Magic-Mirror/gecko-dev
1
0
Fork 0
mirror of https://github.com/mozilla/gecko-dev.git synced 2024-10-17 23:35:34 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Bug 1214151 - If a sticky element does not consume all of the un-adjustment for an async transform, allow a descendant fixed or sticky element to consume it. r=mstange

Browse Source 
MozReview-Commit-ID: HHGjs4GZGNX

--HG--
extra : rebase_source : 9e31e1135e7be90006529ce205d575b2dcd67c27
This commit is contained in:
Botond Ballo 2016-06-29 18:25:31 -04:00
parent da66438e7c
commit be99d4ba83
1 changed files with 16 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
gfx/layers/composite/AsyncCompositionManager.cpp
View File

@ -508,6 +508,11 @@ AsyncCompositionManager::AlignFixedAndStickyLayers(Layer* aTransformedSubtreeRoo
ParentLayerPoint translation = TransformBy(localTransformTyped, transformedAnchor)
- TransformBy(localTransformTyped, anchor);
// A fixed layer will "consume" (be unadjusted by) the entire translation
// calculated above. A sticky layer may consume all, part, or none of it,
// depending on where we are relative to its sticky scroll range.
bool translationConsumed = true;
if (layer->GetIsStickyPosition()) {
// For sticky positioned layers, the difference between the two rectangles
// defines a pair of translation intervals in each dimension through which
@ -519,10 +524,14 @@ AsyncCompositionManager::AlignFixedAndStickyLayers(Layer* aTransformedSubtreeRoo
// TODO: There's a unit mismatch here, as |translation| is in ParentLayer
// space while |stickyOuter| and |stickyInner| are in Layer space.
ParentLayerPoint originalTranslation = translation;
translation.y = IntervalOverlap(translation.y, stickyOuter.y, stickyOuter.YMost()) -
IntervalOverlap(translation.y, stickyInner.y, stickyInner.YMost());
translation.x = IntervalOverlap(translation.x, stickyOuter.x, stickyOuter.XMost()) -
IntervalOverlap(translation.x, stickyInner.x, stickyInner.XMost());
if (translation != originalTranslation) {
translationConsumed = false;
}
}
// Finally, apply the translation to the layer transform. Note that in cases
@ -533,7 +542,13 @@ AsyncCompositionManager::AlignFixedAndStickyLayers(Layer* aTransformedSubtreeRoo
TranslateShadowLayer(layer, ThebesPoint(translation.ToUnknownPoint()),
true, aClipPartsCache);
return TraversalFlag::Skip;
// If we didn't consume the entire translation, continue the traversal
// to allow a descendant fixed or sticky layer to consume the rest.
// TODO: We curently don't handle the case where we consume part but not
// all of the translation correctly. In such a case,
// |a[Previous|Current]TransformForRoot| would need to be adjusted
// to reflect only the unconsumed part of the translation.
return translationConsumed ? TraversalFlag::Skip : TraversalFlag::Continue;
});
}