Get the Slope and Intercept of drawn Lines

You have to draw a line in a graph to obtain the slope of a curve or of its tangent.

Description

 SYNTAX:
       [p1,p2,slope,inter]=getslopeintercept
 OUTPUTS:
       P1= coordinates of the first cliked point
       P2= coordinates of the second cliked point
       SLOPE= slope of the drawn line
       INTER= intercept Y(X=0)
 WHAT ?
       In the current figure, you have to draw a line between 2
       clicked points of a planar graph. The GETSLOPEINTERCEPT
       function then displays the slope and the intercept of the
       drawn line in a text box
 EXAMPLE
       plot([1:10],[1:10].^0.5,'-o')
       getslopeintercept

• MATLAB release: MATLAB 7.4 (R2007a)

[Matt Fig]

This really needs some improvement. Since there is no help of any value, I had to read a bit of the code to figure out what I was supposed to do.

>> plot(1:10)
>> getslopeintercept
??? Cell contents reference from a non-cell array object.
Error in ==> getslopeintercept at 21

Fix the code and have a look at the help for the Matlab function 'max' as an example of how to write the help for your function.

[Jean-Luc Dellis]

Thank you Matt. You were right and i have corrected the bug. It went from the kind of the output of the command
GET(findobj('type','line'),'Zdata')
which is SCALAR when only one line exists, and which is a CELL when several lines are available.
Now, GETSLOPEINTERCEPT can work with several lines and figures as well with only one. As we say in french "on a pas des métiers faciles" indeed when i worked on this function i had allways several open figure and didnt notice the variability of the output of the command. I apologize again.
Cheers,
JLD

[Jean-Luc Dellis]

Oops, i sent (26 march) the updated code... It is not still published. Please before downloading it, wait it appears corrected. You also can find it in the bottom of this page:
http://www.u-picardie.fr/~dellis/
Cheers,
JLD

[Jay]