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Pods/Kingfisher/Sources/Image/ImageTransition.swift

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+//
+//  ImageTransition.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 15/9/18.
+//
+//  Copyright (c) 2019 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.
+
+import Foundation
+#if os(iOS) || os(tvOS)
+import UIKit
+
+/// Transition effect which will be used when an image downloaded and set by `UIImageView`
+/// extension API in Kingfisher. You can assign an enum value with transition duration as
+/// an item in `KingfisherOptionsInfo` to enable the animation transition.
+///
+/// Apple's UIViewAnimationOptions is used under the hood.
+/// For custom transition, you should specified your own transition options, animations and
+/// completion handler as well.
+///
+/// - none: No animation transition.
+/// - fade: Fade in the loaded image in a given duration.
+/// - flipFromLeft: Flip from left transition.
+/// - flipFromRight: Flip from right transition.
+/// - flipFromTop: Flip from top transition.
+/// - flipFromBottom: Flip from bottom transition.
+/// - custom: Custom transition.
+public enum ImageTransition {
+    /// No animation transition.
+    case none
+    /// Fade in the loaded image in a given duration.
+    case fade(TimeInterval)
+    /// Flip from left transition.
+    case flipFromLeft(TimeInterval)
+    /// Flip from right transition.
+    case flipFromRight(TimeInterval)
+    /// Flip from top transition.
+    case flipFromTop(TimeInterval)
+    /// Flip from bottom transition.
+    case flipFromBottom(TimeInterval)
+    /// Custom transition defined by a general animation block.
+    ///    - duration: The time duration of this custom transition.
+    ///    - options: `UIView.AnimationOptions` should be used in the transition.
+    ///    - animations: The animation block will be applied when setting image.
+    ///    - completion: A block called when the transition animation finishes.
+    case custom(duration: TimeInterval,
+                 options: UIView.AnimationOptions,
+              animations: ((UIImageView, UIImage) -> Void)?,
+              completion: ((Bool) -> Void)?)
+    
+    var duration: TimeInterval {
+        switch self {
+        case .none:                          return 0
+        case .fade(let duration):            return duration
+            
+        case .flipFromLeft(let duration):    return duration
+        case .flipFromRight(let duration):   return duration
+        case .flipFromTop(let duration):     return duration
+        case .flipFromBottom(let duration):  return duration
+            
+        case .custom(let duration, _, _, _): return duration
+        }
+    }
+    
+    var animationOptions: UIView.AnimationOptions {
+        switch self {
+        case .none:                         return []
+        case .fade:                         return .transitionCrossDissolve
+            
+        case .flipFromLeft:                 return .transitionFlipFromLeft
+        case .flipFromRight:                return .transitionFlipFromRight
+        case .flipFromTop:                  return .transitionFlipFromTop
+        case .flipFromBottom:               return .transitionFlipFromBottom
+            
+        case .custom(_, let options, _, _): return options
+        }
+    }
+    
+    var animations: ((UIImageView, UIImage) -> Void)? {
+        switch self {
+        case .custom(_, _, let animations, _): return animations
+        default: return { $0.image = $1 }
+        }
+    }
+    
+    var completion: ((Bool) -> Void)? {
+        switch self {
+        case .custom(_, _, _, let completion): return completion
+        default: return nil
+        }
+    }
+}
+#else
+// Just a placeholder for compiling on macOS.
+public enum ImageTransition {
+    case none
+    /// This is a placeholder on macOS now. It is for SwiftUI (KFImage) to identify the fade option only.
+    case fade(TimeInterval)
+}
+#endif