Legacy ImageMagick Discussions Archive

IM 6.8.0.5 Q16 Mac OSX Snow Leopard

Gradients saved as PNGs are not appearing correct and have repeated patterns. They work fine with GIF and JPG.

convert -size 300x500 gradient: tmp.png
vs
convert -size 300x500 gradient: tmp.gif
convert -size 300x500 gradient: tmp.jpg

Similarly with radial-gradient

Note this was not an issue in IM 6.8.0.4 Q16. I just tested that and it looked fine.

Something went wrong withreading and writing 16-bit images. I am seeing the
bug also, with Ubuntu-12.04 and IM-6.8.0-6 beta. works OK (except that the PNG is darker than the GIF but that's another problem).

[edit] Reverting to coders/png.c from IM-6.8.0-4 does not fix the problem.
Rebuilding IM-6.8.0-4 with coders/png.c from IM-6.8.0-5 still works properly
It seems that 16-bit samples are in a different endian storage now. I am looking with
suspicion at the changes to magick/quantum.c, magick/quantum-import.c and
magick/quantum-export.c that occurred between -4 and -5.

We can reproduce the problem and have a patch. Look for it in ImageMagick 6.8.0-6 Beta by sometime tomorrow.

Fix is checked in to coders/png.c in SVN revision 10018 (IM6) and 10019 (IM7).

verified that it is fixed in IM 6.8.0.6 Q16 Mac OSX Snow Leopard

A fix for the too-dark PNG image mentioned above is fixed in
SVN revision 10061, IM-6.8.0-8.