I made a partial fix of this bug - https://bugs.winehq.org/show_bug.cgi?id=17982, only for the PATCOPY rop. It's based on the observation that the Polygon() function does support��arbitrary parallelograms, including when defined through the XFORM matrix, so for PATCOPY we can just delegate the implementation to it (with a NULL_PEN because PatBlt doesn't use a pen).

Is this patch acceptable? I have no idea if delegating to Polygon() will hurt performance. If that is a concern, I can do it only in case the physical coordinates after the world transform are not rectangular.

If it is, I will submit it to wine-patches, then.