v7 -distort changes gamma

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snibgo
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v7 -distort changes gamma

Post 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.
snibgo's IM pages: im.snibgo.com

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magick
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Re: v7 -distort changes gamma

Post 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.

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glennrp
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Re: v7 -distort changes gamma

Post 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").

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magick
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Re: v7 -distort changes gamma

Post by magick »

Try now.

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