Half-Tone Program for Monochrome Suns Wanted

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2 total messages Started by John S. Watson Wed, 15 Oct 1986 22:17

#1530

Author: John S. Watson
Date: Wed, 15 Oct 1986 22:17

21 lines
1392 bytes

/*********************************************************************/

Does anybody have a public domain half-tone program that will take
3 image files (Red Green and Blue), and produce a half-tone image/file, 
suitible for displaying in monochrome screen?  

Currently we have many monochrome Sun workstations, but only a couple of 
color Suns.  It would be nice to preview an image on the monochrome Sun 
a few times before fighting to get on the color Sun.  

I have the color-dither program that recently came accross the net, 
which takes 3 images files (RGB) and makes a color image for the color Sun, so
what I need is a program that does the same thing, only produces a monochrome
image.

Thanx in Advance,
John S. Watson
NASA Ames Research Center

ARPA: watson@ames-titan.arpa
UUCP: ...!nike!watson

Re: Half-Tone Program for Monochrome Suns Wanted

#1554

Author: Ponte
Date: Tue, 21 Oct 1986 14:05

22 lines
1625 bytes

In article <667@nike.UUCP>, watson@nike.UUCP (John S. Watson) writes:
> /*********************************************************************/
> 
> Does anybody have a public domain half-tone program that will take
> 3 image files (Red Green and Blue), and produce a half-tone image/file, 
> suitible for displaying in monochrome screen?  
> 

There is a simple formula to convert a color value (RGB) to a monochrome
value (Intensity).  It is the same way a color picture is shown on a black
and white TV.  The equation is:

          I = RED * 0.30 + GREEN * 0.59 + BLUE * 0.11

The percentage values used for multiplying all add up to 1.  (.3+.59+.11).
If this information does indeed answer your question, it wouldn't be hard
for you to write your own program to read in a color value (RGB) and spit
out an intensity value (I).

My source of information is "Introduction to Computer Graphics" by Foley
and VanDam.  If you have access to a copy of this book you may want to 
look at pg. 613, (Chapter 17.15).

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