How to crop a sprite using SKCropNode

Paul Hudson    February 13th 2018    @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

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