Swift version: 5.6
You can calculate the distance between two CGPoints
by using Pythagoras's theorem, but be warned: calculating square roots is not fast, so if possible you want to avoid it. More on that in a moment, but first here's the code you need:
func CGPointDistanceSquared(from: CGPoint, to: CGPoint) -> CGFloat {
return (from.x - to.x) * (from.x - to.x) + (from.y - to.y) * (from.y - to.y)
}
func CGPointDistance(from: CGPoint, to: CGPoint) -> CGFloat {
return sqrt(CGPointDistanceSquared(from: from, to: to))
}
Note that there are two functions: one for returning the distance between two points, and one for returning the distance squared between two points. The latter one doesn't use a square root, which makes it substantially faster. This means if you want to check "did the user tap within a 10-point radius of this position?" it's faster to square that 10 (to make 100) then use CGPointDistanceSquared()
instead.
SAVE 50% To celebrate Black Friday, all our books and bundles are half price, so you can take your Swift knowledge further without spending big! Get the Swift Power Pack to build your iOS career faster, get the Swift Platform Pack to builds apps for macOS, watchOS, and beyond, or get the Swift Plus Pack to learn advanced design patterns, testing skills, and more.
Sponsor Hacking with Swift and reach the world's largest Swift community!
Available from iOS 2.0
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
Link copied to your pasteboard.