feat(ui): introduce ColumnLayout widget and refactor widget parenting

- Add ColumnLayout widget that arranges children vertically with spacing.
- Refactor Widget::add_child to automatically pass `this` as parent.
- Update DebugCollector to use ColumnLayout for consistent spacing.
- Expose children() accessor in Widget for layout management.

include/Cubed/debug_collector.hpp

@@ -1,5 +1,6 @@
 #pragma once
 
+#include "Cubed/ui/column_layout.hpp"
 #include "Cubed/ui/label.hpp"
 #include "Cubed/ui/widget.hpp"
 
@@ -18,7 +19,7 @@ public:
     bool handle_event(const Event& e);
 
 private:
-    Widget m_widget;
+    ColumnLayout m_widget;
     std::unordered_map<std::string, Label*> m_component;
 };
 

include/Cubed/ui/column_layout.hpp

@@ -0,0 +1,24 @@
+#pragma once
+#include "Cubed/ui/widget.hpp"
+namespace Cubed {
+class ColumnLayout : public Widget {
+public:
+    ColumnLayout(const ColumnLayout&) = delete;
+    ColumnLayout(ColumnLayout&&) = delete;
+    ColumnLayout& operator=(const ColumnLayout&) = delete;
+    ColumnLayout& operator=(ColumnLayout&&) = delete;
+    ColumnLayout(Widget* parent);
+    ~ColumnLayout();
+
+    void update(float dt) override;
+
+    void set_spacing(int spacing);
+    // No need for parent node pointer; do not modify children's anchors and
+    // scale.
+
+    void layout();
+
+private:
+    int m_spacing = 0;
+};
+} // namespace Cubed

include/Cubed/ui/widget.hpp

@@ -32,16 +32,13 @@ public:
     virtual bool handle_mouse_move_event(const MouseMoveEvent& e);
 
     template <typename T, typename... Args> T& add_child(Args&&... args) {
-        auto widget = std::make_unique<T>(std::forward<Args>(args)...);
+        auto widget = std::make_unique<T>(std::forward<Args>(args)..., this);
         T& ref = *widget;
         m_children.emplace_back(std::move(widget));
         return ref;
     };
 
 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;
@@ -50,6 +47,14 @@ protected:
     Anchor m_anchor = Anchor::TOP_LEFT;
     glm::ivec2 m_offset{0, 0};
 
+    std::vector<std::unique_ptr<Widget>>& children();
+
+    const std::vector<std::unique_ptr<Widget>>& children() const;
+
+    virtual void on_update(float dt);
+    virtual void on_render(Renderer& renderer);
+    virtual glm::vec2 compute_position() const;
+
 private:
     std::vector<std::unique_ptr<Widget>> m_children;
 };

src/CMakeLists.txt

@@ -67,4 +67,5 @@ target_sources(${PROJECT_NAME}
         ui/world_ui_manager.cpp
         ui/main_menu_ui_manager.cpp
         scene/main_menu_scene.cpp
+        ui/column_layout.cpp
 )

src/debug_collector.cpp

@@ -13,61 +13,50 @@ DebugCollector& DebugCollector::get() {
 }
 
 void DebugCollector::init(int width, int height) {
-    constexpr int SPACE = 50;
+    constexpr float SCALE = 0.6f;
-    // version_text
+
     m_widget.set_window_size(width, height);
-    auto& version_text = m_widget.add_child<Label>("version", &m_widget);
+    m_widget.set_spacing(15);
+    m_widget.set_anchor(Anchor::TOP_LEFT);
+    m_widget.set_offset({0, 5});
+
+    // version_text
+    auto& version_text = m_widget.add_child<Label>("version");
     std::string version{"Version: " CUBED_VERSION};
+
 #ifdef DEBUG_MODE
     version.append("-debug");
 #else
     version.append("-release");
 #endif
-    version_text.set_color(Color::WHITE)
+
-        .set_text(version)
+    version_text.set_color(Color::WHITE).set_text(version).set_scale(SCALE);
-        .set_scale(0.8f)
-        .set_anchor(Anchor::TOP_LEFT);
-    version_text.set_offset({0, SPACE});
     m_component.try_emplace(version_text.id(), &version_text);
 
     // fps
-    auto& fps_text = m_widget.add_child<Label>("fps", &version_text);
+    auto& fps_text = m_widget.add_child<Label>("fps");
-    fps_text.set_text("FPS: 0")
+    fps_text.set_text("FPS: 0").set_scale(SCALE);
-        .set_scale(0.8f)
-        .set_anchor(Anchor::TOP_LEFT)
-        .set_offset({0, SPACE});
     m_component.try_emplace(fps_text.id(), &fps_text);
 
     // player_pos
-    auto& player_pos_text = m_widget.add_child<Label>("player_pos", &fps_text);
+    auto& player_pos_text = m_widget.add_child<Label>("player_pos");
-    player_pos_text.set_text("x: 0.00 y: 0.00 z: 0.00")
+    player_pos_text.set_text("x: 0.00 y: 0.00 z: 0.00").set_scale(SCALE);
-        .set_scale(0.8f)
-        .set_anchor(Anchor::TOP_LEFT)
-        .set_offset({0, SPACE});
     m_component.try_emplace(player_pos_text.id(), &player_pos_text);
 
     // rendered_chunk
-    auto& rendered_chunk_text =
+    auto& rendered_chunk_text = m_widget.add_child<Label>("rendered_chunk");
-        m_widget.add_child<Label>("rendered_chunk", &player_pos_text);
+    rendered_chunk_text.set_text("Rendered Chunk: 0").set_scale(SCALE);
-    rendered_chunk_text.set_text("Rendered Chunk: 0")
-        .set_scale(0.8f)
-        .set_anchor(Anchor::TOP_LEFT)
-        .set_offset({0, SPACE});
     m_component.try_emplace(rendered_chunk_text.id(), &rendered_chunk_text);
 
     // rss
-    auto& rss_text = m_widget.add_child<Label>("rss", &rendered_chunk_text);
+    auto& rss_text = m_widget.add_child<Label>("rss");
-    rss_text.set_text("RSS: 0mb")
+    rss_text.set_text("RSS: 0mb").set_scale(SCALE);
-        .set_scale(0.8f)
-        .set_anchor(Anchor::TOP_LEFT)
-        .set_offset({0, SPACE});
-
     m_component.try_emplace(rss_text.id(), &rss_text);
 
     // os
     std::string os;
-    auto& os_text = m_widget.add_child<Label>("os", &rss_text);
+    auto& os_text = m_widget.add_child<Label>("os");
-    os_text.set_scale(0.8f).set_anchor(Anchor::TOP_LEFT).set_offset({0, SPACE});
+    os_text.set_scale(SCALE);
     if (Tools::get_os_version(os)) {
         os_text.set_text("OS: " + os);
         Logger::info("System: {}", os);
@@ -77,48 +66,34 @@ void DebugCollector::init(int width, int height) {
     m_component.try_emplace(os_text.id(), &os_text);
 
     // cpu
-    auto& cpu_text = m_widget.add_child<Label>("cpu", &os_text);
+    auto& cpu_text = m_widget.add_child<Label>("cpu");
-    cpu_text.set_text("CPU: " + Tools::get_cpu_info())
+    cpu_text.set_text("CPU: " + Tools::get_cpu_info()).set_scale(SCALE);
-        .set_scale(0.8f)
-        .set_anchor(Anchor::TOP_LEFT)
-        .set_offset({0, SPACE});
     m_component.try_emplace(cpu_text.id(), &cpu_text);
 
     // gpu
-    auto& gpu_text = m_widget.add_child<Label>("gpu", &cpu_text);
+    auto& gpu_text = m_widget.add_child<Label>("gpu");
     gpu_text
         .set_text(std::string{"GPU: "} +
                   reinterpret_cast<const char*>(glGetString(GL_RENDERER)))
-        .set_scale(0.7f)
+        .set_scale(SCALE);
-        .set_anchor(Anchor::TOP_LEFT)
-        .set_offset({0, SPACE});
     m_component.try_emplace(gpu_text.id(), &gpu_text);
 
     // opengl_version
-    auto& opengl_version_text =
+    auto& opengl_version_text = m_widget.add_child<Label>("opengl_version");
-        m_widget.add_child<Label>("opengl_version", &gpu_text);
     opengl_version_text
         .set_text("OpenGL: " + std::to_string(GLVersion.major) + "." +
                   std::to_string(GLVersion.minor))
-        .set_scale(0.7f)
+        .set_scale(SCALE);
-        .set_anchor(Anchor::TOP_LEFT)
-        .set_offset({0, SPACE});
     m_component.try_emplace(opengl_version_text.id(), &opengl_version_text);
 
     // biome
-    auto& biome_text = m_widget.add_child<Label>("biome", &opengl_version_text);
+    auto& biome_text = m_widget.add_child<Label>("biome");
-    biome_text.set_text("Biome: ")
+    biome_text.set_text("Biome: ").set_scale(SCALE);
-        .set_scale(0.8f)
-        .set_anchor(Anchor::TOP_LEFT)
-        .set_offset({0, SPACE});
     m_component.try_emplace(biome_text.id(), &biome_text);
 
     // speed
-    auto& speed_text = m_widget.add_child<Label>("speed", &biome_text);
+    auto& speed_text = m_widget.add_child<Label>("speed");
-    speed_text.set_text("Speed: 0 m/s")
+    speed_text.set_text("Speed: 0 m/s").set_scale(SCALE);
-        .set_scale(0.8f)
-        .set_anchor(Anchor::TOP_LEFT)
-        .set_offset({0, SPACE});
     m_component.try_emplace(speed_text.id(), &speed_text);
 }
 

src/ui/column_layout.cpp

@@ -0,0 +1,24 @@
+#include "Cubed/ui/column_layout.hpp"
+
+namespace Cubed {
+ColumnLayout::ColumnLayout(Widget* parent) : Widget(parent) {}
+ColumnLayout::~ColumnLayout() {}
+
+void ColumnLayout::update(float dt) {
+    Widget::update(dt);
+    layout();
+}
+
+void ColumnLayout::set_spacing(int spacing) { m_spacing = spacing; }
+
+void ColumnLayout::layout() {
+    auto& children = Widget::children();
+    int y = 0;
+    for (auto& child : children) {
+        child->set_offset({0, y});
+        child->set_anchor(Anchor::TOP_LEFT);
+        y += child->height() + m_spacing;
+    }
+}
+
+} // namespace Cubed

src/ui/widget.cpp

@@ -25,6 +25,12 @@ void Widget::render(Renderer& renderer) {
 void Widget::on_update(float) {}
 void Widget::on_render(Renderer&) {}
 
+std::vector<std::unique_ptr<Widget>>& Widget::children() { return m_children; }
+
+const std::vector<std::unique_ptr<Widget>>& Widget::children() const {
+    return m_children;
+}
+
 glm::vec2 Widget::compute_position() const {
     glm::vec2 pos{0, 0};
     float parent_w;