[cairo] Cairo, pango and Win32.. incorrect font rendering

[Peter Clifton]

On Sat, 2010-01-16 at 14:12 +0000, Peter Clifton wrote:
> Hi guys,
> 
> Vague I know, but I wondered if this rang any bells.
> 
> The gEDA suite (electronic design tools) now uses cairo and pango to
> render its schematics. This works really well on Linux, and on Mac OSX
> when the right magic is used to build it.
> 
> However, I've just cross-built for Win32, which has worked in the past,
> and have had reported issues of text rendering at the wrong size.
> 
> (See screen-shot here:
> http://www.xs4all.nl/~ljh4timm/downloads/gschem-1.6.0_add_text_testing.png
> )
> 
> The same program works fine under Wine, but fails under Win32. No other
> font rendering in the program, or the toolkit is affected.
> 
> I built with pango-1.26.0 and cairo 1.8.8.
> 
> Configure logs attached.
> 
> Does anyone have any ideas how to debug this (I have no access to a
> Windows machine), or ideas as to what might be wrong?

Further debug info:

The bounding boxes of the characters remain approx. the same size no
matter how you zoom in or out.

http://www.xs4all.nl/~ljh4timm/downloads/gschem-1.6.0-full%20screen.png
http://www.xs4all.nl/~ljh4timm/downloads/gschem-1.6.0-zoomed%20in.png
http://www.xs4all.nl/~ljh4timm/downloads/gschem-1.6.0-max%20zoomed%
20in.png


This sounds _very_ similar to a bug reported by a user who compiled it
on Mac OS X without the "right" config. In that case, the fonts didn't
scale either - but were reportedly shown much larger.

So I'm guessing this could be our code doing something wrong, or at
least something which doesn't work for non free-type backends. The fact
if behaves differently across different backends does suggest some
inconsistency in them though - even if I'm doing something stupid with
the APIs.

Best wishes,

Peter C.