How would you calculate the degrees between two points on the edge of a circle in Swift.
Given points p1
, p2
on a circle with center center
,
you would compute the difference vectors first:
let v1 = CGVector(dx: p1.x - center.x, dy: p1.y - center.y)
let v2 = CGVector(dx: p2.x - center.x, dy: p2.y - center.y)
Then
let angle = atan2(v2.dy, v2.dx) - atan2(v1.dy, v1.dx)
is the (directed) angle between those vectors in radians, and
var deg = angle * CGFloat(180.0 / M_PI)
the angle in degrees. The computed value can be in the range -360 .. 360, so you might want to normalize it to the range 0 <= deg < 360 with
if deg < 0 { deg += 360.0 }