[EMAIL PROTECTED] on wrote... | Hello all, | I use an old LCD screen with proprietary graphics card as a digital | picture frame. Unfortunately the graphics card only allows "hicolor" mode | (16 bit/pixel) at full resolution due to it's limited vram. | Thus some images, especially those with smooth gradients (like blue skies | etc.) show a quite noticeable banding. My idea is now to dither (error | diffusion or whatever) the 24bits/pixel images to 16bits/pixel for | displaying them; this shouldn't be too big a problem I guess. | Is it possible to do this with ImageMagick, or do I have to code this | myself? I would only do the conversion with IM btw, for displaying the | images I have a small self-written app that mixes images from certain | sources. | 16bit/pixel is a special color mapping knonw as 556 color map that is 5bits of red, and green and 6 bits for blue. Check an make sure that is the case.
IM can do ordered dithering of that type directly -ordered-dither o8x8,5,5,6 Or you can create a 556 colormap and use a E-dither using the -map command. Both dither types (for a 332 color map) are shown on http://imagemagick.org/Usage/quantize/ Do not however save the image as JPEG as it will chnage the colros slightly, use PNG instead to feed you display program. Anthony Thyssen ( System Programmer ) <[EMAIL PROTECTED]> ----------------------------------------------------------------------------- ``"Set a new course. There's coffee in that nebula.'' Captain Janeway -- Startrek Voyager, ``The Cloud'' ----------------------------------------------------------------------------- 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
