"Jon Perkin" on wrote...
| Hi Forest.
|
| > > If one of my images has 16 colours or less, PerlMagick 'cleverly'
| > > creates a 4-bit (16-colour palette) PNG image, even if I've
| specified
| > > depth=3D>8. The 4-bit version does not work on my target platform.
| >=20
| > This sounds like a case of a brain-damaged implementation on the
| target
| > platform, as the PNG > spec is entirely designed to do this sort of
| > optimization.
|
| I agree that full PNG support means supporting 4-bit images. However, I
| would have thought that if I explicitly specify 8-bit, Image Magick
| should produce 8-bit.
|
| My target platform is as I said an embedded platform (a wide variety of
| digital TV Set-Top Boxes to be precise), and support for 4-bit images
| was initially omitted because code size is extremely tight on the STBs.
| As it happens, support for 4-bit has since been added, but I have to
| support STBs running older firmware.
|
| I have found a solution: a little command-line utility called PNGOUT
| which optimises PNG images but has the option to force an 8-bit palette.
| PNGOUT gives me 8-bit output files that are smaller than the 4-bit input
| files I created using Image Magick. Thanks to Ken Silverman for PNGOUT.
|
I have added a link to this from the Non-IM PNG utilities section of IM
examples...
http://imagemagick.org/Usage/formats/#png_non_im
Anthony Thyssen ( System Programmer ) <[EMAIL PROTECTED]>
-----------------------------------------------------------------------------
"[A computer is] like an Old Testament god,
with a lot of rules and no mercy." --- Joseph Campbell
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Anthony's Home is his Castle http://www.cit.gu.edu.au/~anthony/
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