On Sun, Sep 24, 2000 at 10:08:42AM -0400, Kijang Jung wrote:
> I'm dealing with grayscale images dithered from 256-color, or true color
> images.
> In this case, Scanline and RLE are both NOT good to compress grayscales. So
> now I'm implementing LZW to compress grayscale images. LZW can compress
> grayscale image to about its half size.
LZW is supposedly patented, so if you aren't a licensee you might be
in for a fight; http://www.tuxedo.org/~esr/gif2png/ has some of the
info. PNG uses ZLib which doesn't have this problem.
> I already tested Scanline coding which is supported by PalmOS, especially by
> 'WinDrawBitmap() function. (so that it's very convenient to display the
> bitmap compressed with scanline coding.)
Is scanline just the bitmap indicating which bytes changed and then
only the changed bytes?
> If you need the scanline coding, let me know that. I will send you my code..
It would help if you would describe it (or post the core code).
--
For information on using the Palm Developer Forums, or to unsubscribe, please see
http://www.palmos.com/dev/tech/support/forums/
