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=>8. The 4-bit version does not work on my target platform. > > 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. Cheers, Jon. _______________________________________________ Magick-users mailing list [email protected] http://studio.imagemagick.org/mailman/listinfo/magick-users
