[webkit-changes] [WebKit/WebKit] dc7fdb: Add RenderBox::lastLineBaseline and implementation...

[Sammy Gill]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: dc7fdb2e0a351c834cb5bd7e74eae44778e1cbcf
      https://github.com/WebKit/WebKit/commit/dc7fdb2e0a351c834cb5bd7e74eae44778e1cbcf
  Author: Sammy Gill <sammy.gill at apple.com>
  Date:   2022-10-05 (Wed, 05 Oct 2022)

  Changed paths:
    M Source/WebCore/layout/integration/inline/LayoutIntegrationLineLayout.cpp
    M Source/WebCore/layout/integration/inline/LayoutIntegrationLineLayout.h
    M Source/WebCore/rendering/RenderBlock.cpp
    M Source/WebCore/rendering/RenderBlock.h
    M Source/WebCore/rendering/RenderBlockFlow.cpp
    M Source/WebCore/rendering/RenderBlockFlow.h
    M Source/WebCore/rendering/RenderBox.h

  Log Message:
  -----------
  Add RenderBox::lastLineBaseline and implementation for block flow objects
https://bugs.webkit.org/show_bug.cgi?id=245792
rdar://100516446

Reviewed by Alan Bujtas.

In order to begin implementing last baseline alignment in various
sceanrios, we need to add a lastLineBaseline method in RenderBox similar
to how we have firstLineBaseline defined. This patch adds that method
along with an implementation for block items. Future patches that
implement last baseline alignment, such as for items in flex containers,
can use lastLineBaseline to get the last baseline of the items. Other
objects besides block objects will need an implementation as
necessary.

CSS Box Alignment Module Level 3 defines the last baseline of block
elements to be:  the dominant last baseline of the last in-flow line
box in the block container, or is taken from the last in-flow
block-level child in the block container that contributes a set of
last baselines, whichever comes first/last. The logic for this ends up
being very similar to the first baseline logic, but we are simply
starting from the last child and working our way up instead of the other
way around.

* Source/WebCore/layout/integration/inline/LayoutIntegrationLineLayout.cpp:
(WebCore::LayoutIntegration::LineLayout::firstLinePhysicalBaseline const):
(WebCore::LayoutIntegration::LineLayout::lastLinePhysicalBaseline const):
(WebCore::LayoutIntegration::LineLayout::physicalBaselineFromWritingMode const):
* Source/WebCore/layout/integration/inline/LayoutIntegrationLineLayout.h:
* Source/WebCore/rendering/RenderBlock.cpp:
(WebCore::RenderBlock::firstLineBaseline const):
(WebCore::RenderBlock::lastLineBaseline const):
* Source/WebCore/rendering/RenderBlock.h:
* Source/WebCore/rendering/RenderBlockFlow.cpp:
(WebCore::RenderBlockFlow::lastLineBaseline const):
* Source/WebCore/rendering/RenderBlockFlow.h:
* Source/WebCore/rendering/RenderBox.h:
(WebCore::RenderBox::lastLineBaseline const):
(WebCore::RenderBox::firstInFlowChildBox const):
(WebCore::RenderBox::lastInFlowChildBox const):
(WebCore::RenderBox::nextInFlowSiblingBox const):

Canonical link: https://commits.webkit.org/255179@main