Kingfisher/Sources/Image/Image.swift

//
//  Image.swift
//  Kingfisher
//
//  Created by Wei Wang on 16/1/6.
//
//  Copyright (c) 2018 Wei Wang <onevcat@gmail.com>
//
//  Permission is hereby granted, free of charge, to any person obtaining a copy
//  of this software and associated documentation files (the "Software"), to deal
//  in the Software without restriction, including without limitation the rights
//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//  copies of the Software, and to permit persons to whom the Software is
//  furnished to do so, subject to the following conditions:
//
//  The above copyright notice and this permission notice shall be included in
//  all copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
//  THE SOFTWARE.


#if os(macOS)
import AppKit
private var imagesKey: Void?
private var durationKey: Void?
#else
import UIKit
import MobileCoreServices
private var imageSourceKey: Void?
#endif

#if !os(watchOS)
import CoreImage
#endif

import CoreGraphics
import ImageIO

private var animatedImageDataKey: Void?

// MARK: - Image Properties
extension KingfisherWrapper where Base: Image {
    private(set) var animatedImageData: Data? {
        get { return getAssociatedObject(base, &animatedImageDataKey) }
        set { setRetainedAssociatedObject(base, &animatedImageDataKey, newValue) }
    }
    
    #if os(macOS)
    var cgImage: CGImage? {
        return base.cgImage(forProposedRect: nil, context: nil, hints: nil)
    }
    
    var scale: CGFloat {
        return 1.0
    }
    
    private(set) var images: [Image]? {
        get { return getAssociatedObject(base, &imagesKey) }
        set { setRetainedAssociatedObject(base, &imagesKey, newValue) }
    }
    
    private(set) var duration: TimeInterval {
        get { return getAssociatedObject(base, &durationKey) ?? 0.0 }
        set { setRetainedAssociatedObject(base, &durationKey, newValue) }
    }
    
    var size: CGSize {
        return base.representations.reduce(.zero) { size, rep in
            let width = max(size.width, CGFloat(rep.pixelsWide))
            let height = max(size.height, CGFloat(rep.pixelsHigh))
            return CGSize(width: width, height: height)
        }
    }
    #else
    var cgImage: CGImage? { return base.cgImage }
    var scale: CGFloat { return base.scale }
    var images: [Image]? { return base.images }
    var duration: TimeInterval { return base.duration }
    var size: CGSize { return base.size }
    
    private(set) var imageSource: CGImageSource? {
        get { return getAssociatedObject(base, &imageSourceKey) }
        set { setRetainedAssociatedObject(base, &imageSourceKey, newValue) }
    }
    #endif

    // Bitmap memory cost with bytes.
    var cost: Int {
        let pixel = Int(size.width * size.height * scale * scale)
        guard let cgImage = cgImage else {
            return pixel * 4
        }
        return pixel * cgImage.bitsPerPixel / 8
    }
}

// MARK: - Image Conversion
extension KingfisherWrapper where Base: Image {
    #if os(macOS)
    static func image(cgImage: CGImage, scale: CGFloat, refImage: Image?) -> Image {
        return Image(cgImage: cgImage, size: .zero)
    }
    
    /// Normalize the image. This getter does nothing on macOS but return the image itself.
    public var normalized: Image { return base }

    #else
    /// Creating an image from a give `CGImage` at scale and orientation for refImage. The method signature is for
    /// compability of macOS version.
    static func image(cgImage: CGImage, scale: CGFloat, refImage: Image?) -> Image {
        return Image(cgImage: cgImage, scale: scale, orientation: refImage?.imageOrientation ?? .up)
    }
    
    /// Returns normalized image for current `base` image.
    /// This method will try to redraw an image with orientation and scale considered.
    public var normalized: Image {
        // prevent animated image (GIF) lose it's images
        guard images == nil else { return base }
        // No need to do anything if already up
        guard base.imageOrientation != .up else { return base }
    
        return draw(to: size) { _ in
            base.draw(in: CGRect(origin: .zero, size: size))
        }
    }
    #endif
}

// MARK: - Image Representation
extension KingfisherWrapper where Base: Image {
    // MARK: - PNG
    /// Returns PNG representation of `base` image.
    ///
    /// - Returns: PNG data of image.
    public func pngRepresentation() -> Data? {
        #if os(macOS)
            guard let cgimage = cgImage else {
                return nil
            }
            let rep = NSBitmapImageRep(cgImage: cgimage)
            return rep.representation(using: .png, properties: [:])
        #else
            #if swift(>=4.2)
            return base.pngData()
            #else
            return UIImagePNGRepresentation(base)
            #endif
        #endif
    }
    
    // MARK: - JPEG
    /// Returns JPEG representation of `base` image.
    ///
    /// - Parameter compressionQuality: The compression quality when converting image to JPEG data.
    /// - Returns: JPEG data of image.
    public func jpegRepresentation(compressionQuality: CGFloat) -> Data? {
        #if os(macOS)
            guard let cgImage = cgImage else {
                return nil
            }
            let rep = NSBitmapImageRep(cgImage: cgImage)
            return rep.representation(using:.jpeg, properties: [.compressionFactor: compressionQuality])
        #else
            #if swift(>=4.2)
            return base.jpegData(compressionQuality: compressionQuality)
            #else
            return UIImageJPEGRepresentation(base, compressionQuality)
            #endif
        #endif
    }
    
    // MARK: - GIF
    /// Returns GIF representation of `base` image.
    ///
    /// - Returns: Original GIF data of image.
    public func gifRepresentation() -> Data? {
        return animatedImageData
    }
}

// MARK: - Create images from data
extension KingfisherWrapper where Base: Image {

    /// Creates an animated image from a given data and options. Currently only GIF data is supported.
    ///
    /// - Parameters:
    ///   - data: The animated image data.
    ///   - options: Options to use when creating the animated image.
    /// - Returns: An `Image` object represents the animated image. It is in form of an array of image frames with a
    ///            certain duration. `nil` if anything wrong when creating animated image.
    public static func animatedImage(data: Data, options: ImageCreatingOptions) -> Image? {
        let info: [String: Any] = [
            kCGImageSourceShouldCache as String: true,
            kCGImageSourceTypeIdentifierHint as String: kUTTypeGIF
        ]
        
        guard let imageSource = CGImageSourceCreateWithData(data as CFData, info as CFDictionary) else {
            return nil
        }
        
        #if os(macOS)
        guard let animatedImage = GIFAnimatedImage(from: imageSource, for: info, options: options) else {
            return nil
        }
        let image: Image?
        if options.onlyFirstFrame {
            image = animatedImage.images.first
        } else {
            image = Image(data: data)
            var kf = image?.kf
            kf?.images = animatedImage.images
            kf?.duration = animatedImage.duration
        }
        image?.kf.animatedImageData = data
        return image
        #else
        
        let image: Image?
        if options.preloadAll || options.onlyFirstFrame {
            // Use `images` image if you want to preload all animated data
            guard let animatedImage = GIFAnimatedImage(from: imageSource, for: info, options: options) else {
                return nil
            }
            if options.onlyFirstFrame {
                image = animatedImage.images.first
            } else {
                let duration = options.duration <= 0.0 ? animatedImage.duration : options.duration
                image = .animatedImage(with: animatedImage.images, duration: duration)
            }
            image?.kf.animatedImageData = data
        } else {
            image = Image(data: data, scale: options.scale)
            var kf = image?.kf
            kf?.imageSource = imageSource
            kf?.animatedImageData = data
        }
        
        return image
        #endif
    }

    /// Creates an image from a given data and options. `.JPEG`, `.PNG` or `.GIF` is supported. For other
    /// image format, image initilizer from system will be used. If no image object could be created from
    /// the given `data`, `nil` will be returned.
    ///
    /// - Parameters:
    ///   - data: The image data representation.
    ///   - options: Options to use when creating the image.
    /// - Returns: An `Image` object represents the image if created. If the `data` is invalid or not supported, `nil`
    ///            will be returned.
    public static func image(data: Data, options: ImageCreatingOptions) -> Image? {
        var image: Image?
        switch data.kf.imageFormat {
        case .JPEG:
            image = Image(data: data, scale: options.scale)
        case .PNG:
            image = Image(data: data, scale: options.scale)
        case .GIF:
            image = KingfisherWrapper.animatedImage(data: data, options: options)
        case .unknown:
            image = Image(data: data, scale: options.scale)
        }
        return image
    }
    
    /// Creates a downsampled image from given data to a certain size and scale.
    ///
    /// - Parameters:
    ///   - data: The image data contains a JPEG or PNG image.
    ///   - pointSize: The target size in point to which the image should be downsampled.
    ///   - scale: The scale of result image.
    /// - Returns: A downsampled `Image` object following the input conditions.
    ///
    /// - Note:
    /// Different from image `resize` methods, downsampling will not render the original
    /// input image in pixel format. It does downsampling from the image data, so it is much
    /// more memory efficient and friendly. Choose to use downsampling as possible as you can.
    ///
    /// The input size should be smaller than the size of input image. If it is larger than the
    /// original image size, the result image will be the same size of input without downsampling.
    public static func downsampledImage(data: Data, to pointSize: CGSize, scale: CGFloat) -> Image? {
        let imageSourceOptions = [kCGImageSourceShouldCache: false] as CFDictionary
        guard let imageSource = CGImageSourceCreateWithData(data as CFData, imageSourceOptions) else {
            return nil
        }
        
        let maxDimensionInPixels = max(pointSize.width, pointSize.height) * scale
        let downsampleOptions = [
            kCGImageSourceCreateThumbnailFromImageAlways: true,
            kCGImageSourceShouldCacheImmediately: true,
            kCGImageSourceCreateThumbnailWithTransform: true,
            kCGImageSourceThumbnailMaxPixelSize: maxDimensionInPixels] as CFDictionary
        let downsampledImage = CGImageSourceCreateThumbnailAtIndex(imageSource, 0, downsampleOptions)!
        return KingfisherWrapper.image(cgImage: downsampledImage, scale: scale, refImage: nil)
    }
}