Work around incorrect dimensions for recording from iOS Simulator

Related to #76

Gifski/util.swift

@@ -492,6 +492,39 @@ extension CGSize {
 }
 
 
+extension NSImage {
+ /// UIImage polyfill
+ convenience init(cgImage: CGImage) {
+ let size = CGSize(width: cgImage.width, height: cgImage.height)
+ self.init(cgImage: cgImage, size: size)
+ }
+}
+
+
+extension CGImage {
+ var nsImage: NSImage {
+ return NSImage(cgImage: self)
+ }
+}
+
+
+extension AVAssetImageGenerator {
+ func image(at time: CMTime) -> NSImage? {
+ return (try? copyCGImage(at: time, actualTime: nil))?.nsImage
+ }
+}
+
+extension AVAsset {
+ func image(at time: CMTime) -> NSImage? {
+ let imageGenerator = AVAssetImageGenerator(asset: self)
+ imageGenerator.appliesPreferredTrackTransform = true
+ imageGenerator.requestedTimeToleranceAfter = .zero
+ imageGenerator.requestedTimeToleranceBefore = .zero
+ return imageGenerator.image(at: time)
+ }
+}
+
+
 extension AVAssetTrack {
  /// Returns the dimensions of the track if it's a video.
  var dimensions: CGSize? {
@@ -500,7 +533,14 @@ extension AVAssetTrack {
  }
 
  let size = naturalSize.applying(preferredTransform)
- return CGSize(width: abs(size.width), height: abs(size.height))
+ let preferredSize = CGSize(width: abs(size.width), height: abs(size.height))
+
+ // Workaround for https://github.com/sindresorhus/gifski-app/issues/76
+ guard preferredSize != .zero else {
+ return asset?.image(at: CMTime(seconds: 0, preferredTimescale: .video))?.size
+ }
+
+ return preferredSize
  }
 
  /// Returns the frame rate of the track if it's a video.