possible bug MPC and histogram IM 6.9.1.0 Q16 Mac OSX

[fmw42]

For the the following command using MPC, I get an error:

Code: Select all

convert rose: rose.mpc
convert rose.mpc -define histogram:unique-colors=false histogram:- | convert - rose_hist.gif

convert: unable to open pixel cache `/var/tmp/magick-31255c8jH6vPkJTNn': No such file or directory @ error/cache.c/OpenPixelCache/3655.
convert: unable to persist pixel cache `/var/tmp/magick-31255c8jH6vPkJTNn' @ error/mpc.c/ReadMPCImage/944.
convert: no images defined `rose_hist.gif' @ error/convert.c/ConvertImageCommand/3212.



But it works fine with MIFF:

Code: Select all

convert rose: rose.miff
convert rose.miff -define histogram:unique-colors=false histogram:- | convert - rose_hist.gif

[magick]

Recall MPC requires 2 files, one for metadata and another for the image pixels. You can't use it for stdin / stdout. We'll investigate permitting the metadata to pass through stdin / stdout while writing the image pixels to disk. If that fails, we'll issue a better exception message. We'll need a few days to add the patch to ImageMagick.

[fmw42]

This worked in previous releases of IM. I will try to find out where it changed. It also fails in IM 7.

Note if need be I can switch to miff.


It worked at IM 6.8.6.10 and before and fails for 6.8.7.0 and after.

Nothing is obvious about any change to MCP in the changelog for 6.8.7.0

[magick]

We can reproduce the problem you posted and have a patch in ImageMagick 6.9.1-1 Beta, available by sometime tomorrow. Thanks.