This code is no longer needed because tiling is enabled on all
scrollable layers on B2G, and so we only draw tile-sized chunks
of the displayport. Therefore the textures created will never
exceed the max texture size. On non-B2G platforms this code is
not used anyway so there is no effect. Going forward we should
always be enabling tiling before enabling APZ on new platforms
so it is unlikely that we will need this code.
- Extended nsIScrollableFrame and nsGfxScrollFrame to return destination
of smooth scrolls which are to be animated on the compositor thread.
- Added apz.smooth_scroll_repaint_interval preference.
- Implemented AsyncPanZoomController::PanZoomState::SMOOTH_MSD_SCROLL state
and AsyncPanZoomController::SmoothScrollAnimation class to animate smooth
scroll animations on the compositor thread.
- Extended FrameMetrics to report requests for smooth scrolls to be animated
on the compositor thread and their corresponding destination positions.
- AsyncPanZoomController now checks FrameMetrics for requests to perform
smooth scrolling on the compositor thread. It will ensure that they
are cancelled as needed by mousewheel, touchpanel, keyboard, and
CSSOM-View instant scrolling DOM methods.
- The layout/generic/test/test_scroll_behavior.html mochitest has been
commented as depending on Bug 1062609 before being enabled for APZ.
- Verify that instant scroll-behavior is synchronous.
- Verify that smooth scroll-behavior is asynchronous.
- Verify that smooth scroll-behavior is triggered by CSSOM-View DOM methods.
- Verify that instant scroll-behavior interrupts smooth scroll-behavior
animation.
- Verify that smooth scroll-behavior is not framerate dependant.
- Verify that smooth scroll-behavior physics simulations used by animations
converge and allow the animation to reach completion.
- CSSOM-View scroll-behavior smooth scroll animations must produce the same
results indendently of frame-rate:
- Reference samples of scroll position for each frame are captured from a
smooth scroll at 120fps for variations in X-Distance, Y-Distance.
- Test samples are captured from an animation with the same parameters at
varying framerates.
- Variance in position at each sampled interval is compared to the 120fps
reference. To pass the test, the position of each test sample must match
the reference position with a tolerance of one test sample frame's range
of motion. This range of motion is calculated by the position delta of
the reference samples one test frame duration before and after.
- The duration of the reference sample animation and the test sample
animation must match within 1 frame to pass the test.
- The simulation driving the animation must converge and stop on the
destination position for the test to pass.
- When a smooth scroll is being processed on a frame, mouse wheel and trackpad
momentum scroll event updates will no longer cancel the SMOOTH or SMOOTH_MSD
scroll animations, enabling scripts that depend on them to be responsive
without forcing the user to wait for the fling animations to completely stop.
- Added nsIScrollableFrame::ScrollMode::SMOOTH_MSD to differentiate
existing smooth scrolls used by keyboard and mousewheel events from the
CSSOM-View scroll-behavior's MSD motion scrolling.
- Implemented ScrollFrameHelper::AsyncSmoothMSDScroll, which takes the role
of ScrollFrameHelper::AsyncScroll when SMOOTH_MSD scrolls are requested.
- Implemented glue code to handle callbacks from AsyncSmoothMSDScroll and
to hand off velocity between the classes when one scroll animation is
interrupted by another.
Whole-layer invalidations are always expensive, but they're especially
expensive on mobile. Avoid them on mobile by always aligning to pixel
values, even if it means the scroll position will fall out of bounds.
