Make a line of same magnitude move in opposite direction at endpoint

xyValues = dlmread('Batman.txt');

xsLogo = xyValues(:,1);

ysLogo = xyValues(:,2);

%BatBeam

launchBeam = plot(xClic + xsLogo,yClic + ysLogo,'k');

hText = text(xClic,yClic,'BatBeam');

title('Alright, your laser is gonna fire now');

% Plot that point

plot(xClic, yClic)

xlim([0,100])

ylim([0,100])

hold on

% Compute y intercept for slope of 1

b = yClic+1*xClic;

% Plot the line between the click point and the y intercept

batBeam = plot([xClic,0],[yClic,b],'b--');

This code plots a dashed line depending where the user clicks and the line always ends when x=0. I want to start a new line of the same magnitude move in an opposite direction starting at the current endpoint. Any pointers? I need urgent help for a project and appreciate legitimate answers with a tangible conclusion.

[darova]

Can you show do you want the result to look like? (maybe simple drawing/picture)

[Aarav Shah]

Yes I can. Please give me a moment and stay on.

[Aarav Shah]

the point stops at x=0. at this point, it should bounce. in the opposite direction. thanks. @ darova

[darova]

To reflect this line

batBeam = plot([xClic,0],[yClic,b],'b--');

use

n = [xClick b-yClic];
n = 10*n/norm(n);
batBeam = plot([10*n(1),0],[10*n(2)+b,b],'r--');

[Aarav Shah]

That's awesome darova. Any chance to get that to happen a second/third time? This time bouncing off the top x axis and maybe the right y axis?

[darova]

Find intersection point and use vector again