NEW: Nominations are now open for the 2019 Swift Community Awards! >>

How to filter images using Core Image and CIFilter

Swift version: 5.1

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
        }
    }
}

SAVE 20% ON iOS CONF SG The largest iOS conference in Southeast Asia is back in Singapore for the 5th time in January 2020, now with two days of workshops plus two days of talks on SwiftUI, Combine, GraphQL, and more! Save a massive 20% on your tickets by clicking on this link.

Available from iOS 5.0 – see Hacking with Swift tutorial 13

Similar solutions…

About the Swift Knowledge Base

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

MASTER SWIFT NOW
Buy Testing Swift Buy Practical iOS 12 Buy Pro Swift Buy Swift Design Patterns 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 Advanced iOS Volume Two 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 us know!

Average rating: 4.0/5