Legacy ImageMagick Discussions Archive

convert -version
Version: ImageMagick 6.6.7-7 2011-02-13 Q16 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2011 ImageMagick Studio LLC
Features:

Mac OSX Tiger (Powerpc)

Glenn,

1) The following still shows no transparency

convert logo: -transparent white -type palettematte PNG8:logo_test1.png


2) And the following also shows no transparency

convert logo: -transparent white miff:- | convert - -type palettematte PNG8:logo_test2.png

3) But the following works:

convert logo: -transparent white gif:- | convert - -type palettematte PNG8:logo_test3.png

Fred

I'm fighting situations where the PNG decoder has to guess whether it's the colormap that is bogus or the pixel opacities that are bogus. Every time I sqash one of those, then we start losing transparency again. In this particular case (my "problem 41") the PNG decoder is handed image->matte==MagickTrue and a 256-color colormap with no transparent entry. If I fix that, then my "problem 42" will be broken again. It seems that if I omit the "-type palettematte" option I get what you want (except the wizard's beard is transparent so you probably want to do a floodfill instead.

Glenn,

OK. I can live with

convert logo: -transparent white gif:- | convert - -type palettematte PNG8:logo_test3.png

until you find a better solution.


I was just reminding you of the problem that you had noted earlier and was not sure if you had thought you had implemented a solution, yet, that was not working again. But apparently you are on top of it, but have not a good solution, yet, to implement. So I can wait.

Thanks

Fred

I am also losing transparency if I write a MIFF instead of a PNG. It seems that
the "-type palettematte" option is the source of the problem, not the PNG encoder.

Glenn