Attachment 461212 Details for Bug 243197 – Patch

[patch] Patch

bug-243197-20220725221437.patch (text/plain), 4.26 KB, created by alan on 2022-07-25 22:14:37 PDT

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Creator: alan

Created: 2022-07-25 22:14:37 PDT

Size: 4.26 KB

patch

obsolete

>From 124101aee5cb49454cb3ad737c1cfc954fae7185 Mon Sep 17 00:00:00 2001
>From: Alan Bujtas <zalan@apple.com>
>Date: Mon, 25 Jul 2022 21:52:09 -0700
>Subject: [PATCH] [LFC][IFC] Inconsistent integral rounding of baseline
> relative logical top values https://bugs.webkit.org/show_bug.cgi?id=243197
>
>Reviewed by NOBODY (OOPS!).
>
>Inline level box's logical top is relative to the parent inline box (mostly root inline box) baseline position. In most cases this translate to a negative top value. It later gets resolved to a value relative to the line box (turns the negative value to a positive one).
>
>The simplest case (assume a font metric with 16px ascent)
>  <div><span>baseline aligned content</span></div>
>produces a -16px 'top' for the <span>, relative to the root's baseline, which gets resolved to 0px relative to the line box (-> 16px (root's baseline value) + (-16px) (nested inline box's top) = 0px).
>
>This patches fixes the cases when (soon-to-be-removed) integral rounding produces incorrect top values by rounding 0.5 values to 1 while -0.5 to 0. Such (correct) rounding produces off-by-one resolved top values (e.g. root's baseline is at 10.5px. Nested inline box, in flush with the root, top computes to -10.5px. 10.5 rounds to 11 while -10.5 rounds to -10 and we end up resolving the inline box's top to 11 + (-10) -> 1 instead of 0.
>
>* LayoutTests/fast/inline/incorrect-integral-top-value-with-baseline-align-expected.html: Added.
>* LayoutTests/fast/inline/incorrect-integral-top-value-with-baseline-align.html: Added.
>* Source/WebCore/layout/formattingContexts/inline/InlineLevelBox.h:
>(WebCore::Layout::InlineLevelBox::setLogicalTop):
>---
> .../formattingContexts/inline/InlineLevelBox.h     |  2 +-
> ...ral-top-value-with-baseline-align-expected.html |  8 ++++++++
> ...ect-integral-top-value-with-baseline-align.html | 14 ++++++++++++++
> 3 files changed, 23 insertions(+), 1 deletion(-)
> create mode 100644 LayoutTests/fast/inline/incorrect-integral-top-value-with-baseline-align-expected.html
> create mode 100644 LayoutTests/fast/inline/incorrect-integral-top-value-with-baseline-align.html
>
>diff --git a/Source/WebCore/layout/formattingContexts/inline/InlineLevelBox.h b/Source/WebCore/layout/formattingContexts/inline/InlineLevelBox.h
>index 4e9219c990c2..4f3d89920c2f 100644
>--- a/Source/WebCore/layout/formattingContexts/inline/InlineLevelBox.h
>+++ b/Source/WebCore/layout/formattingContexts/inline/InlineLevelBox.h
>@@ -124,7 +124,7 @@ private:
>     // FIXME: Remove legacy rounding.
>     void setLogicalWidth(InlineLayoutUnit logicalWidth) { m_logicalRect.setWidth(logicalWidth); }
>     void setLogicalHeight(InlineLayoutUnit logicalHeight) { m_logicalRect.setHeight(roundToInt(logicalHeight)); }
>-    void setLogicalTop(InlineLayoutUnit logicalTop) { m_logicalRect.setTop(roundToInt(logicalTop)); }
>+    void setLogicalTop(InlineLayoutUnit logicalTop) { logicalTop >= 0 ? m_logicalRect.setTop(roundToInt(logicalTop)) : m_logicalRect.setTop(-roundToInt(-logicalTop)); }
>     void setAscent(InlineLayoutUnit ascent) { m_ascent = roundToInt(ascent); }
>     void setDescent(InlineLayoutUnit descent) { m_descent = roundToInt(descent); }
>     void setLayoutBounds(const LayoutBounds& layoutBounds) { m_layoutBounds = { InlineLayoutUnit(roundToInt(layoutBounds.ascent)), InlineLayoutUnit(roundToInt(layoutBounds.descent)) }; }
>diff --git a/LayoutTests/fast/inline/incorrect-integral-top-value-with-baseline-align-expected.html b/LayoutTests/fast/inline/incorrect-integral-top-value-with-baseline-align-expected.html
>new file mode 100644
>index 000000000000..80f4718baa0b
>--- /dev/null
>+++ b/LayoutTests/fast/inline/incorrect-integral-top-value-with-baseline-align-expected.html
>@@ -0,0 +1,8 @@
>+<style>
>+div {
>+  background-color: green;
>+  height: 50px;
>+  width: 50px;
>+}
>+</style>
>+<div></div>
>diff --git a/LayoutTests/fast/inline/incorrect-integral-top-value-with-baseline-align.html b/LayoutTests/fast/inline/incorrect-integral-top-value-with-baseline-align.html
>new file mode 100644
>index 000000000000..b3a0f7a88324
>--- /dev/null
>+++ b/LayoutTests/fast/inline/incorrect-integral-top-value-with-baseline-align.html
>@@ -0,0 +1,14 @@
>+<style>
>+div {
>+  background-color: red;
>+  float: left;
>+}
>+span {
>+ display: inline-block;
>+ background-color: green;
>+ height: 50px;
>+ width: 50px;
>+ vertical-align: 0.5;
>+}
>+</style>
>+<div><span></span></div>

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