NEW! Master Swift design patterns with my latest book! >>

How to find the scale from a CGAffineTransform

Paul Hudson       @twostraws

If you have a CGAffineTransform and want to know what its scale component is – regardless of whether it has been rotated or translated – use this code:

func scale(from transform: CGAffineTransform) -> Double {
    return sqrt(Double(transform.a * transform.a + transform.c * transform.c))
}

Available from iOS 2.0

Did this solution work for you? Please pass it on!

Other people are reading…

About the Swift Knowledge Base

This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.

Become a Swift expert

I wrote a book called Pro Swift that's dedicated to helping you master the Swift language, and it includes seven hours of video demonstrating each technique!

MASTER SWIFT NOW
Buy Practical iOS 12 Buy Pro Swift Buy Swift Design Patterns Buy Practical iOS 11 Buy Swift Coding Challenges Buy Server-Side Swift (Vapor Edition) Buy Server-Side Swift (Kitura Edition) Buy Hacking with macOS Buy Advanced iOS Volume One Buy Hacking with watchOS Buy Hacking with tvOS Buy Hacking with Swift Buy Dive Into SpriteKit Buy Swift in Sixty Seconds Buy Objective-C for Swift Developers Buy Beyond Code

Was this page useful? Let me know!

Click here to visit the Hacking with Swift store >>