How to plot the second point of line at mouse location

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]

What have you tried so far? Where specifically are you stuck?

[Dominik Mattioli]

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.

Answer 1

[KSSV]

P = rand(1,2) ;
figure
axis([-1 1 -1 1])
hold on
plot(P(1,1),P(1,2),'.r')
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')
    drawnow
end

double click , at a desired point when figure is opened.

[Dominik Mattioli]

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.