Re: Plotting line between mouse clicks

[Ethan A M. <merritt@u.washington.edu>]

On Sunday 23 March 2008 08:15, Rex Walburn wrote:
> Hi
> 
> I am trying to do this. The user plots any complicated curve.
> Then the user clicks at one point (x1,y1) on the graph plot and stores the
> value of MOUSE_X and MOUSE_Y in variables x_1 and y_1.
> Then the user clicks at another point (x2,y2) on the graph plot and stores
> the value of MOUSE_X and MOUSE_Y in variables x_2 and y_2.
> 
> I am trying to draw a line segment between the points (x_1,y_1) and
> (x_2,y_2).

set arrow N from x_1,y_1 to x_2,y_2 nohead
replot


 
> Is there anyway to do this from the commandline without having to dump the
> values of (x_1,y_1) and (x_2,y_2) into a text file in column format and then
> re-read it in gnuplot.
> I wrote a function my_line(x) = y_1 + ((y_2 - y_1)/(x_2 - x_1))*x and tried
> plotting it but it keeps giving me "all points y value undefined!" error.
> 
> How do I do this ?
> 
> Any help will be appreciated.
> 
> Thanks
> RW
> 

-- 
Ethan A Merritt
Biomolecular Structure Center
University of Washington, Seattle 98195-7742