# decode Returns the decode array for a bitmap image. ``` var decode: UnsafePointer? { get } ``` ## Discussion For a bitmap image or image mask, for each color component in the source color space, the decode array contains a pair of values denoting the upper and lower limits of a range. When the image is rendered, a linear transform maps the original component value into a relative number, within the designated range, that is appropriate for the destination color space. If remapping of the image’s color values is not allowed, the returned value will be `NULL`. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)