Comment 26 for bug 80921

Looking at the poppler core and glib parts, it seems that the surface used is not a cairo-xlib, but a cairo-image surface. To me that sounds like a reasonable explanation for cairo not using the xlib options!

Maybe a solution would be to create temporarily a small xlib surface, copy its font options using cairo_surface_get_font_options() and apply them using cairo_set_font_options()?