Comment 3 for bug 80921

Here is a proof-of-concept kludge. It’s a ~10 line patch that forces subpixel rendering in the cairo backend:
  <http://anders.kaseorg.com/pub/patches/poppler-subpixel.patch>

The major issue is that I disabled the clipping region. My debugging revealed that when the dimensions of the clipping rectangle translate to non-integral numbers of pixels, cairo fails to translate this rectangle into a pixman region in _cairo_traps_extract_region, and instead uses some fallback code that doesn’t support subpixel rendering. BTW, I wonder if this fallback code is also a performance problem...

I'm not familiar enough with Cairo to say what should be done about this, but maybe this will give someone else ideas.