tiling pattern not rendered (singular matrix)
The example PDF drawing.pdf contains a pattern. It is easily visible in Firefox's PDF viewer.
poppler (e.g. in evince) fails to render this pattern:
pdftocairo drawing.pdf -png Syntax Error (159): Singular matrix in tiling pattern fill
This may be related to #190 (closed) because
pdftocairo page-332.pdf -png will also not show the pattern, but there is no error message /warning about a singular matrix.