Contents

toneCurve()

Alters an image’s tone curve according to a series of data points.

Declaration

class func toneCurve() -> any CIFilter & CIToneCurve

Return Value

The modified image.

Discussion

This method applies the tone curve filter to an image. The effect calculates the adjustment of the tone curve by the sum of the red, green, and blue color values with the point value properties specified.

The tone curve filter uses the following properties:

point0

A vector containing the position of the first point of the tone curve as a CIVector.

point1

A vector containing the position of the second point of the tone curve as a CIVector.

point2

A vector containing the position of the third point of the tone curve as a CIVector.

point3

A vector containing the position of the fourth point of the tone curve as a CIVector.

point4

A vector containing the position of the fifth point of the tone curve as a CIVector.

inputImage

An image with the type CIImage.

The following code creates a filter that adds brightness to the input image:

func toneCurve(inputImage: CIImage) -> CIImage {
    let toneCurveFilter = CIFilter.toneCurve()
    toneCurveFilter.inputImage = inputImage
    toneCurveFilter.point0 = CGPoint(x: 0, y: 0)
    toneCurveFilter.point1 = CGPoint(x: 0.22, y: 0.25)
    toneCurveFilter.point2 = CGPoint(x: 0.4, y: 0.5)
    toneCurveFilter.point3 = CGPoint(x: 0.65, y: 0.75)
    toneCurveFilter.point4 = CGPoint(x: 1, y: 1)
    return toneCurveFilter.outputImage!
}

[Image]

See Also

Filters