Sdk/Widgets: Make the canvas aware of itself as a widget

SDK/include/NDK/BaseWidget.hpp

@@ -95,8 +95,10 @@ namespace Ndk
 
 			inline void DestroyChild(BaseWidget* widget);
 			void DestroyChildren();
+			void RegisterToCanvas();
 			inline void NotifyParentResized(const Nz::Vector2f& newSize);
 			inline void UpdateCanvasIndex(std::size_t index);
+			void UnregisterFromCanvas();
 
 			std::size_t m_canvasIndex;
 			std::vector<EntityOwner> m_entities;

SDK/include/NDK/Canvas.hpp

@@ -33,8 +33,6 @@ namespace Ndk
 			Canvas& operator=(Canvas&&) = delete;
 
 		protected:
-			void Layout() override;
-
 			void NotifyWidgetUpdate(std::size_t index);
 
 			std::size_t RegisterWidget(BaseWidget* widget);

SDK/include/NDK/Canvas.inl

@@ -12,6 +12,10 @@ namespace Ndk
 	m_world(std::move(world))
 	{
 		m_canvas = this;
+		m_widgetParent = nullptr;
+
+		// Widgetception
+		m_canvasIndex = m_canvas->RegisterWidget(this);
 
 		m_keyPressedSlot.Connect(eventHandler.OnKeyPressed, this, &Canvas::OnKeyPressed);
 		m_keyReleasedSlot.Connect(eventHandler.OnKeyReleased, this, &Canvas::OnKeyReleased);
@@ -20,12 +24,17 @@ namespace Ndk
 		m_mouseMovedSlot.Connect(eventHandler.OnMouseMoved, this, &Canvas::OnMouseMoved);
 		m_mouseLeftSlot.Connect(eventHandler.OnMouseLeft, this, &Canvas::OnMouseLeft);
 		m_textEnteredSlot.Connect(eventHandler.OnTextEntered, this, &Canvas::OnTextEntered);
+
+		SetPadding(0.f, 0.f, 0.f, 0.f);
 	}
 
 	inline Canvas::~Canvas()
 	{
-		// Destroy children explicitly because they signal us when getting destroyed, and that can't happend after our own destruction
+		// Destroy children explicitly because they signal us when getting destroyed, and that can't happen after our own destruction
 		DestroyChildren();
+
+		// Prevent our parent from trying to call us
+		m_canvasIndex = std::numeric_limits<std::size_t>::max();
 	}
 
 	inline const WorldHandle& Canvas::GetWorld() const

SDK/src/NDK/BaseWidget.cpp

@@ -21,13 +21,12 @@ namespace Ndk
 		m_widgetParent = parent;
 		m_world = m_canvas->GetWorld();
 
-		m_canvasIndex = m_canvas->RegisterWidget(this);
+		RegisterToCanvas();
 	}
 
 	BaseWidget::~BaseWidget()
 	{
-		if (m_canvasIndex != std::numeric_limits<std::size_t>::max())
-			m_canvas->UnregisterWidget(m_canvasIndex);
+		UnregisterFromCanvas();
 	}
 
 	void BaseWidget::Destroy()
@@ -88,6 +87,11 @@ namespace Ndk
 		{
 			m_visible = show;
 
+			if (m_visible)
+				RegisterToCanvas();
+			else
+				UnregisterFromCanvas();
+
 			for (const EntityHandle& entity : m_entities)
 				entity->Enable(show);
 
@@ -182,4 +186,20 @@ namespace Ndk
 	{
 		m_children.clear();
 	}
+
+	void BaseWidget::RegisterToCanvas()
+	{
+		NazaraAssert(m_canvasIndex == std::numeric_limits<std::size_t>::max(), "Widget is already registered to canvas");
+
+		m_canvasIndex = m_canvas->RegisterWidget(this);
+	}
+
+	void BaseWidget::UnregisterFromCanvas()
+	{
+		if (m_canvasIndex != std::numeric_limits<std::size_t>::max())
+		{
+			m_canvas->UnregisterWidget(m_canvasIndex);
+			m_canvasIndex = std::numeric_limits<std::size_t>::max();
+		}
+	}
 }

SDK/src/NDK/Canvas.cpp

@@ -14,14 +14,6 @@ namespace Ndk
 	{
 	}
 
-	void Canvas::Layout()
-	{
-		if (m_backgroundEntity)
-		{
-			m_backgroundSprite->SetSize(m_contentSize.x + m_padding.left + m_padding.right, m_contentSize.y + m_padding.top + m_padding.bottom);
-		}
-	}
-
 	void Canvas::NotifyWidgetUpdate(std::size_t index)
 	{
 		WidgetBox& entry = m_widgetBoxes[index];