74 lines
2.0 KiB
Swift
74 lines
2.0 KiB
Swift
//
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// LoadImageOperation.swift
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// Delta
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//
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// Created by Riley Testut on 2/26/16.
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// Copyright © 2016 Riley Testut. All rights reserved.
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//
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import Foundation
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import ImageIO
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import Roxas
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public class LoadImageOperation: RSTOperation
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{
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public let URL: Foundation.URL
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public var completionHandler: ((UIImage?) -> Void)? {
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didSet {
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self.completionBlock = {
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rst_dispatch_sync_on_main_thread() {
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self.completionHandler?(self.image)
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}
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}
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}
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}
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public var imageCache: NSCache<NSURL, UIImage>? {
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didSet {
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// Ensures if an image is cached, it will be returned immediately, to prevent temporary flash of placeholder image
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self.isImmediate = self.imageCache?.object(forKey: self.URL as NSURL) != nil
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}
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}
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fileprivate var image: UIImage?
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public init(URL: Foundation.URL)
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{
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self.URL = URL
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super.init()
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}
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}
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public extension LoadImageOperation
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{
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override public func main()
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{
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guard !self.isCancelled else { return }
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if let cachedImage = self.imageCache?.object(forKey: self.URL as NSURL)
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{
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self.image = cachedImage
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return
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}
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let options: NSDictionary = [kCGImageSourceShouldCache as NSString: true]
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if let imageSource = CGImageSourceCreateWithURL(self.URL as CFURL, options), let quartzImage = CGImageSourceCreateImageAtIndex(imageSource, 0, options)
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{
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let loadedImage = UIImage(cgImage: quartzImage)
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// Force decompression of image
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UIGraphicsBeginImageContextWithOptions(CGSize(width: 1, height: 1), true, 1.0)
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loadedImage.draw(at: CGPoint.zero)
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UIGraphicsEndImageContext()
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self.imageCache?.setObject(loadedImage, forKey: self.URL as NSURL)
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self.image = loadedImage
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}
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}
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}
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