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Re: separate modifies channel values!
Posted: 2013-09-24T09:55:57-07:00
by shadowhand
Okay, it appears that 6.8.6-10 works well for Mac, but does not work properly on Linux:
Code: Select all
linux # convert -version
Version: ImageMagick 6.8.6-10 2013-09-24 Q8 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2013 ImageMagick Studio LLC
Features: DPC OpenMP
Delegates: bzlib fontconfig freetype jbig jng jp2 jpeg lcms ltdl lzma png png tiff xml zlib
linux # for file in alpha false-alpha no-alpha alpha-partial; do echo $file; convert "rgb-$file.png" -channel a -separate -format "%[fx:minima] %[fx:maxima]\n" info:; done
alpha
0 1
false-alpha
1 1
no-alpha
0 1
alpha-partial
0.501961 1
Still getting the wrong result for the no-alpha test file.
Re: separate modifies channel values!
Posted: 2013-10-02T19:42:43-07:00
by anthony
I am just wondering if the separation leaves a alpha channel present, though perhaps turned off (CF: -alpha off)
Perhaps %[fx:minima]; is not respecting the 'alpha switch', and still looking at left over data in the switched off alpha channel.
Re: separate modifies channel values!
Posted: 2013-10-08T09:23:38-07:00
by shadowhand
6.8.7 has the same issue under linux:
Code: Select all
linux # convert -version
Version: ImageMagick 6.8.7-0 2013-10-07 Q8 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2013 ImageMagick Studio LLC
Features: DPC OpenMP
Delegates: bzlib fontconfig freetype jbig jng jp2 jpeg lcms ltdl lzma png png tiff xml zlib
linux # for file in alpha false_alpha no_alpha alpha_partial; do echo $file; convert "rgb_$file.png" -channel o -separate -format "%[fx:minima] %[fx:maxima]\n" info:; done
alpha
0 1
false_alpha
1 1
no_alpha
0 1
alpha_partial
0.501961 1
Tests show that "no alpha" test is still failing under linux.
Re: separate modifies channel values!
Posted: 2013-10-23T20:04:10-07:00
by shadowhand
Bump? No new releases of IM in the last month?
Re: separate modifies channel values!
Posted: 2013-10-23T21:07:43-07:00
by fmw42
Re: separate modifies channel values!
Posted: 2013-10-24T15:59:08-07:00
by shadowhand
Still the same problem with latest release:
Code: Select all
linux # convert -version
Version: ImageMagick 6.8.7-2 2013-10-24 Q8 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2013 ImageMagick Studio LLC
Features: DPC OpenMP
Delegates: bzlib fontconfig freetype jbig jng jp2 jpeg lcms ltdl lzma png png tiff xml zlib
linux # for file in alpha false-alpha no-alpha alpha-partial; do echo $file; convert "rgb-$file.png" -channel a -separate -format "%[fx:minima] %[fx:maxima]\n" info:; done
alpha
0 1
false-alpha
1 1
no-alpha
0 1
alpha-partial
0.501961 1