Question

I’m not a programmer primarily, so this might be a simple answer.

I’m working on a script in Illustrator where you select three points and then it does stuff. First it makes a triangle. Then, it recreates two of the line segments in the triangle and rotates them 90 degrees. Then, I find the intersect of those points so that I can make a circumcircle.

I’m actually moving along quite well, but the only problem I don’t know how to solve at the moment is when two points that comprise the triangle have the same y-coordinates. When I make the perpendicular line, that line is vertical and therefore has no slope. It throws an error.

How do I account for a vertical slope with JavaScript? I was thinking about something along the lines of, “if the slope is NaN, then set the slope value to 9999999” or something like that, but this seemed a bit crude. Any better options?

Answer 1

You could normalise your gradient in the range -1 to 1. Anything larger than 1, or a NaN, is clamped at 1. The same goes for negative numbers, but with -1.