gdiplus: When copying an image do not round pixel positions up.

Vincent Povirk madewokherd at
Mon Aug 27 20:32:26 CDT 2012

> In my tests (which replicate the behaviour of a target application) if
> an image of say 10x10 pixels is being copied with a magnification world
> transform then the destination image has right/bottom border completely
> wrong, and my patch fixes this. Besides, bilinear interpolation does
> exactly that already - doesn't round pixel positions up, which contradicts
> your explanation.

The same rule about pixel centers applies with bilinear interpolation.
That means that at the lower-right corner of a stretched image you end
up with places where the lower-right pixel was blended with a pixel
from outside the image.

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