feat(ui): introduce anchor-based widget positioning system

Replace set_position with anchor and offset for relative positioning. Add parent pointer to widget hierarchy. Remove manual resize logic in UI managers.

include/Cubed/debug_collector.hpp

@@ -13,8 +13,9 @@ public:
     DebugCollector();
 
     void report(const std::string& name, std::string_view content);
-    void init_text();
+    void init(int width, int height);
     Widget& get_widget();
+    bool handle_event(const Event& e);
 
 private:
     Widget m_widget;

include/Cubed/ui/anchor.hpp

@@ -0,0 +1,15 @@
+#pragma once
+
+enum class Anchor {
+    TOP_LEFT,
+    TOP_CENTER,
+    TOP_RIGHT,
+
+    CENTER_LEFT,
+    CENTER,
+    CENTER_RIGHT,
+
+    BOTTOM_LEFT,
+    BOTTOM_CENTER,
+    BOTTOM_RIGHT,
+};

include/Cubed/ui/button.hpp

@@ -9,7 +9,7 @@
 namespace Cubed {
 class Button : public Widget {
 public:
-    Button();
+    Button(Widget* parent);
 
     Button(const Button&) = delete;
     Button(Button&&) = delete;
@@ -21,10 +21,11 @@ public:
 
     bool handle_mouse_move_event(const MouseMoveEvent& e) override;
     bool handle_mouse_button_event(const MouseButtonEvent& e) override;
-
-    Widget& set_position(const glm::vec2& pos) override;
-    Widget& set_position(float x, float y) override;
+    void set_window_size(int width, int height) override;
     Button& set_scale(float scale);
+    Widget& set_anchor(Anchor anchor) override;
+    Widget& set_offset(glm::ivec2 offset) override;
+    glm::vec2 pos() const override;
     float width() const override;
     float height() const override;
     float scale() const;
@@ -34,16 +35,17 @@ public:
     }
 
     template <typename T, typename... Args> T& set_background(Args&&... args) {
-        auto w = std::make_unique<T>(std::forward<Args>(args)...);
+        auto w = std::make_unique<T>(std::forward<Args>(args)..., m_parent);
         T& ref = *w;
         m_background = std::move(w);
         return ref;
     }
 
     template <typename T, typename... Args> T& set_foreground(Args&&... args) {
-        auto w = std::make_unique<T>(std::forward<Args>(args)...);
+        auto w = std::make_unique<T>(std::forward<Args>(args)..., this);
         T& ref = *w;
         m_foreground = std::move(w);
+        m_foreground->set_anchor(Anchor::CENTER);
         return ref;
     }
 
@@ -52,7 +54,5 @@ private:
     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;
 };
 } // namespace Cubed

include/Cubed/ui/image.hpp

@@ -8,7 +8,7 @@ namespace Cubed {
 class TextureManager;
 class Image : public Widget {
 public:
-    Image();
+    Image(Widget* parent);
     void update(float dt) override;
     void render(Renderer& renderer) override;
 

include/Cubed/ui/label.hpp

@@ -10,8 +10,8 @@ public:
     Label& operator=(const Label&) = delete;
     Label& operator=(Label&&) = delete;
 
-    Label(const std::string& id);
-    Label();
+    Label(const std::string& id, Widget* parent);
+    Label(Widget* parent);
     virtual ~Label() = default;
 
     Label& set_text(std::string_view text);

include/Cubed/ui/widget.hpp

@@ -1,7 +1,8 @@
 #pragma once
 #include "Cubed/input/event.hpp"
-#include "glm/ext/vector_float2.hpp"
+#include "Cubed/ui/anchor.hpp"
 
+#include <glm/glm.hpp>
 #include <memory>
 #include <vector>
 namespace Cubed {
@@ -10,18 +11,19 @@ class Renderer;
 class Widget {
 
 public:
-    Widget(const std::string& id);
-    Widget() = default;
+    Widget(const std::string& id, Widget* parent);
+    Widget(Widget* parent);
     virtual ~Widget() = default;
     virtual void update(float dt);
     virtual void render(Renderer& renderer);
     virtual const std::string& id() const;
-    virtual Widget& set_position(const glm::vec2& pos);
-    virtual Widget& set_position(float x, float y);
+    virtual Widget& set_anchor(Anchor anchor);
+    virtual Widget& set_offset(glm::ivec2 offset);
+    virtual void set_window_size(int width, int height);
     // Returns the final display size
     virtual float width() const;
     virtual float height() const;
-    virtual const glm::vec2& pos() const;
+    virtual glm::vec2 pos() const;
 
     virtual bool handle_key_event(const KeyEvent& e);
     virtual bool handle_mouse_button_event(const MouseButtonEvent& e);
@@ -39,12 +41,16 @@ public:
 protected:
     virtual void on_update(float dt);
     virtual void on_render(Renderer& renderer);
+    virtual glm::vec2 compute_position() const;
+    Widget* m_parent = nullptr;
     std::string m_id;
+    float m_window_height = 0;
+    float m_window_width = 0;
     // Center is at the top-left corner, position is at the top-left corner
-    glm::vec2 m_pos{0.0f, 0.0f};
+    Anchor m_anchor = Anchor::TOP_LEFT;
+    glm::ivec2 m_offset{0, 0};
 
 private:
-    Widget* m_parent = nullptr;
     std::vector<std::unique_ptr<Widget>> m_children;
 };
 } // namespace Cubed