"Alan M. Evans" on wrote...
| Hello!
|
| I've been trying for nearly two full days, and googling everything I can
| think. I'll be stuffed if I can figure out how to convert a large number
| of RGB PNG files into indexed PNG files. Surely this is a simple
| operation, no?
|
| The closest I've come is: "mogrify -colors 4 *.png". With version 2.6.8
| (Fedora Core 6) it does the conversion, but the resulting images are all
| jumbled up. With version 6.3.8 (Fedora 9), it changes the images
| somehow, and they all look fine, but leaves them as RGB.
|
| I've run out of ideas. Help me please!
|
For all the information you need see..
IM Examples, Common Image File Formats,
PNG Image File Format
http://www.imagemagick.org/Usage/formats/#png
IM only generates a indexed PNG by using the PNG8: output coder.
mogrify -format png8 *.png
OR
mogrify -type Palette *.png
WARNING: mogrify is dangerious, I recomend you do a test run on a copy
of the the images first, or use a -path to specify a alturnative output
directory.
See IM Examples, Basics, Mogrify
http://www.imagemagick.org/Usage/basics/#mogrify
WARNING: PNG8 is equivelent to GIF, 256 color limit, with one color
optionally made to represent transparency, and thus only boolean on/off
transparency. It does NOT support semi-transparency like a full index
PNG coder could.
See PNG Output Formats
http://www.imagemagick.org/Usage/formats/#png_formats
especially in the use of a "-type" setting to control the output.
Indexed PNG is generally regarded as being best performed by a dedicated
PNG compressor, such as "pngquant" or the newer one "pngnq".
See Non-ImageMagick PNG Processing
http://www.imagemagick.org/Usage/formats/#png_non-im
Anthony Thyssen ( System Programmer ) <[EMAIL PROTECTED]>
-----------------------------------------------------------------------------
The only way to discover the limits of the possible
is to go beyond them into the impossible. -- Arthur C. Clarke
-----------------------------------------------------------------------------
Anthony's Home is his Castle http://www.cit.gu.edu.au/~anthony/
_______________________________________________
Magick-users mailing list
[email protected]
http://studio.imagemagick.org/mailman/listinfo/magick-users
