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

src/tools/font.cpp

@@ -62,11 +62,16 @@ void Font::setup_font_character() {
     m_text_texture->set_clamp_to_edge(false, true, true);
 }
 
-std::vector<Vertex2D> Font::vertices(const std::string& text) {
+TextMesh Font::vertices(const std::string& text) {
     static Font font;
 
     std::vector<Vertex2D> vertices;
 
+    float min_x = std::numeric_limits<float>::max();
+    float min_y = std::numeric_limits<float>::max();
+    float max_x = std::numeric_limits<float>::lowest();
+    float max_y = std::numeric_limits<float>::lowest();
+
     float pen_x = 0.0f;
     float pen_y = 0.0f;
 
@@ -85,6 +90,12 @@ std::vector<Vertex2D> Font::vertices(const std::string& text) {
         float w = ch.size.x;
         float h = ch.size.y;
 
+        min_x = std::min(min_x, xpos);
+        min_y = std::min(min_y, ypos);
+
+        max_x = std::max(max_x, xpos + w);
+        max_y = std::max(max_y, ypos + h);
+
         vertices.emplace_back(xpos, ypos + h, ch.uv_min.x, ch.uv_max.y,
                               static_cast<float>(c));
         vertices.emplace_back(xpos, ypos, ch.uv_min.x, ch.uv_min.y,
@@ -101,8 +112,13 @@ std::vector<Vertex2D> Font::vertices(const std::string& text) {
 
         pen_x += (ch.advance >> 6);
     }
+    // Top-left anchor point
+    for (auto& v : vertices) {
+        v.x -= min_x;
+        v.y -= min_y;
+    }
 
-    return vertices;
+    return {std::move(vertices), max_x - min_x, max_y - min_y, 0, 0};
 }
 
 const Texture* Font::text_texture() { return m_text_texture.get(); }

src/ui/button.cpp

@@ -51,8 +51,8 @@ Widget& Button::set_position(const glm::vec2& pos) {
     m_foreground->set_position(pos);
     m_min_pos = pos;
 
-    m_max_pos.x = m_min_pos.x + m_background->width() * m_scale;
-    m_max_pos.y = m_min_pos.y + m_background->height() * m_scale;
+    m_max_pos.x = m_min_pos.x + width();
+    m_max_pos.y = m_min_pos.y + height();
 
     return *this;
 }
@@ -62,11 +62,11 @@ Widget& Button::set_position(float x, float y) {
 Widget& Button::set_scale(float scale) {
     m_scale = scale;
     m_background->set_scale(scale);
-    m_max_pos.x = m_min_pos.x + m_background->width() * m_scale;
-    m_max_pos.y = m_min_pos.y + m_background->height() * m_scale;
+    m_max_pos.x = m_min_pos.x + width();
+    m_max_pos.y = m_min_pos.y + height();
     return *this;
 }
-float Button::width() const { return m_background->width(); }
-float Button::height() const { return m_background->height(); }
+float Button::width() const { return m_background->width() * m_scale; }
+float Button::height() const { return m_background->height() * m_scale; }
 
 } // namespace Cubed

src/ui/label.cpp

@@ -7,7 +7,7 @@ Label::Label(const std::string& id) : Widget(id) {}
 Label::Label() {}
 Label& Label::set_text(std::string_view text) {
     m_text.text = text;
-    m_dirty = true;
+    update_vertices();
     return *this;
 }
 
@@ -18,25 +18,30 @@ Label& Label::set_color(Color color) {
 
 void Label::update(float dt) { on_update(dt); }
 
-void Label::on_update(float dt) {
-    (void)dt;
-    if (m_dirty) {
-        update_vertices();
-        m_dirty = false;
-    }
-}
+void Label::on_update(float dt) { (void)dt; }
 
 void Label::render(Renderer& renderer) { on_render(renderer); }
 
 void Label::on_render(Renderer& renderer) { renderer.render_lable(*this); }
 
 void Label::update_vertices() {
-    m_data.m_vertices = Font::vertices(m_text.text);
+    auto textmesh = Font::vertices(m_text.text);
+    m_data.m_vertices = std::move(textmesh.vertices);
+
+    m_offset_x = textmesh.min_x;
+    m_offset_y = textmesh.min_y;
+    m_width = textmesh.width;
+    m_height = textmesh.height;
+
     m_data.update_sum();
     m_data.upload();
 }
 
 const UIVertexData& Label::data() const { return m_data; }
 const TextStyle& Label::text_style() const { return m_text; }
+float Label::width() const { return m_width; }
+float Label::height() const { return m_height; }
+float Label::offset_x() const { return m_offset_x; }
+float Label::offset_y() const { return m_offset_y; }
 
 } // namespace Cubed