[webkit-changes] [WebKit/WebKit] d7611e: Horizontal scrollbars unusable with rtl element

[Simon Fraser]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: d7611e7b6b1a052b3d55fefc52f620a45b6089ed
      https://github.com/WebKit/WebKit/commit/d7611e7b6b1a052b3d55fefc52f620a45b6089ed
  Author: Simon Fraser <simon.fraser at apple.com>
  Date:   2023-12-22 (Fri, 22 Dec 2023)

  Changed paths:
    M LayoutTests/platform/ios/TestExpectations
    A LayoutTests/scrollbars/scrollbar-drag-thumb-rtl-expected.txt
    A LayoutTests/scrollbars/scrollbar-drag-thumb-rtl.html
    M Source/WebCore/platform/ScrollableArea.cpp
    M Source/WebCore/platform/Scrollbar.cpp
    M Source/WebCore/rendering/RenderListBox.cpp
    M Source/WebCore/rendering/RenderListBox.h

  Log Message:
  -----------
  Horizontal scrollbars unusable with rtl element
https://bugs.webkit.org/show_bug.cgi?id=256995
rdar://109858866

Reviewed by Aditya Keerthi and Antti Koivisto.

Fix scroll offset/position confusion in ScrollableArea::scrollToOffsetWithoutAnimation().
In RTL, the offset is zero-based, but the position is relative to the scroll origin.

This also revealed offset/position confusion in RenderListBox, breaking vertical-rl
tests. Fix that code to do proper offset/position conversions.

* LayoutTests/platform/ios/TestExpectations:
* LayoutTests/scrollbars/scrollbar-drag-thumb-rtl-expected.txt: Added.
* LayoutTests/scrollbars/scrollbar-drag-thumb-rtl.html: Added.
* Source/WebCore/platform/ScrollableArea.cpp:
(WebCore::ScrollableArea::scrollToOffsetWithoutAnimation):
* Source/WebCore/platform/Scrollbar.cpp:
(WebCore::Scrollbar::moveThumb):
* Source/WebCore/rendering/RenderListBox.cpp:
(WebCore::RenderListBox::scrollToRevealElementAtListIndex):
(WebCore::RenderListBox::scrollToPosition):
(WebCore::RenderListBox::setLogicalScrollTop):
* Source/WebCore/rendering/RenderListBox.h:

Canonical link: https://commits.webkit.org/272466@main