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v7 -distort changes gamma

Posted: 2016-06-12T14:10:54-07:00
by snibgo
Initially reported in thread viewtopic.php?f=1&t=29895

In v7.0.1-4 (Windows 8.1), all the "-distort" options change the gamma to 0.4545 (without changing the pixel values).

For example:

Code: Select all

f:\web\im>%IMG7%magick -size 1x100 gradient: -grayscale Rec709Luminance -verbose +write info: -distort Barrel "0,0,1" -verbose info: |findstr Gamma

  Gamma: 1
  Gamma: 0.454545

f:\web\im>%IMG7%magick -size 1x100 gradient: -grayscale Rec709Luminance -verbose +write info: -distort Shepards "0,0,1,1" -verbose info: |findstr Gamma

  Gamma: 1
  Gamma: 0.454545

f:\web\im>%IMG7%magick -size 1x100 gradient: -grayscale Rec709Luminance -verbose +write info: -distort SRT "1,0" -verbose info: |findstr Gamma

  Gamma: 1
  Gamma: 0.454545
"findstr" is a Microsoft version of grep.

This problem did not occur in v6.9.2-5.

Re: v7 -distort changes gamma

Posted: 2016-06-12T16:43:13-07:00
by magick
Thanks for the problem report. We can reproduce it and will have a patch to fix it in GIT master branch @ https://github.com/ImageMagick/ImageMagick later today. The patch will be available in the beta releases of ImageMagick @ http://www.imagemagick.org/download/beta/ by sometime tomorrow.

Re: v7 -distort changes gamma

Posted: 2016-06-12T16:50:10-07:00
by glennrp
I don't see "-grayscale <colorspace>" listed among the commandline options at http://imagemagick.org/script/command-l ... php#option (although "-grayscale <method>" does show up on the help screen if I type "magick convert").

Re: v7 -distort changes gamma

Posted: 2016-06-12T17:35:07-07:00
by magick
Try now.