[cairo] Clamping stroke weight rendering glyphs to a minimum size

[Peter Clifton]

Hi guys,

Is there any way when rendering glyphs with pango / cairo, to clamp the
stroke weight of the glyphs at some minimum size?

Rendering with Helvetica, once the schematic page is zoomed out in
gschem, the visual weight of all my text is fading due to anti-aliasing
of < 1px lines, and I'd like some way to control that. The fading is
causing a reduction in legibility when compared to our old line-font
rendered at that size. (I probably ought to let text fade out once it
gets _really_ small).

I've filed a bug against pango (#565158) which relates to a corollary of
this; in-spite the glyph strokes going below 1px, and fading out, pango
reports the metrics for an underline clamped to 1px - so if you render
using that metric, the resulting line _doesn't_ fade out.

Any ideas would be much appreciated.

Best regards,

-- 
Peter Clifton

Electrical Engineering Division,
Engineering Department,
University of Cambridge,
9, JJ Thomson Avenue,
Cambridge
CB3 0FA

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