I have found a PDF file, which looks horrible when rendered with poppler-glib or pdftocairo. It does render (mostly) fine in okular, so I guess it's either specific to poppler-glib or the cairo backend.
You can reproduce that bug with:
pdftocairo -png -r 90 -f 15 -l 20 exphy.pdf
or with Evince.
I am using archlinux with poppler 0.20.0 and cairo 1.12.2, but it also happens on a gentoo system with 0.18.4 and 1.10.2.
P.S.: I also experiences crashes when rendering this PDF file to a cairo PDFSurface, but only if I would use poppler_page_render() instead of render_for_printing().
Created attachment 62919 [details]
the problematic PDF (shortened. used to be 15MB in size)
The problem is with rendering bitmap fonts (e.g. TeX Type 3 fonts), or embedded black and white images, such as scanned images. Some 5 years ago there was a discussion of this on Ubuntu launchpad with a few examples that are still displayed without antialiasing in poppler/cairo even using poppler 0.26.5.
-- GitLab Migration Automatic Message --
This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.
You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/poppler/poppler/issues/487.