Convert visual layers to scene nodes.

src/ui_elements/widgets/Label.h

@@ -4,6 +4,8 @@
 
 #include <string>
 
+class TextNode;
+
 class Label : public Widget
 {
 
@@ -11,14 +13,21 @@ public:
 
     Label();
 
+    virtual ~Label() = default;
+
     static std::unique_ptr<Label> Create();
 
     void setLabel(const std::string& text);
 
-    void onPaintEvent(const PaintEvent* event) override;
-
 private:
+    bool isDirty() const override;
+    void doPaint(const PaintEvent* event) override;
+
+    void updateLabel(const PaintEvent* event);
+
     std::string mLabel;
+    std::unique_ptr<TextNode> mTextNode;
+    bool mContentDirty{true};
 
 };