Legacy ImageMagick Discussions Archive

On Windows 7 (64bit)

p:\tmp>magick -version
Version: ImageMagick 7.0.5-6 Q16 x64 2017-05-13 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2015 ImageMagick Studio LLC
License: http://www.imagemagick.org/script/license.php
Visual C++: 180040629
Features: Cipher DPC HDRI Modules OpenMP Delegates (built-in): bzlib cairo flif freetype jng jp2 jpeg lcms lqr openexr pangocairo png ps rsvg tiff webp xml zlib

Both of

p:\tmp>magick logo: PNG32:logo32.png
p:\tmp>magick logo: PNG64:logo64.png

generate all transparent image. However, no problem with the following:

p:\tmp>magick rose: PNG32:rose32.png
p:\tmp>magick rose: PNG64:rose64.png

I can confirm

magick logo: PNG32:logo32.png

produces fully transparent image on IM 7.0.5.6 Q16 Mac OSX

fmw42 wrote: ↑2017-05-18T09:13:56-07:00I can confirm

magick logo: PNG32:logo32.png

produces fully transparent image on IM 7.0.5.6 Q16 Mac OSX

It may or may not be helpful to solving the issue, but adding "-alpha set" after reading in the image outputs an image that is not transparent.

Yes, that does work (stop-gap). But IM 7 does not match IM 6 in this regard. In IM 6, that is not needed.

Perhaps it has to do with logo: being 8-bit palette and rose: being 24-bit color.

Confirmed that this bug exists in 7.0.5-0 and as far back as 7.0.1-0.
Version 6.9.8-5 produces a correct png32 but a fully transparent png64.