Path: utzoo!mnetor!uunet!tektronix!reed!percival!bucket!parsely!agora!rickc
From: rickc@agora.UUCP (Rick Coates)
Newsgroups: comp.graphics
Subject: Mapping algorithm question - NOT cartograpy
Message-ID: <844@agora.UUCP>
Date: 8 Apr 88 01:42:14 GMT
Organization: Advanced Solutions, Hillsboro, OR
Lines: 30
Keywords: 2d mapping

A new question:  I am interested in mapping one 2d area into another.
The first area may be rectangular, the second a collection of vectors
with four points defined as corresponding to the original rectangle's.

This is a 'rubber sheet' analogy, where you draw a picture on a stretchable
sheet, then deform it.

Any references?  The closest I have found is some references in older
ray tracing papers on texture mapping, but the articles just discuss
this as a concept, not how to do it.

I have seen this done - at SIGGRAPH 85 a French company had some
presentation graphics (? I think) running on a Tektronix 4115 that
seemed to do this, but I didn't have a chance to play with it.

I realize that this problem is not completely defined - behavior in
in extreme cases may be odd.  I am interested in any and all input.

Some other comments: it isn't necessary to transform lines or other
complex shapes, just points will do - long vectors can be broken into
short enough ones. Holes might be interesting (what happens if your
hole goes outside the outer boundary? Do you invert?).

Many thanks in advance,

Rick Coates

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