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121 lines
5.3 KiB
121 lines
5.3 KiB
//
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// AnimatedImage.swift
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// Kingfisher
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//
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// Created by onevcat on 2018/09/26.
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//
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// Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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import Foundation
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import ImageIO
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/// Represents a set of image creating options used in Kingfisher.
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public struct ImageCreatingOptions {
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/// The target scale of image needs to be created.
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public let scale: CGFloat
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/// The expected animation duration if an animated image being created.
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public let duration: TimeInterval
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/// For an animated image, whether or not all frames should be loaded before displaying.
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public let preloadAll: Bool
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/// For an animated image, whether or not only the first image should be
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/// loaded as a static image. It is useful for preview purpose of an animated image.
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public let onlyFirstFrame: Bool
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/// Creates an `ImageCreatingOptions` object.
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///
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/// - Parameters:
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/// - scale: The target scale of image needs to be created. Default is `1.0`.
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/// - duration: The expected animation duration if an animated image being created.
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/// A value less or equal to `0.0` means the animated image duration will
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/// be determined by the frame data. Default is `0.0`.
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/// - preloadAll: For an animated image, whether or not all frames should be loaded before displaying.
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/// Default is `false`.
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/// - onlyFirstFrame: For an animated image, whether or not only the first image should be
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/// loaded as a static image. It is useful for preview purpose of an animated image.
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/// Default is `false`.
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public init(
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scale: CGFloat = 1.0,
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duration: TimeInterval = 0.0,
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preloadAll: Bool = false,
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onlyFirstFrame: Bool = false)
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{
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self.scale = scale
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self.duration = duration
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self.preloadAll = preloadAll
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self.onlyFirstFrame = onlyFirstFrame
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}
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}
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// Represents the decoding for a GIF image. This class extracts frames from an `imageSource`, then
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// hold the images for later use.
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class GIFAnimatedImage {
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let images: [Image]
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let duration: TimeInterval
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init?(from imageSource: CGImageSource, for info: [String: Any], options: ImageCreatingOptions) {
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let frameCount = CGImageSourceGetCount(imageSource)
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var images = [Image]()
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var gifDuration = 0.0
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for i in 0 ..< frameCount {
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guard let imageRef = CGImageSourceCreateImageAtIndex(imageSource, i, info as CFDictionary) else {
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return nil
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}
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if frameCount == 1 {
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gifDuration = .infinity
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} else {
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// Get current animated GIF frame duration
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gifDuration += GIFAnimatedImage.getFrameDuration(from: imageSource, at: i)
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}
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images.append(KingfisherWrapper.image(cgImage: imageRef, scale: options.scale, refImage: nil))
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if options.onlyFirstFrame { break }
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}
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self.images = images
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self.duration = gifDuration
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}
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// Calculates frame duration for a gif frame out of the kCGImagePropertyGIFDictionary dictionary.
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static func getFrameDuration(from gifInfo: [String: Any]?) -> TimeInterval {
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let defaultFrameDuration = 0.1
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guard let gifInfo = gifInfo else { return defaultFrameDuration }
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let unclampedDelayTime = gifInfo[kCGImagePropertyGIFUnclampedDelayTime as String] as? NSNumber
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let delayTime = gifInfo[kCGImagePropertyGIFDelayTime as String] as? NSNumber
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let duration = unclampedDelayTime ?? delayTime
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guard let frameDuration = duration else { return defaultFrameDuration }
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return frameDuration.doubleValue > 0.011 ? frameDuration.doubleValue : defaultFrameDuration
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}
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// Calculates frame duration at a specific index for a gif from an `imageSource`.
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static func getFrameDuration(from imageSource: CGImageSource, at index: Int) -> TimeInterval {
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guard let properties = CGImageSourceCopyPropertiesAtIndex(imageSource, index, nil)
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as? [String: Any] else { return 0.0 }
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let gifInfo = properties[kCGImagePropertyGIFDictionary as String] as? [String: Any]
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return getFrameDuration(from: gifInfo)
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}
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}
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