The viewport wasn't being recalculated when the viewport margins changed, and
was also subject to some rounding errors. Round off the values before
comparing them (as they're screen pixels), and make sure to update the viewport
when the margins change. Margins were also not correctly being altered when
in overscroll, which could cause bottom-aligned fixed position content to be
incorrectly offset.
This patch matches previous behaviour, but adds the following scenarios:
- When rendering is aborted due to the viewport falling out of the displayport,
enable low precision rendering.
- When the viewport falls out of the displayport during low precision rendering,
low precision rendering will be enabled on the next frame.
Make sure to offset the viewport *after* setting the Gecko viewport on
setFirstPaintViewport callbacks, so that we don't store an incorrect viewport
origin and end up offsetting events incorrectly.
Similarly, on page size updates, the Java-side viewport metrics are used to
update the Gecko metrics, so make sure they're clamped so that they aren't
incorrect during overscroll.
If overscroll eats into a fixed margin, we need to apply the opposite
offset to the opposite side of the axis this occurred on. This has the effect
of fixed-position elements aligned to the bottom of the screen remaining
visible when at the top of the page.
This changes compositor creation so that we can specify an initial size and
makes sure the local variable in nsWindow reflects that the compositor starts
unpaused.
This fixes the conflicting animations when the dynamic toolbar is hiding/showing
and overscroll is snapping back simultaneously. This is by not clamping the
entire viewport on margin-setting, and by making sure that only calling
setFixedLayerMargins changes the fixed layer margins.
This uses the aforementioned method on nsIDOMWindowUtils to make sure layout's
idea of the fixed position margins matches those used in the compositor.
This causes the viewport size to differ, depending on the length of the page.
This has the effect of pages that size themselves to the size of the window
always having the toolbar visible, making sites like Google Maps more usable.
This makes it possible to scroll to the top of the page with the toolbar visible
in Firefox for Android. It also causes JavaScript scrolling to position 0 to
expose the toolbar.
Offset fixed layers in the compositor so that the toolbar in Firefox for Android
doesn't obscure them. This does not affect layout, so input on the elements in
said layers will appear broken.
This uses the aforementioned method on nsIDOMWindowUtils to make sure layout's
idea of the fixed position margins matches those used in the compositor.
This causes the viewport size to differ, depending on the length of the page.
This has the effect of pages that size themselves to the size of the window
always having the toolbar visible, making sites like Google Maps more usable.
This makes it possible to scroll to the top of the page with the toolbar visible
in Firefox for Android. It also causes JavaScript scrolling to position 0 to
expose the toolbar.
Offset fixed layers in the compositor so that the toolbar in Firefox for Android
doesn't obscure them. This does not affect layout, so input on the elements in
said layers will appear broken.
This uses the aforementioned method on nsIDOMWindowUtils to make sure layout's
idea of the fixed position margins matches those used in the compositor.
