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On Sun, Jan 27, 2008 at 02:54:15PM +0100, Penguin Lover Erik squawked: |
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> I need to find the difference between images (like the text-file diff |
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> command, but for RGBA images). I tried "compare A.png A.png |
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> difference.png". This should obviously produce some kind of blank image |
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> because A.png and A.png are the same file, but for some weird reason the |
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> produced difference.png has recognizable content! Is there a fix for |
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> that bug or any other image diff program that is sane? |
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It seems that you do not understand how the compare function works |
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http://www.imagemagick.org/script/compare.php |
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The output image is the second image overlaid with a red "mask". The |
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pixels that are tinted red in the output shows the pixels that differ |
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from the original one. The ones that are not tinted red are unchanged. |
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So if you compare A to A, you will get something that looks like A |
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tinted by white. |
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What you want is something like |
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composite A.jpg -compose minus A.jpg Out.jpg |
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Look at |
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http://www.imagemagick.org/script/command-line-options.php#compose |
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to see what composite operators you can use for doing the comparison. |
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W |
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-- |
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Heineken (/hnkt/)... since the second millennium B.C., middle kingdom. |
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Sortir en Pantoufles: up 415 days, 16:27 |
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