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keystoneCorrectionVertical()

Vertically adjusts an image to remove distortion.

Declaration

class func keystoneCorrectionVertical() -> any CIFilter & CIKeystoneCorrectionVertical

Return Value

The adjusted image.

Discussion

This method applies the keystone correction vertical. The effect performs vertical adjustment of the image to shape the image to be rectangular. This effect is commonly used with multimedia projectors to correct the distortion caused by the projector being lower or higher than the projected screen.

The keystone vertical filter uses the following properties:

inputImage

An image with the type CIImage.

topLeft

A CGPoint in the input image mapped to the top-left corner of the output image.

topRight

A CGPoint in the input image mapped to the top-right corner of the output image.

bottomLeft

A CGPoint in the input image mapped to the bottom-left corner of the output image.

bottomRight

A CGPoint in the input image mapped to the bottom-right corner of the output image.

focalLength

A float representing the simulated focal length as an NSNumber.

The following code creates a filter that distorts the image:

func keystoneCorrectionVertical(inputImage: CIImage) -> CIImage {
    let keystoneCorrect = CIFilter.keystoneCorrectionVertical()
    keystoneCorrect.inputImage = inputImage
    keystoneCorrect.topLeft = CGPoint(x: 0, y: 3024)
    keystoneCorrect.topRight = CGPoint(x: 4032, y: 3024)
    keystoneCorrect.bottomLeft = CGPoint(x: 200, y: 0)
    keystoneCorrect.bottomRight = CGPoint(x: 4032, y: 0)
    keystoneCorrect.focalLength = 18
    return keystoneCorrect.outputImage!
}

[Image]

See Also

Filters