An evaluation context for rendering image processing results and performing image analysis.
- iOS 5.0+
- macOS 10.4+
- tvOS 9.0+
- Core Image
CIContext class provides an evaluation context for Core Image processing with Quartz 2D, Metal, or OpenGL. You use
CIContext objects in conjunction with other Core Image classes, such as
CIColor, to process images using Core Image filters. You also use a Core Image context with the
CIDetector class to analyze images—for example, to detect faces or barcodes.
CIImage objects are immutable, so multiple threads can use the same
CIContext object to render
CIImage objects. However,
CIFilter objects are mutable and thus cannot be shared safely among threads. Each thread must create its own
CIFilter objects, but you can pass a filter’s immutable input and output
CIImage objects between threads.