commit 64ca376c6f0b1b588062c64b103878d33b54536b
parent eb408c452f2b4059dd9f9b33e07dcf28242cedbc
Author: Botond Ballo <botond@mozilla.com>
Date: Wed, 3 Dec 2025 20:04:37 +0000
Bug 1999440 - Rename existing layout.css.scroll-behavior.* prefs to layout.css.scroll-snap.*. r=hiro,layout-reviewers,perftest-reviewers,aglavic
These prefs are no longer used for scroll-behavior if
layout.css.scroll-behavior.same-physics-as-user-input=true,
which will be the default in the future.
They are always used for scroll-snap, so it's more accurate to
name the prefs after scroll-snap.
The patch also updates tests which deliberately tweak these prefs to
control the speed of a scroll animation governed by scroll-behavior
(e.g. to slow it down), to also set
layout.css.scroll-behavior.same-physics-as-user-input=false,
so that the prefs continue to have their intended effect on the test.
Differential Revision: https://phabricator.services.mozilla.com/D272350
Diffstat:
10 files changed, 45 insertions(+), 28 deletions(-)
diff --git a/gfx/layers/apz/test/mochitest/helper_scroll_snap_resnap_after_async_scroll.html b/gfx/layers/apz/test/mochitest/helper_scroll_snap_resnap_after_async_scroll.html
@@ -62,7 +62,7 @@
// Now trigger another wheel scroll to escape from the last snap point.
transformEndPromise = promiseTransformEnd();
- // With a small `layout.css.scroll-behavior.spring-constant` preference
+ // With a small `layout.css.scroll-snap.spring-constant` preference
// value (it's set in test_group_scroll_snap.html), an async scroll
// operation, e.g. a wheel scroll operation, fires multiple scroll events
// so that here we wait the first scroll event here by specifying
diff --git a/gfx/layers/apz/test/mochitest/test_abort_smooth_scroll_by_instant_scroll.html b/gfx/layers/apz/test/mochitest/test_abort_smooth_scroll_by_instant_scroll.html
@@ -16,7 +16,7 @@ async function test() {
// Trigger a smooth scroll.
document.scrollingElement.scrollTo({ top: 90000, behavior: "smooth" });
// Need to wait for a scroll event here since with the very small
- // layout.css.scroll-behavior.spring-constant value it's possible that the
+ // layout.css.scroll-snap.spring-constant value it's possible that the
// scroll position hasn't yet been changed after a promiseApzFlushedRepaints
// call.
await waitForScrollEvent(window);
@@ -41,7 +41,10 @@ SimpleTest.waitForExplicitFinish();
// Use a very small spring constant value for smooth scrolling so that the
// smooth scrollling keeps running at least for a few seconds.
-pushPrefs([["layout.css.scroll-behavior.spring-constant", 1]])
+pushPrefs([
+ ["layout.css.scroll-snap.spring-constant", 1],
+ // This ensures scrollTo() uses scroll-snap physics settings.
+ ["layout.css.scroll-behavior.same-physics-as-user-input", false]])
.then(waitUntilApzStable)
.then(test)
.then(SimpleTest.finish, SimpleTest.finishWithFailure);
diff --git a/gfx/layers/apz/test/mochitest/test_group_mainthread.html b/gfx/layers/apz/test/mochitest/test_group_mainthread.html
@@ -20,9 +20,11 @@ var subtests = [
{"file": "helper_scroll_anchoring_smooth_scroll_with_set_timeout.html", prefs: [
// Unlike helper_scroll_anchoring_smooth_scroll.html, this test checks that
// scroll anchoring __is__ invoked when an async scroll animation triggered
- // by mouse wheel is running so the animation needs to keep running for a
- // while.
- ["layout.css.scroll-behavior.spring-constant", 10]
+ // by scrollIntoView() is running so the animation needs to keep running for
+ // a while.
+ ["layout.css.scroll-snap.spring-constant", 10],
+ // This ensures scrollIntoView() uses scroll-snap physics settings.
+ ["layout.css.scroll-behavior.same-physics-as-user-input", false]
]},
{"file": "helper_visualscroll_clamp_restore.html", prefs: [
["apz.test.logging_enabled", true],
diff --git a/gfx/layers/apz/test/mochitest/test_group_scroll_snap.html b/gfx/layers/apz/test/mochitest/test_group_scroll_snap.html
@@ -22,28 +22,34 @@ const subtests = [
{"file": "helper_bug1960053_scroll_snap_align_start.html",
"prefs": [["apz.test.mac.synth_wheel_input", true]]},
{"file": "helper_scroll_snap_resnap_after_async_scroll.html",
- // Specify a small `layout.css.scroll-behavior.spring-constant` value to
+ // Specify a small `layout.css.scroll-snap.spring-constant` value to
// keep the smooth scroll animation running long enough so that we can
// trigger a reflow during the animation.
- "prefs": [["layout.css.scroll-behavior.spring-constant", 10],
+ // FIXME: This test uses promiseMoveMouseAndScrollWheelOver(), so even
+ // with layout.css.scroll-behavior.same-physics-as-user-input=false,
+ // layout.css.scroll-snap.* prefs have no impact on scroll
+ // animation speed.
+ "prefs": [["layout.css.scroll-snap.spring-constant", 10],
+ ["layout.css.scroll-behavior.same-physics-as-user-input", false],
["apz.test.mac.synth_wheel_input", true]]},
{"file": "helper_scroll_snap_resnap_after_async_scroll.html",
"prefs": [["general.smoothScroll", false],
["apz.test.mac.synth_wheel_input", true]]},
{"file": "helper_scroll_snap_resnap_after_async_scrollBy.html",
// Same as above helper_scroll_snap_resnap_after_async_scroll.html.
- "prefs": [["layout.css.scroll-behavior.spring-constant", 10]]},
+ "prefs": [["layout.css.scroll-snap.spring-constant", 10],
+ ["layout.css.scroll-behavior.same-physics-as-user-input", false]]},
{"file": "helper_scroll_snap_not_resnap_during_panning.html",
// Specify a strong spring constant to make scroll snap animation be
// effective in a short span of time.
- "prefs": [["layout.css.scroll-behavior.spring-constant", 1000]]},
+ "prefs": [["layout.css.scroll-snap.spring-constant", 1000]]},
{"file": "helper_scroll_snap_not_resnap_during_scrollbar_dragging.html",
// Same as above helper_scroll_snap_not_resnap_during_scrollbar_dragging.html.
- "prefs": [["layout.css.scroll-behavior.spring-constant", 1000]]},
+ "prefs": [["layout.css.scroll-snap.spring-constant", 1000]]},
{"file": "helper_bug1780701.html"},
{"file": "helper_bug1783936.html",
// Shorten the scroll snap animation duration.
- "prefs": [["layout.css.scroll-behavior.spring-constant", 1000],
+ "prefs": [["layout.css.scroll-snap.spring-constant", 1000],
// Avoid fling at the end of pan.
["apz.fling_min_velocity_threshold", "10000"],
// This test needs mSimilateMomentum flag on headless mode.
diff --git a/layout/generic/ScrollAnimationMSDPhysics.cpp b/layout/generic/ScrollAnimationMSDPhysics.cpp
@@ -83,7 +83,7 @@ void ScrollAnimationMSDPhysics::ApplyContentShift(const CSSPoint& aShiftDelta) {
double ScrollAnimationMSDPhysics::GetDampingRatio() const {
if (mAnimationKind == ScrollAnimationKind::SmoothMsd) {
- return StaticPrefs::layout_css_scroll_behavior_damping_ratio();
+ return StaticPrefs::layout_css_scroll_snap_damping_ratio();
}
return 1.0;
}
@@ -91,7 +91,7 @@ double ScrollAnimationMSDPhysics::GetDampingRatio() const {
double ScrollAnimationMSDPhysics::ComputeSpringConstant(
const TimeStamp& aTime) {
if (mAnimationKind == ScrollAnimationKind::SmoothMsd) {
- return StaticPrefs::layout_css_scroll_behavior_spring_constant();
+ return StaticPrefs::layout_css_scroll_snap_spring_constant();
}
if (!mPreviousEventTime) {
diff --git a/layout/generic/ScrollContainerFrame.cpp b/layout/generic/ScrollContainerFrame.cpp
@@ -1877,12 +1877,12 @@ class ScrollContainerFrame::AsyncSmoothMSDScroll final
ScrollTriggeredByScript aTriggeredByScript)
: mXAxisModel(aInitialPosition.x, aInitialDestination.x,
aInitialVelocity.width,
- StaticPrefs::layout_css_scroll_behavior_spring_constant(),
- StaticPrefs::layout_css_scroll_behavior_damping_ratio()),
+ StaticPrefs::layout_css_scroll_snap_spring_constant(),
+ StaticPrefs::layout_css_scroll_snap_damping_ratio()),
mYAxisModel(aInitialPosition.y, aInitialDestination.y,
aInitialVelocity.height,
- StaticPrefs::layout_css_scroll_behavior_spring_constant(),
- StaticPrefs::layout_css_scroll_behavior_damping_ratio()),
+ StaticPrefs::layout_css_scroll_snap_spring_constant(),
+ StaticPrefs::layout_css_scroll_snap_damping_ratio()),
mRange(aRange),
mStartPosition(aInitialPosition),
mLastRefreshTime(aStartTime),
diff --git a/modules/libpref/init/StaticPrefList.yaml b/modules/libpref/init/StaticPrefList.yaml
@@ -10386,7 +10386,7 @@
#endif
mirror: always
-- name: layout.css.scroll-behavior.damping-ratio
+- name: layout.css.scroll-snap.damping-ratio
type: AtomicFloat
value: 1.0f
mirror: always
@@ -10394,7 +10394,7 @@
# Tuning of the smooth scroll motion used by CSSOM-View scroll-behavior.
# Spring-constant controls the strength of the simulated MSD
# (Mass-Spring-Damper).
-- name: layout.css.scroll-behavior.spring-constant
+- name: layout.css.scroll-snap.spring-constant
type: AtomicFloat
value: 250.0f
mirror: always
diff --git a/testing/perfdocs/generated/talos.rst b/testing/perfdocs/generated/talos.rst
@@ -7801,7 +7801,7 @@ For the sample commands found below, note that the capitalization used is import
* Slowdown in rasterization of content
* Slowdown in composite times
* gecko_profile_interval: 2
- * preferences: {'layout.frame_rate': 0, 'docshell.event_starvation_delay_hint': 1, 'dom.send_after_paint_to_content': True, 'apz.paint_skipping.enabled': False, 'layout.css.scroll-behavior.spring-constant': "'10'", 'toolkit.framesRecording.bufferSize': 10000}
+ * preferences: {'layout.frame_rate': 0, 'docshell.event_starvation_delay_hint': 1, 'dom.send_after_paint_to_content': True, 'apz.paint_skipping.enabled': False, 'layout.css.scroll-snap.spring-constant': "'10'", 'layout.css.scroll-behavior.same-physics-as-user-input': False, 'toolkit.framesRecording.bufferSize': 10000}
* tpcycles: 1
* tpmanifest: ${talos}/tests/tp5n/tp5o.manifest
* tpmozafterpaint: False
@@ -8591,7 +8591,7 @@ For the sample commands found below, note that the capitalization used is import
* gecko_profile_interval: 1
* pine: False
- * preferences: {'layout.frame_rate': 0, 'docshell.event_starvation_delay_hint': 1, 'dom.send_after_paint_to_content': True, 'apz.paint_skipping.enabled': False, 'layout.css.scroll-behavior.spring-constant': "'10'", 'toolkit.framesRecording.bufferSize': 10000}
+ * preferences: {'layout.frame_rate': 0, 'docshell.event_starvation_delay_hint': 1, 'dom.send_after_paint_to_content': True, 'apz.paint_skipping.enabled': False, 'layout.css.scroll-snap.spring-constant': "'10'", 'layout.css.scroll-behavior.same-physics-as-user-input': False, 'toolkit.framesRecording.bufferSize': 10000}
* timeout: 600
* tpchrome: False
* tpcycles: 1
diff --git a/testing/talos/talos/test.py b/testing/talos/talos/test.py
@@ -1040,7 +1040,8 @@ class tp5o_scroll(PageloaderTest):
"docshell.event_starvation_delay_hint": 1,
"dom.send_after_paint_to_content": True,
"apz.paint_skipping.enabled": False,
- "layout.css.scroll-behavior.spring-constant": "'10'",
+ "layout.css.scroll-snap.spring-constant": "'10'",
+ "layout.css.scroll-behavior.same-physics-as-user-input": False,
"toolkit.framesRecording.bufferSize": 10000,
}
filters = filter.ignore_first.prepare(1) + filter.median.prepare()
@@ -1058,7 +1059,8 @@ class tp5o_scroll_paint_skip(tp5o_scroll):
"docshell.event_starvation_delay_hint": 1,
"dom.send_after_paint_to_content": True,
"apz.paint_skipping.enabled": True,
- "layout.css.scroll-behavior.spring-constant": "'10'",
+ "layout.css.scroll-snap.spring-constant": "'10'",
+ "layout.css.scroll-behavior.same-physics-as-user-input": False,
"toolkit.framesRecording.bufferSize": 10000,
}
@@ -1286,7 +1288,8 @@ class tscrollx(PageloaderTest):
"docshell.event_starvation_delay_hint": 1,
"dom.send_after_paint_to_content": True,
"apz.paint_skipping.enabled": False,
- "layout.css.scroll-behavior.spring-constant": "'10'",
+ "layout.css.scroll-snap.spring-constant": "'10'",
+ "layout.css.scroll-behavior.same-physics-as-user-input": False,
"toolkit.framesRecording.bufferSize": 10000,
}
filters = filter.ignore_first.prepare(5) + filter.median.prepare()
@@ -1305,7 +1308,8 @@ class tscrollx_paint_skip(tscrollx):
"docshell.event_starvation_delay_hint": 1,
"dom.send_after_paint_to_content": True,
"apz.paint_skipping.enabled": True,
- "layout.css.scroll-behavior.spring-constant": "'10'",
+ "layout.css.scroll-snap.spring-constant": "'10'",
+ "layout.css.scroll-behavior.same-physics-as-user-input": False,
"toolkit.framesRecording.bufferSize": 10000,
}
diff --git a/testing/talos/talos/unittests/test_config.py b/testing/talos/talos/unittests/test_config.py
@@ -1032,7 +1032,8 @@ class Test_get_config:
"layout.frame_rate": 0,
"docshell.event_starvation_delay_hint": 1,
"dom.send_after_paint_to_content": False,
- "layout.css.scroll-behavior.spring-constant": "'10'",
+ "layout.css.scroll-snap.spring-constant": "'10'",
+ "layout.css.scroll-behavior.same-physics-as-user-input": False,
"toolkit.framesRecording.bufferSize": 10000,
}
assert test_config["filters"] is not None
@@ -1216,7 +1217,8 @@ class Test_get_config:
"layout.frame_rate": 0,
"docshell.event_starvation_delay_hint": 1,
"dom.send_after_paint_to_content": False,
- "layout.css.scroll-behavior.spring-constant": "'10'",
+ "layout.css.scroll-snap.spring-constant": "'10'",
+ "layout.css.scroll-behavior.same-physics-as-user-input": False,
"toolkit.framesRecording.bufferSize": 10000,
}
assert test_config["filters"] is not None
