From help-request at octave dot org Sat May 15 12:00:46 2004
Subject: RE: Draw a line through 2 points
From: (Ted Harding) <Ted dot Harding at nessie dot mcc dot ac dot uk>
To: Sue Stones <suzo at spin dot net dot au>
Cc: help at octave dot org
Date: Sat, 15 May 2004 15:57:30 +0100 (BST)

On 15-May-04 Sue Stones wrote:
> How do I draw a line through 2 points.  Not just between the points
> but going off the graph on either side?
> 
> sue

You can do it by specifying two other points to define a line which
includes the two given points.

e.g. (adjust t1, t2 to your taste; the values below extend the line
between p1 and p2 to either side by 10 times the distance between
p1 and p2):

  p1=[x1;y1]; p2=[x2;y2];
  t1=(-10); t2=(+10);
  P1=p1 + t1*(p2-p1) ; P2=p2 + t2*(p2-p1);

Now draw a line from P1 to P2 (when t1=0 and t2=0 you get the original
points p1 and p2).

Hope this helps,
Ted.


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Date: 15-May-04                                       Time: 15:57:30
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