HELP! Its Those Damned Colormaps!

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2 total messages Started by Jeff Michel Tue, 22 Dec 1992 19:57

#609

Author: Jeff Michel
Date: Tue, 22 Dec 1992 19:57

24 lines
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I *hope* this is a FAQ.

I'm doing frame-by-frame animation on Sun-4's.  My approach is to
put up sequences of images converted to the Sun-specific, video-RAM specific
(pixrect) format and colormap format (pixrect) of the graphics hardware (cg6) of
the machine.  (This graphics architecture makes use of a 24-bit, 256 color
colormap.)

The problem with this approach has been that when the colormaps of two
consecutive images in the sequence differ, there is a brief instant during which
the colormap for the previous image is loaded, but the image loaded on the screen
needs a different colormap.  The result of this is an annoying *flicker*.  Are
you nodding your head?  Have you seen this problem?

What I'd like is for all of the video-RAM format images to have the *same*
colormap so that the problem of flicker never arises.  So, after three
paragraphs, my question is: "Is there any software available which will allow me
to normalize the colormaps of a sequence of Sun rasterfile images into *one*
common colormap including all or most of the colors of the images of the
sequence?"  If not for Sun, then is there source code for the normalization of
*any* colormap-oriented graphics architecture (eg. VGA)?

Thanks,
Jeff Michel	jrm2k@Virginia.EDU

Re: HELP! Its Those Damned Colormaps!

#610

Author: Richard Ottolini
Date: Wed, 23 Dec 1992 00:35

13 lines
1264 bytes

In article <1992Dec22.195753.8789@murdoch.acc.Virginia.EDU> jrm2k@uvacs.cs.Virginia.EDU (Jeff Michel) writes:
>paragraphs, my question is: "Is there any software available which will allow me
>to normalize the colormaps of a sequence of Sun rasterfile images into *one*
>common colormap including all or most of the colors of the images of the
>sequence?"  If not for Sun, then is there source code for the normalization of
>*any* colormap-oriented graphics architecture (eg. VGA)?

Yes,, but it it is tedious.
The pbmplus system distributed with XWindows.
First  convert all images to ppms.
Then the ppmquant program will reduce the entire set or subset to a common
color table of arbitray size.
Then convert back to the original format.

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