By caching the SkImage that is reused across repaints, we allow Skia t
optimize GPU texture caching.
ImmutableBitmap is chosen to own the SkImage because it guarantees that
the underlying pixels cannot be modified. This is not the case for
Gfx::Bitmap, where invalidating the SkImage would be challenging since
it exposes pointers to underlying data through methods like scanline().
This is implemented by using a GPU-accelerated surface for <canvas> when
a GPU context is available.
A side effect of this change is that all canvas modifications have to be
performed through Gfx::Painter, and whenever its content has to be
accessed, we need to take a snapshot of the corresponding GPU surface.
A new DrawPaintingSurface display list command is introduced to allow
cheap blitting of canvas content without having to read GPU surface
content into RAM.
Always assuming unpremultiplied color data only worked for PNGs (which
are specced as unpremultiplied) and bitmaps with alpha set to 100%.
Properly propagate the Gfx::AlphaType of a bitmap to Skia.
The reference tests were updated to reflect this change, but visually
it's practically impossible to see the difference. A new test was added
to clearly expose this issue.
Fixes#1104
This thing is essentially a wrapper around an SkPath, although we do
some indirection via a PathImpl class to keep the door open for
alternative rasterizer/path backends in the future.
We also update the 2D canvas code, since that was the only code that
used Painter+DeprecatedPath, and this allows us to just drop that
code instead of temporarily supporting it until the next commit.
This new painter is written with a virtual interface from the start,
and we begin with a Skia backend.
This patch adds enough to support our basic 2D HTML canvas usecase.
