Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!suntc!jh34607
From: jh34607@suntc.UUCP (john howell)
Newsgroups: comp.lang.postscript
Subject: Full Color Raster Images in PostScript - How?
Keywords: Color, Image
Message-ID: <144@suntc.UUCP>
Date: 7 Dec 89 19:06:44 GMT
Organization: Deere & Co. Technical Center, Moline,IL
Lines: 33

I am writing a PostScript file/program that has a color raster image as
part of it.  When I refered to the RED BOOK I noticed the following
footnote:

	At present, the POSTSCRIPT language does not provide a way to
	represent full color in a single image.  However, under suitable
	conditions, full color can be represented as three color
	separations each defined by a gray-scale image.  Such image
	processing is beyond the scope of this manual.

OK, in my case I have two situations:
	1)	Raster image data is encoutered as a single scan line
		consisting of RGB full color pixels.
	2)	Raster image data is encountered as a rectangular block
		very much like the regular gray scale images, except the
		block consists of RGB pixels.
I was hoping to use the "image" descriptor, but it appears unavailable.
Another way would be to draw each pixel as a small filled rectangle and
I could probably do some run length encoding, but this seems excessive.

Can someone recommend a way to handle these images ... perhaps a
reference to the color separation technique described in the RED BOOK?

Thanks.


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