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.
The size of the frame is scaled by the local resolution of it's presshell. The widget contains the document, so it's size is scaled the parent presshell resolution, but not the local presshell resolution. So comparing the widget size and the frame size directly without taking into account resolution is wrong.
The PositionedEventTargeting code allows input events to be dispatched to a
target not directly under the input event point. However, the coordinates of the
input event can then end up outside the bounding rect of the event target. This
state is generally unexpected by web content and may cause compatibility issues.
Fennec's front-end code used to deal with this by repositioning the input event
coordinates to be inside the bounding rect; now that Fennec is using the shared
C++ code we need to have that code here. This behaviour is guarded by a pref and
disabled by default (but enabled on Fennec).
