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convertRGBtoLab()

Converts an image from RGB to CIELAB color space.

Declaration

class func convertRGBtoLab() -> any CIFilter & CIConvertLab

Return Value

The converted CIImage.

Discussion

This filter converts an image from RGB to CIELAB color space. The CIELAB color space expresses color as three values: L* for the perceptual lightness, and a*b* for the colors red, green, blue, and yellow. The RGB color space expresses colors using the intensities of the three primary colors: red, green, and blue.

inputImage

A CIImage containing the RGB image.

normalize

If true, the three output channels are in the range 0 to 1. If false, the L* channel is in the range 0 to 100 and the a*b* channels are in the range -128 to 128.

The following code applies the convertRGBToLabFilter to an image with the normalize flag set to the true:

func convertRGBToLab(inputImage: CIImage) -> CIImage {
    let convertRGBToLabFilter = CIFilter.convertRGBtoLab()
    convertRGBToLabFilter.inputImage = inputImage
    convertRGBToLabFilter.normalize = true
    return convertRGBToLabFilter.outputImage!
}

[Image]

See Also

Color Effect Filters