[Webkit-unassigned] [Bug 50619] [GTK] Glyphs in vertical text tests are rotated 90 degrees clockwise

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=50619





--- Comment #16 from Koan-Sin Tan <koansin.tan at gmail.com>  2010-12-24 16:54:05 PST ---
(In reply to comment #15)
> > WebCore/platform/graphics/cairo/FontCairo.cpp:63
> > +        cairo_matrix_rotate(&fontMatrix, M_PI*0.5);
> Is there any reason this is better than M_PI / 2?

I think multiplication is cheaper than division :-)
How about M_PI_2? it seems most unix platforms have M_PI_2, and I can add
    #if !defined(M_PI_2)
    #define M_PI_2      1.57079632679489661923132169163975144   /* pi/2 */
    #endif

> > WebCore/platform/graphics/freetype/GlyphPageTreeNodeFreeType.cpp:48
> > +static bool substituteWithVerticalGlyphs(unsigned offset, unsigned length, const SimpleFontData* fontData, FT_Face face, GlyphPage* glyphPage)
> 
> Is this called for many glyphs? If so is there a lot of overhead for doing this over and over again for each one?
>

Yes, I already avoid those in isCJKIdeographs. Many glyphs have vertical forms, esp. in Japanese fonts. To reduce the overhead, the only way I can think of right now is to load and parse the table using freetype, cache it in memory.

> > WebCore/platform/graphics/freetype/SimpleFontDataFreeType.cpp:59
> > +    // if the font doesn't have vertical metrics, we don't rotate it 90 degress counterclockwise 
> > +    if (m_orientation == Vertical) {
> > +        FT_Face face = cairo_ft_scaled_font_lock_face(m_platformData.scaledFont());
> > +        if (!FT_HAS_VERTICAL(face))
> > +            m_orientation = Horizontal;
> > +        cairo_ft_scaled_font_unlock_face(m_platformData.scaledFont());
> > +    }
> > +
> 
> I still think it might be better to do this check in  FontPlatformData::initializeWithFontFace so that we can avoid undoing the rotation in drawGlyphs above.

OK, I'll try that.

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