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From: sbanner1@uvicctr.UUCP (S. John Banner)
Newsgroups: comp.graphics
Subject: Thining out a bitmap image.
Message-ID: <275@uvicctr.UUCP>
Date: Fri, 17-Jul-87 17:06:13 EDT
Article-I.D.: uvicctr.275
Posted: Fri Jul 17 17:06:13 1987
Date-Received: Sun, 19-Jul-87 20:47:08 EDT
Organization: University of Victoria, Victoria B.C. Canada
Lines: 29


    Hello,

    I have recently been called upon to write a program that takes
a bitmap image, and converts it to a second bitmap image, such that
no two points within a given radius of each other are left on.  I
have had a couple of suggestions given to me, but they all seem to
have some problems that I have knoticed (most noteably, grey scales
will get turned to "black", or "white").  What I am currently using,
is an algorithm where you read in a bunch of lines, then scan through
the image, point by point until you get to an on pixel, then blank
out everything within the given radius, and continue on.  The one
other restriction on the algorithm, is that the program should not
have to read in the entire bitmap (only a small fraction of the map
will fit, I currently keep about 10 or so scan lines in memory at any
given time, though I am sure that I can fit more, but just how many
more I don't know, as the resolution may get quite high).

		  Thanks in advance,

                      S. John Banner

...!uw-beaver!uvicctr!sol!sbanner1
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ccsjb@uvvm
sbanner1@sol.UVIC.CDN

PS.  (and I will summarize to the net, unless there is a great out
cry not to...  :-).     sjb