init(rect:in:)

Declaration

convenience init(rect: CGRect, in texture: SKTexture)

Parameters

• rect:

  A rectangle in the unit coordinate space that specifies the portion of the texture to use.

• texture:

  The texture to create the new texture from.

Mentioned in

• Maximizing Node Drawing Performance

Return Value

A new texture object.

Discussion

The returned texture object shares the same texture data as the original texture object, meaning that only one copy of the texture data is kept in memory.

If you call this method on a texture that itself was created using this method, the original texture is used as the source instead. That is, the rectangle is considered to be in the source texture’s coordinate system. To do this, you should use the source texture’s textureRect() rather than relying on hard coded {(0,0) (1,1)} as the coordinates.

Listing 1 shows, in Swift, how you can use the source texture’s textureRect() to calculate the portion of the texture to use.

Listing 1. Creating a texture from a portion of another texture.

let originalTexture = SKTexture(imageNamed: "sourceImage.png")

let rect = CGRect(origin: originalTexture.textureRect().origin,
                  size: CGSize(width: originalTexture.textureRect().midX,
                               height: originalTexture.textureRect().midY))

let croppedTexture = SKTexture(rect: rect,
                               in: originalTexture)

In the above example, if originalTexture had a size of (348.0, 282.0) and a textureRect() of {(0,0) (1,1)}, croppedTexture will have a size of (174.0, 141.0) and a textureRect() of {(0,0) (1,1)}. croppedTexture will be a copy of the bottom left quadrant of originalTexture.