Finds the angle relative to the origin 0,0, given an X and Y coordinate. For instance, vectorToAngle(100,200)=63.435. You can also find the angle relative to an offset - for instance, vectorToAngle(x-x',y-y'). VectorToAngle(100-200,150-250) will find the angle between the points 100,150 and 200,250, or -135 degrees.