[cairo] PDF text doesn't render

[Adrian Johnson]

Lichtl, Adam wrote:
> Hi Carl,
> 
> Attached are two more files which really get to the root of my pdf problem.
> The "sample_ps2pdf.pdf" file is perfect - it was made from a .tex file
including
> the .ps graphics from cairo, and was created by "latex" followed by
"ps2pdf."
> The "sample_pdflatex.pdf" is made from a .tex file including the .pdf
graphics
> from cairo, and is a mess -- it only looks reasonable on acroread
(although the
> colors looked washed out when compared to "sample_ps2pdf.pdf"!)
> 
> Can this be fixed in cairo?
> 
> Thanks,
> -Adam

sample_pdflatex.pdf looks fine in xpdf 3.02, and ESP Ghostscript 8.15.

If the cairo generated PDF file looks fine in acroread before it is
embedded by pdflatex this suggests that it is a pdflatex bug. The washed
out colors is due to the RGB colors being converted to CMYK and blended
in CMYK color space then converted back to RGB. Cairo had the same
problem in versions prior to 1.4.2. It was fixed by specifying the color
space to do the blending by putting "/CS /DeviceRGB" in the transparency
group in the PDF. Looking at the sample_pdflatex.pdf file, the "/CS
/DeviceRGB" has been stripped out. This is a problem with pdflatex.