After fixing bug 690868 - big part of page black (due to mask problem), it is found that page 3 of CATX0988.pdf contains a few non-90 degree rotated image are not rendered correctly. Non-90-degree rotated images are rendered as painted rectangles; rectangles are special cases and not using the code path for polygon path fills. I suspect there might be some 16-bit maths issues and/or rounding issue in that part as well. This is filed just so that I can keep track of unresolved issues but close the older bug.
Created attachment 5660 [details] x11 screenshot of pspcl6 This is how the problem looks like. The icon in the middle of the 4 tilted images is also wrong - ATM I have no idea why it is like that; it is not rotated (at least not from how I see it) but seems to show similiar problem as the tilted images.
Comment on attachment 5660 [details] x11 screenshot of pspcl6 derived from private files
The bug description is all wrong. The difference in appearance for page 3 of CATX0988.pdf is because the pdf uses zero-width clip paths quite extensively over the images, and zero-width clips are treated differently by gs and ghostpdl. Filing another bug.