The code in render/picture.c assumes that if the source drawable doesn't have alpha then the source doesn't have alpha, but that isn't true for RepeatNone - sampling off the edge of the picture will introduce alpha. Will attach a patch fixing the problem. It doesn't try to perfectly capture every case where the optimization *is* possible, though it does catch the simple common case where there is no transform on the source picture.
Created attachment 15706 [details] [review] The patch
Fixed in 1.5 branch and master, thanks!
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