In order to support blend modes, we need to use a clear background
whilst rendering the PDF, which inspired the use of DEST_OVER to avoid
having to render to an intermediate surface. However, the adjunct of
using subpixel text means that we cannot simply using the alpha channel
as the sole mask and so need to render to an intermediate and paint it
over an opaque background.
This reverts commit 506b2ebe71.
We have conflicting requirements here. In order to support extended
blend modes correctly we need to use DEST_OVER, at the expense of
supporting subpixel text. More thought required.
Using DEST_OVER in this form to paint the background white fails in the
presence of subpixel geometry (particular text), so remove the hack and
simply paint the background white prior to passing the surface to
poppler. KISS.
This introduced a rather gratuitous dependency on a newer version of
poppler, which caused a fair amount of pain for no significant
benefit.
This reverts 253472492e commit.
Build pdf2png if possible.
Add support for testing the PDF backend.
New utility program to convert a PDF file into a PNG image using poppler (thanks to Kristian Høgsberg).
Ignore new stuff generated by PDF backend testing.
