commit df302ed05bddfa002cafa191cbc86880e9e80b55
parent 271284c1c82a7c27442f04d64bf5ad0545f8acd0
Author: Hiroyuki Ikezoe <hikezoe.birchill@mozilla.com>
Date: Fri, 7 Nov 2025 01:58:04 +0000
Bug 1978682 - Use ScrollPositionUpdate::mSource as the scroll origin of relavei/instant scroll position updates if the APZC is default. r=botond
Differential Revision: https://phabricator.services.mozilla.com/D269175
Diffstat:
4 files changed, 66 insertions(+), 14 deletions(-)
diff --git a/gfx/layers/FrameMetrics.cpp b/gfx/layers/FrameMetrics.cpp
@@ -168,11 +168,18 @@ bool FrameMetrics::ScrollLayoutViewportTo(const CSSPoint& aDestination) {
}
CSSPoint FrameMetrics::ApplyRelativeScrollUpdateFrom(
- const ScrollPositionUpdate& aUpdate) {
+ const ScrollPositionUpdate& aUpdate, IsDefaultApzc aIsDefaultApzc) {
MOZ_ASSERT(aUpdate.GetType() == ScrollUpdateType::Relative);
MOZ_ASSERT(aUpdate.GetMode() != ScrollMode::Smooth &&
aUpdate.GetMode() != ScrollMode::SmoothMsd);
- CSSPoint origin = GetVisualScrollOffset();
+
+ // If the APZC is default, i.e. newly created one, any relative instant
+ // scroll position update has been already reflected as the visual scroll
+ // offset, so we use the mSource in this ScrollPositionUpdate, which is the
+ // original scroll offset when this relative scroll update operation happened
+ // on the content.
+ CSSPoint origin =
+ bool(aIsDefaultApzc) ? aUpdate.GetSource() : GetVisualScrollOffset();
CSSPoint delta = (aUpdate.GetDestination() - aUpdate.GetSource());
SetVisualScrollOffset(origin + delta);
return GetVisualScrollOffset() - origin;
diff --git a/gfx/layers/FrameMetrics.h b/gfx/layers/FrameMetrics.h
@@ -255,7 +255,12 @@ struct FrameMetrics {
*
* @returns The clamped scroll offset delta that was applied
*/
- CSSPoint ApplyRelativeScrollUpdateFrom(const ScrollPositionUpdate& aUpdate);
+ enum class IsDefaultApzc {
+ No,
+ Yes,
+ };
+ CSSPoint ApplyRelativeScrollUpdateFrom(const ScrollPositionUpdate& aUpdate,
+ IsDefaultApzc aIsDefaultApzc);
CSSPoint ApplyPureRelativeScrollUpdateFrom(
const ScrollPositionUpdate& aUpdate);
diff --git a/gfx/layers/apz/src/AsyncPanZoomController.cpp b/gfx/layers/apz/src/AsyncPanZoomController.cpp
@@ -5921,10 +5921,11 @@ void AsyncPanZoomController::NotifyLayersUpdated(
Maybe<CSSPoint> relativeDelta;
if (scrollUpdate.GetType() == ScrollUpdateType::Relative) {
APZC_LOG(
- "%p relative updating scroll offset from %s by %s\n", this,
- ToString(Metrics().GetVisualScrollOffset()).c_str(),
+ "%p relative updating scroll offset from %s by %s, isDefault(%d)\n",
+ this, ToString(Metrics().GetVisualScrollOffset()).c_str(),
ToString(scrollUpdate.GetDestination() - scrollUpdate.GetSource())
- .c_str());
+ .c_str(),
+ isDefault);
scrollOffsetUpdated = true;
@@ -5938,8 +5939,8 @@ void AsyncPanZoomController::NotifyLayersUpdated(
contentRepaintType = RepaintUpdateType::eUserAction;
}
- relativeDelta =
- Some(Metrics().ApplyRelativeScrollUpdateFrom(scrollUpdate));
+ relativeDelta = Some(Metrics().ApplyRelativeScrollUpdateFrom(
+ scrollUpdate, FrameMetrics::IsDefaultApzc{isDefault}));
Metrics().RecalculateLayoutViewportOffset();
} else if (scrollUpdate.GetType() == ScrollUpdateType::PureRelative) {
APZC_LOG("%p pure-relative updating scroll offset from %s by %s\n", this,
diff --git a/gfx/layers/apz/test/gtest/TestBasic.cpp b/gfx/layers/apz/test/gtest/TestBasic.cpp
@@ -390,7 +390,7 @@ TEST_F(APZCBasicTester, MultipleSmoothScrollsSmooth) {
}
}
-TEST_F(APZCBasicTester, NotifyLayersUpdate_WithScrollUpdates) {
+TEST_F(APZCBasicTester, NotifyLayersUpdate_WithScrollUpdate) {
// Set an empty metadata as if the APZC is now newly created.
// This replicates when a document in a background tab now becomes forground.
ScrollMetadata metadata;
@@ -415,7 +415,7 @@ TEST_F(APZCBasicTester, NotifyLayersUpdate_WithScrollUpdates) {
CSSPoint::ToAppUnits(CSSPoint(15, 15))));
metadata.SetScrollUpdates(scrollUpdates);
metrics.SetScrollGeneration(scrollUpdates.LastElement().GetGeneration());
- // With the above scroll updates, now the layout/visual scroll offsets (on the
+ // With the above scroll update, now the layout/visual scroll offsets (on the
// main-thread) need to be updated.
metrics.SetVisualScrollOffset(CSSPoint(15, 15));
metrics.SetLayoutViewport(CSSRect(15, 15, 10, 10));
@@ -426,10 +426,49 @@ TEST_F(APZCBasicTester, NotifyLayersUpdate_WithScrollUpdates) {
// The layout/visual scroll ofsets and the relative scroll update need to be
// reflected.
- ASSERT_EQ(apzc->GetFrameMetrics().GetLayoutScrollOffset(), CSSPoint(20, 20))
- << "If the actual value is (15, 15), you fixed bug 1978682, thanks!";
- ASSERT_EQ(apzc->GetFrameMetrics().GetVisualScrollOffset(), CSSPoint(20, 20))
- << "If the actual value is (15, 15), you fixed bug 1978682, thanks!";
+ ASSERT_EQ(apzc->GetFrameMetrics().GetLayoutScrollOffset(), CSSPoint(15, 15));
+ ASSERT_EQ(apzc->GetFrameMetrics().GetVisualScrollOffset(), CSSPoint(15, 15));
+}
+
+TEST_F(APZCBasicTester, NotifyLayersUpdate_WithMultipleScrollUpdates) {
+ // Set an empty metadata as if the APZC is now newly created.
+ // This replicates when a document in a background tab now becomes foreground.
+ ScrollMetadata metadata;
+ apzc->SetScrollMetadata(metadata);
+ ASSERT_TRUE(apzc->GetScrollMetadata().IsDefault());
+
+ FrameMetrics& metrics = metadata.GetMetrics();
+ metrics.SetDisplayPort(CSSRect(0, 0, 10, 10));
+ metrics.SetCompositionBounds(ParentLayerRect(0, 0, 10, 10));
+ metrics.SetScrollableRect(CSSRect(0, 0, 100, 100));
+
+ metrics.SetVisualScrollOffset(CSSPoint(0, 0));
+ metrics.SetLayoutViewport(CSSRect(0, 0, 10, 10));
+ metrics.SetScrollId(ScrollableLayerGuid::START_SCROLL_ID);
+
+ AutoTArray<ScrollPositionUpdate, 2> scrollUpdates;
+ // Append a new scroll frame as if the scroll frame was reconstructed.
+ scrollUpdates.AppendElement(ScrollPositionUpdate::NewScrollframe(
+ CSSPoint::ToAppUnits(CSSPoint(0, 0))));
+ // Append a new relative scroll update (0, 0) -> (20, 20).
+ scrollUpdates.AppendElement(ScrollPositionUpdate::NewRelativeScroll(
+ CSSPoint::ToAppUnits(CSSPoint(0, 0)),
+ CSSPoint::ToAppUnits(CSSPoint(20, 20))));
+ metadata.SetScrollUpdates(scrollUpdates);
+ metrics.SetScrollGeneration(scrollUpdates.LastElement().GetGeneration());
+ // With the above scroll updates, now the layout/visual scroll offsets (on the
+ // main-thread) need to be updated.
+ metrics.SetVisualScrollOffset(CSSPoint(20, 20));
+ metrics.SetLayoutViewport(CSSRect(20, 20, 10, 10));
+
+ // It's not first-paint when switching tab.
+ apzc->NotifyLayersUpdated(metadata, /*isFirstPaint=*/false,
+ /*thisLayerTreeUpdated=*/true);
+
+ // The layout/visual scroll ofsets and the relative scroll update need to be
+ // reflected.
+ ASSERT_EQ(apzc->GetFrameMetrics().GetLayoutScrollOffset(), CSSPoint(20, 20));
+ ASSERT_EQ(apzc->GetFrameMetrics().GetVisualScrollOffset(), CSSPoint(20, 20));
}
class APZCSmoothScrollTester : public APZCBasicTester {
