Lottie 3.0 - A complete rewrite of Lottie in Swift! #777

buba447 · 2019-03-11T16:27:43Z

Lottie 3.0 Now in Swift!

This PR removes the old Objective-C implementation of Lottie and replaces it, in its entirety, with a Swift implementation. With this comes many bug fixes, and new features.

Migrating

Lottie 3.0 is a complete rewrite of Lottie in Swift 4.0! Please Note that the Api and Class names have changed slightly. (No more LOT prefix). Read About Migrating Here

Legacy Objective C Support

To continue using, and contributing to, the Obj-c version of Lottie point to this branch objectiveC

New Features

In addition to completely rebuilding the entire animation engine, several new features have been added:

New documentation fully covers Lottie API.
Text Rendering (No Glyphs) now supported
Gradient Stroke now supported
Individual Trim paths now supported
Alpha inverted masks now supprted
Marker support
Skew now supported
Fully support all UIView content modes
New api for dynamic properties.
Animation now fully supports Codable. You can decode and encode JSON data.
Animated Button component
New more flexible ImageProvider
Play animations in their native framerate
Read animation progress in realtime
Spatial Interpolation now more accurate
Added API for getting animation properties
Rewritten render system, fixing many bugs.
JSON Decoding supports Default values
JSON Coding unit testing
Trim paths are now more accurate
Bug fixes, bug fixes, bug fixes.

New Documentation

Documentation has also been completely revamped here. A new contributor documentation has been written that runs through the tech side of Lottie here

Coeur · 2019-03-12T07:22:01Z

Please see #780 (a Pull Request targeting your branch), with some impact on public API:

backgroundBehvior renamed backgroundBehavior
textOuputNode renamed textOutputNode
etc.

Coeur · 2019-03-12T07:28:15Z

A little bit sad that:

You did many fundamental changes instead of offering a direct conversion from the existing Objective-C implementation. This means that this PR may break (or solve) things which are unrelated to a Swift migration: it doesn't make it easy to review. The new features could have come as a separate PR, for easier reviewing.
You removed the existing tests instead of converting them, which makes it even harder to ensure that you're not breaking anything: this framework is not just to display the Lottie logo. ;)

But happy that it's now on Swift and happy of the changelog.

Coeur

OK, just a quick partial overall overview. I wouldn't have enough time to review it fully.

Coeur · 2019-03-12T07:44:30Z

lottie-swift/src/Private/LayerContainers/CompLayers/MaskContainerLayer.swift

+extension MaskMode {
+  var usableMode: MaskMode {
+    switch self {
+    case .add:


Maybe just need one case for lighten, one case for difference, and the rest as default: return self.

This is the full list of mask modes supported by body movin. If we add it, code will come 👍

Coeur · 2019-03-12T07:46:22Z

lottie-swift/src/Private/LayerContainers/CompLayers/MaskContainerLayer.swift

+
+extension CGRect {
+  static var veryLargeRect: CGRect {
+    return CGRect(x: -100000000,


SwiftLint would recommend to separate thousands as in -100_000_000.

Coeur · 2019-03-12T07:55:18Z

lottie-swift/src/Private/LayerContainers/CompLayers/PreCompositionLayer.swift

+
+  let frameRate: CGFloat
+  let remappingNode: NodeProperty<Vector1D>?
+  fileprivate var animationLayers: [CompositionLayer]


with fileprivate var animationLayers: [CompositionLayer] = [], we wouldn't need to explicitly set it in init functions.

I prefer it this way, so if additional initializers are added the compiler will tell you to handle animationLayers

Coeur · 2019-03-12T07:59:52Z

lottie-swift/src/Private/LayerContainers/Utility/LayerImageProvider.swift

+  init(imageProvider: AnimationImageProvider, assets: [String : ImageAsset]?) {
+    self.imageProvider = imageProvider
+    self.imageLayers = [ImageCompositionLayer]()
+    if let assets = assets {


Simply use the nil coalescing operator: self.imageAssets = assets ?? [:]

Coeur · 2019-03-12T08:01:55Z

lottie-swift/src/Private/LayerContainers/CompLayers/ImageCompositionLayer.swift

+
+  var image: CGImage? = nil {
+    didSet {
+      if let image = image {


No need for if/else, directly write: contentsLayer.contents = image

Coeur · 2019-03-12T08:06:13Z

lottie-swift/src/Private/Model/Objects/Transform.swift

+
+
+    // Scale
+    self.scale = try container.decodeIfPresent(KeyframeGroup<Vector3D>.self, forKey: .scale) ?? KeyframeGroup(Vector3D(x: Double(100), y: 100, z: 100))


There aren't any overload for this initializer of Vector3D, so the explicit cast to Double is not needed.

Theres one for CGFloat and Double

Oh, right, I didn't notice the private extension earlier.
Note that personally I would have wrote it 100 as Double, but it's fine. ;)

Coeur · 2019-03-12T08:21:50Z

lottie-swift/src/Public/Animation/AnimationPublic.swift

+
+   - Returns: Deseralized `Animation`. Optional.
+   */
+  public static func named(_ name: String,


Xcode 10.2 will warn for all users: 'public' modifier is redundant for static method declared in a public extension.

Coeur · 2019-03-12T08:28:45Z

lottie-swift/src/Public/Animation/AnimationPublic.swift

+    }
+
+    /// Make sure the file exists.
+    guard FileManager.default.fileExists(atPath: filepath) else {


Using fileExists is against Apple recommendations. Apple advices to directly attempt the file operation without it. See the note of https://developer.apple.com/documentation/foundation/filemanager/1415645-fileexists

buba447 · 2019-03-12T13:31:49Z

@Coeur

What fundamental changes are you referring to? I tried to keep the api as close as possible to the objective c while also respecting swift code styling.
The tests still exist! They have been moved to a private repo that also contains about 2,000 animations from other companies that wish to keep their IP private. There are actually more tests now than ever before. I've added tests that also test the json encoding/decoding. Im happy to report that all tests pass as well.

spelling

Coeur · 2019-03-12T13:51:40Z

Oh, I wasn't aware of the private repo with the tests. Then it's all good. Changes approved. :)

Just try to fix the "'public' modifier is redundant" warnings from Xcode 10.2 before releasing.

thedrick · 2019-03-12T17:35:19Z

@Coeur thanks so much for giving this a review! Just wanted to let you know that Airbnb is now using this version of Lottie in our production app and I've tested all of our animations using it. Really appreciate all of your feedback :) (and +1 to fixing the public modifier warnings)

This fixes warnings in Xcode 10.2 related to access modifiers

Fix warnings in Xcode 10.2

vlozko · 2019-03-14T18:32:10Z

lottie-swift/src/Private/LayerContainers/CompLayers/ImageCompositionLayer.swift

+      fatalError("init(layer:) Wrong Layer Class")
+    }
+    self.imageReferenceID = layer.imageReferenceID
+    self.image = nil


Given that image is already defaulted to nil, would this line be necessary?

Definitely not necessary.

vlozko · 2019-03-14T18:43:31Z

lottie-swift/src/Private/LayerContainers/Utility/LayerImageProvider.swift

+  }
+
+  func addImageLayers(_ layers: [ImageCompositionLayer]) {
+    for layer in layers {


Not sure if it's too unreadable but this can be written with a two-liner:

let foundLayers = layers.filter { imageAssets[$0.imageReferenceID] != nil } imageLayers.append(contentsOf: foundLayers)

vlozko · 2019-03-14T18:58:17Z

lottie-swift/src/Private/Model/Animation.swift

+    self.markers = try container.decodeIfPresent([Marker].self, forKey: .markers)
+
+    if let markers = markers {
+      var markerMap: [String : Marker] = [:]


Any thoughts on writing this whole if-let-else statement to this?

self.markerMap = markers?.reduce([String : Marker](), { markerMap, marker, in markerMap[marker.name] = marker }

reduce(::) will copy the dictionary at each iteration. You should use reduce(into::) for this!

You’re right, I did mean reduce(into::) as my code probably won’t compile.

skborhan · 2019-09-13T04:35:24Z

HI, Im trying to add Lottie (animated sticker) in video. I can export it but I can't play it in runtime AVSynchronizedLayer. Is there any way to use Lottie view/layer in avsynchronizedlayer? Im using Lottie - 2.5.2 (Objective C).

Coeur · 2019-09-17T02:13:24Z

@skborhan please fill a new GitHub issue or a StackOverflow question for a matter that isn't directly related to the review of the pull request, thank you.

Lottie 3.0 - A complete rewrite of Lottie in Swift!

buba447 added 3 commits March 6, 2019 17:05

Initial commit of lottie-swift

a607fc1

Fixed init(layer) bug

63fb999

updated compatibility and init

445379a

buba447 added 2 commits March 11, 2019 12:39

Updated documentation:

8e3af02

Updated issue template

718f4ae

thedrick approved these changes Mar 11, 2019

View reviewed changes

Coeur added 2 commits March 12, 2019 14:21

spelling

b2bc7d5

spelling

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Coeur reviewed Mar 12, 2019

View reviewed changes

Merge pull request #780 from Coeur/spelling

93d49d1

spelling

buba447 mentioned this pull request Mar 13, 2019

Add support for SwiftPM-based dependency managers #781

Closed

buba447 and others added 3 commits March 13, 2019 12:32

Small style updates

bc223d7

Fix warnings in Xcode 10.2

da1b423

This fixes warnings in Xcode 10.2 related to access modifiers

Merge pull request #784 from airbnb/thedrick-fix-warnings

f5e1254

Fix warnings in Xcode 10.2

Coeur approved these changes Mar 14, 2019

View reviewed changes

Cleaned up podspec

e44bd65

vlozko reviewed Mar 14, 2019

View reviewed changes

buba447 deleted the btw/lottie-swift branch November 25, 2019 16:46

NSGolova pushed a commit to clario-tech/lottie-ios that referenced this pull request Nov 19, 2020

Merge pull request airbnb#777 from airbnb/btw/lottie-swift

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Lottie 3.0 - A complete rewrite of Lottie in Swift!

calda pushed a commit that referenced this pull request Dec 1, 2022

Merge pull request #777 from airbnb/btw/lottie-swift

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Lottie 3.0 - A complete rewrite of Lottie in Swift!

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Lottie 3.0 - A complete rewrite of Lottie in Swift! #777

Lottie 3.0 - A complete rewrite of Lottie in Swift! #777

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		// Scale
		self.scale = try container.decodeIfPresent(KeyframeGroup<Vector3D>.self, forKey: .scale) ?? KeyframeGroup(Vector3D(x: Double(100), y: 100, z: 100))

Lottie 3.0 - A complete rewrite of Lottie in Swift! #777

Lottie 3.0 - A complete rewrite of Lottie in Swift! #777

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buba447 commented Mar 11, 2019 • edited

Lottie 3.0 Now in Swift!

Migrating

Legacy Objective C Support

New Features

New Documentation

Coeur commented Mar 12, 2019

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