refactor(font): return TextMesh from Font::vertices to include bounding box

Replace the plain vertex vector with a TextMesh struct that carries width, height, and min coordinates. Update Label to compute and store these values immediately on text change (removing lazy dirty update). Fix Button's width/height to factor in scale and use concrete widget types for background and foreground.

include/Cubed/tools/font.hpp

@@ -22,6 +22,16 @@ struct Character {
     GLuint advance;
 };
 
+struct TextMesh {
+    std::vector<Vertex2D> vertices;
+
+    float width;
+    float height;
+
+    float min_x;
+    float min_y;
+};
+
 class Shader;
 
 class Font {
@@ -29,7 +39,7 @@ public:
     Font();
     ~Font();
 
-    static std::vector<Vertex2D> vertices(const std::string& text);
+    static TextMesh vertices(const std::string& text);
     static const Texture* text_texture();
     static const std::string& font_path();
 

include/Cubed/ui/button.hpp

@@ -1,5 +1,7 @@
 #pragma once
 
+#include "Cubed/ui/image.hpp"
+#include "Cubed/ui/label.hpp"
 #include "Cubed/ui/widget.hpp"
 
 #include <functional>
@@ -47,8 +49,8 @@ public:
 
 private:
     std::function<void()> m_clicked;
-    std::unique_ptr<Widget> m_background;
-    std::unique_ptr<Widget> m_foreground;
+    std::unique_ptr<Image> m_background;
+    std::unique_ptr<Label> m_foreground;
     bool m_hovered = false;
     glm::vec2 m_min_pos;
     glm::vec2 m_max_pos;

include/Cubed/ui/label.hpp

@@ -24,6 +24,11 @@ public:
 
     const TextStyle& text_style() const;
 
+    float width() const override;
+    float height() const override;
+    float offset_x() const;
+    float offset_y() const;
+
 protected:
     virtual void on_update(float dt) override;
     virtual void on_render(Renderer& renderer) override;
@@ -31,7 +36,10 @@ protected:
 private:
     TextStyle m_text;
     UIVertexData m_data;
-    bool m_dirty = false;
+    float m_width = 0.0f;
+    float m_height = 0.0f;
+    float m_offset_x = 0.0f;
+    float m_offset_y = 0.0f;
     void update_vertices();
 };
 } // namespace Cubed