This API can be used to back a view and its children with either a
software layer (bitmap) or hardware layer (FBO). Layers have
various usages, including color filtering and performance
improvements during animations.
Change-Id: Ifc3bea847918042730fc5a8c2d4206dd6c9420a3
Layers require that drawing methods potentially
draw in more than one bitmaps.
To handle this this patch offers the following:
- move all drawing methods to use Drawable
- Drawables are now handled by GcSnapshot since
its the one handling the layers
- moved Canvas_Delegate.createCustomGraphics to
GcSnapshot which does not expose the Graphics2D
objects anymore so its draw() methods are the only
way to draw.
- handles creating layers in GcSnapshot.save() and
blitting them in restore()
Other changes:
- Clean up the create/save API in GcSnapshot
- Fixed drawing bitmaps with alpha and other
composite modes.
Change-Id: I1e230087493d044a10de71f4b6d29083e3f3bf64