NSNumber object containing the compression factor of the image.
Used only for JPEG files. JPEG compression in TIFF files is not supported, and the factor is ignored. The value is a float between 0.0 and 1.0, with 1.0 resulting in no compression and 0.0 resulting in the maximum compression possible. It’s set when reading in and used when writing out the image.
static let fallbackBackgroundColor: NSBitmapImageRep.PropertyKey
Specifies the background color to use when writing to an image format (such as JPEG) that doesn't support alpha. The color's alpha value is ignored. The default background color, when this property is not specified, is white. The value of the property should be an
NSColor object. This constant corresponds to the kCGImageDestinationBackgroundColor constant in Quartz.