[webkit-changes] [WebKit/WebKit] dc24dd: [IFC][truncation] Content gets truncated too early...

[Alan Baradlay]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: dc24ddb00a13231636ca62db45abd05ebc089b89
      https://github.com/WebKit/WebKit/commit/dc24ddb00a13231636ca62db45abd05ebc089b89
  Author: Alan Baradlay <zalan at apple.com>
  Date:   2023-04-26 (Wed, 26 Apr 2023)

  Changed paths:
    M LayoutTests/TestExpectations
    M LayoutTests/imported/w3c/web-platform-tests/css/css-ui/text-overflow-028.html
    M Source/WebCore/layout/formattingContexts/inline/display/InlineDisplayLineBuilder.cpp

  Log Message:
  -----------
  [IFC][truncation] Content gets truncated too early caused by subpixel flooring
https://bugs.webkit.org/show_bug.cgi?id=255991

Reviewed by Antti Koivisto.

This is caused by using LayoutUnit on block level to set the constraint value on the inline content,
while using InlineLayoutUnit (float) to accumulate inline content on the line.
e.g. <div width="10ch"> with ch length of 7.82px -> 78.2px which gets turned into a LayoutUnit : 5004.8 -> floored to 5004 raw value.

This is similar to what we do for regular line breaking at LineBuilder:availableWidth.

* LayoutTests/TestExpectations:
* LayoutTests/imported/w3c/web-platform-tests/css/css-ui/text-overflow-028.html:
* Source/WebCore/layout/formattingContexts/inline/display/InlineDisplayLineBuilder.cpp:
(WebCore::Layout::truncateOverflowingDisplayBoxes):

Canonical link: https://commits.webkit.org/263428@main