RE: [Freetype] improving render quality

[Turner David]

Hello Steve,

> -----Original Message-----
> From: address@hidden 
> [mailto:address@hidden
> Behalf Of Steve Dekorte
> Sent: Friday, January 16, 2004 10:05 PM
> To: address@hidden
> Subject: [Freetype] improving render quality
> 
> 
> 
> Attached is an image of the same font (LucidaGrande) rendered on the 
> left with FreeType and on the right with the native OSX font 
> renderer. 
> Notice how the OSX version is cleaner and smoother? 

Well, this is a very subjective statement. Some people will prefer
the left image undoubtedly. I know I do :-)

> Is there any way I can get the FreeType version to look as
> good? Perhaps by tweaking some smoothing options? (I have
> access to the source code)
> 
The best way is the following:

  - disable hinting when loading glyph images (for those who
    didn't realize it, MacOS X doesn't perform hinting at all
    by default !!)

  - filter the resulting image with a convolution kernel
    to make the image sharper / more contrasted if you need
    to

  - don't forget to use gamma-corrected alpha-blending when
    drawing text on your target surfaces.

this should get you very, very close to what MacOS X gives
you. Extra points for finding the ideal convolution kernel
(i.e. fast to implement while giving good quality)

Regards,

- David Turner
- The FreeType Project  (www.freetype.org)

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