[magick-users] PNGs with palettes and multibit alpha channels

[Anthony Thyssen]

"Sam Kerner" on  wrote...
| Hello,
|     I have some PNGs which do not use a palette and have
| semi-transparent pixels.  Each image has fewer than 256 unique colors.
|  To reduce the size of these files, I would like to convert them to
| PNGs with a palette.  When I use 'convert in.png png8:out.png',
| out.png has a one-bit alpha channel, so the semitransparent pixels are
| no longer semi-transparent.  I also tried '-type palette' and '-colors
| 256', without success.
|     Can a PNG use a palette and have semi-transparent pixels?  If so,
| how do I create one with imagemagick?
| 
At this time no, not directly.

You can use optipng to convert to a 8bit pallete with semi-transparency
and you can use pngng to do color quantization to the same thing.


  Anthony Thyssen ( System Programmer )    <A.Thyssen at griffith.edu.au>
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    If your going to have delusions, you might as well go for the
    really satisfying ones.                   -- Marcus, Babylon 5
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     Anthony's Home is his Castle     http://www.cit.gu.edu.au/~anthony/