Given an invalidation rect, called the recycle rect, which represents
the area which may have changed between the current frame and the frame
we are recycling, we can not only reuse the buffer itself to avoid an
allocation and free, we can also avoid copying pixel data from the
restore frame which is already set.
Differential Revision: https://phabricator.services.mozilla.com/D7507
This new SurfaceFilter can be added to a SurfacePipe to perform the
blending of a previous frame with the current partial frame, for an
animated image. This functionality is currently provided by
FrameAnimator and must be performed each time we want to advance the
displayed frame, all on the main thread. Moving this to SurfacePipe
allows us to do the same operation once per frame decode, and on a
decoder thread.
This should reduce the cost of a refresh tick since advancing animated
images is reduced to merely checking if the frame is available. Also, if
the image is below the discard frames threshold (to save memory), then
we will also save CPU due to only blending once at decode.
This new SurfaceFilter can be added to a SurfacePipe to perform the
blending of a previous frame with the current partial frame, for an
animated image. This functionality is currently provided by
FrameAnimator and must be performed each time we want to advance the
displayed frame, all on the main thread. Moving this to SurfacePipe
allows us to do the same operation once per frame decode, and on a
decoder thread.
This should reduce the cost of a refresh tick since advancing animated
images is reduced to merely checking if the frame is available. Also, if
the image is below the discard frames threshold (to save memory), then
we will also save CPU due to only blending once at decode.
Andrew Osmond
Coroiu Cristina
Milan Sreckovic
Seth Fowler
Seth Fowler