Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: e8b8f75b41b3d873fb5aadda2df4da3f1d744f8d
https://github.com/WebKit/WebKit/commit/e8b8f75b41b3d873fb5aadda2df4da3f1d744f8d
Author: Wenson Hsieh <wenson_hs...@apple.com>
Date: 2023-11-27 (Mon, 27 Nov 2023)
Changed paths:
M Source/WebKit/SourcesCocoa.txt
M Source/WebKit/UIProcess/API/ios/WKWebViewIOS.h
M Source/WebKit/UIProcess/API/ios/WKWebViewIOS.mm
M Source/WebKit/UIProcess/RemoteLayerTree/ios/RemoteLayerTreeViews.h
M
Source/WebKit/UIProcess/RemoteLayerTree/ios/ScrollingTreeScrollingNodeDelegateIOS.mm
A Source/WebKit/UIProcess/ios/WKAxisLockingScrollView.h
A Source/WebKit/UIProcess/ios/WKAxisLockingScrollView.mm
M Source/WebKit/UIProcess/ios/WKContentViewInteraction.mm
M Source/WebKit/UIProcess/ios/WKVelocityTrackingScrollView.h
M Source/WebKit/WebKit.xcodeproj/project.pbxproj
Log Message:
-----------
Stop using SPI:
-_scrollView:adjustedOffsetForOffset:translation:startPoint:horizontalVelocity:verticalVelocity:
https://bugs.webkit.org/show_bug.cgi?id=265215
rdar://118696702
Reviewed by Megan Gardner.
Move off of the private `UIScrollViewDelegate` method
`-_scrollView:adjustedOffsetForOffset:…:`,
which allows clients to retarget the would-be target content offset right
before a pan gesture (or
pan-gesture-induced momentum scrolling). We currently use this to implement
`touch-action: pan-x|y`
by retargeting the content offset such that the `x` or `y` offsets are locked
to their initial
values at the start of scrolling, which has the effect of locking
pan-gesture-based scrolling to a
single axis.
To achieve the same effect without adopting any scroll view SPI, we can instead
create and deploy a
new scroll view subclass, `WKAxisLockingScrollView`, which allows clients, in
the form of a
`WKAxisLockingScrollViewDelegate`, to choose which axis to prevent scrolling
during a pan gesture by
returning `UIAxisHorizontal` and/or `UIAxisVertical` in a new internal delegate
method. For example,
we return `UIAxisVertical` to prevent scrolling in the y-axis, when `pan-x` is
specified (and vice-
versa for `pan-y`).
To implement this subclass, we:
1. Add our own pan gesture recognizer (the "axis locking pan gesture") to the
scroll view, right as
UIKit is about to add the built-in `UIScrollViewPanGestureRecognizer`. The
order in which these
two gestures are added to the scroll view is important, since this
guarantees that the gesture
action for the axis locking pan gesture will always fire right before the
scroll view's default
scrolling pan gesture.
2. We build on this by calling out to the axis locking delegate to get the set
of axes to prevent
scrolling and use this information to call `-[UIPanGestureRecognizer
setTranslation:inView:]` on
the scroll view's built-in pan gesture recognizer, zeroing out either the
`x` or `y` component
of the translation (depending on what the delegate method returned). This
allows us to make
UIKit behave as if the user was scrolling perfectly along the x or y axis
upon converting the
pan gesture translation amount into scroll deltas, using the built-in pan
gesture recognizer.
* Source/WebKit/SourcesCocoa.txt:
* Source/WebKit/UIProcess/API/ios/WKWebViewIOS.h:
* Source/WebKit/UIProcess/API/ios/WKWebViewIOS.mm:
(-[WKWebView _setupScrollAndContentViews]):
(-[WKWebView scrollViewWillEndDragging:withVelocity:targetContentOffset:]):
(-[WKWebView axesToPreventScrollingForPanGestureInScrollView:]):
(-[WKWebView
_scrollView:adjustedOffsetForOffset:translation:startPoint:locationInView:horizontalVelocity:verticalVelocity:]):
Deleted.
Delete this SPI delegate method implementation, and instead move the
corresponding logic into the
new `-axesToPreventScrollingForPanGestureInScrollView:` delegate method.
* Source/WebKit/UIProcess/RemoteLayerTree/ios/RemoteLayerTreeViews.h:
Make `WKChildScrollView` subclass the new `WKAxisLockingScrollView`.
*
Source/WebKit/UIProcess/RemoteLayerTree/ios/ScrollingTreeScrollingNodeDelegateIOS.mm:
(-[WKScrollingNodeScrollViewDelegate
scrollViewWillEndDragging:withVelocity:targetContentOffset:]):
Because the new `-axesToPreventScrollingForPanGestureInScrollView:` delegate
method isn't called
after scrolling ends, we need a separate mechanism in order to limit momentum
scrolling to the
locked scrolling axis. Achieve this by keeping track of the axes where we
prevented scrolling in the
`WKAxisLockingScrollView` during the pan gesutre, and then use public scroll
view delegate API to
retarget the default scrolling destination to the current offset value,
effectively canceling out
any momentum scrolling in that axis.
(-[WKScrollingNodeScrollViewDelegate
axesToPreventScrollingForPanGestureInScrollView:]):
(WebKit::ScrollingTreeScrollingNodeDelegateIOS::commitStateAfterChildren):
(-[WKScrollingNodeScrollViewDelegate
_scrollView:adjustedOffsetForOffset:translation:startPoint:locationInView:horizontalVelocity:verticalVelocity:]):
Deleted.
Same as above; move this logic into
`-axesToPreventScrollingForPanGestureInScrollView:` to service
the overflow scrolling case.
* Source/WebKit/UIProcess/ios/WKAxisLockingScrollView.h: Copied from
Source/WebKit/UIProcess/ios/WKVelocityTrackingScrollView.h.
* Source/WebKit/UIProcess/ios/WKAxisLockingScrollView.mm: Added.
(-[WKAxisLockingScrollView initWithFrame:]):
(-[WKAxisLockingScrollView addGestureRecognizer:]):
(-[WKAxisLockingScrollView removeGestureRecognizer:]):
(-[WKAxisLockingScrollView _updatePanGestureToPreventScrolling]):
(-[WKAxisLockingScrollView _axesToPreventScrollingFromDelegate]):
(-[WKAxisLockingScrollView
gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer:]):
(-[WKAxisLockingScrollView gestureRecognizerShouldBegin:]):
Add the new internal scroll view subclass; see above for more details.
* Source/WebKit/UIProcess/ios/WKContentViewInteraction.mm:
(-[WKContentView setUpInteraction]):
(Drive-by): give these `_touchAction*SwipeGestureRecognizer`s human-readable
names, so that they're
easier to identify and debug.
* Source/WebKit/UIProcess/ios/WKVelocityTrackingScrollView.h:
Make the velocity tracking scroll view subclass `WKAxisLockingScrollView`
(`WKScrollView`, in turn,
subclasses this).
* Source/WebKit/WebKit.xcodeproj/project.pbxproj:
Canonical link: https://commits.webkit.org/271171@main
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