REGRESSION(r182286): Tatechuyoko following ruby is drawn too far to the right

• Component: New Bugs
• Status: RESOLVED FIXED

[Myles C. Maxfield]

Tatechuyoko following ruby is drawn too far to the right

[Myles C. Maxfield]

Created attachment 264843 [details]
Patch

[Myles C. Maxfield]

Comment on attachment 264843 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=264843&action=review

> Source/WebCore/rendering/RenderBlockLineLayout.cpp:721
> +        return ForbidLeadingExpansion | ForbidTrailingExpansion;

This actually isn't quite right, for two reasons:

1. There may be a span inside the tatechuyoko
2. If an expansion opportunity is found inside the tatechuyoko, it should be forced to its neighbor (similar to ruby).

[Myles C. Maxfield]

Created attachment 264845 [details]
Patch

[Myles C. Maxfield]

<rdar://problem/22728382>

[Myles C. Maxfield]

Comment on attachment 264845 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=264845&action=review

> Source/WebCore/rendering/RenderBlockLineLayout.cpp:783
> +                    if (FontCascade::leadingExpansionOpportunity(downcast<RenderText>(previousRun->renderer()).stringView(), previousRun->box()->direction())) {

Trailing

[Myles C. Maxfield]

Comment on attachment 264845 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=264845&action=review

> Source/WebCore/rendering/RenderBlockLineLayout.cpp:801
> +            ASSERT(textBox.renderer().style().textCombine() == TextCombineHorizontal);
> +            if (nextRun && nextRun->renderer().style().textCombine() == TextCombineNone && textBox.renderer().style().collapseWhiteSpace()) {
> +                ASSERT(!setTrailingExpansion);
> +                setTrailingExpansion = true;
> +                result |= ForbidTrailingExpansion;
> +            }
> +            if (previousRun && previousRun->renderer().style().textCombine() == TextCombineNone && textBox.renderer().style().collapseWhiteSpace()) {
> +                ASSERT(!setLeadingExpansion);
> +                setLeadingExpansion = true;
> +                result |= ForbidLeadingExpansion;
> +            }

Turns out this is all dead code, since tatechuyoko, once combined, is modeled as the Object Replacement Character (U+FFFC), which will never have any expansion opportunities either inside it or directly adjacent to it. The first patch works just as well as this one, and is much simpler.

[Myles C. Maxfield]

Created attachment 264920 [details]
Patch for committing

[Myles C. Maxfield]

Committed r192120: <http://trac.webkit.org/changeset/192120>