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

How to crop a sprite using SKCropNode

Written by Paul Hudson    @twostraws

SpriteKit has a dedicated node type for handling cropping, and you can add things to it, position it where you want, then add it to your scene just like any other node.

However, its role is to crop the nodes it contains: when you assign a node to its maskNode property, SpriteKit looks at the colors of the mask and uses that to crop all the child nodes of the crop node. So, you might create an SKCropNode with five child nodes, then give it a circular mask node so that parts of the children are invisible. Everything that has a color in the mask won’t be cropped, and everything that is invisible will be.

Let’s look at some code. First you create and position your crop node:

let cropNode = SKCropNode()
cropNode.position = CGPoint(x: 50, y: 50)

Next you set its maskNode property to any SpriteKit node. Using a sprite node is easy enough:

cropNode.maskNode = SKSpriteNode(imageNamed: "cropMask")

Third you create a child node, position it inside the crop node, then add it to the crop node:

childNode = SKSpriteNode(imageNamed: "child")
childNode.position = CGPoint(x: 0, y: -90)
childNode.name = "character"
cropNode.addChild(childNode)

Finally add the crop node to your main scene:

addChild(cropNode)

Available from iOS 7.1

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.

Get six books for only $150

The Swift Power Pack includes my first six books for one low price, helping you jumpstart a new career in iOS development – check it out!

Click here to visit the Hacking with Swift store >>