tree 9915b30a73241ac2a6d90e797feecbccdddb7cfa
parent d3065d04f42e2032bab878eaa06760bc197657d7
author carlosgc@webkit.org <carlosgc@webkit.org@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1557381987 +0000
committer carlosgc@webkit.org <carlosgc@webkit.org@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1557381987 +0000

REGRESSION(r239915): [FreeType] White space skipped when rendering plain text with noto CJK font
https://bugs.webkit.org/show_bug.cgi?id=197658

Reviewed by Michael Catanzaro.

Since r239915 we no longer overwrite control characters with zero width space, they are handled later when
filling the glyph pages. In Font::platformGlyphInit() there's an optimization to get the glyph of zero with
space character that assumes that control characters are always overwritten. Since the glyph for character at 0
index is always overwritten with zero width space, we can avoid loading the page for the actual zero width space
character and use the first page instead. In the particular case of noto CJK font, character at 0 is mapped to
the same glyph as space character, so space and zero width space end up being the same glyph. That breaks the
space width calculation, that returns 0 when isZeroWidthSpaceGlyph() is true. That's why spaces are no
longer rendered, ComplexTextController::adjustGlyphsAndAdvances() is setting the x advance for the space glyphs
to 0.

* platform/graphics/Font.cpp:
(WebCore::Font::platformGlyphInit): Use the actual zero width space page to get the glyph instead of 0 when
using FreeType.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@245094 268f45cc-cd09-0410-ab3c-d52691b4dbfc