Since revision 13011 (http://trac.imagemagick.org/changeset/1 ... /enhance.c), the LevelColorsImageChannel function always returns 0 (MagickFalse).
This causes RMagick's level_colors to fail with recent ImageMagick versions (https://github.com/rmagick/rmagick/issues/94).
The 'status' variable is initialized to MagickFalse (http://trac.imagemagick.org/browser/Ima ... ce.c#L3283), and remains MagickFalse since status&=MagickTrue is still MagickFalse. It should probably be initialized to MagickTrue.
LevelColorsImageChannel returns wrong status
Re: LevelColorsImageChannel returns wrong status
We can reproduce the problem you posted and have a patch in ImageMagick 6.8.8-2 Beta available by sometime tomorrow. Thanks.