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

How to filter images using Core Image and CIFilter

Paul Hudson       @twostraws

Core Image is the one of the most powerful frameworks available to iOS developers: it makes hardware-accelerated image manipulation ridiculously easy, which means you get to add powerful graphical effects to your apps and games with very little work.

Most of the work is done by choosing the right CIFilter. Apple's official documentation goes into great detail about the various filters you can use, and you can also read Hacking with Swift project 13 for a hands-on tutorial showing off various effects. The code below applies a 50% sepia tone effect to an image:

let inputImage = UIImage(named: "taylor-swift")!
let context = CIContext(options: nil)

if let currentFilter = CIFilter(name: "CISepiaTone") {
    let beginImage = CIImage(image: inputImage)
    currentFilter.setValue(beginImage, forKey: kCIInputImageKey)
    currentFilter.setValue(0.5, forKey: kCIInputIntensityKey)

    if let output = currentFilter.outputImage {
        if let cgimg = context.createCGImage(output, from: output.extent) {
            let processedImage = UIImage(cgImage: cgimg)
            // do something interesting with the processed image
        }
    }
}

Available from iOS 5.0 – see Hacking with Swift tutorial 13

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.

Learn Server-Side Swift now!

Take your Swift code to the server and become a full-stack developer with my latest book: Server-Side Swift!

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 >>