Re: [AD] slow fonts

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On Tue, 2009-07-28 at 22:57 -0700, Paul Suntsov wrote:

> I've traced down the problem (at least on my machine) to the
> invocation of FT_Load_Glyph. According to the FreeType documentation
> this function is very slow, and removing its call from the addon sped
> up ex_ttf 3-4 times for me. The only thing we use FT_Load_Glyph during
> normal operation (i.e. after we cached the glyph) is to get the new
> advance values. I figured that there should be no problem in caching
> these advance values, so that FT_Load_Glyph call can be eliminated. In
> my testing I did not see any apparent difference between cached and
> non-cached versions of the code, while seeing significant speedup:
> ex_ttf went from 150 FPS to 550 FPS for me. The diff is attached.

Really nice.

You must have better documentation than me. All the Freetype examples
have a call to FT_Load_Glyph for each glyph (and all it does according
to the docs is fill in the FT_Face->face slot, which would not take any
time). So I'd never have looked at this for speed improvement, with not mention anything. Seems this function actually did a lot more though.

Elias Pschernig <elias@xxxxxxxxxx>

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