL}
+    _orientation {Orientation::VERTICAL},
+    _step {.05F}
 {
     _button_minus->text("▲");
     _button_plus->text("▼");
 
-    _button_minus->click_handler([this](auto) { value(value() - 5); });
-    _button_plus->click_handler([this](auto) { value(value() + 5); });
+    _button_minus->click_handler([this](auto) { value(value() - _step); });
+    _button_plus->click_handler([this](auto) { value(value() + _step); });
     click_handler([this](const SDL_MouseButtonEvent ev) {
         SDL_Point p {ev.x - viewport().x - _bar_area.x,
                      ev.y - viewport().y - _bar_area.y};
         if (_orientation == Orientation::VERTICAL) {
-            value(p.y * 100 / _bar_area.h);
+            value(p.y / static_cast<float>(_bar_area.h));
         }
         else {
-            value(p.x * 100 / _bar_area.w);
+            value(p.x / static_cast<float>(_bar_area.w));
         }
     });
     mouse_motion_handler([this](SDL_MouseMotionEvent ev) {
@@ -52,20 +53,20 @@ ScrollBarImpl::ScrollBarImpl(Widget* parent)
         SDL_Point p = {ev.x - viewport().x - _bar_area.x,
                        ev.y - viewport().y - _bar_area.y};
         if (_orientation == Orientation::VERTICAL) {
-            value(clamp(p.y, 0, _bar_area.h) * 100 / _bar_area.h);
+            value(clamp(p.y, 0, _bar_area.h) / static_cast<float>(_bar_area.h));
         }
         else {
-            value(clamp(p.x, 0, _bar_area.w) * 100 / _bar_area.w);
+            value(clamp(p.x, 0, _bar_area.w) / static_cast<float>(_bar_area.w));
         }
     });
     mouse_wheel_handler([this](SDL_MouseWheelEvent ev) {
         if (orientation() == ScrollBar::Orientation::VERTICAL) {
-            if (ev.y < 0) value(value() + 5);
-            else if (ev.y > 0) value(value() - 5);
+            if (ev.y < 0) value(value() + _step);
+            else if (ev.y > 0) value(value() - _step);
         }
         else {
-            if (ev.x > 0) value(value() + 5);
-            else if (ev.x < 0) value(value() - 5);
+            if (ev.x > 0) value(value() + _step);
+            else if (ev.x < 0) value(value() - _step);
         }
     });
     enable_mouse_handler(_bar_area, viewport());
@@ -74,11 +75,11 @@ ScrollBarImpl::ScrollBarImpl(Widget* parent)
 auto ScrollBarImpl::cursor_area() const -> SDL_Rect
 {
     if (_orientation == Orientation::VERTICAL) {
-        const auto offset = value() * _bar_area.h / 100;
+        const auto offset = static_cast<int>(value() * _bar_area.h);
         return {_bar_area.x, _bar_area.y + offset - _cursor_size.h / 2, _bar_area.w,
                 _cursor_size.h};
     }
-    const auto offset = value() * _bar_area.w / 100;
+    const auto offset = static_cast<int>(value() * _bar_area.w);
     return {_bar_area.x + offset - _cursor_size.h / 2, _bar_area.y, _cursor_size.h,
             _bar_area.h};
 }
@@ -90,7 +91,7 @@ void ScrollBarImpl::handle_event(const SDL_Event& ev)
     _button_plus->handle_event(ev);
 }
 
-void ScrollBarImpl::on_scroll(function<void(int)> cb)
+void ScrollBarImpl::on_scroll(function<void(float)> cb)
 {
     _on_scroll = move(cb);
 }
@@ -136,14 +137,24 @@ auto ScrollBarImpl::size() const noexcept -> Size
     return {height, button_size + button_size + 3 * _cursor_size.h};
 }
 
-auto ScrollBarImpl::value() const -> int
+auto ScrollBarImpl::step() const -> float
+{
+    return _step;
+}
+
+void ScrollBarImpl::step(float s)
+{
+    _step = s;
+}
+
+auto ScrollBarImpl::value() const -> float
 {
     return _value;
 }
 
-void ScrollBarImpl::value(const int v)
+void ScrollBarImpl::value(const float v)
 {
-    const auto new_value = clamp(v, 0, 100);
+    const auto new_value = clamp(v, 0.F, 1.F);
     if (new_value != _value) {
         _value = new_value;
         if (_on_scroll) _on_scroll(new_value);