half workaround to fix corner glitch in draw_rect and minor changes

examples/button_example.cpp

@@ -13,7 +13,7 @@ int main()
                 std::cout << "button(" << x << ',' << y << "):click!" << std::endl;
             };
             w->font(f);
-            w->text("¡jello!");
+            w->text("+");
             });
     return 0;
 }

examples/example_example.cpp

@@ -0,0 +1,11 @@
+#include "example_widget.hpp"
+#include "run.hpp"
+
+int main()
+{
+    run_example<Example>([](Example* w, core::Font*, int x, int y) {
+            w->cycle_r = (x + 1) * 3000;
+            w->cycle_b = (y + 1) * 3000;
+            w->cycle_b = (1 + x + y) * (y + 1) * 400;
+            });
+}

examples/example_widget.hpp

@@ -0,0 +1,55 @@
+#ifndef BWIDGET_EXAMPLES_EXAMPLE_WIDGET_
+#define BWIDGET_EXAMPLES_EXAMPLE_WIDGET_
+
+#include <SDL2/SDL_timer.h>
+
+#include <basic_widgets/core/math.hpp>
+#include <basic_widgets/core/renderer.hpp>
+#include <basic_widgets/w/base/widget.hpp>
+
+using bwidgets::core::rect_margin;
+using bwidgets::core::Renderer;
+using bwidgets::core::Size;
+using bwidgets::widget::Widget;
+
+class Example final : public Widget
+{
+private:
+    virtual void _handle_geometry_change(const SDL_Rect& vp) noexcept override
+    {
+        _widget_area = {2, 2, vp.w - 4, vp.h - 4};
+    }
+
+    virtual void _handle_rendering() override
+    {
+        auto now = SDL_GetTicks();
+        uint8_t r = 255 * (now % cycle_r / (float)cycle_r);
+        uint8_t g = 255 * (now % cycle_g / (float)cycle_g);
+        uint8_t b = 255 * (now % cycle_b / (float)cycle_b);
+        SDL_Color base_color {r, g, b, 255};
+
+        int border = 10;
+        for (auto i = 0; i < border; i+=3)
+        {
+            uint8_t alpha = 255 * i / border;
+            _renderer->draw_color({base_color.r, base_color.g, base_color.b, alpha})
+                ->draw_rect(rect_margin(_widget_area, {i, i}));
+        }
+
+        _renderer->draw_color(base_color)
+            ->draw_rect(nullptr)
+            ->fill_rect(rect_margin(_widget_area, {border*2, border*2}));
+    }
+
+public:
+    unsigned int cycle_r {3500};
+    unsigned int cycle_g {3500};
+    unsigned int cycle_b {3500};
+
+    virtual Size size() const noexcept
+    {
+        return {128, 64};
+    }
+};
+
+#endif

examples/run.hpp

@@ -36,6 +36,7 @@ void run_example(std::function<void (W*, core::Font*, int, int)> setup, int w=3,
                 size_init.w, size_init.h,
                 SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE | SDL_WINDOW_UTILITY)};
         auto* renderer {new core::Renderer(win, -1, SDL_RENDERER_ACCELERATED)};
+        renderer->blend_mode(SDL_BLENDMODE_BLEND);
 
         auto* layout   {new widget::HorizontalLayout()};
 

inc/basic_widgets/w/base/widget.hpp

@@ -39,6 +39,9 @@ namespace bwidgets::widget
                 return this;
             }
 
+            virtual inline const SDL_Rect& viewport() const noexcept final {
+                return _viewport;
+            }
             virtual inline Widget* viewport(const SDL_Rect& vp) noexcept final {
                 _handle_geometry_change(vp);
                 _viewport = vp;

inc/basic_widgets/w/caption.hpp

@@ -21,7 +21,7 @@ namespace bwidgets::widget
                 RIGHT
             };
 
-        private:
+        protected:
             SDL_Color      _color_fg     {0, 0, 0, SDL_ALPHA_OPAQUE};
             SDL_Color      _color_bg     {255, 255, 255, SDL_ALPHA_TRANSPARENT};
             core::Font::RenderMode _render_mode {core::Font::RenderMode::SHADED};

meson.build

@@ -7,7 +7,7 @@ project('sdl2_basic_widgets', 'cpp',
         'optimization=g'],
     license: 'EUPL-1.2')
 
-add_project_arguments('-Winline', '-pedantic', language: 'cpp')
+add_project_arguments('-pedantic', language: 'cpp')
 
 sdl = [
     dependency('sdl2', version: '>=2.0.5'),
@@ -52,6 +52,12 @@ executable('caption_demo',
     link_with : libbasic_widgets,
     install : false)
 
+executable('example_demo',
+    'examples/example_example.cpp',
+    include_directories : pub_api,
+    link_with : libbasic_widgets,
+    install : false)
+
 executable('input_demo',
     'examples/input_example.cpp',
     include_directories : pub_api,

src/core/renderer.cpp

@@ -111,9 +111,22 @@ core::Renderer* core::Renderer::draw_points(const std::vector<SDL_Point> pts)
 
 core::Renderer* core::Renderer::draw_rect(const SDL_Rect* r)
 {
-    SDLError::success_or_throw(SDL_RenderDrawRect(c_pod, r),
+    auto vp = viewport();
+    // Has glitch at top-left and bottom-right corner.
+    // The first corner has an extra pixel at y-1 and surimpression.
+    // The second corner is missing a pixel.
+    if (r)
+        viewport({vp.x + r->x, vp.y + r->y, r->w - 1, r->h - 1}); // crop extra pixel
+    SDLError::success_or_throw(SDL_RenderDrawRect(c_pod, nullptr),
             __FILE__, __FUNCTION__, __LINE__);
 
+    if (r)
+        draw_point({r->w - 1, r->h - 1}); // add missing pixel
+    else
+        draw_point({vp.w - 1, vp.h - 1});
+
+    viewport(vp);
+
     return this;
 }
 

src/w/base/widget.cpp

@@ -48,7 +48,7 @@ widget::Widget* widget::Widget::render()
     if (!_renderer)
         return this;
 
-#ifndef _NDEBUG
+#ifdef _NDEBUG
     _renderer->draw_color({0, 255, 0, SDL_ALPHA_TRANSPARENT})
         ->draw_rect(nullptr);
 #endif

src/w/button.cpp

@@ -118,7 +118,8 @@ void widget::Button::_handle_rendering()
                     color_shade(c.g, max, biggest),
                     color_shade(c.b, max, biggest),
                     c.a
-                    })->draw_rect(core::rect_margin(_widget_area, margin));
+                    })
+            ->draw_rect(core::rect_margin(_widget_area, margin));
             if (x < border_size.w)
                 x++;
             if (y < border_size.h)

src/w/caption.cpp

@@ -88,7 +88,11 @@ void widget::Caption::_handle_renderer_change(core::Renderer*)
 
 void widget::Caption::_handle_rendering()
 {
-    _renderer->draw_color(_color_bg)->fill_rect({0, 0, _viewport.w, _viewport.h});
+    if (!_text_texture)
+        _handle_texture_update();
+
+    if (_render_mode == core::Font::RenderMode::SHADED)
+        _renderer->draw_color(_color_bg)->fill_rect({0, 0, _viewport.w, _viewport.h});
 
     if (!_text_texture)
         _handle_texture_update();