[Image-SIG] Pasting with pixmaps broken in 1.0 final?

Fredrik Lundh fredrik@pythonware.com
Fri, 3 Dec 1999 13:30:29 +0100

I wrote:

> Robert Kern <kern@its.caltech.edu> wrote:
> > Under 1.0b1, the image is a square gradient going from red to green on a
> > red background.  Under 1.0 final, the image has the left half of the
> > gradient the same as previous, but the right half is a solid light blue,
> > no gradient at all.
> > 
> > Something in ImagingFill2 perhaps?
> I can repeat the problem it on other platforms, so
> I guess I cannot blame your compiler ;-)
> it's probably a signed/unsigned problem.  I'll look
> into it as soon as I find some time to spare.

a quick look reveals that the code in Paste.c
is completely braindead: filling with constant
colors and matte masks ("L" and "RGBA") simply
doesn't work.

filling with binary masks (mode "1") works fine,

a rough workaround is to emulate what earlier
versions did: create a new image with the same
size as the pasted area and the fill colour, and
paste it. e.g:

    x0, y0, x1, y1 = bbox
        Image.new("RGB", (x1-x0, y1-y0), color),
        bbox, mask

I'll post patches for Paste.c during this weekend
(and update our regression test suite...)