possible bug -posterize with dither IM 6.8.1.10 Q16

Post any defects you find in the released or beta versions of the ImageMagick software here. Include the ImageMagick version, OS, and any command-line required to reproduce the problem. Got a patch for a bug? Post it here.
Post Reply
User avatar
fmw42
Posts: 25562
Joined: 2007-07-02T17:14:51-07:00
Authentication code: 1152
Location: Sunnyvale, California, USA

possible bug -posterize with dither IM 6.8.1.10 Q16

Post by fmw42 »

IM 6.8.1.10 Q16 Mac OSX Snow Leopard.

Using the example colorwheel.png image at http://www.imagemagick.org/Usage/quantize/#posterize, I see no difference with dither on or off with these commands


convert colorwheel.png +dither -posterize 3 show:
convert colorwheel.png -dither Riemersma -posterize 3 show:
convert colorwheel.png -dither FloydSteinberg -posterize 3 show:
convert colorwheel.png -posterize 3 show:

Is this a bug or am I missing something?
User avatar
anthony
Posts: 8883
Joined: 2004-05-31T19:27:03-07:00
Authentication code: 8675308
Location: Brisbane, Australia

Re: possible bug -posterize with dither IM 6.8.1.10 Q16

Post by anthony »

Dither does not work with posterize. I have no idea why, I reported it years ago.
Anthony Thyssen -- Webmaster for ImageMagick Example Pages
https://imagemagick.org/Usage/
Post Reply