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List:       freetype-devel
Subject:    [Devel] Re: FreeType performance issue
From:       Werner LEMBERG <wl () gnu ! org>
Date:       2004-12-28 7:27:45
Message-ID: 20041228.082745.26533677.wl () gnu ! org
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> [...]
>
> In 'ftgrays.c ' file, the 'gray_convert_glyph' function calls
> 'gray_compute_cbox' function first to get an glyph boundary.
>
> *gray_compute_cbox function costs O(n) - n is the number of points
>
> But in this time, I think FreeType can use (raster->target).width,
> (raster->target).height.  I think the code can be changed like this
>
>     /*gray_compute_cbox( RAS_VAR );*/                // Don't need
>     raster->min_ex = 0;                              // Added
>     raster->max_ex = (raster->target).width;         // Added
>     raster->min_ey = 0;                              // Added
>     raster->max_ey = (raster->target).height;        // Added
>     ...
>
> Would you tell me if there is any reason that I can't do like this?

I'm not an expert in optimizing C code for speed, but your change
looks promising.  After the 2.1.10 release (which should happen soon)
I invite you to contribute changes which makes FreeType faster --
please provide a patch produced with the `diff' program, using the
`-u' switch, together with a ChangeLog entry.

Thanks in advance.


    Werner

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