void
APZCCallbackHelper::UpdateRootFrame(nsIDOMWindowUtils* aUtils,
FrameMetrics& aMetrics)
{
// Precondition checks
MOZ_ASSERT(aUtils);
if (aMetrics.mScrollId == FrameMetrics::NULL_SCROLL_ID) {
return;
}
// Set the scroll port size, which determines the scroll range. For example if
// a 500-pixel document is shown in a 100-pixel frame, the scroll port length would
// be 100, and gecko would limit the maximum scroll offset to 400 (so as to prevent
// overscroll). Note that if the content here was zoomed to 2x, the document would
// be 1000 pixels long but the frame would still be 100 pixels, and so the maximum
// scroll range would be 900. Therefore this calculation depends on the zoom applied
// to the content relative to the container.
CSSSize scrollPort = aMetrics.CalculateCompositedRectInCssPixels().Size();
aUtils->SetScrollPositionClampingScrollPortSize(scrollPort.width, scrollPort.height);
// Scroll the window to the desired spot
nsIScrollableFrame* sf = nsLayoutUtils::FindScrollableFrameFor(aMetrics.mScrollId);
CSSPoint actualScrollOffset = ScrollFrameTo(sf, aMetrics.mScrollOffset);
// Correct the display port due to the difference between mScrollOffset and the
// actual scroll offset, possibly align it to tile boundaries (if tiled layers are
// enabled), and clamp it to the scrollable rect.
MaybeAlignAndClampDisplayPort(aMetrics, actualScrollOffset);
aMetrics.mScrollOffset = actualScrollOffset;
// The mZoom variable on the frame metrics stores the CSS-to-screen scale for this
// frame. This scale includes all of the (cumulative) resolutions set on the presShells
// from the root down to this frame. However, when setting the resolution, we only
// want the piece of the resolution that corresponds to this presShell, rather than
// all of the cumulative stuff, so we need to divide out the parent resolutions.
// Finally, we multiply by a ScreenToLayerScale of 1.0f because the goal here is to
// take the async zoom calculated by the APZC and tell gecko about it (turning it into
// a "sync" zoom) which will update the resolution at which the layer is painted.
mozilla::layers::ParentLayerToLayerScale presShellResolution =
aMetrics.mZoom
/ aMetrics.mDevPixelsPerCSSPixel
/ aMetrics.GetParentResolution()
* ScreenToLayerScale(1.0f);
aUtils->SetResolution(presShellResolution.scale, presShellResolution.scale);
// Finally, we set the displayport.
nsCOMPtr<nsIContent> content = nsLayoutUtils::FindContentFor(aMetrics.mScrollId);
if (!content) {
return;
}
nsCOMPtr<nsIDOMElement> element = do_QueryInterface(content);
if (!element) {
return;
}
aUtils->SetDisplayPortForElement(aMetrics.mDisplayPort.x,
aMetrics.mDisplayPort.y,
aMetrics.mDisplayPort.width,
aMetrics.mDisplayPort.height,
element);
}
void
APZCCallbackHelper::UpdateRootFrame(nsIDOMWindowUtils* aUtils,
FrameMetrics& aMetrics)
{
// Precondition checks
MOZ_ASSERT(aUtils);
MOZ_ASSERT(aMetrics.GetUseDisplayPortMargins());
if (aMetrics.GetScrollId() == FrameMetrics::NULL_SCROLL_ID) {
return;
}
// Set the scroll port size, which determines the scroll range. For example if
// a 500-pixel document is shown in a 100-pixel frame, the scroll port length would
// be 100, and gecko would limit the maximum scroll offset to 400 (so as to prevent
// overscroll). Note that if the content here was zoomed to 2x, the document would
// be 1000 pixels long but the frame would still be 100 pixels, and so the maximum
// scroll range would be 900. Therefore this calculation depends on the zoom applied
// to the content relative to the container.
CSSSize scrollPort = aMetrics.CalculateCompositedSizeInCssPixels();
aUtils->SetScrollPositionClampingScrollPortSize(scrollPort.width, scrollPort.height);
// Scroll the window to the desired spot
nsIScrollableFrame* sf = nsLayoutUtils::FindScrollableFrameFor(aMetrics.GetScrollId());
bool scrollUpdated = false;
CSSPoint actualScrollOffset = ScrollFrameTo(sf, aMetrics.GetScrollOffset(), scrollUpdated);
if (scrollUpdated) {
// Correct the display port due to the difference between mScrollOffset and the
// actual scroll offset.
AdjustDisplayPortForScrollDelta(aMetrics, actualScrollOffset);
} else {
// For whatever reason we couldn't update the scroll offset on the scroll frame,
// which means the data APZ used for its displayport calculation is stale. Fall
// back to a sane default behaviour. Note that we don't tile-align the recentered
// displayport because tile-alignment depends on the scroll position, and the
// scroll position here is out of our control. See bug 966507 comment 21 for a
// more detailed explanation.
RecenterDisplayPort(aMetrics);
}
aMetrics.SetScrollOffset(actualScrollOffset);
// The mZoom variable on the frame metrics stores the CSS-to-screen scale for this
// frame. This scale includes all of the (cumulative) resolutions set on the presShells
// from the root down to this frame. However, when setting the resolution, we only
// want the piece of the resolution that corresponds to this presShell, rather than
// all of the cumulative stuff, so we need to divide out the parent resolutions.
// Finally, we multiply by a ScreenToLayerScale of 1.0f because the goal here is to
// take the async zoom calculated by the APZC and tell gecko about it (turning it into
// a "sync" zoom) which will update the resolution at which the layer is painted.
ParentLayerToLayerScale presShellResolution =
aMetrics.GetZoom()
/ aMetrics.mDevPixelsPerCSSPixel
/ aMetrics.GetParentResolution()
* ScreenToLayerScale(1.0f);
aUtils->SetResolution(presShellResolution.scale, presShellResolution.scale);
// Finally, we set the displayport.
nsCOMPtr<nsIContent> content = nsLayoutUtils::FindContentFor(aMetrics.GetScrollId());
if (!content) {
return;
}
nsCOMPtr<nsIDOMElement> element = do_QueryInterface(content);
if (!element) {
return;
}
gfx::IntSize alignment = gfxPrefs::LayersTilesEnabled()
? gfx::IntSize(gfxPrefs::LayersTileWidth(), gfxPrefs::LayersTileHeight()) :
gfx::IntSize(0, 0);
LayerMargin margins = aMetrics.GetDisplayPortMargins();
aUtils->SetDisplayPortMarginsForElement(margins.left,
margins.top,
margins.right,
margins.bottom,
alignment.width,
alignment.height,
element, 0);
CSSRect baseCSS = aMetrics.CalculateCompositedRectInCssPixels();
nsRect base(baseCSS.x * nsPresContext::AppUnitsPerCSSPixel(),
baseCSS.y * nsPresContext::AppUnitsPerCSSPixel(),
baseCSS.width * nsPresContext::AppUnitsPerCSSPixel(),
baseCSS.height * nsPresContext::AppUnitsPerCSSPixel());
nsLayoutUtils::SetDisplayPortBaseIfNotSet(content, base);
}