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How to plot the second point of line at mouse location

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Dominik Mattioli
Dominik Mattioli on 31 Jul 2018
I'd like to plot a line defined by two points, one that is already selected in [x,y] space, and the other that is unselected, but previewed by plotting the second point at the current position of the mouse (get(h,'CurrentPoint')).
Additionally, a plot object shows the resulting line between these two points as the cursor moves in the window.
The second point is selected with a mouse click.


Greg on 1 Aug 2018
What have you tried so far? Where specifically are you stuck?
Dominik Mattioli
Dominik Mattioli on 1 Aug 2018
I'm trying to learn about the ButtonDownFcn, WindowButtonMotionFcn, and the other mouse callbacks. I don't think the documentation has any examples and it seems like you just need to "figure it out" on your own somehow, so I'm asking this question as an example problem.

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Answers (1)

KSSV on 1 Aug 2018
P = rand(1,2) ;
axis([-1 1 -1 1])
hold on
pts = zeros([],2) ;
for i = 1:10
[px,py] = getpts() ;
pts(i,:) = [px py] ;
plot(px,py,'.b') ;
plot([P(1,1) pts(i,1)],[P(1,2) pts(i,2)],'r')
double click , at a desired point when figure is opened.

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Dominik Mattioli
Dominik Mattioli on 1 Aug 2018
This is nice and very close to what I'm trying to do. I'm curious if you know how to make the plot update the second point as you move your cursor? Very similar to the imline function.

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