CIEdgePreserveUpsampleFilter usage

CIEdgePreserveUpsampleFilter.swift

//
//  CIEdgePreserveUpsampleFilter.swift
//
//  Created by Harshil Shah on 18/08/17.
//  Copyright © 2017 Harshil Shah. All rights reserved.
//

import CoreImage

extension CIImage {
    
    /// Method to upsample a `CIImage` while preserving the edges as shown
    /// in a guide image
    ///
    /// - Parameter guideImage: The guide image with respect to which the image
    ///   should be upsampled
    /// - Returns: The upsampled image. Returns nil if the filter doesn't exist
    ///   on the target platform (`CIEdgePreserveUpsampleFilter` is available on
    ///   iOS 10, tvOS 10, and higher)
    func upsampled(withGuideImage guideImage: CIImage) -> CIImage? {
        guard let upsampleFilter = CIFilter(name: "CIEdgePreserveUpsampleFilter") else {
            return nil
        }
        
        upsampleFilter.setValue(self, forKey: "inputSmallImage")
        upsampleFilter.setValue(guideImage, forKey: kCIInputImageKey)
        return upsampleFilter.outputImage
    }
    
}