Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!munnari.oz.au!murtoa.cs.mu.oz.au!ditmela!agi.oz!cn
From: cn@allgfx.agi.oz (Con Neri)
Newsgroups: comp.graphics
Subject: Inverse rendering?????
Message-ID: <1990Feb21.062501.9478@allgfx.agi.oz>
Date: 21 Feb 90 06:25:01 GMT
Distribution: comp
Organization: All Graphic R+D
Lines: 42

Does anybody know of an algorithm that can be used to derive the endpoints of
a line in a raster given the rendered points? The accuracy I wish to work to 
is 1/2 a pixel.

ie.	Given

		0 1 2 3 4 5 6 7 8 9 
 	       0| | | | | | | | | | | |
 		| | | | | | | | | | | |
 		| |X|X|X| | | | | | | |
 		| | | |X|X|X| | | | | |
 		| | | | | |X|X|X| | | |
 		| | | | | | | | | | | |

	the endpoints would be: (1,2.5) (5,5.5)

	AND
			
		0 1 2 3 4 5 6 7 8 9 
 		| | | | | | | | | | | |
 		| | | | | | | | | | | |
 		| |X| | | |X| | | | | |
 		| | |X| | |X| | | | | |
 		| | | |X| |X| | | | | |
 		| | | | |X|X| | | | | |
 		| | | | | |X| | | | | |
 		| | | | | | | | | | | |

	would produce: (1,2.5) (6,7.5) (6,2)

Any help or giudance in how to approach this problem would be much appreciated.
If you have any suggestions can you please e-mail rather than posting because
sometimes the gremlins eat up the news en route to OZ.

Thanks in advance.
CON NERI

All Graphic R+D				e-mail: cn@allgfx.agi.oz.au
73 Whiteman ST				tele:   +61-3-6966401
South Melbourne				tele:   +61-3-6464333
Vic 3205				tele:   +61-3-6906788
AUSTRALIA