Flesh out the Painting API a bit.

sky/engine/core/painting/Canvas.h

Index: sky/engine/core/painting/Canvas.h
diff --git a/sky/engine/core/painting/Canvas.h b/sky/engine/core/painting/Canvas.h
index 8cb0b21ba530138306c792e5f647e223f0ca4e04..36fcd47619250b285b00d6e7085c3acac6e477ae 100644
--- a/sky/engine/core/painting/Canvas.h
+++ b/sky/engine/core/painting/Canvas.h
@@ -25,6 +25,21 @@ public:
     double width() const { return m_size.width(); }
     double height() const { return m_size.height(); }
 
+    void save();
+    void saveLayer(Vector<float> bounds, Paint* paint);
+    void restore();
+
+    void translate(float dx, float dy);
+    void scale(float sx, float sy);
+    void rotate(float degrees);
+    void skew(float sx, float sy);
+    void concat(Vector<float> matrix);
+
+    void clipRect(Vector<float> rect);
+
+    void drawPaint(Paint* paint);
+    void drawRect(Vector<float> rect, Paint* paint);
+    void drawOval(Vector<float> rect, Paint* paint);
     void drawCircle(double x, double y, double radius, Paint* paint);
 
 protected: