[cairo] Userfont hinting

Peter Clifton pcjc2 at cam.ac.uk
Thu May 8 09:46:39 PDT 2008

On Thu, 2008-05-08 at 17:13 -0400, Behdad Esfahbod wrote:

> Tonight I plan to break it down to a series of commits and go ahead and
> push it to master.


> In the mean time I found that I may need to tweak a few things to allow
> supporting subpixel rendering with user fonts in the future.  I don't
> like where the thinking got me (which was, making cairo-scaled-font.c do
> subpixel rendering if the backend doesn't support it).  But in the mean
> time I'm going to make the following change:
>   - After the render_glyph function returns, we'll inspect its set font
> options and use that to decide what kind of image surface to use.  If it
> has hinting off, we use A1.  If it has subpixel on, we'll use ARGB32.
> So this will make the scaled font options decide the glyph format
> automatically, but if your user font render functions decides to, it can
> override that decision.  This affects our longer term plan to support
> ARGB glyphs there are not subpixel masks, but real colored glyphs...
> So yeah, look for user-fonts merging tomorrow.

Will do.

>From the above description, I guess the proposed changes won't affect
the aliasing I was seeing at certain sizes. Did you see those yourself,
or did I mess up my re-base?

Could that be a numerical precision issue, or am I misusing the API?

Peter Clifton

Electrical Engineering Division,
Engineering Department,
University of Cambridge,
9, JJ Thomson Avenue,

Tel: +44 (0)7729 980173 - (No signal in the lab!)

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