Contents

contentHeadroom

Returns the content headroom of the image.

Declaration

var contentHeadroom: Float { get }

Discussion

If the image headroom is unknown, then the value 0.0 will be returned.

If the image headroom is known, then a value greater than or equal to 1.0 will be returned. A value of 1.0 will be returned if the image is SDR. A value greater than 1.0 will be returned if the image is HDR.

The image headroom may known when a CIImage is first initialized. If the a CIImage is initialized using:

  • NSURL or NSData : the headroom may be determined by associated metadata or deduced from pixel format or colorSpace information.

  • CGImage : headroom may be determined by CGImageGetHeadroomInfo() or deduced from pixel format or colorSpace information.

  • IOSurface : then the headroom will be determined by kIOSurfaceContentHeadroom. or deduced from pixel format or colorSpace information.

  • CVPixelBuffer : then the headroom will be determined by kCVImageBufferContentLightLevelInfoKey. or deduced from pixel format or colorSpace information.

  • BitmapData : headroom may be deduced from pixel format or colorSpace information.

If the image is the result of applying a CIFilter or CIKernel, this method will return 0.0.

There are exceptions to this. Applying a CIWarpKernel`` or certain ``CIFilter-class`` (e.g. CIGaussianBlur, CILanczosScaleTransform, CIAreaAverageand some others) to an image will result in a ``CIImage`` instance with the samecontentHeadroom` property value.

See Also

Instance Properties