[Fontconfig] Application fonts with Pango+fontconfig

Behdad Esfahbod behdad at behdad.org
Wed May 13 13:10:03 PDT 2015

On 15-05-13 06:17 AM, Khaled Hosny wrote:
> On Tue, May 12, 2015 at 03:34:59PM -0700, Behdad Esfahbod wrote:
>> On 15-05-10 12:10 PM, Khaled Hosny wrote:
>>> This seems to be a general Pango issue, if I modify a font while
>>> an application is using it, I get similar issues. 
>> This sounds like caching inside cairo messing things up.  I'll think about it.
>>  Not sure how to best address it...
> What is cached by cairo and how is that different from drawing the glyph
> on cairo directly rather than through pango-cairo?

In your old code you create FT_Face and pass it to cairo.  pangocairo however,
passes a FcPattern to cairo and let cairo create the FT_Face.  Cairo caches
FT_Face based on filename and face index, which obviously is broken here...

I have other issues with the cairo FT_Face handling to fix.  I might end up
considerably revamp cairo-ft internals (very tricky and time-consuming), or in
the mean time fix pangocairo to create its own FT_Face and pass to cairo.


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