This makes APZ behave nicely with most uses of a css transform:scale.
Summary of changes:
- FrameMetrics::mCumulativeResolution now includes the css-driven resolution
in addition to the pres-shell resolution.
- Displayports are now stored in Screen pixels rather than Layer pixels.
This is what we want anyways (as we'd like the displayport size to remain
constant as a fraction of the screen size), but it was necessary to make
this change as part of this patch because continuing to store them in
Layer pixels in the presence of a css-driven resolution would have
required a bunch of infrastructure to implement correctly.
Remaining work:
- Layout painting a scrollable layer at a resolution different from the
scale induced by the css transform causes problems. These will go away
with bug 1076192.
- Different resolutions on the x and y axes are not supported. This is
tracked by bug 1039967.
This makes APZ behave nicely with most uses of a css transform:scale.
Summary of changes:
- FrameMetrics::mCumulativeResolution now includes the css-driven resolution
in addition to the pres-shell resolution.
- Displayports are now stored in Screen pixels rather than Layer pixels.
This is what we want anyways (as we'd like the displayport size to remain
constant as a fraction of the screen size), but it was necessary to make
this change as part of this patch because continuing to store them in
Layer pixels in the presence of a css-driven resolution would have
required a bunch of infrastructure to implement correctly.
Remaining work:
- Layout painting a scrollable layer at a resolution different from the
scale induced by the css transform causes problems. These will go away
with bug 1076192.
- Different resolutions on the x and y axes are not supported. This is
tracked by bug 1039967.
- 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.
Surabhi Anand
Kartikaya Gupta
Botond Ballo
David Anderson
Kartikaya Gupta
Benoit Girard
Carsten "Tomcat" Book
Milan Sreckovic
Kearwood (Kip) Gilbert
Aryeh Gregor
Benoit Jacob
David Zbarsky
Debbe Heisler
Timothy Nikkel
Vivien Nicolas