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circularScreen()

Adds a circular overlay to an image.

Declaration

class func circularScreen() -> any CIFilter & CICircularScreen

Return Value

The modified image.

Discussion

This method applies a circular screen filter to an image. The effect generates a monochrome image containing a series of circular rings. The halftone effect is a set of lines, dots, or circles that contain detail. When viewing the image from a distance, the markings blend together, creating the illusion of continuous lines and shapes. Print media commonly uses this effect.

The circular screen filter uses the following properties:

inputImage

An image with the type CIImage.

center

A set of coordinates marking the center of the image as a CGPoint.

width

A float representing the distance between each circle in the pattern as an NSNumber.

sharpness

A float representing the sharpness of the circles in the pattern as an NSNumber.

The following code creates a filter that results in a monochrome image with a large circular pattern overlaying the image:

func circular(inputImage: CIImage) -> CIImage {
    let circularHalftone = CIFilter.circularScreen()
    circularHalftone.inputImage = inputImage
    circularHalftone.center = CGPoint(x: 2016, y: 1512)
    circularHalftone.width = 35
    circularHalftone.sharpness = 0.70
    return circularHalftone.outputImage!
}

[Image]

See Also

Filters