88 lines
3.0 KiB
Swift
88 lines
3.0 KiB
Swift
import UIKit
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/// A subclass of `UIImageView` that can be animated using an image name string or raw data.
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public class AnimatableImageView: UIImageView {
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/// An `Animator` instance that holds the frames of a specific image in memory.
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var animator: Animator?
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/// A display link that keeps calling the `updateFrame` method on every screen refresh.
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lazy var displayLink: CADisplayLink = CADisplayLink(target: self, selector: Selector("updateFrame"))
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/// The size of the frame cache.
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public var framePreloadCount = 50
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/// A computed property that returns whether the image view is animating.
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public var isAnimatingGIF: Bool {
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return !displayLink.paused
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}
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/// Prepares the frames using a GIF image file name, without starting the animation.
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/// The file name should include the `.gif` extension.
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///
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/// - parameter imageName: The name of the GIF file. The method looks for the file in the app bundle.
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public func prepareForAnimation(imageNamed imageName: String) {
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let imagePath = NSBundle.mainBundle().bundleURL.URLByAppendingPathComponent(imageName)
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prepareForAnimation <^> NSData(contentsOfURL: imagePath)
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}
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/// Prepares the frames using raw GIF image data, without starting the animation.
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///
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/// - parameter data: GIF image data.
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public func prepareForAnimation(imageData data: NSData) {
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image = UIImage(data: data)
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animator = Animator(data: data, size: frame.size, contentMode: contentMode, framePreloadCount: framePreloadCount)
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animator?.prepareFrames()
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attachDisplayLink()
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}
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/// Prepares the frames using a GIF image file name and starts animating the image view.
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///
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/// - parameter imageName: The name of the GIF file. The method looks for the file in the app bundle.
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public func animateWithImage(named imageName: String) {
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prepareForAnimation(imageNamed: imageName)
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startAnimatingGIF()
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}
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/// Prepares the frames using raw GIF image data and starts animating the image view.
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///
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/// - parameter data: GIF image data.
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public func animateWithImageData(data: NSData) {
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prepareForAnimation(imageData: data)
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startAnimatingGIF()
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}
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/// Updates the `image` property of the image view if necessary. This method should not be called manually.
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override public func displayLayer(layer: CALayer) {
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image = animator?.currentFrame
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}
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/// Starts the image view animation.
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public func startAnimatingGIF() {
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if animator?.isAnimatable ?? false {
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displayLink.paused = false
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}
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}
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/// Stops the image view animation.
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public func stopAnimatingGIF() {
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displayLink.paused = true
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}
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/// Update the current frame with the displayLink duration
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func updateFrame() {
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if animator?.updateCurrentFrame(displayLink.duration) ?? false {
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layer.setNeedsDisplay()
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}
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}
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/// Invalidate the displayLink so it releases this object.
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deinit {
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displayLink.invalidate()
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}
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/// Attaches the display link.
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func attachDisplayLink() {
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displayLink.addToRunLoop(.mainRunLoop(), forMode: NSRunLoopCommonModes)
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}
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}
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