Error in indexed PNG output if number of colors <= 16

[xrw]

Conversion to an indexed PNG is erroneous if the number of colors in the input image is 1, 2, or 5 to 16, no matter if the input is indexed or not.

Example input

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~ $ convert in.png png8:out.png

Output

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~ $ convert -type palette in.png png8:out2.png

Output

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~ $ convert out2.png png8:out3.png

Output

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~ $ convert out3.png png8:out4.png

Output

Another example with a random image:

Input , output

This seems to be the same issue as for croco.png in this thread, but I opened a new thread because there was already confusion about 2 issues in 1 thread.

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~ $ convert -version
Version: ImageMagick 6.4.3 2008-08-20 Q16 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2008 ImageMagick Studio LLC

[magick]

We have a fix for the problem you reported in the Subversion trunk. It will also be available in the next point release.

[xrw]

I applied the patch from http://trac.imagemagick.org/changeset/11997 to 6.4.3-0 and it works for me now. Thanks for the quick fix!

BTW, this also seems to have fixed the bug with duplicate palette entries.