Re: [ft-devel] [RFC] FT_LCD_FILTER_HEAVY

[Eric Rannaud]

On Sun, Nov 20, 2011 at 11:29 AM, Infinality <address@hidden>
wrote:> I second the idea of adding configurable LCD filter settings
to fontconfig!
So I wrote the attached patch for fontconfig, that I will submit to
the fontconfig ML.
With the patch and freetype2, lcdfilter=lcddefault would correspond to:
  <match target="font">    <edit mode="assign" name="lcdfilter">
<const>lcdcustom</const>    </edit>  </match>  <match target="font">
 <edit mode="assign" name="lcdfiltercustom">      <string>.0625 .25
.4375 .25 .0625</string>    </edit>  </match>
But it's not perfect, as users of the fontconfig API would have to
parse the lcdfiltercustom string themselves. I will ask if the
fontconfig developers see a better way of specifying a list of double.

Questions:- Would there ever be a good reason to not have a symmetric
FIR? Should be the option be specified as ".4375 .25 .0625" (first
half, reverse order) and assume symmetry for the other weights?- Could
the size of the filter be different? Or is 5 likely to be fairly
universal, even for other renderers?
- When specified from the center value ".4375 .25 .0625", missing
values can be assumed to be 0, and extra values can be ignored. I'm
tempted to specify the option this way instead, unless asymmetric
filters are useful.
Thanks.

0001-Add-lcdfiltercustom-option-controls-the-filter-indiv.patch
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