PaintNode -> Paint
ShapeNode -> Shape
SceneNode -> Scene
We can keep clean and neat shorter names.
Change-Id: Ic8521d456d947985e5fbe1ba2bde06faa1f52469
This allocates nodes slots in advance to avoid memory grow & copy.
it will be benefit if you know how many shapes will be used in your canvas.
Change-Id: I7d93d166c9c054078bd86593d3471a2ade3671ee