How to use AspectScaledToFitAndCenterSizeFilter in kingFisher library in swift

Question

In my project I was using AlamofireImage in swift. Now we replaced AlamofireImage with the KingFisher library. I have created a struct using below to fit the filter

struct AspectScaledToFitAndCenterSizeFilter: ImageFilter, Sizable {
    /// The size of the filter.
    let size: CGSize

    /// Initializes the `AspectScaledToFitSizeFilter` instance with the given size.
    ///
    /// - parameter size: The size.
    ///
    /// - returns: The new `AspectScaledToFitSizeFilter` instance.
    init(size: CGSize) {
        self.size = size
    }

    /// The filter closure used to create the modified representation of the given image.
    var filter: (UIImage) -> UIImage {
        { image in
            image.imageAspectScaledAndCenter(toFit: self.size)
        }
    }
} 

When we are using AlmofireImage using the below code to set image url

imageView.af.setImage(withURL: imageURL.mediaURL(), placeholderImage: #imageLiteral(resourceName: "icMissingEntreeGrid"), filter: AspectScaledToFitAndCenterSizeFilter(size: imageSize))

Now I replace the code with

imageView.kf.setImage(with: imageURL.mediaURL(), placeholder:  imageLiteral(resourceName: "icMissingEntreeGrid"))

But how to add that “AspectScaledToFitAndCenterSizeFilter(size: imageSize)” using KingFisher library. Could anyone please help me out here. Thanks in advance.

Answer 1

To create Kingfisher image processor you need to implement ImageProcessor protocol:

class AspectScaledToFitAndCenterSizeFilter: ImageProcessor {
    /// Identifier of the processor.
    /// - Note: See documentation of `ImageProcessor` protocol for more.
    let identifier: String

    /// The size of the filter.
    let size: CGSize

    /// Initializes the `AspectScaledToFitSizeFilter` instance with the given size.
    ///
    /// - parameter size: The size.
    ///
    /// - returns: The new `AspectScaledToFitSizeFilter` instance.
    init(size: CGSize) {
        self.size = size
        identifier = "com.package.AspectScaledToFitAndCenterSizeFilter(\(size))"
    }

    func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
        switch item {
        case .image(let image):
            return image.imageAspectScaledAndCenter(toFit: self.size)
        case .data:
            return (DefaultImageProcessor.default |> self).process(item: item, options: options)
        }
    }
}

Usage:

imageView.kf.setImage(
    with: imageURL.mediaURL(),
    placeholder: #imageLiteral(resourceName: "icMissingEntreeGrid"),
    options: [
        .processor(AspectScaledToFitAndCenterSizeFilter(size: .zero))
    ]
)

Check out more processor usages in documentation.