Merge branch 'image_updates' into 'master'

image updates.

See merge request upm-packages/ui-widgets/com.unity.uiwidgets!2

Runtime/animation/listener_helpers.mixin.njk

 using System;
 using System.Collections.Generic;
-using UIWidgets.foundation;
-using UIWidgets.ui;
+using Unity.UIWidgets.foundation;
+using Unity.UIWidgets.ui;
-namespace UIWidgets.animation {
+namespace Unity.UIWidgets.animation {
 {% macro AnimationLazyListenerMixin(with) %} 
     public abstract class AnimationLazyListenerMixin{{with | safe}} : {{with | safe}} {
         int _listenerCounter = 0;

Runtime/async/microtask_queue.cs

 
 namespace Unity.UIWidgets.async {
     public class MicrotaskQueue {
-        private Queue<Action> _queue = new Queue<Action>();
+        readonly Queue<Action> _queue = new Queue<Action>();
 
         public void scheduleMicrotask(Action action) {
             this._queue.Enqueue(action);

Runtime/async/timer.cs

 using System;
 using System.Collections.Generic;
 using UnityEngine;
+#if UNITY_EDITOR
+using UnityEditor;
+
+#endif
-        static readonly TimerProvider _globalTimerProvider = new TimerProvider();
-        
-        public static Timer run(TimeSpan duration, Action callback) {
-            return _globalTimerProvider.run(duration, callback);
+        public static double timeSinceStartup {
+            get {
+#if UNITY_EDITOR
+                return EditorApplication.timeSinceStartup;
+#else
+                return Time.realtimeSinceStartup;
+#endif
+            }
-        public static Timer run(Action callback) {
-            return run(TimeSpan.Zero, callback);
-        }
-        
-        public static Timer periodic(TimeSpan duration, Action callback) {
-            return _globalTimerProvider.periodic(duration, callback);
+        public static TimeSpan timespanSinceStartup => TimeSpan.FromSeconds(timeSinceStartup);
+
+        static readonly List<Action> _callbacks = new List<Action>();
+
+        public static void runInMain(Action callback) {
+            lock (_callbacks) {
+                _callbacks.Add(callback);
+            }
-            _globalTimerProvider.update();
+            Action[] callbacks;
+
+            lock (_callbacks) {
+                callbacks = _callbacks.ToArray();
+                _callbacks.Clear();
+            }
+
+            foreach (var callback in callbacks) {
+                try {
+                    callback();
+                }
+                catch (Exception ex) {
+                    Debug.LogError("Error to execute runInMain callback: " + ex);
+                }
+            }
         }
     }
 
         public Timer run(TimeSpan duration, Action callback) {
             var timer = new TimerImpl(duration, callback);
 
-            lock (this._queue) {
-                this._queue.enqueue(timer);
-            }
-
+            this._queue.enqueue(timer);
             return timer;
         }
 
-            lock (this._queue) {
-                this._queue.enqueue(timer);
-            }
-
+            this._queue.enqueue(timer);
-        
+
-            var now = DateTime.Now;
-            
+            var now = Timer.timeSinceStartup;
+
-            
-            lock (this._queue) {
-                while (this._queue.count > 0 && this._queue.peek().deadline <= now) {
-                    var timer = this._queue.dequeue();
-                    if (timers == null) {
-                        timers = new List<TimerImpl>();
-                    }
-                    timers.Add(timer);
+
+            while (this._queue.count > 0 && this._queue.peek().deadline <= now) {
+                var timer = this._queue.dequeue();
+                if (timers == null) {
+                    timers = new List<TimerImpl>();
+
+                timers.Add(timer);
             }
 
             if (timers != null) {
                         if (appendList == null) {
                             appendList = new List<TimerImpl>();
                         }
+
                         appendList.Add(timer);
                     }
                 }
                 }
             }
         }
-        
+
-            private DateTime _deadline;
+            private double _deadline;
-           
+
-                this._deadline = DateTime.Now + duration;
+                this._deadline = Timer.timeSinceStartup + duration.TotalSeconds;
                 this._callback = callback;
                 this.periodic = periodic;
                 this._done = false;
             }
 
-            public DateTime deadline
-            {
-                get { return _deadline; }
-            }
-            
+            public double deadline => this._deadline;
+
-            public bool done
-            {
-                get { return _done; }
-            }
-            
+            public bool done => this._done;
+
-                DateTime now = DateTime.Now;
-                if (!periodic)
-                {
-                    this._done = true;    
+                var now = Timer.timeSinceStartup;
+                if (!this.periodic) {
+                    this._done = true;
                 }
 
                 try {
                 }
 
                 if (this.periodic) {
-                    this._deadline = now + this.internval;
+                    this._deadline = now + this.internval.TotalSeconds;
                 }
             }
 

Runtime/debugger/inpsector_panel.cs

 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Unity.UIWidgets.async;
 using Unity.UIWidgets.foundation;
 using UnityEditor;
 using UnityEditor.IMGUI.Controls;
         private List<DiagnosticsNode> m_Properties;
         private InspectorInstanceRef m_SelectedNodeRef;
         private bool m_VisibleToUser;
-        private DateTime m_LastPropertyRefresh = DateTime.MinValue;
+        private TimeSpan m_LastPropertyRefresh = TimeSpan.Zero;
         private float m_SplitOffset = -1;
 
 
             updateDetailTree();
 
             if (treeType == WidgetTreeType.Render &&
-                DateTime.Now - m_LastPropertyRefresh > TimeSpan.FromMilliseconds(200))
+                Timer.timespanSinceStartup - m_LastPropertyRefresh > TimeSpan.FromMilliseconds(200))
-                m_LastPropertyRefresh = DateTime.Now;
+                m_LastPropertyRefresh = Timer.timespanSinceStartup;
                 m_Properties = m_SelectedNodeRef == null
                     ? new List<DiagnosticsNode>()
                     : m_InspectorService.getProperties(m_SelectedNodeRef, m_GroupName);

Runtime/editor/editor_window.cs

         float _lastWindowWidth;
         float _lastWindowHeight;
 
-        readonly DateTime _epoch = new DateTime(Stopwatch.GetTimestamp());
+        readonly TimeSpan _epoch = new TimeSpan(Stopwatch.GetTimestamp());
+        readonly WindowCallbacks _windowCallbacks = new WindowCallbacks();
         readonly TextInput _textInput = new TextInput();
         readonly Rasterizer _rasterizer = new Rasterizer();
 
         bool _alive;
         
-
         public bool alive
         {
             get { return this._alive; }
         
         void _beginFrame() {
             if (this.onBeginFrame != null) {
-                this.onBeginFrame(new DateTime(Stopwatch.GetTimestamp()) - this._epoch);
+                this.onBeginFrame(new TimeSpan(Stopwatch.GetTimestamp()) - this._epoch);
             }
 
             this.flushMicrotasks();
 
                 if (evt.type == EventType.MouseDown) {
                     pointerData = new PointerData(
-                        timeStamp: DateTime.Now,
+                        timeStamp: Timer.timespanSinceStartup,
                         change: PointerChange.down,
                         kind: PointerDeviceKind.mouse,
                         device: evt.button,
                 } else if (evt.type == EventType.MouseUp || evt.rawType == EventType.MouseUp) {
                     pointerData = new PointerData(
-                        timeStamp: DateTime.Now,
+                        timeStamp: Timer.timespanSinceStartup,
                         change: PointerChange.up,
                         kind: PointerDeviceKind.mouse,
                         device: evt.button,
                 } else if (evt.type == EventType.MouseDrag) {
                     pointerData = new PointerData(
-                        timeStamp: DateTime.Now,
+                        timeStamp: Timer.timespanSinceStartup,
                         change: PointerChange.move,
                         kind: PointerDeviceKind.mouse,
                         device: evt.button,
                 } else if (evt.type == EventType.MouseMove) {
                     pointerData = new PointerData(
-                        timeStamp: DateTime.Now,
+                        timeStamp: Timer.timespanSinceStartup,
                         change: PointerChange.hover,
                         kind: PointerDeviceKind.mouse,
                         device: evt.button,
             Timer.update();
             
             using (this.getScope()) {
-                this.doUpdate();
+                this._doUpdate();
-        private void doUpdate() {
+        void _doUpdate() {
+            this._windowCallbacks.update();
             this._timerProvider.update();
         }
 
             return periodic
                 ? this._timerProvider.periodic(duration, callback)
                 : this._timerProvider.run(duration, callback);
+        }
+
+        public override IDisposable onUpdate(VoidCallback callback) {
+            return this._windowCallbacks.onUpdate(callback);
         }
 
         public void attachRootRenderBox(RenderBox root) {

Runtime/editor/surface.cs

 
         public void Dispose() {
             D.assert(this._renderTexture);
-            Object.DestroyImmediate(this._renderTexture);
-            this._renderTexture = null;
-
+            this._renderTexture = ObjectUtils.SafeDestroy(this._renderTexture);
+            
             D.assert(this._canvas != null);
             this._canvas = null;
         }

Runtime/engine/WidgetCanvas.cs

 using System;
+using Unity.UIWidgets.async;
 using Unity.UIWidgets.editor;
 using Unity.UIWidgets.painting;
 using Unity.UIWidgets.ui;
         IPointerEnterHandler, IPointerExitHandler
     {
         private WindowAdapter _windowAdapter;
-        private PaintingBinding _paintingBinding;
         private Texture _texture;
         private Vector2 _lastMouseMove;
         private bool _mouseEntered;
 
             if (_windowAdapter == null)
             {
-                this._paintingBinding = new PaintingBinding(null);
-                _paintingBinding.initInstances();
                 _windowAdapter = new UIWidgetWindowAdapter(this);
             }
             
 
         private void OnMouseOver()
         {
-           
-            // Debug.Log(string.Format("mouse move {0} {1}", pos.x, pos.y));
-                timeStamp: DateTime.Now,
+                timeStamp: Timer.timespanSinceStartup,
                 change: PointerChange.hover,
                 kind: PointerDeviceKind.mouse,
                 device: getMouseButtonDown(),
             EventSystem.current.SetSelectedGameObject(gameObject, eventData);
             var position = getPointPosition(eventData);
             this._windowAdapter.PostPointerEvent(new PointerData(
-                timeStamp: DateTime.Now,
+                timeStamp: Timer.timespanSinceStartup,
                 change: PointerChange.down,
                 kind: PointerDeviceKind.mouse,
                 device: (int) eventData.button,
         {
             var position = getPointPosition(eventData);
             this._windowAdapter.PostPointerEvent(new PointerData(
-                timeStamp: DateTime.Now,
+                timeStamp: Timer.timespanSinceStartup,
                 change: PointerChange.up,
                 kind: PointerDeviceKind.mouse,
                 device: (int) eventData.button,
         {
             var position = getPointPosition(eventData);
             this._windowAdapter.PostPointerEvent(new PointerData(
-                timeStamp: DateTime.Now,
+                timeStamp: Timer.timespanSinceStartup,
                 change: PointerChange.move,
                 kind: PointerDeviceKind.mouse,
                 device: (int) eventData.button,
             _lastMouseMove = eventData.position;
             var position = getPointPosition(eventData);
             this._windowAdapter.PostPointerEvent(new PointerData(
-                timeStamp: DateTime.Now,
+                timeStamp: Timer.timespanSinceStartup,
                 change: PointerChange.hover,
                 kind: PointerDeviceKind.mouse,
                 device: (int) eventData.button,
             _mouseEntered = false;
             var position = getPointPosition(eventData);
             this._windowAdapter.PostPointerEvent(new PointerData(
-                timeStamp: DateTime.Now,
+                timeStamp: Timer.timespanSinceStartup,
                 change: PointerChange.hover,
                 kind: PointerDeviceKind.mouse,
                 device: (int) eventData.button,

Runtime/flow/raster_cache.cs

 using Unity.UIWidgets.ui;
 using UnityEngine;
 using Canvas = Unity.UIWidgets.ui.Canvas;
-using Object = UnityEngine.Object;
-        public RasterCacheResult(Texture texture, Rect logicalRect, float devicePixelRatio) {
-            D.assert(texture != null);
+        public RasterCacheResult(Image image, Rect logicalRect, float devicePixelRatio) {
+            D.assert(image != null);
-            this.texture = texture;
+            this.image = image;
-        public readonly Texture texture;
+        public readonly Image image;
 
         public readonly Rect logicalRect;
 
                 var textureWidth = Mathf.CeilToInt((float) bounds.width * this.devicePixelRatio);
                 var textureHeight = Mathf.CeilToInt((float) bounds.height * this.devicePixelRatio);
 
-                D.assert(this.texture.width == textureWidth);
-                D.assert(this.texture.height == textureHeight);
+                D.assert(this.image.width == textureWidth);
+                D.assert(this.image.height == textureHeight);
                 return true;
             });
 
                 canvas.resetMatrix();
-                canvas.drawImage(this.texture, bounds.topLeft, new Paint());
+                canvas.drawImage(this.image, bounds.topLeft, new Paint());
             }
             finally {
                 canvas.restore();
             canvas.drawPicture(picture);
             canvas.flush();
 
-            return new RasterCacheResult(renderTexture, bounds, devicePixelRatio);
+            return new RasterCacheResult(new Image(renderTexture), bounds, devicePixelRatio);
         }
 
         public void sweepAfterFrame() {
             foreach (var entry in dead) {
                 this._cache.Remove(entry.Key);
                 if (entry.Value.image != null) {
-                    Object.DestroyImmediate(entry.Value.image.texture);
+                    entry.Value.image.image.Dispose();
                 }
             }
         }
                 if (entry.Value.image != null) {
-                    Object.DestroyImmediate(entry.Value.image.texture);
+                    entry.Value.image.image.Dispose();
                 }
             }
             this._cache.Clear();

Runtime/foundation/basic_types.cs

 using System;
-using System.Collections;
+using UnityEngine;
+using Object = UnityEngine.Object;
 
 namespace Unity.UIWidgets.foundation {
     
+
+    public static class ObjectUtils {
+        public static T SafeDestroy<T>(T obj) where T : Object {
+            if (Application.isEditor) {
+                Object.DestroyImmediate(obj);
+            } else {
+                Object.Destroy(obj);
+            }
+
+            return null;
+        }
+    }
 
     public static class CollectionUtils {
         public static V putIfAbsent<K, V>(this IDictionary<K, V> it, K key, Func<V> ifAbsent) {

Runtime/foundation/debug.cs

 using System;
 using System.Diagnostics;
+using System.Linq;
 using Unity.UIWidgets.painting;
 using Unity.UIWidgets.ui;
 
     [Serializable]
     public class AssertionError : Exception {
         public AssertionError(string message) : base(message) {
+        }
+
+        public override string StackTrace {
+            get {
+                var stackTrace = base.StackTrace;
+                var lines = stackTrace.Split('\n');
+                var strippedLines = lines.Skip(1);
+
+                return string.Join("\n", strippedLines);
+            }
         }
     }
 }

Runtime/foundation/node.mixin.gen.cs

 using System;
 using System.Collections.Generic;
 using System.Runtime.CompilerServices;
+using Unity.UIWidgets.async;
 
 namespace Unity.UIWidgets.foundation {
 
                 return this._canonical;
             }
 
-            var weakReference = _canonicalObjects.putIfAbsent(this._getDependencyList(), () => {
-                return new WeakReference(this);
-            });
+            var weakReference = _canonicalObjects.putIfAbsent(this._getDependencyList(), () => new WeakReference(this));
             if (weakReference.Target == null) {
                 weakReference.Target = this;
             }
 
         ~CanonicalMixinDiagnosticableTree() {
-            if (this == this._canonical) {
-                _canonicalObjects.Remove(this._dependencyList);
+            if (object.ReferenceEquals(this, this._canonical)) {
+                var dependencyList = this._dependencyList;
+                if (dependencyList != null) {
+                    Timer.runInMain(() => { _canonicalObjects.Remove(dependencyList); });
+                }
             }
         }
         

Runtime/foundation/node.mixin.njk

 using System;
 using System.Collections.Generic;
 using System.Runtime.CompilerServices;
+using Unity.UIWidgets.async;
-namespace UIWidgets.foundation {
+namespace Unity.UIWidgets.foundation {
 {% macro AbstractNodeMixin(with) %}
 	{% set className = 'AbstractNode' if with == '' else 'AbstractNodeMixin' + with %}
 
                 return this._canonical;
             }
 
-            var weakReference = _canonicalObjects.putIfAbsent(this._getDependencyList(), () => {
-                return new WeakReference(this);
-            });
+            var weakReference = _canonicalObjects.putIfAbsent(this._getDependencyList(), () => new WeakReference(this));
             if (weakReference.Target == null) {
                 weakReference.Target = this;
             }
 
         ~CanonicalMixin{{with}}() {
-            if (this == this._canonical) {
-                _canonicalObjects.Remove(this._dependencyList);
+            if (object.ReferenceEquals(this, this._canonical)) {
+                var dependencyList = this._dependencyList;
+                if (dependencyList != null) {
+                    Timer.runInMain(() => { _canonicalObjects.Remove(dependencyList); });
+                }
             }
         }
         

Runtime/gestures/binding.cs

 using System;
 using System.Collections.Generic;
+using Unity.UIWidgets.async;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.rendering;
 using Unity.UIWidgets.scheduler;
             }
 
             this._pendingPointerEvents.Enqueue(
-                new PointerCancelEvent(timeStamp: DateTime.Now, pointer: pointer));
+                new PointerCancelEvent(timeStamp: Timer.timespanSinceStartup, pointer: pointer));
         }
 
         void _flushPointerEventQueue() {

Runtime/gestures/drag_details.cs

     public delegate void GestureDragDownCallback(DragDownDetails details);
 
     public class DragStartDetails {
-        public DragStartDetails(DateTime sourceTimeStamp, Offset globalPosition = null) {
+        public DragStartDetails(TimeSpan sourceTimeStamp, Offset globalPosition = null) {
-        public readonly DateTime sourceTimeStamp;
+        public readonly TimeSpan sourceTimeStamp;
 
         public readonly Offset globalPosition;
 
 
     public class DragUpdateDetails {
         public DragUpdateDetails(
-            DateTime sourceTimeStamp,
+            TimeSpan sourceTimeStamp,
             Offset delta = null,
             double? primaryDelta = null,
             Offset globalPosition = null) {
                      || primaryDelta == this.delta.dy && this.delta.dx == 0.0);
         }
 
-        public readonly DateTime sourceTimeStamp;
+        public readonly TimeSpan sourceTimeStamp;
 
         public readonly Offset delta;
 

Runtime/gestures/events.cs

 namespace Unity.UIWidgets.gestures {
     public abstract class PointerEvent {
         public PointerEvent(
-            DateTime timeStamp,
+            TimeSpan timeStamp,
             int pointer = 0,
             PointerDeviceKind kind = PointerDeviceKind.mouse,
             int device = 0,
             this.synthesized = synthesized;
         }
 
-        public readonly DateTime timeStamp;
+        public readonly TimeSpan timeStamp;
 
         public readonly int pointer;
 
 
     public class PointerAddedEvent : PointerEvent {
         public PointerAddedEvent(
-            DateTime timeStamp,
+            TimeSpan timeStamp,
             PointerDeviceKind kind = PointerDeviceKind.touch,
             int device = 0,
             Offset position = null
 
     public class PointerRemovedEvent : PointerEvent {
         public PointerRemovedEvent(
-            DateTime timeStamp,
+            TimeSpan timeStamp,
             PointerDeviceKind kind = PointerDeviceKind.touch,
             int device = 0
         ) : base(
     public class PointerHoverEvent : PointerEvent
     {
         public PointerHoverEvent(
-            DateTime timeStamp,
+            TimeSpan timeStamp,
             int pointer = 0,
             PointerDeviceKind kind = PointerDeviceKind.mouse,
             int device = 0,
     public class PointerEnterEvent : PointerEvent
     {
         public PointerEnterEvent(
-            DateTime timeStamp,
+            TimeSpan timeStamp,
             int pointer = 0,
             PointerDeviceKind kind = PointerDeviceKind.mouse,
             int device = 0,
     public class PointerLeaveEvent : PointerEvent
     {
         public PointerLeaveEvent(
-            DateTime timeStamp,
+            TimeSpan timeStamp,
             int pointer = 0,
             PointerDeviceKind kind = PointerDeviceKind.mouse,
             int device = 0,
 
     public class PointerDownEvent : PointerEvent {
         public PointerDownEvent(
-            DateTime timeStamp,
+            TimeSpan timeStamp,
             int pointer = 0,
             PointerDeviceKind kind = PointerDeviceKind.mouse,
             int device = 0,
 
     public class PointerMoveEvent : PointerEvent {
         public PointerMoveEvent(
-            DateTime timeStamp,
+            TimeSpan timeStamp,
             int pointer = 0,
             PointerDeviceKind kind = PointerDeviceKind.mouse,
             int device = 0,
 
     public class PointerUpEvent : PointerEvent {
         public PointerUpEvent(
-            DateTime timeStamp,
+            TimeSpan timeStamp,
             int pointer = 0,
             PointerDeviceKind kind = PointerDeviceKind.mouse,
             int device = 0,
 
     public class PointerCancelEvent : PointerEvent {
         public PointerCancelEvent(
-            DateTime timeStamp,
+            TimeSpan timeStamp,
             int pointer = 0,
             PointerDeviceKind kind = PointerDeviceKind.mouse,
             int device = 0,

Runtime/gestures/monodrag.cs

         _DragState _state = _DragState.ready;
         Offset _initialPosition;
         protected Offset _pendingDragOffset;
-        DateTime _lastPendingEventTimestamp;
+        TimeSpan _lastPendingEventTimestamp;
 
         protected abstract bool _isFlingGesture(VelocityEstimate estimate);
         protected abstract Offset _getDeltaForDetails(Offset delta);
                 Offset delta = this._pendingDragOffset;
                 var timestamp = this._lastPendingEventTimestamp;
                 this._pendingDragOffset = Offset.zero;
-                this._lastPendingEventTimestamp = default(DateTime);
+                this._lastPendingEventTimestamp = default(TimeSpan);
                 if (this.onStart != null) {
                     this.invokeCallback<object>("onStart", () => {
                         this.onStart(new DragStartDetails(

Runtime/gestures/velocity_tracker.cs

     }
 
     class _PointAtTime {
-        internal _PointAtTime(Offset point, DateTime time) {
+        internal _PointAtTime(Offset point, TimeSpan time) {
             D.assert(point != null);
             this.point = point;
             this.time = time;
 
-        public readonly DateTime time;
+        public readonly TimeSpan time;
 
         public override string ToString() {
             return string.Format("_PointAtTime({0} at {1})", this.point, this.time);
         readonly List<_PointAtTime> _samples = Enumerable.Repeat<_PointAtTime>(null, _historySize).ToList();
         int _index = 0;
 
-        public void addPosition(DateTime time, Offset position) {
+        public void addPosition(TimeSpan time, Offset position) {
             this._index += 1;
             if (this._index == _historySize) {
                 this._index = 0;

Runtime/painting/binding.cs

-using Unity.UIWidgets.ui;
+using Unity.UIWidgets.gestures;
-    public class PaintingBinding {
-
-        public PaintingBinding(Window window) {
-            this._window = window;
+    public class PaintingBinding : GestureBinding {
+        public static new PaintingBinding instance {
+            get { return (PaintingBinding) GestureBinding.instance; }
+            set { GestureBinding.instance = value; }
-        
-        private static PaintingBinding _instance;
-        public readonly Window _window;
-        public static PaintingBinding instance {
-            get { return _instance; }
+        public PaintingBinding() {
-        private ImageCache _imageCache;
+        ImageCache _imageCache;
-            get { return _imageCache; }
-        }
+            get {
+                if (this._imageCache == null) {
+                    this._imageCache = this.createImageCache();
+                }
-        public ImageCache createImageCache() {
-            return new ImageCache();
+                return this._imageCache;
+            }
-        public void initInstances() {
-            _instance = this;
-            _imageCache = createImageCache();
+        protected virtual ImageCache createImageCache() {
+            return new ImageCache();
         }
     }
 }

Runtime/painting/decoration_image.cs

-using System;
+using Unity.UIWidgets.foundation;
-    /// How to paint any portions of a box not covered by an image.
-        /// Repeat the image in both the x and y directions until the box is filled.
-
-        /// Repeat the image in the x direction until the box is filled horizontally.
-
-        /// Repeat the image in the y direction until the box is filled vertically.
-
-        /// Leave uncovered portions of the box transparent.
         noRepeat,
     }
 
     }
 
-    public static class DecorationImageUtil {
+    public static class ImageUtils {
-            Canvas canvas,
-            Rect rect,
-            ui.Image image,
-//            ColorFilter colorFileter,
-            BoxFit? fit,
-            Rect centerSlice,
+            Canvas canvas = null,
+            Rect rect = null,
+            Image image = null,
+            double scale = 1.0,
+            ColorFilter colorFilter = null,
+            BoxFit? fit = null,
-            ImageRepeat repeat = ImageRepeat.noRepeat
-//            bool flipHorizontally = false
+            Rect centerSlice = null,
+            ImageRepeat repeat = ImageRepeat.noRepeat,
+            bool invertColors = false,
+            FilterMode filterMode = FilterMode.Point
-            if (rect.isEmpty)
+            D.assert(canvas != null);
+            D.assert(rect != null);
+            D.assert(image != null);
+            alignment = alignment ?? Alignment.center;
+
+            if (rect.isEmpty) {
-            alignment = alignment ?? Alignment.center;
+            }
+
             Size outputSize = rect.size;
             Size inputSize = new Size(image.width, image.height);
             Offset sliceBorder = null;
                 inputSize -= sliceBorder;
             }
 
-            if (fit == null) {
-                fit = centerSlice == null ? BoxFit.scaleDown : BoxFit.fill;
-            }
-            FittedSizes fittedSizes = FittedSizes.applyBoxFit(fit.Value, inputSize, outputSize);
-            Size sourceSize = fittedSizes.source;
+            fit = fit ?? (centerSlice == null ? BoxFit.scaleDown : BoxFit.fill);
+            D.assert(centerSlice == null || (fit != BoxFit.none && fit != BoxFit.cover));
+            FittedSizes fittedSizes = FittedSizes.applyBoxFit(fit.Value, inputSize / scale, outputSize);
+            Size sourceSize = fittedSizes.source * scale;
+                D.assert(sourceSize == inputSize,
+                    "centerSlice was used with a BoxFit that does not guarantee that the image is fully visible.");
             }
 
             if (repeat != ImageRepeat.noRepeat && destinationSize == outputSize) {
-            Paint paint = new Paint(); // ..isAntiAlias = false;
-//            if (colorFilter != null)
-//                paint.colorFilter = colorFilter;
+            Paint paint = new Paint();
+            if (colorFilter != null) {
+                paint.colorFilter = colorFilter;
+            }
+
-                // Use the "low" quality setting to scale the image, which corresponds to
-                // bilinear interpolation, rather than the default "none" which corresponds
-                // to nearest-neighbor.
-//                paint.filterQuality = FilterQuality.low;
+                paint.filterMode = filterMode;
             }
 
             double halfWidthDelta = (outputSize.width - destinationSize.width) / 2.0;
             Offset destinationPosition = rect.topLeft.translate(dx, dy);
             Rect destinationRect = destinationPosition & destinationSize;
             bool needSave = repeat != ImageRepeat.noRepeat;
-            if (needSave)
+            if (needSave) {
-            if (repeat != ImageRepeat.noRepeat)
+            }
+
+            if (repeat != ImageRepeat.noRepeat) {
+            }
+
-                    canvas.drawImageRect(image.texture, sourceRect, tileRect, paint);
+                    canvas.drawImageRect(image, sourceRect, tileRect, paint);
-            }
-            else {
-                // todo
+            } else {
-//                canvas.drawImageNine(image, centerSlice, tileRect, paint);
+                    canvas.drawImageNine(image, centerSlice, tileRect, paint);
-            if (needSave)
+            if (needSave) {
+            }
-        public static List<Rect> _generateImageTileRects(Rect outputRect, Rect fundamentalRect,
+        static IEnumerable<Rect> _generateImageTileRects(Rect outputRect, Rect fundamentalRect,
-            List<Rect> tileRects = new List<Rect>();
-                tileRects.Add(fundamentalRect);
-                return tileRects;
+                yield return fundamentalRect;
+                yield break;
             }
 
             int startX = 0;
             double strideY = fundamentalRect.height;
 
             if (repeat == ImageRepeat.repeat || repeat == ImageRepeat.repeatX) {
-                startX = (int) Math.Floor((outputRect.left - fundamentalRect.left) / strideX);
-                stopX = (int) Math.Ceiling((outputRect.right - fundamentalRect.right) / strideX);
+                startX = ((outputRect.left - fundamentalRect.left) / strideX).floor();
+                stopX = ((outputRect.right - fundamentalRect.right) / strideX).ceil();
-                startY = (int) Math.Floor((outputRect.top - fundamentalRect.top) / strideY);
-                stopY = (int) Math.Ceiling((outputRect.bottom - fundamentalRect.bottom) / strideY);
+                startY = ((outputRect.top - fundamentalRect.top) / strideY).floor();
+                stopY = ((outputRect.bottom - fundamentalRect.bottom) / strideY).ceil();
-                    tileRects.Add(fundamentalRect.shift(new Offset(i * strideX, j * strideY)));
+                    yield return fundamentalRect.shift(new Offset(i * strideX, j * strideY));
-
-            return tileRects;
         }
     }
 }

Runtime/painting/image_cache.cs

+using System;
-using Object = System.Object;
+using Unity.UIWidgets.foundation;
-        private const int _kDefaultSize = 1000;
-        private const int _kDefaultSizeBytes = 20 << 20; // 20 MiB
+        const int _kDefaultSize = 1000;
+        const int _kDefaultSizeBytes = 100 << 20; // 100 MiB
-        public Dictionary<Object, ImageStreamCompleter> _pendingImages =
-            new Dictionary<Object, ImageStreamCompleter>();
+        readonly Dictionary<object, ImageStreamCompleter> _pendingImages =
+            new Dictionary<object, ImageStreamCompleter>();
-        public Dictionary<Object, _CachedImage> _cache = new Dictionary<Object, _CachedImage>();
-        public LinkedList<Object> _lruKeys = new LinkedList<Object>();
+        readonly Dictionary<object, _CachedImage> _cache = new Dictionary<object, _CachedImage>();
+        readonly LinkedList<object> _lruKeys = new LinkedList<object>();
-        private int _maximumSize = _kDefaultSize;
+        int _maximumSize = _kDefaultSize;
-            get { return _maximumSize; }
+            get => this._maximumSize;
-                if (value == maximumSize) {
+                D.assert(value >= 0);
+                if (value == this._maximumSize) {
-                _maximumSize = value;
-                if (maximumSize == 0) {
-                    _cache.Clear();
-                    _lruKeys.Clear();
-                    _currentSizeBytes = 0;
-                }
-                else {
-                    _checkCacheSize();
+                this._maximumSize = value;
+                if (this._maximumSize == 0) {
+                    this.clear();
+                } else {
+                    this._checkCacheSize();
-        public int currentSize {
-            get { return _cache.Count; }
-        }
+        public int currentSize => this._cache.Count;
-        private int _maximumSizeBytes = _kDefaultSizeBytes;
+        int _maximumSizeBytes = _kDefaultSizeBytes;
-            get { return _maximumSizeBytes; }
+            get { return this._maximumSizeBytes; }
-                if (value == _maximumSizeBytes) {
+                D.assert(value >= 0);
+                if (value == this._maximumSizeBytes) {
-                _maximumSizeBytes = value;
-                if (_maximumSizeBytes == 0) {
-                    _cache.Clear();
-                    _lruKeys.Clear();
-                    _currentSizeBytes = 0;
-                }
-                else {
-                    _checkCacheSize();
+                this._maximumSizeBytes = value;
+                if (this._maximumSizeBytes == 0) {
+                    this.clear();
+                } else {
+                    this._checkCacheSize();
-        private int _currentSizeBytes;
+        int _currentSizeBytes;
-        public int currentSizeBytes {
-            get { return _currentSizeBytes; }
-        }
+        public int currentSizeBytes => this._currentSizeBytes;
-            _cache.Clear();
-            _lruKeys.Clear();
-            _currentSizeBytes = 0;
+            this._cache.Clear();
+            this._lruKeys.Clear();
+            this._currentSizeBytes = 0;
-        public delegate ImageStreamCompleter Loader();
+        public bool evict(object key) {
+            D.assert(key != null);
-        public ImageStreamCompleter putIfAbsent(Object key, Loader loader) {
-            ImageStreamCompleter result;
-            if (_pendingImages.TryGetValue(key, out result)) {
+            if (this._cache.TryGetValue(key, out var image)) {
+                this._currentSizeBytes -= image.sizeBytes;
+                this._cache.Remove(image.node);
+                this._lruKeys.Remove(image.node);
+                return true;
+            }
+
+            return false;
+        }
+
+        public ImageStreamCompleter putIfAbsent(object key, Func<ImageStreamCompleter> loader) {
+            D.assert(key != null);
+            D.assert(loader != null);
+
+            if (this._pendingImages.TryGetValue(key, out var result)) {
-            _CachedImage image;
-            if (_cache.TryGetValue(key, out image)) {
+            if (this._cache.TryGetValue(key, out var image)) {
-                _lruKeys.Remove(key);
-                _lruKeys.AddLast(key);
-            }
-
-            if (image != null) {
+                this._lruKeys.Remove(image.node);
+                image.node = this._lruKeys.AddLast(key);
-            if (maximumSize > 0 && maximumSizeBytes > 0) {
-                _pendingImages[key] = result;
-                result.addListener((info, syncCall) => {
-//                    int imageSize = info.image == null ? 0 : info.image.height * info.image.width * 4;
-                    // now we use length or raw bytes array as image size
-                    int imageSize = info.image == null ? 0 : info.image.rawData.Length;
-                    _CachedImage cachedImage = new _CachedImage(result, imageSize);
-                    if (maximumSizeBytes > 0 && imageSize > maximumSizeBytes) {
-                        _maximumSize = imageSize + 1000;
+            if (this._maximumSize > 0 && this._maximumSizeBytes > 0) {
+                D.assert(!this._pendingImages.ContainsKey(key));
+                this._pendingImages[key] = result;
+
+                ImageListener listener = null;
+                listener = (info, syncCall) => {
+                    result.removeListener(listener);
+                    
+                    D.assert(this._pendingImages.ContainsKey(key));
+                    this._pendingImages.Remove(key);
+
+                    int imageSize = info?.image == null ? 0 : info.image.width & info.image.height * 4;
+                    _CachedImage cachedImage = new _CachedImage {
+                        completer = result,
+                        sizeBytes = imageSize,
+                    };
+
+                    // If the image is bigger than the maximum cache size, and the cache size
+                    // is not zero, then increase the cache size to the size of the image plus
+                    // some change.
+                    if (this._maximumSizeBytes > 0 && imageSize > this._maximumSizeBytes) {
+                        this._maximumSizeBytes = imageSize + 1000;
-                    _currentSizeBytes += imageSize;
-                    _pendingImages.Remove(key);
-                    _cache[key] = cachedImage;
-                    _lruKeys.AddLast(key);
+                    this._currentSizeBytes += imageSize;
+
+                    D.assert(!this._cache.ContainsKey(key));
+                    this._cache[key] = cachedImage;
+                    cachedImage.node = this._lruKeys.AddLast(key);
+
-                }, null);
+                };
+                result.addListener(listener);
             }
 
             return result;
-            while (_currentSizeBytes > _maximumSizeBytes || _cache.Count > _maximumSize) {
-                Object key = _lruKeys.First.Value; // get the LRU item
-                _CachedImage image = _cache[key];
-                bool removed = _cache.Remove(key);
-                if (image != null && removed) {
-                    _currentSizeBytes -= image.sizeBytes;
-                    _lruKeys.Remove(key);
-                }
+            while (this._currentSizeBytes > this._maximumSizeBytes || this._cache.Count > this._maximumSize) {
+                var node = this._lruKeys.First;
+                var key = node.Value; // get the LRU item
+
+                D.assert(this._cache.ContainsKey(key));
+                _CachedImage image = this._cache[key];
+
+                D.assert(node == image.node);
+                this._currentSizeBytes -= image.sizeBytes;
+                this._cache.Remove(key);
+                this._lruKeys.Remove(image.node);
-        }
-    }
-    public class _CachedImage {
-        public _CachedImage(ImageStreamCompleter completer, int sizeBytes) {
-            this.completer = completer;
-            this.sizeBytes = sizeBytes;
+            D.assert(this._currentSizeBytes >= 0);
+            D.assert(this._cache.Count <= this.maximumSize);
+            D.assert(this._currentSizeBytes <= this.maximumSizeBytes);
+    }
+    class _CachedImage {
+        public LinkedListNode<object> node;
     }
 }

Runtime/painting/image_provider.cs

 using System.Collections.Generic;
 using RSG;
-using System.Net;
-using System.IO;
-using Unity.UIWidgets.lib.cache_manager;
+using System.Collections;
+using System.Text;
+using Unity.UIWidgets.async;
+using Unity.UIWidgets.foundation;
+using UnityEngine;
+using UnityEngine.Networking;
+    public class ImageConfiguration : IEquatable<ImageConfiguration> {
+        public ImageConfiguration(
+            AssetBundle bundle = null,
+            double? devicePixelRatio = null,
+            Locale locale = null,
+            Size size = null,
+            RuntimePlatform? platform = null
+        ) {
+            this.bundle = bundle;
+            this.devicePixelRatio = devicePixelRatio;
+            this.locale = locale;
+            this.size = size;
+            this.platform = platform;
+        }
+
+        public ImageConfiguration copyWith(
+            AssetBundle bundle = null,
+            double? devicePixelRatio = null,
+            Locale locale = null,
+            Size size = null,
+            RuntimePlatform? platform = null
+        ) {
+            return new ImageConfiguration(
+                bundle: bundle ? bundle : this.bundle,
+                devicePixelRatio: devicePixelRatio ?? this.devicePixelRatio,
+                locale: locale ?? this.locale,
+                size: size ?? this.size,
+                platform: platform ?? this.platform
+            );
+        }
+
+        public readonly AssetBundle bundle;
+
+        public readonly double? devicePixelRatio;
+
+        public readonly Locale locale;
+
+        public readonly Size size;
+
+        public readonly RuntimePlatform? platform;
+
+        public static readonly ImageConfiguration empty = new ImageConfiguration();
+
+        public bool Equals(ImageConfiguration other) {
+            if (ReferenceEquals(null, other)) return false;
+            if (ReferenceEquals(this, other)) return true;
+            return Equals(this.bundle, other.bundle) && this.devicePixelRatio.Equals(other.devicePixelRatio) &&
+                   Equals(this.locale, other.locale) && Equals(this.size, other.size) &&
+                   this.platform == other.platform;
+        }
+
+        public override bool Equals(object obj) {
+            if (ReferenceEquals(null, obj)) return false;
+            if (ReferenceEquals(this, obj)) return true;
+            if (obj.GetType() != this.GetType()) return false;
+            return this.Equals((ImageConfiguration) obj);
+        }
+
+        public override int GetHashCode() {
+            unchecked {
+                var hashCode = (this.bundle != null ? this.bundle.GetHashCode() : 0);
+                hashCode = (hashCode * 397) ^ this.devicePixelRatio.GetHashCode();
+                hashCode = (hashCode * 397) ^ (this.locale != null ? this.locale.GetHashCode() : 0);
+                hashCode = (hashCode * 397) ^ (this.size != null ? this.size.GetHashCode() : 0);
+                hashCode = (hashCode * 397) ^ this.platform.GetHashCode();
+                return hashCode;
+            }
+        }
+
+        public static bool operator ==(ImageConfiguration left, ImageConfiguration right) {
+            return Equals(left, right);
+        }
+
+        public static bool operator !=(ImageConfiguration left, ImageConfiguration right) {
+            return !Equals(left, right);
+        }
+
+        public override string ToString() {
+            var result = new StringBuilder();
+            result.Append("ImageConfiguration(");
+            bool hasArguments = false;
+            if (this.bundle != null) {
+                if (hasArguments) {
+                    result.Append(", ");
+                }
+
+                result.Append($"bundle: {this.bundle}");
+                hasArguments = true;
+            }
+
+            if (this.devicePixelRatio != null) {
+                if (hasArguments) {
+                    result.Append(", ");
+                }
+
+                result.Append($"devicePixelRatio: {this.devicePixelRatio:F1}");
+                hasArguments = true;
+            }
+
+            if (this.locale != null) {
+                if (hasArguments) {
+                    result.Append(", ");
+                }
+
+                result.Append($"locale: {this.locale}");
+                hasArguments = true;
+            }
+
+            if (this.size != null) {
+                if (hasArguments) {
+                    result.Append(", ");
+                }
+
+                result.Append($"size: {this.size}");
+                hasArguments = true;
+            }
+
+            if (this.platform != null) {
+                if (hasArguments) {
+                    result.Append(", ");
+                }
+
+                result.Append($"platform: {this.platform}");
+                hasArguments = true;
+            }
+
+            result.Append(")");
+            return result.ToString();
+        }
+    }
+
     public abstract class ImageProvider {
         public abstract ImageStream resolve(ImageConfiguration configuration);
     }
+            D.assert(configuration != null);
+
-            T obtainedKey;
-            obtainedKey = obtainKey(configuration);
-            stream.setCompleter(PaintingBinding.instance.imageCache.putIfAbsent(obtainedKey, () => load(obtainedKey)));
+            T obtainedKey = default;
+
+            this.obtainKey(configuration).Then(key => {
+                obtainedKey = key;
+                stream.setCompleter(PaintingBinding.instance.imageCache.putIfAbsent(key, () => this.load(key)));
+            }).Catch(ex => {
+                UIWidgetsError.reportError(new UIWidgetsErrorDetails(
+                    exception: ex,
+                    library: "services library",
+                    context: "while resolving an image",
+                    silent: true,
+                    informationCollector: information => {
+                        information.AppendLine($"Image provider: {this}");
+                        information.AppendLine($"Image configuration: {configuration}");
+                        if (obtainedKey != null) {
+                            information.AppendLine($"Image key: {obtainedKey}");
+                        }
+                    }
+                ));
+            });
+
-        public abstract ImageStreamCompleter load(T key);
+        public IPromise<bool> evict(ImageCache cache = null, ImageConfiguration configuration = null) {
+            configuration = configuration ?? ImageConfiguration.empty;
+            cache = cache ?? PaintingBinding.instance.imageCache;
+
+            return this.obtainKey(configuration).Then(key => cache.evict(key));
+        }
+
+        protected abstract ImageStreamCompleter load(T key);
+
+        protected abstract IPromise<T> obtainKey(ImageConfiguration configuration);
+    }
+
+    public class AssetBundleImageKey : IEquatable<AssetBundleImageKey> {
+
+        public AssetBundleImageKey(
+            AssetBundle bundle,
+            string name,
+            double scale
+        ) {
+            D.assert(bundle != null);
+            D.assert(name != null);
+            D.assert(scale >= 0.0);
+
+            this.bundle = bundle;
+            this.name = name;
+            this.scale = scale;
+        }
+
+        public readonly AssetBundle bundle;
+
+        public readonly string name;
+
+        public readonly double scale;
+
+        public bool Equals(AssetBundleImageKey other) {
+            if (ReferenceEquals(null, other)) return false;
+            if (ReferenceEquals(this, other)) return true;
+            return Equals(this.bundle, other.bundle) && string.Equals(this.name, other.name) &&
+                   this.scale.Equals(other.scale);
+        }
+
+        public override bool Equals(object obj) {
+            if (ReferenceEquals(null, obj)) return false;
+            if (ReferenceEquals(this, obj)) return true;
+            if (obj.GetType() != this.GetType()) return false;
+            return this.Equals((AssetBundleImageKey) obj);
+        }
+
+        public override int GetHashCode() {
+            unchecked {
+                var hashCode = (this.bundle != null ? this.bundle.GetHashCode() : 0);
+                hashCode = (hashCode * 397) ^ (this.name != null ? this.name.GetHashCode() : 0);
+                hashCode = (hashCode * 397) ^ this.scale.GetHashCode();
+                return hashCode;
+            }
+        }
+
+        public static bool operator ==(AssetBundleImageKey left, AssetBundleImageKey right) {
+            return Equals(left, right);
+        }
+
+        public static bool operator !=(AssetBundleImageKey left, AssetBundleImageKey right) {
+            return !Equals(left, right);
+        }
+
+        public override string ToString() {
+            return $"{this.GetType()}(bundle: {this.bundle}, name: \"{this.name}\", scale: {this.scale})";
+        }
+    }
+
+    public abstract class AssetBundleImageProvider : ImageProvider<AssetBundleImageKey> {
+        protected AssetBundleImageProvider() {
+        }
-        public abstract T obtainKey(ImageConfiguration configuration);
+        protected override ImageStreamCompleter load(AssetBundleImageKey key) {
+            return new MultiFrameImageStreamCompleter(
+                codec: this._loadAsync(key),
+                scale: key.scale,
+                informationCollector: information => {
+                    information.AppendLine($"Image provider: {this}");
+                    information.Append($"Image key: {key}");
+                }
+            );
+        }
+
+        protected virtual IPromise<Codec> _loadAsync(AssetBundleImageKey key) {
+            var coroutine = Window.instance.startCoroutine(this._loadAssetAsync(key));
+            return coroutine.promise.Then(result => {
+                if (result == null) {
+                    if (key.bundle == null) {
+                        throw new Exception($"Unable to find asset \"{key.name}\" from Resources folder");
+                    }
+
+                    throw new Exception($"Unable to find asset \"{key.name}\" from asset bundle \"{key.bundle}\"");
+                }
+
+                return CodecUtils.getCodec((Texture2D) result);
+            });
+        }
+
+        IEnumerator _loadAssetAsync(AssetBundleImageKey key) {
+            if (key.bundle == null) {
+                yield return Resources.LoadAsync<Texture2D>(key.name);
+                yield break;
+            }
+
+            yield return key.bundle.LoadAssetAsync(key.name);
+        }
-    public class NetworkImage : ImageProvider<NetworkImage> {
-        public NetworkImage(string url, Dictionary<string, string> headers, double scale = 1.0) {
+    public class NetworkImage : ImageProvider<NetworkImage>, IEquatable<NetworkImage> {
+        public NetworkImage(string url,
+            double scale = 1.0,
+            IDictionary<string, string> headers = null) {
+            D.assert(url != null);
-            this.headers = headers;
+            this.headers = headers;
-        /// The URL from which the image will be fetched.
-        string url;
+        public readonly string url;
-        /// The scale to place in the [ImageInfo] object of the image.
-        double scale;
+        public readonly double scale;
-        /// The HTTP headers that will be used with [HttpClient.get] to fetch image from network.
-        Dictionary<string, string> headers;
+        public readonly IDictionary<string, string> headers;
-        public override NetworkImage obtainKey(ImageConfiguration configuration) {
-            return this;
+        protected override IPromise<NetworkImage> obtainKey(ImageConfiguration configuration) {
+            return Promise<NetworkImage>.Resolved(this);
-        public override ImageStreamCompleter load(NetworkImage key) {
-//            return new OneFrameImageStreamCompleter(_loadAsync(key));
-            return new OneFrameImageStreamCompleter(_loadAsyncWithCache(key));
+        protected override ImageStreamCompleter load(NetworkImage key) {
+            return new MultiFrameImageStreamCompleter(
+                codec: this._loadAsync(key),
+                scale: key.scale,
+                informationCollector: information => {
+                    information.AppendLine($"Image provider: {this}");
+                    information.Append($"Image key: {key}");
+                }
+            );
-        public static IPromise<ImageInfo> _loadAsync(NetworkImage key) {
-            var promise = new Promise<ImageInfo>(); // Create promise.
-            using (var client = new WebClient()) {
-                client.DownloadDataCompleted += // Monitor event for download completed.
-                    (s, ev) => {
-                        if (ev.Error != null) {
-                            promise.Reject(ev.Error); // Error during download, reject the promise.
-                        }
-                        else {
-                            var bytes = ev.Result;
-                            var imageInfo = new ImageInfo(new ui.Image(
-                                bytes
-                            ));
-                            promise.Resolve(imageInfo); // Downloaded completed successfully, resolve the promise.
+        IPromise<Codec> _loadAsync(NetworkImage key) {
+            var coroutine = Window.instance.startCoroutine(this._loadBytes(key));
+            return coroutine.promise.Then(obj => {
+                if (obj is byte[] bytes) {
+                    return CodecUtils.getCodec(bytes);
+                }
+
+                return CodecUtils.getCodec((Texture2D) obj);
+            });
+        }
+
+        IEnumerator _loadBytes(NetworkImage key) {
+            D.assert(key == this);
+            var uri = new Uri(key.url);
+
+            if (uri.LocalPath.EndsWith(".gif")) {
+                using (var www = UnityWebRequest.Get(uri)) {
+                    if (this.headers != null) {
+                        foreach (var header in this.headers) {
+                            www.SetRequestHeader(header.Key, header.Value);
-                    };
+                    }
+
+                    yield return www.SendWebRequest();
-                client.DownloadDataAsync(new Uri(key.url)); // Initiate async op.
+                    if (www.isNetworkError || www.isHttpError) {
+                        throw new Exception($"Failed to load from url \"{uri}\": {www.error}");
+                    }
+
+                    var data = www.downloadHandler.data;
+                    yield return data;
+                }
+
+                yield break;
-            return promise; // Return the promise so the caller can await resolution (or error).
+            using (var www = UnityWebRequestTexture.GetTexture(uri)) {
+                if (this.headers != null) {
+                    foreach (var header in this.headers) {
+                        www.SetRequestHeader(header.Key, header.Value);
+                    }
+                }
+
+                yield return www.SendWebRequest();
+
+                if (www.isNetworkError || www.isHttpError) {
+                    throw new Exception($"Failed to load from url \"{uri}\": {www.error}");
+                }
+
+                var data = ((DownloadHandlerTexture) www.downloadHandler).texture;
+                yield return data;
+            }
-        
-        public static IPromise<ImageInfo> _loadAsyncWithCache(NetworkImage key) {
-            var cache = CacheManager.getInstance();
-            var result = cache.getMeta(key.url).
-                Then(meta => cache.downloadFileIfNeeded(meta)).
-                Then(meta => cache.updateMeta(meta)).
-                Then(path => cache.loadCacheFile(path));
-            return result;
+
+        public bool Equals(NetworkImage other) {
+            if (ReferenceEquals(null, other)) return false;
+            if (ReferenceEquals(this, other)) return true;
+            return string.Equals(this.url, other.url) && this.scale.Equals(other.scale);
+        }
+
+        public override bool Equals(object obj) {
+            if (ReferenceEquals(null, obj)) return false;
+            if (ReferenceEquals(this, obj)) return true;
+            if (obj.GetType() != this.GetType()) return false;
+            return this.Equals((NetworkImage) obj);
+        }
+
+        public override int GetHashCode() {
+            unchecked {
+                return ((this.url != null ? this.url.GetHashCode() : 0) * 397) ^ this.scale.GetHashCode();
+            }
+        }
+
+        public static bool operator ==(NetworkImage left, NetworkImage right) {
+            return Equals(left, right);
+        }
+
+        public static bool operator !=(NetworkImage left, NetworkImage right) {
+            return !Equals(left, right);
-            return "NetworkImage with Url: " + this.url;
+            return $"runtimeType(\"{this.url}\", scale: {this.scale})";
+        }
+    }
+
+    public class FileImage : ImageProvider<FileImage>, IEquatable<FileImage> {
+        public FileImage(string file, double scale = 1.0) {
+            D.assert(file != null);
+            this.file = file;
+            this.scale = scale;
+        }
+
+        public readonly string file;
+
+        public readonly double scale;
+
+        protected override IPromise<FileImage> obtainKey(ImageConfiguration configuration) {
+            return Promise<FileImage>.Resolved(this);
+        }
+
+        protected override ImageStreamCompleter load(FileImage key) {
+            return new MultiFrameImageStreamCompleter(this._loadAsync(key),
+                scale: key.scale,
+                informationCollector: information => {
+                information.AppendLine($"Path: {this.file}");
+            });
+        }
+
+        IPromise<Codec> _loadAsync(FileImage key) {
+            var coroutine = Window.instance.startCoroutine(this._loadBytes(key));
+            return coroutine.promise.Then(obj => {
+                if (obj is byte[] bytes) {
+                    return CodecUtils.getCodec(bytes);
+                }
+
+                return CodecUtils.getCodec((Texture2D) obj);
+            });
-        public bool Equals(NetworkImage other) {
-            return this.url.Equals(other.url) && this.scale.Equals(other.scale);
+        IEnumerator _loadBytes(FileImage key) {
+            D.assert(key == this);
+            var uri = "file://" + key.file;
+
+            if (uri.EndsWith(".gif")) {
+                using (var www = UnityWebRequest.Get(uri)) {
+                    yield return www.SendWebRequest();
+
+                    if (www.isNetworkError || www.isHttpError) {
+                        throw new Exception($"Failed to get file \"{uri}\": {www.error}");
+                    }
+
+                    var data = www.downloadHandler.data;
+                    yield return data;
+                }
+                
+                yield break;
+            }
+            
+            using (var www = UnityWebRequestTexture.GetTexture(uri)) {
+                yield return www.SendWebRequest();
+
+                if (www.isNetworkError || www.isHttpError) {
+                    throw new Exception($"Failed to get file \"{uri}\": {www.error}");
+                }
+
+                var data = ((DownloadHandlerTexture) www.downloadHandler).texture;
+                yield return data;
+            }
+        }
+
+        public bool Equals(FileImage other) {
+            if (ReferenceEquals(null, other)) return false;
+            if (ReferenceEquals(this, other)) return true;
+            return string.Equals(this.file, other.file) && this.scale.Equals(other.scale);
-            if (object.ReferenceEquals(null, obj)) return false;
-            if (object.ReferenceEquals(this, obj)) return true;
-            return obj is NetworkImage && this.Equals((NetworkImage) obj);
+            if (ReferenceEquals(null, obj)) return false;
+            if (ReferenceEquals(this, obj)) return true;
+            if (obj.GetType() != this.GetType()) return false;
+            return this.Equals((FileImage) obj);
-                var hashCode = this.url.GetHashCode();
-                hashCode = (hashCode * 397) ^ this.scale.GetHashCode();
-                return hashCode;
+                return ((this.file != null ? this.file.GetHashCode() : 0) * 397) ^ this.scale.GetHashCode();
+
+        public static bool operator ==(FileImage left, FileImage right) {
+            return Equals(left, right);
+        }
+
+        public static bool operator !=(FileImage left, FileImage right) {
+            return !Equals(left, right);
+        }
+
+        public override string ToString() {
+            return $"{this.GetType()}(\"{this.file}\", scale: {this.scale})";
+        }
-    public class FileImage : ImageProvider<FileImage> {
-        public FileImage(string path, double scale = 1.0) {
-            this.path = path;
+    public class MemoryImage : ImageProvider<MemoryImage>, IEquatable<MemoryImage> {
+
+        public MemoryImage(byte[] bytes, double scale = 1.0) {
+            D.assert(bytes != null);
+            this.bytes = bytes;
-
-        public string path;
-        public double scale;
+        public readonly byte[] bytes;
+
+        public readonly double scale;
-        public override FileImage obtainKey(ImageConfiguration configuration) {
-            return this;
+        protected override IPromise<MemoryImage> obtainKey(ImageConfiguration configuration) {
+            return Promise<MemoryImage>.Resolved(this);
+        }
+
+        protected override ImageStreamCompleter load(MemoryImage key) {
+            return new MultiFrameImageStreamCompleter(
+                this._loadAsync(key),
+                scale: key.scale);
-        public override ImageStreamCompleter load(FileImage key) {
-            return new OneFrameImageStreamCompleter(_loadAsync(key));
+        IPromise<Codec> _loadAsync(MemoryImage key) {
+            D.assert(key == this);
+
+            return CodecUtils.getCodec(this.bytes);
+        }
+
+        public bool Equals(MemoryImage other) {
+            if (ReferenceEquals(null, other)) return false;
+            if (ReferenceEquals(this, other)) return true;
+            return Equals(this.bytes, other.bytes) && this.scale.Equals(other.scale);
+        }
+
+        public override bool Equals(object obj) {
+            if (ReferenceEquals(null, obj)) return false;
+            if (ReferenceEquals(this, obj)) return true;
+            if (obj.GetType() != this.GetType()) return false;
+            return this.Equals((MemoryImage) obj);
+        }
+
+        public override int GetHashCode() {
+            unchecked {
+                return ((this.bytes != null ? this.bytes.GetHashCode() : 0) * 397) ^ this.scale.GetHashCode();
+            }
+        }
+
+        public static bool operator ==(MemoryImage left, MemoryImage right) {
+            return Equals(left, right);
-        
-        public static IPromise<ImageInfo> _loadAsync(FileImage key) {
-            var promise = new Promise<ImageInfo>();
-            var bytes = File.ReadAllBytes(key.path);
-            var imageInfo = new ImageInfo(new ui.Image(
-                bytes
-            ));
-            promise.Resolve(imageInfo);
-            return promise;
+        public static bool operator !=(MemoryImage left, MemoryImage right) {
+            return !Equals(left, right);
-        
+
-            return "FileImage with Path: " + this.path;
+            return $"{this.GetType()}({Diagnostics.describeIdentity(this.bytes)}), scale: {this.scale}";
+        }
+    }
+
+    public class ExactAssetImage : AssetBundleImageProvider, IEquatable<ExactAssetImage> {
+
+        public ExactAssetImage(
+            string assetName,
+            double scale = 1.0,
+            AssetBundle bundle = null
+        ) {
+            D.assert(assetName != null);
+            this.assetName = assetName;
+            this.scale = scale;
+            this.bundle = bundle;
+        }
+
+        public readonly string assetName;
+
+        public readonly double scale;
+
+        public readonly AssetBundle bundle;
+
+        protected override IPromise<AssetBundleImageKey> obtainKey(ImageConfiguration configuration) {
+            return Promise<AssetBundleImageKey>.Resolved(new AssetBundleImageKey(
+                bundle: this.bundle ? this.bundle : configuration.bundle,
+                name: this.assetName,
+                scale: this.scale
+            ));
-        public bool Equals(FileImage other) {
-            return this.path.Equals(other.path) && this.scale.Equals(other.scale);
+        public bool Equals(ExactAssetImage other) {
+            if (ReferenceEquals(null, other)) return false;
+            if (ReferenceEquals(this, other)) return true;
+            return string.Equals(this.assetName, other.assetName) && this.scale.Equals(other.scale) &&
+                   Equals(this.bundle, other.bundle);
-            if (object.ReferenceEquals(null, obj)) return false;
-            if (object.ReferenceEquals(this, obj)) return true;
-            return obj is FileImage && this.Equals((FileImage) obj);
+            if (ReferenceEquals(null, obj)) return false;
+            if (ReferenceEquals(this, obj)) return true;
+            if (obj.GetType() != this.GetType()) return false;
+            return this.Equals((ExactAssetImage) obj);
-                var hashCode = this.path.GetHashCode();
+                var hashCode = (this.assetName != null ? this.assetName.GetHashCode() : 0);
+                hashCode = (hashCode * 397) ^ (this.bundle != null ? this.bundle.GetHashCode() : 0);
-    }
-    public class ImageConfiguration {
-        public ImageConfiguration(Size size = null) {
-            this.size = size;
+        public static bool operator ==(ExactAssetImage left, ExactAssetImage right) {
+            return Equals(left, right);
-        public static readonly ImageConfiguration empty = new ImageConfiguration();
+        public static bool operator !=(ExactAssetImage left, ExactAssetImage right) {
+            return !Equals(left, right);
+        }
-        public ImageConfiguration copyWith(Size size = null) {
-            return new ImageConfiguration(
-                size: size ?? this.size
-            );
+        public override string ToString() {
+            return $"{this.GetType()}(name: \"{this.assetName}\", scale: {this.scale}, bundle: {this.bundle})";
-
-        public readonly Size size;
     }
 }

Runtime/painting/image_stream.cs

 using UnityEngine;
 using System;
 using System.Collections.Generic;
-using System.IO;
+using Unity.UIWidgets.async;
+using Unity.UIWidgets.foundation;
+using Unity.UIWidgets.scheduler;
-    public delegate void ImageListener(ImageInfo image, bool synchronousCall);
-
-    public delegate void ImageErrorListerner(System.Object exception, string stackTrack);
+    public class ImageInfo : IEquatable<ImageInfo> {
+        public ImageInfo(Image image, double scale = 1.0) {
+            D.assert(image != null);
-    public class ImageInfo {
-        public ImageInfo(Image image, double scale = 1.0) {
-        public Image image;
-        public double scale;
-    }
+        public readonly Image image;
+        public readonly double scale;
-    public class ImageStream {
-        public ImageStream() {
+        public bool Equals(ImageInfo other) {
+            if (ReferenceEquals(null, other)) return false;
+            if (ReferenceEquals(this, other)) return true;
+            return Equals(this.image, other.image) && this.scale.Equals(other.scale);
-        private ImageStreamCompleter _completer;
-        private List<_ImageListenerPair> _listeners;
+        public override bool Equals(object obj) {
+            if (ReferenceEquals(null, obj)) return false;
+            if (ReferenceEquals(this, obj)) return true;
+            if (obj.GetType() != this.GetType()) return false;
+            return this.Equals((ImageInfo) obj);
+        }
-        public System.Object key {
-            get {
-               return  _completer != null ? (object) _completer : this;
+        public override int GetHashCode() {
+            unchecked {
+                return ((this.image != null ? this.image.GetHashCode() : 0) * 397) ^ this.scale.GetHashCode();
-        public ImageStreamCompleter completer {
-            get { return _completer; }
+        public static bool operator ==(ImageInfo left, ImageInfo right) {
+            return Equals(left, right);
+        }
+
+        public static bool operator !=(ImageInfo left, ImageInfo right) {
+            return !Equals(left, right);
+        }
+
+        public override string ToString() {
+            return $"{this.image} @ {this.scale}x";
+        }
+    }
+
+    public delegate void ImageListener(ImageInfo image, bool synchronousCall);
+
+    public delegate void ImageErrorListener(Exception exception);
+
+    internal class _ImageListenerPair {
+        public ImageListener listener;
+        public ImageErrorListener errorListener;
+    }
+
+    public class ImageStream : Diagnosticable {
+        public ImageStream() {
+        ImageStreamCompleter _completer;
+        public ImageStreamCompleter completer => this._completer;
+
+        List<_ImageListenerPair> _listeners;
+
-            _completer = value;
-            if (_listeners != null) {
-                List<_ImageListenerPair> initialListeners = _listeners;
-                _listeners = null;
+            D.assert(this._completer == null);
+
+            this._completer = value;
+            if (this._listeners != null) {
+                var initialListeners = this._listeners;
+                this._listeners = null;
-                    _completer.addListener(
+                    this._completer.addListener(
                         listenerPair.listener,
                         listenerPair.errorListener
                     );
 
-        public void addListener(ImageListener listener,  ImageErrorListerner onError = null) {
-            if (_completer != null) {
-                _completer.addListener(listener, onError);
-            } else {
-                if (_listeners == null) {
-                    _listeners = new List<_ImageListenerPair>();
-                }
-                _listeners.Add(new _ImageListenerPair(listener, onError));
+        public void addListener(ImageListener listener, ImageErrorListener onError = null) {
+            if (this._completer != null) {
+                this._completer.addListener(listener, onError);
+                return;
+
+            if (this._listeners == null) {
+                this._listeners = new List<_ImageListenerPair>();
+            }
+
+            this._listeners.Add(new _ImageListenerPair {listener = listener, errorListener = onError});
-            if (_completer != null) {
-                _completer.removeListener(listener);
-            } else {
-                _listeners.RemoveAll(listenerPair => listenerPair.listener == listener);
+            if (this._completer != null) {
+                this._completer.removeListener(listener);
+                return;
+            }
+
+            D.assert(this._listeners != null);
+            for (int i = 0; i < this._listeners.Count; i++) {
+                if (this._listeners[i].listener == listener) {
+                    this._listeners.RemoveAt(i);
+                    break;
+                }
+
+        public object key => this._completer != null ? (object) this._completer : this;
+
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties);
+            properties.add(new ObjectFlagProperty<ImageStreamCompleter>(
+                "completer",
+                this._completer,
+                ifPresent: this._completer?.toStringShort(),
+                ifNull: "unresolved"
+            ));
+            properties.add(new ObjectFlagProperty<List<_ImageListenerPair>>(
+                "listeners",
+                this._listeners,
+                ifPresent: $"{this._listeners?.Count} listener{(this._listeners?.Count == 1 ? "" : "s")}",
+                ifNull: "no listeners",
+                level: this._completer != null ? DiagnosticLevel.hidden : DiagnosticLevel.info
+            ));
+            this._completer?.debugFillProperties(properties);
+        }
-    public abstract class ImageStreamCompleter {
-        public List<_ImageListenerPair> _listeners = new List<_ImageListenerPair>();
-        public ImageInfo _currentImgae;
+    public abstract class ImageStreamCompleter : Diagnosticable {
+        internal readonly List<_ImageListenerPair> _listeners = new List<_ImageListenerPair>();
+        public ImageInfo currentImage;
+        public UIWidgetsErrorDetails currentError;
-        public void addListener(ImageListener listener, ImageErrorListerner onError) {
-            this._listeners.Add(new _ImageListenerPair(listener, onError));
-            if (_currentImgae != null) {
+        public virtual void addListener(ImageListener listener, ImageErrorListener onError = null) {
+            this._listeners.Add(new _ImageListenerPair {listener = listener, errorListener = onError});
+
+            if (this.currentImage != null) {
-                    listener(_currentImgae, true);
-                    this.removeListener(listener);
+                    listener(this.currentImage, true);
-                catch (Exception e) {
-                    Console.WriteLine("{0} Exception caught.", e);
+                catch (Exception ex) {
+                    this.reportError(
+                        context: "by a synchronously-called image listener",
+                        exception: ex
+                    );
-            // todo call onError
+            if (this.currentError != null && onError != null) {
+                try {
+                    onError(this.currentError.exception);
+                }
+                catch (Exception ex) {
+                    UIWidgetsError.reportError(
+                        new UIWidgetsErrorDetails(
+                            exception: ex,
+                            library: "image resource service",
+                            context: "by a synchronously-called image error listener"
+                        )
+                    );
+                }
+            }
-        public void removeListener(ImageListener listener) {
-            var pairToRemove = this._listeners.Single(lp => lp.listener == listener);
-            this._listeners.Remove(pairToRemove);
+        public virtual void removeListener(ImageListener listener) {
+            for (int i = 0; i < this._listeners.Count; i++) {
+                if (this._listeners[i].listener == listener) {
+                    this._listeners.RemoveAt(i);
+                    break;
+                }
+            }
-        public void setImage(ImageInfo image) {
-            _currentImgae = image;
-            if (_listeners.Count == 0) {
+        protected void setImage(ImageInfo image) {
+            this.currentImage = image;
+            if (this._listeners.isEmpty()) {
-            foreach (var lp in _listeners.ToList()) {
-                // todo refine
-                var listener = lp.listener;
+            var localListeners = this._listeners.Select(l => l.listener).ToList();
+            foreach (var listener in localListeners) {
-                    this.removeListener(listener);
-                catch (Exception e) {
-                    Console.WriteLine("{0} Exception caught.", e);
+                catch (Exception ex) {
+                    this.reportError(
+                        context: "by an image listener",
+                        exception: ex
+                    );
+            }
+        }
-                // todo call onError
+        protected void reportError(
+            string context = null,
+            Exception exception = null,
+            InformationCollector informationCollector = null,
+            bool silent = false) {
+            this.currentError = new UIWidgetsErrorDetails(
+                exception: exception,
+                library: "image resource service",
+                context: context,
+                informationCollector: informationCollector,
+                silent: silent
+            );
+
+            var localErrorListeners = this._listeners.Select(l => l.errorListener).Where(l => l != null).ToList();
+
+            if (localErrorListeners.isEmpty()) {
+                UIWidgetsError.reportError(this.currentError);
+            } else {
+                foreach (var errorListener in localErrorListeners) {
+                    try {
+                        errorListener(exception);
+                    }
+                    catch (Exception ex) {
+                        UIWidgetsError.reportError(
+                            new UIWidgetsErrorDetails(
+                                context: "by an image error listener",
+                                library: "image resource service",
+                                exception: ex
+                            )
+                        );
+                    }
+                }
+
+        public override void debugFillProperties(DiagnosticPropertiesBuilder description) {
+            base.debugFillProperties(description);
+            description.add(new DiagnosticsProperty<ImageInfo>(
+                "current", this.currentImage, ifNull: "unresolved", showName: false));
+            description.add(new ObjectFlagProperty<List<_ImageListenerPair>>(
+                "listeners",
+                this._listeners,
+                ifPresent: $"{this._listeners.Count} listener{(this._listeners.Count == 1 ? "" : "s")}"
+            ));
+        }
-        public OneFrameImageStreamCompleter(IPromise<ImageInfo> image) {
-            image.Then(result => { setImage(result); }).Catch(err => { Debug.Log(err); });
+        public OneFrameImageStreamCompleter(IPromise<ImageInfo> image,
+            InformationCollector informationCollector = null) {
+            D.assert(image != null);
+
+            image.Then(result => {
+                this.setImage(result);
+            }).Catch(err => {
+                this.reportError(
+                    context: "resolving a single-frame image stream",
+                    exception: err,
+                    informationCollector: informationCollector,
+                    silent: true
+                );
+            });
-    public class _ImageListenerPair {
-        public _ImageListenerPair(ImageListener listener, ImageErrorListerner errorListener) {
-            this.listener = listener;
-            this.errorListener = errorListener;
+    public class MultiFrameImageStreamCompleter : ImageStreamCompleter {
+        public MultiFrameImageStreamCompleter(
+            IPromise<Codec> codec,
+            double scale,
+            InformationCollector informationCollector = null
+        ) {
+            D.assert(codec != null);
+
+            this._scale = scale;
+            this._informationCollector = informationCollector;
+
+            this._framesEmitted = 0;
+            this._timer = null;
+
+            codec.Then((Action<Codec>) this._handleCodecReady, ex => {
+                this.reportError(
+                    context: "resolving an image codec",
+                    exception: ex,
+                    informationCollector: informationCollector,
+                    silent: true
+                );
+            });
-        public ImageListener listener;
-        public ImageErrorListerner errorListener;
+        Codec _codec;
+        readonly double _scale;
+        readonly InformationCollector _informationCollector;
+
+        FrameInfo _nextFrame;
+        TimeSpan? _shownTimestamp;
+        TimeSpan? _frameDuration;
+        int _framesEmitted;
+        Timer _timer;
+
+        void _handleCodecReady(Codec codec) {
+            this._codec = codec;
+            D.assert(this._codec != null);
+
+            this._decodeNextFrameAndSchedule();
+        }
+
+        void _handleAppFrame(TimeSpan timestamp) {
+            if (!this._hasActiveListeners) {
+                return;
+            }
+
+            if (this._isFirstFrame() || this._hasFrameDurationPassed(timestamp)) {
+                this._emitFrame(new ImageInfo(image: this._nextFrame.image, scale: this._scale));
+                this._shownTimestamp = timestamp;
+                this._frameDuration = this._nextFrame.duration;
+                this._nextFrame = null;
+                int completedCycles = this._codec.frameCount == 0 ? 0 : this._framesEmitted / this._codec.frameCount;
+
+                if (this._codec.repetitionCount == -1 || completedCycles <= this._codec.repetitionCount) {
+                    this._decodeNextFrameAndSchedule();
+                }
+
+                return;
+            }
+
+            TimeSpan delay = this._frameDuration.Value - (timestamp - this._shownTimestamp.Value);
+            delay = new TimeSpan((long) (delay.Ticks * SchedulerBinding.instance.timeDilation));
+            this._timer = Window.instance.run(delay,
+                () => { SchedulerBinding.instance.scheduleFrameCallback(this._handleAppFrame); });
+        }
+
+        bool _isFirstFrame() {
+            return this._frameDuration == null;
+        }
+
+        bool _hasFrameDurationPassed(TimeSpan timestamp) {
+            D.assert(this._shownTimestamp != null);
+            return timestamp - this._shownTimestamp >= this._frameDuration;
+        }
+
+        void _decodeNextFrameAndSchedule() {
+            this._codec.getNextFrame().Then(frame => {
+                    this._nextFrame = frame;
+
+                    if (this._codec.frameCount == 1) {
+                        this._emitFrame(new ImageInfo(image: this._nextFrame.image, scale: this._scale));
+                        return;
+                    }
+
+                    SchedulerBinding.instance.scheduleFrameCallback(this._handleAppFrame);
+                },
+                ex => {
+                    this.reportError(
+                        context: "resolving an image frame",
+                        exception: ex,
+                        informationCollector: this._informationCollector,
+                        silent: true
+                    );
+                });
+        }
+
+        void _emitFrame(ImageInfo imageInfo) {
+            this.setImage(imageInfo);
+            this._framesEmitted += 1;
+        }
+
+        bool _hasActiveListeners => this._listeners.isNotEmpty();
+
+        public override void addListener(ImageListener listener, ImageErrorListener onError = null) {
+            if (!this._hasActiveListeners && this._codec != null) {
+                this._decodeNextFrameAndSchedule();
+            }
+
+            base.addListener(listener, onError: onError);
+        }
+
+        public override void removeListener(ImageListener listener) {
+            base.removeListener(listener);
+            if (!this._hasActiveListeners) {
+                this._timer?.cancel();
+                this._timer = null;
+            }
+        }
     }
 }

Runtime/promise/Promise.cs

         /// </summary>
         public static IPromise<PromisedT> Resolved(PromisedT promisedValue)
         {
-            var promise = new Promise<PromisedT>();
+            var promise = new Promise<PromisedT>(isSync: true);
             promise.Resolve(promisedValue);
             return promise;
         }

Runtime/promise/Promise_NonGeneric.cs

         /// </summary>
         public static IPromise Resolved()
         {
-            var promise = new Promise();
+            var promise = new Promise(isSync: true);
             promise.Resolve();
             return promise;
         }

Runtime/rendering/binding.cs

 using System;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.gestures;
-using Unity.UIWidgets.scheduler;
+using Unity.UIWidgets.painting;
-    public class RendererBinding : GestureBinding {
+    public class RendererBinding : PaintingBinding {
-            get { return (RendererBinding) GestureBinding.instance; }
-            set { GestureBinding.instance = value; }
+            get { return (RendererBinding) PaintingBinding.instance; }
+            set { PaintingBinding.instance = value; }
         }
         
         public RendererBinding() {

Runtime/rendering/box.mixin.njk

 using System;
 using System.Collections.Generic;
-using UIWidgets.gestures;
-using UIWidgets.ui;
+using Unity.UIWidgets.gestures;
+using Unity.UIWidgets.ui;
-namespace UIWidgets.rendering {
+namespace Unity.UIWidgets.rendering {
 {% macro RenderBoxContainerDefaultsMixin(with) %} 
     public abstract class
         RenderBoxContainerDefaultsMixin{{with}}<ChildType, ParentDataType>

Runtime/rendering/image.cs

+using Unity.UIWidgets.foundation;
+using Image = Unity.UIWidgets.ui.Image;
-        public RenderImage(ui.Image image,
-            Color color,
-            ui.BlendMode colorBlendMode,
-            BoxFit fit,
-            ImageRepeat repeat,
-            Rect centerSlice,
-            double? width,
-            double? height,
+        public RenderImage(
+            Image image = null,
+            double? width = null,
+            double? height = null,
+            double scale = 1.0,
+            Color color = null,
+            BlendMode colorBlendMode = BlendMode.srcIn,
+            BoxFit? fit = null,
-            double scale = 1.0
+            ImageRepeat repeat = ImageRepeat.noRepeat,
+            Rect centerSlice = null,
+            bool invertColors = false,
+            FilterMode filterMode = FilterMode.Point
         ) {
             this._image = image;
             this._width = width;
             this._repeat = repeat;
             this._centerSlice = centerSlice;
             this._alignment = alignment ?? Alignment.center;
+            this._invertColors = invertColors;
+            this._filterMode = filterMode;
-        Alignment _resolvedAlignment;
+        Image _image;
-        void _resolve() {
-            if (_resolvedAlignment != null)
-                return;
-            _resolvedAlignment = alignment;
-        }
+        public Image image {
+            get => this._image;
+            set {
+                if (value == this._image) {
+                    return;
+                }
-        void _markNeedsResolution() {
-            _resolvedAlignment = null;
-            markNeedsPaint();
+                this._image = value;
+                this.markNeedsPaint();
+                if (this._width == null || this._height == null) {
+                    this.markNeedsLayout();
+                }
+            }
-        private ui.Image _image;
+        double? _width;
-        public ui.Image image {
-            get { return this._image; }
+        public double? width {
+            get => this._width;
-                if (value == _image)
+                if (value == this._width) {
-                _image = value;
-                markNeedsPaint();
-                if (_width == 0.0 || _height == 0.0)
-                    markNeedsLayout();
+                }
+
+                this._width = value;
+                this.markNeedsLayout();
-        private double? _width;
+        double? _height;
-        public double? width {
-            get { return _width; }
+        public double? height {
+            get => this._height;
-                if (value == _width)
+                if (value == this._height) {
-                _width = value;
-                markNeedsLayout();
+                }
+
+                this._height = value;
+                this.markNeedsLayout();
-        private double? _height;
+        double _scale;
-        public double? height {
-            get { return _height; }
+        public double scale {
+            get => this._scale;
-                if (value == _height)
+                if (value == this._scale) {
-                _height = value;
-                markNeedsLayout();
+                }
+
+                this._scale = value;
+                this.markNeedsLayout();
-        private double _scale;
+        Color _color;
-        public double scale {
-            get { return _scale; }
+        public Color color {
+            get => this._color;
-                if (value == _scale)
+                if (value == this._color) {
-                _scale = value;
-                markNeedsLayout();
+                }
+
+                this._color = value;
+                this.markNeedsPaint();
-        private Color _color;
+        BlendMode _colorBlendMode;
-        public Color color {
-            get { return _color; }
+        public BlendMode colorBlendMode {
+            get => this._colorBlendMode;
-                if (value == _color)
+                if (value == this._colorBlendMode) {
-                _color = value;
-                markNeedsPaint();
+                }
+
+                this._colorBlendMode = value;
+                this.markNeedsPaint();
-        private ui.BlendMode _colorBlendMode;
+        FilterMode _filterMode;
-        public ui.BlendMode colorBlendMode {
-            get { return _colorBlendMode; }
+        public FilterMode filterMode {
+            get => this._filterMode;
-                if (value == _colorBlendMode)
+                if (value == this._filterMode) {
-                _colorBlendMode = value;
-                markNeedsPaint();
+                }
+
+                this._filterMode = value;
+                this.markNeedsPaint();
-        private BoxFit _fit;
+        BoxFit? _fit;
-        public BoxFit fit {
-            get { return _fit; }
+        public BoxFit? fit {
+            get => this._fit;
-                if (value == _fit)
+                if (value == this._fit) {
-                _fit = value;
-                markNeedsPaint();
+                }
+
+                this._fit = value;
+                this.markNeedsPaint();
-        private Alignment _alignment;
+        Alignment _alignment;
-            get { return _alignment; }
+            get => this._alignment;
-                if (value == _alignment)
+                if (value == this._alignment) {
-                _alignment = value;
-                _markNeedsResolution();
+                }
+
+                this._alignment = value;
+                this.markNeedsPaint();
-        private ImageRepeat _repeat;
+        ImageRepeat _repeat;
-            get { return _repeat; }
+            get => this._repeat;
-                if (value == _repeat)
+                if (value == this._repeat) {
-                _repeat = value;
-                markNeedsPaint();
+                }
+
+                this._repeat = value;
+                this.markNeedsPaint();
-        private Rect _centerSlice;
+        Rect _centerSlice;
-            get { return _centerSlice; }
+            get => this._centerSlice;
-                if (value == _centerSlice)
+                if (value == this._centerSlice) {
-                _centerSlice = value;
-                markNeedsPaint();
+                }
+
+                this._centerSlice = value;
+                this.markNeedsPaint();
+            }
+        }
+
+        bool _invertColors;
+
+        public bool invertColors {
+            get => this._invertColors;
+            set {
+                if (value == this._invertColors) {
+                    return;
+                }
+
+                this._invertColors = value;
+                this.markNeedsPaint();
-            // Folds the given |width| and |height| into |constraints| so they can all
-            // be treated uniformly.
-                _width,
-                _height
+                this._width,
+                this._height
-            if (_image == null)
+            if (this._image == null) {
+            }
-                _image.width / _scale,
-                _image.height / _scale
+                this._image.width / this._scale,
+                this._image.height / this._scale
-        
+
+        protected override double computeMinIntrinsicWidth(double height) {
+            D.assert(height >= 0.0);
+            if (this._width == null && this._height == null) {
+                return 0.0;
+            }
+
+            return this._sizeForConstraints(BoxConstraints.tightForFinite(height: height)).width;
+        }
+
+        protected override double computeMaxIntrinsicWidth(double height) {
+            D.assert(height >= 0.0);
+            return this._sizeForConstraints(BoxConstraints.tightForFinite(height: height)).width;
+        }
+
+        protected override double computeMinIntrinsicHeight(double width) {
+            D.assert(width >= 0.0);
+            if (this._width == null && this._height == null) {
+                return 0.0;
+            }
+
+            return this._sizeForConstraints(BoxConstraints.tightForFinite(width: width)).height;
+        }
+
+        protected override double computeMaxIntrinsicHeight(double width) {
+            D.assert(width >= 0.0);
+            return this._sizeForConstraints(BoxConstraints.tightForFinite(width: width)).height;
+        }
+
+        protected override bool hitTestSelf(Offset position) => true;
+
-            this.size = _sizeForConstraints(constraints);
+            this.size = this._sizeForConstraints(this.constraints);
-            if (_image == null)
+            if (this._image == null) {
-            _resolve();
-            DecorationImageUtil.paintImage(
-                context.canvas,
-                offset & size,
-                _image,
-                _fit,
-                _centerSlice,
-                _resolvedAlignment,
-                _repeat
+            }
+
+            ImageUtils.paintImage(
+                canvas: context.canvas,
+                rect: offset & this.size,
+                image: this._image,
+                scale: this._scale,
+                // colorFilter: this._colorFilter,
+                fit: this._fit,
+                alignment: this._alignment,
+                centerSlice: this._centerSlice,
+                repeat: this._repeat,
+                invertColors: this._invertColors,
+                filterMode: this._filterMode
+        }
+
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties);
+            properties.add(new DiagnosticsProperty<Image>("image", this.image));
+            properties.add(new DoubleProperty("width", this.width, defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new DoubleProperty("height", this.height, defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new DoubleProperty("scale", this.scale, defaultValue: 1.0));
+            properties.add(new DiagnosticsProperty<Color>("color", this.color,
+                defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new EnumProperty<BlendMode>("colorBlendMode", this.colorBlendMode,
+                defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new EnumProperty<BoxFit?>("fit", this.fit, defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new DiagnosticsProperty<Alignment>("alignment", this.alignment,
+                defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new EnumProperty<ImageRepeat>("repeat", this.repeat, defaultValue: ImageRepeat.noRepeat));
+            properties.add(new DiagnosticsProperty<Rect>("centerSlice", this.centerSlice,
+                defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new DiagnosticsProperty<bool>("invertColors", this.invertColors));
+            properties.add(new EnumProperty<FilterMode>("filterMode", this.filterMode));
         }
     }
 }

Runtime/rendering/object.mixin.njk

 // AUTO-GENERATED, DO NOT EDIT BY HAND
 
 using System.Collections.Generic;
-using UIWidgets.foundation;
+using Unity.UIWidgets.foundation;
-namespace UIWidgets.rendering {
+namespace Unity.UIWidgets.rendering {
 {% macro RenderObjectWithChildMixin(with) %}
     public abstract class RenderObjectWithChildMixin{{with}}<ChildType> : {{with}}, RenderObjectWithChildMixin<ChildType>, RenderObjectWithChildMixin where ChildType : RenderObject {
         public bool debugValidateChild(RenderObject child) {

Runtime/rendering/proxy_box.mixin.njk

-using UIWidgets.ui;
-using UIWidgets.gestures;
+using Unity.UIWidgets.ui;
+using Unity.UIWidgets.gestures;
-namespace UIWidgets.rendering {
+namespace Unity.UIWidgets.rendering {
 
 {% macro RenderProxyBoxMixin(with) %}
     public abstract class RenderProxyBoxMixin{{with}}<T> : {{with}}<T> where T : RenderBox {

Runtime/ui/geometry.cs

 using System;
+using UnityEngine;
 
 namespace Unity.UIWidgets.ui {
     public static class MathUtils {
 
         public static int floor(this double value) {
             return (int) Math.Floor(value);
+        }
+        
+        public static int ceil(this double value) {
+            return (int) Math.Ceiling(value);
+        }
+
+        public static int round(this float value) {
+            return Mathf.RoundToInt(value);
+        }
+
+        public static int floor(this float value) {
+            return Mathf.FloorToInt(value);
+        }
+
+        public static int ceil(this float value) {
+            return Mathf.CeilToInt(value);
         }
     }
 

Runtime/ui/painting/canvas.cs

 using System;
 using Unity.UIWidgets.ui.txt;
-using UnityEngine;
 
 namespace Unity.UIWidgets.ui {
     public interface Canvas {
 
         void drawPath(Path path, Paint paint);
 
-        void drawImage(Texture image, Offset offset, Paint paint);
+        void drawImage(Image image, Offset offset, Paint paint);
-        void drawImageRect(Texture image, Rect dst, Paint paint);
+        void drawImageRect(Image image, Rect dst, Paint paint);
-        void drawImageRect(Texture image, Rect src, Rect dst, Paint paint);
+        void drawImageRect(Image image, Rect src, Rect dst, Paint paint);
-        void drawImageNine(Texture image, Rect center, Rect dst, Paint paint);
+        void drawImageNine(Image image, Rect center, Rect dst, Paint paint);
-        void drawImageNine(Texture image, Rect src, Rect center, Rect dst, Paint paint);
+        void drawImageNine(Image image, Rect src, Rect center, Rect dst, Paint paint);
 
         void drawPicture(Picture picture);
 
             });
         }
 
-        public void drawImage(Texture image, Offset offset, Paint paint) {
+        public void drawImage(Image image, Offset offset, Paint paint) {
             this._recorder.addDrawCmd(new DrawImage {
                 image = image,
                 offset = offset,
 
-        public void drawImageRect(Texture image, Rect dst, Paint paint) {
+        public void drawImageRect(Image image, Rect dst, Paint paint) {
             this._recorder.addDrawCmd(new DrawImageRect {
                 image = image,
                 dst = dst,
 
-        public void drawImageRect(Texture image, Rect src, Rect dst, Paint paint) {
+        public void drawImageRect(Image image, Rect src, Rect dst, Paint paint) {
             this._recorder.addDrawCmd(new DrawImageRect {
                 image = image,
                 src = src,
         }
 
-        public void drawImageNine(Texture image, Rect center, Rect dst, Paint paint) {
+        public void drawImageNine(Image image, Rect center, Rect dst, Paint paint) {
             this._recorder.addDrawCmd(new DrawImageNine {
                 image = image,
                 center = center,
         }
 
-        public void drawImageNine(Texture image, Rect src, Rect center, Rect dst, Paint paint) {
+        public void drawImageNine(Image image, Rect src, Rect center, Rect dst, Paint paint) {
             this._recorder.addDrawCmd(new DrawImageNine {
                 image = image,
                 src = src,

Runtime/ui/painting/canvas_impl.cs

             }
         }
 
-        public void drawImage(Texture image, Offset offset, Paint paint) {
-            D.assert(image);
+        public void drawImage(Image image, Offset offset, Paint paint) {
+            D.assert(image != null);
             D.assert(offset != null);
             D.assert(paint != null);
 
             return properties;
         }
 
-        public void drawImageRect(Texture image, Rect dst, Paint paint) {
+        public void drawImageRect(Image image, Rect dst, Paint paint) {
-        public void drawImageRect(Texture image, Rect src, Rect dst, Paint paint) {
-            D.assert(image);
+        public void drawImageRect(Image image, Rect src, Rect dst, Paint paint) {
+            D.assert(image != null);
             D.assert(dst != null);
             D.assert(paint != null);
 
             }
 
             var mat = this._getMat(paint);
-            var properties = this._getMatPropsForImage(image, paint);
+            var properties = this._getMatPropsForImage(image.texture, paint);
+                image = image, // to keep a reference to avoid GC.
-        public void drawImageNine(Texture image, Rect center, Rect dst, Paint paint) {
+        public void drawImageNine(Image image, Rect center, Rect dst, Paint paint) {
-        public void drawImageNine(Texture image, Rect src, Rect center, Rect dst, Paint paint) {
-            D.assert(image);
+        public void drawImageNine(Image image, Rect src, Rect center, Rect dst, Paint paint) {
+            D.assert(image != null);
             D.assert(center != null);
             D.assert(dst != null);
             D.assert(paint != null);
             }
 
             var mat = this._getMat(paint);
-            var properties = this._getMatPropsForImage(image, paint);
+            var properties = this._getMatPropsForImage(image.texture, paint);
+                image = image, // to keep a reference to avoid GC.
                 properties = properties,
             });
         }
             public MaterialPropertyBlock properties;
             public RenderLayer layer;
             public Material material;
+            public Image image; // just to keep a reference to avoid GC.
 
             public void onExecute(CommandBuffer cmdBuf) {
                 if (this.layer != null) {
             }
 
             public void onDestroy() {
-                Object.DestroyImmediate(this.mesh);
+                this.mesh = ObjectUtils.SafeDestroy(this.mesh);
             }
         }
 

Runtime/ui/painting/draw_cmd.cs

 using Unity.UIWidgets.ui.txt;
-using UnityEngine;
 
 namespace Unity.UIWidgets.ui {
     public abstract class DrawCmd {
     }
 
     public class DrawImage : DrawCmd {
-        public Texture image;
+        public Image image;
-        public Texture image;
+        public Image image;
         public Rect src;
         public Rect dst;
         public Paint paint;
-        public Texture image;
+        public Image image;
         public Rect src;
         public Rect center;
         public Rect dst;

Runtime/ui/painting/image.cs

+using System;
+using Unity.UIWidgets.async;
+using Unity.UIWidgets.foundation;
-    public class Image {
-        public Image(byte[] raw = null, Texture2D texture = null) {
-            this.rawData = raw ?? new byte[0];
+    public class Image : IEquatable<Image>, IDisposable {
+        Texture _texture;
+        readonly bool _isOwner;
+
+        public Image(Texture texture, bool isOwner = true) {
+            this._isOwner = isOwner;
-        public byte[] rawData;
+        public int width => this._texture != null ? this._texture.width : 0;
+
+        public int height => this._texture != null ? this._texture.height : 0;
+
+        public Texture texture => this._texture;
+
+        ~Image() {
+            Timer.runInMain(this._dispose);
+        }
+
+        void _dispose() {
+            if (this._isOwner) {
+                this._texture = ObjectUtils.SafeDestroy(this._texture);
+            }
+        }
+
+        public void Dispose() {
+            this._dispose();
+            GC.SuppressFinalize(this);
+        }
+
+        public bool Equals(Image other) {
+            if (ReferenceEquals(null, other)) return false;
+            if (ReferenceEquals(this, other)) return true;
+            return Equals(this._texture, other._texture);
+        }
-        public int height {
-            get { return texture != null ? texture.height : 0; }
+        public override bool Equals(object obj) {
+            if (ReferenceEquals(null, obj)) return false;
+            if (ReferenceEquals(this, obj)) return true;
+            if (obj.GetType() != this.GetType()) return false;
+            return this.Equals((Image) obj);
-        public int width {
-            get { return texture != null ? texture.width : 0; }
+        public override int GetHashCode() {
+            return (this._texture != null ? this._texture.GetHashCode() : 0);
-        public Texture2D texture {
-            get {
-                if (_texture == null && rawData.Length != 0) {
-                    _texture = new Texture2D(2, 2);
-                    _texture.LoadImage(rawData);
-                }
+        public static bool operator ==(Image left, Image right) {
+            return Equals(left, right);
+        }
-                return _texture;
-            }
+        public static bool operator !=(Image left, Image right) {
+            return !Equals(left, right);
-        private Texture2D _texture;
+        public override string ToString() {
+            return $"[{this.width}\u00D7{this.height}]";
+        }
     }
 }

Runtime/ui/pointer.cs

 
     public class PointerData {
         public PointerData(
-            DateTime timeStamp,
+            TimeSpan timeStamp,
             PointerChange change,
             PointerDeviceKind kind,
             int device,
             this.physicalY = physicalY;
         }
 
-        public readonly DateTime timeStamp;
+        public readonly TimeSpan timeStamp;
         public PointerChange change;
         public PointerDeviceKind kind;
         public int device;

Runtime/ui/window.cs

                 D.assert(_instance != null, "Window.instance is null");
                 return _instance;
             }
-            
+
             set {
                 if (value == null) {
                     D.assert(_instance != null, "Window.instance is already cleared.");
         }
 
         VoidCallback _onDrawFrame;
-
+        
         public PointerDataPacketCallback onPointerEvent {
             get { return this._onPointerEvent; }
             set { this._onPointerEvent = value; }
         public abstract void flushMicrotasks();
 
         public abstract Timer run(TimeSpan duration, Action callback, bool periodic = false);
-
+        
+        public abstract IDisposable onUpdate(VoidCallback callback);
+
+    }
+
+
+    public class Locale : IEquatable<Locale> {
+        public Locale(string languageCode, string countryCode = null) {
+            D.assert(languageCode != null);
+            this._languageCode = languageCode;
+            this._countryCode = countryCode;
+        }
+
+        readonly string _languageCode;
+
+        public string languageCode => this._languageCode;
+
+        readonly string _countryCode;
+
+        public string countryCode => this._countryCode;
+
+        public bool Equals(Locale other) {
+            if (ReferenceEquals(null, other)) return false;
+            if (ReferenceEquals(this, other)) return true;
+            return string.Equals(this._languageCode, other._languageCode) &&
+                   string.Equals(this._countryCode, other._countryCode);
+        }
+
+        public override bool Equals(object obj) {
+            if (ReferenceEquals(null, obj)) return false;
+            if (ReferenceEquals(this, obj)) return true;
+            if (obj.GetType() != this.GetType()) return false;
+            return this.Equals((Locale) obj);
+        }
+
+        public override int GetHashCode() {
+            unchecked {
+                return ((this._languageCode != null ? this._languageCode.GetHashCode() : 0) * 397) ^
+                       (this._countryCode != null ? this._countryCode.GetHashCode() : 0);
+            }
+        }
+
+        public static bool operator ==(Locale left, Locale right) {
+            return Equals(left, right);
+        }
+
+        public static bool operator !=(Locale left, Locale right) {
+            return !Equals(left, right);
+        }
+
+        public override string ToString() {
+            if (this.countryCode == null) {
+                return this.languageCode;
+            }
+
+            return $"{this.languageCode}_{this.countryCode}";
+        }
     }
 }

Runtime/widgets/basic.cs

 
     public class RawImage : LeafRenderObjectWidget {
         public RawImage(
-            Key key,
-            ui.Image image,
-            double scale,
-            Color color,
-            BlendMode colorBlendMode,
-            BoxFit fit,
-            Rect centerSlice,
+            Key key = null,
+            ui.Image image = null,
+            double scale = 1.0,
+            Color color = null,
+            BlendMode colorBlendMode = BlendMode.srcIn,
+            BoxFit? fit = null,
-            ImageRepeat repeat = ImageRepeat.noRepeat
+            ImageRepeat repeat = ImageRepeat.noRepeat,
+            Rect centerSlice = null,
+            bool invertColors = false,
+            FilterMode filterMode = FilterMode.Point
         ) : base(key) {
             this.image = image;
             this.width = width;
-            this.blendMode = colorBlendMode;
-            this.centerSlice = centerSlice;
+            this.colorBlendMode = colorBlendMode;
-            this.alignment = alignment == null ? Alignment.center : alignment;
+            this.alignment = alignment ?? Alignment.center;
+            this.centerSlice = centerSlice;
+            this.invertColors = invertColors;
+            this.filterMode = filterMode;
+        public readonly ui.Image image;
+        public readonly double? width;
+        public readonly double? height;
+        public readonly double scale;
+        public readonly Color color;
+        public readonly FilterMode filterMode;
+        public readonly BlendMode colorBlendMode;
+        public readonly BoxFit? fit;
+        public readonly Alignment alignment;
+        public readonly ImageRepeat repeat;
+        public readonly Rect centerSlice;
+        public readonly bool invertColors;
+
-                this.image,
-                this.color,
-                this.blendMode,
-                this.fit,
-                this.repeat,
-                this.centerSlice,
-                this.width,
-                this.height,
-                this.alignment
+                image: this.image,
+                width: this.width,
+                height: this.height,
+                scale: this.scale,
+                color: this.color,
+                colorBlendMode: this.colorBlendMode,
+                fit: this.fit,
+                alignment: this.alignment,
+                repeat: this.repeat,
+                centerSlice: this.centerSlice,
+                invertColors: this.invertColors,
+                filterMode: this.filterMode
-            ((RenderImage) renderObject).image = this.image;
-            ((RenderImage) renderObject).width = this.width;
-            ((RenderImage) renderObject).height = this.height;
-            ((RenderImage) renderObject).color = this.color;
-            ((RenderImage) renderObject).fit = this.fit;
-            ((RenderImage) renderObject).repeat = this.repeat;
-            ((RenderImage) renderObject).centerSlice = this.centerSlice;
-            ((RenderImage) renderObject).alignment = this.alignment;
+            var renderImage = (RenderImage) renderObject;
+            
+            renderImage.image = this.image;
+            renderImage.width = this.width;
+            renderImage.height = this.height;
+            renderImage.scale = this.scale;
+            renderImage.color = this.color;
+            renderImage.colorBlendMode = this.colorBlendMode;
+            renderImage.alignment = this.alignment;
+            renderImage.fit = this.fit;
+            renderImage.repeat = this.repeat;
+            renderImage.centerSlice = this.centerSlice;
+            renderImage.invertColors = this.invertColors;
+            renderImage.filterMode = this.filterMode;
+        }
+
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties);
+            properties.add(new DiagnosticsProperty<ui.Image>("image", this.image));
+            properties.add(new DoubleProperty("width", this.width, defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new DoubleProperty("height", this.height, defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new DoubleProperty("scale", this.scale, defaultValue: 1.0));
+            properties.add(new DiagnosticsProperty<Color>("color", this.color,
+                defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new EnumProperty<BlendMode>("colorBlendMode", this.colorBlendMode,
+                defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new EnumProperty<BoxFit?>("fit", this.fit, defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new DiagnosticsProperty<Alignment>("alignment", this.alignment,
+                defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new EnumProperty<ImageRepeat>("repeat", this.repeat, defaultValue: ImageRepeat.noRepeat));
+            properties.add(new DiagnosticsProperty<Rect>("centerSlice", this.centerSlice,
+                defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new DiagnosticsProperty<bool>("invertColors", this.invertColors));
+            properties.add(new EnumProperty<FilterMode>("filterMode", this.filterMode));
+        }
+    }
+
+    public class DefaultAssetBundle : InheritedWidget {
+        public DefaultAssetBundle(
+            Key key = null,
+            AssetBundle bundle = null,
+            Widget child = null
+        ) : base(key: key, child: child) {
+            D.assert(bundle != null);
+            D.assert(child != null);
+            this.bundle = bundle;
+        }
+
+        public readonly AssetBundle bundle;
+
+        public static AssetBundle of(BuildContext context) {
+            DefaultAssetBundle result =
+                (DefaultAssetBundle) context.inheritFromWidgetOfExactType(typeof(DefaultAssetBundle));
+            return result?.bundle;
-        public readonly ui.Image image;
-        public readonly double? width;
-        public readonly double? height;
-        public readonly double scale;
-        public readonly Color color;
-        public readonly BlendMode blendMode;
-        public readonly BoxFit fit;
-        public readonly Alignment alignment;
-        public readonly ImageRepeat repeat;
-        public readonly Rect centerSlice;
+        public override bool updateShouldNotify(InheritedWidget oldWidget) {
+            return this.bundle != ((DefaultAssetBundle) oldWidget).bundle;
+        }
     }
 
     public class Listener : SingleChildRenderObjectWidget {

Runtime/widgets/container.cs

             return new RenderDecoratedBox(
                 decoration: this.decoration,
                 position: this.position,
-                configuration: ImageUtil.createLocalImageConfiguration(context)
+                configuration: ImageUtils.createLocalImageConfiguration(context)
             );
         }
 
-            renderObject.configuration = ImageUtil.createLocalImageConfiguration(context);
+            renderObject.configuration = ImageUtils.createLocalImageConfiguration(context);
             renderObject.position = this.position;
         }
 

Runtime/widgets/image.cs

 using System;
 using System.Collections.Generic;
+using RSG;
+using Rect = Unity.UIWidgets.ui.Rect;
-    internal class ImageUtil {
+    public class ImageUtils {
-                size: size
+                bundle: DefaultAssetBundle.of(context),
+                //TODO: add MediaQuery & Localizations.
+                //devicePixelRatio: MediaQuery.of(context, nullOk: true)?.devicePixelRatio ?? 1.0,
+                //locale: Localizations.localeOf(context, nullOk: true),
+                size: size,
+                platform: Application.platform
-    }
-    public class Image : StatefulWidget {
-        public ImageProvider image;
-        public double? width;
-        public double? height;
-        public Color color;
-        public BoxFit fit;
-        public Alignment alignment;
-        public BlendMode colorBlendMode;
-        public ImageRepeat repeat;
-        public ui.Rect centerSlice;
+        public IPromise precacheImage(
+            ImageProvider provider,
+            BuildContext context,
+            Size size = null,
+            ImageErrorListener onError = null
+        ) {
+            ImageConfiguration config = createLocalImageConfiguration(context, size: size);
+            var completer = new Promise();
+            ImageStream stream = provider.resolve(config);
-        public bool gaplessPlayback;
+            void listener(ImageInfo image, bool sync) {
+                completer.Resolve();
+            }
+            void errorListener(Exception exception) {
+                completer.Resolve();
+                if (onError != null) {
+                    onError(exception);
+                } else {
+                    UIWidgetsError.reportError(new UIWidgetsErrorDetails(
+                        context: "image failed to precache",
+                        library: "image resource service",
+                        exception: exception,
+                        silent: true
+                    ));
+                }
+            }
+
+            stream.addListener(listener, onError: errorListener);
+            completer.Then(() => { stream.removeListener(listener); });
+            return completer;
+        }
+    }
+
+    public class Image : StatefulWidget {
-            Key key,
-            ImageProvider image,
-            Color color,
-            BlendMode colorBlendMode,
-            BoxFit fit,
-            ui.Rect centerSlice,
-            Alignment alignment,
+            Key key = null,
+            ImageProvider image = null,
+            Color color = null,
+            BlendMode colorBlendMode = BlendMode.srcIn,
+            BoxFit? fit = null,
+            Alignment alignment = null,
-            bool gaplessPlayback = false
+            Rect centerSlice = null,
+            bool gaplessPlayback = false,
+            FilterMode filterMode = FilterMode.Point
+            D.assert(image != null);
             this.image = image;
             this.width = width;
             this.height = height;
-            this.alignment = alignment == null ? Alignment.center : alignment;
+            this.alignment = alignment ?? Alignment.center;
+            this.filterMode = filterMode;
+            double scale = 1.0,
-            BlendMode colorBlendMode = BlendMode.srcOver,
-            BoxFit fit = BoxFit.none,
+            BlendMode colorBlendMode = BlendMode.srcIn,
+            BoxFit? fit = null,
-            ui.Rect centerSlice = null,
-            Dictionary<String, String> headers = null,
+            Rect centerSlice = null,
-            double scale = 1.0
+            FilterMode filterMode = FilterMode.Point,
+            IDictionary<String, String> headers = null
-            var networkImage = new NetworkImage(src, headers, scale);
+            var networkImage = new NetworkImage(src, scale, headers);
+                width,
+                height,
-                centerSlice,
-                width,
-                height,
-                gaplessPlayback
+                centerSlice,
+                gaplessPlayback,
+                filterMode
-            string path,
+            string file,
+            double scale = 1.0,
-            BlendMode colorBlendMode = BlendMode.srcOver,
-            BoxFit fit = BoxFit.none,
+            BlendMode colorBlendMode = BlendMode.srcIn,
+            BoxFit? fit = null,
-            ui.Rect centerSlice = null,
+            Rect centerSlice = null,
-            double scale = 1.0
+            FilterMode filterMode = FilterMode.Point
-            var fileImage = new FileImage(path, scale);
+            var fileImage = new FileImage(file, scale);
+                width,
+                height,
+                alignment,
+                repeat,
-                alignment,
+                gaplessPlayback,
+                filterMode
+            );
+        }
+
+        public static Image memory(
+            byte[] bytes,
+            Key key = null,
+            double scale = 1.0,
+            double? width = null,
+            double? height = null,
+            Color color = null,
+            BlendMode colorBlendMode = BlendMode.srcIn,
+            BoxFit? fit = null,
+            Alignment alignment = null,
+            ImageRepeat repeat = ImageRepeat.noRepeat,
+            Rect centerSlice = null,
+            bool gaplessPlayback = false,
+            FilterMode filterMode = FilterMode.Point
+        ) {
+            var memoryImage = new MemoryImage(bytes, scale);
+            return new Image(
+                key,
+                memoryImage,
+                color,
+                colorBlendMode,
+                fit,
+                alignment,
-                gaplessPlayback
+                centerSlice,
+                gaplessPlayback,
+                filterMode
+        public readonly ImageProvider image;
+        public readonly double? width;
+        public readonly double? height;
+        public readonly Color color;
+        public readonly FilterMode filterMode;
+        public readonly BlendMode colorBlendMode;
+        public readonly BoxFit? fit;
+        public readonly Alignment alignment;
+        public readonly ImageRepeat repeat;
+        public readonly Rect centerSlice;
+        public readonly bool gaplessPlayback;
+
+
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties);
+
+            properties.add(new DiagnosticsProperty<ImageProvider>("image", this.image));
+            properties.add(new DoubleProperty("width", this.width, defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new DoubleProperty("height", this.height, defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new DiagnosticsProperty<Color>("color", this.color,
+                defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new EnumProperty<BlendMode>("colorBlendMode", this.colorBlendMode,
+                defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new EnumProperty<BoxFit?>("fit", this.fit, defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new DiagnosticsProperty<Alignment>("alignment", this.alignment,
+                defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new EnumProperty<ImageRepeat>("repeat", this.repeat, defaultValue: ImageRepeat.noRepeat));
+            properties.add(new DiagnosticsProperty<Rect>("centerSlice", this.centerSlice,
+                defaultValue: Diagnostics.kNullDefaultValue));
+            properties.add(new EnumProperty<FilterMode>("filterMode", this.filterMode, Diagnostics.kNullDefaultValue));
+        }
-    public class _ImageState : State {
+    public class _ImageState : State<Image> {
+        bool _invertColors;
-            _resolveImage();
-            if (TickerMode.of(context))
-                _listenToStream();
-            else
-                _stopListeningToStream();
+            this._invertColors = false;
+
+            this._resolveImage();
+
+            if (TickerMode.of(this.context)) {
+                this._listenToStream();
+            } else {
+                this._stopListeningToStream();
+            }
+
+            base.didChangeDependencies();
-            if (((Image) widget).image != ((Image) oldWidget).image)
-                _resolveImage();
+            base.didUpdateWidget(oldWidget);
+
+            if (this.widget.image != ((Image) oldWidget).image) {
+                this._resolveImage();
+            }
-//        public override void reassemble() {
-//            _resolveImage(); // in case the image cache was flushed
-//        }
-
-            var imageWidget = (Image) widget;
-                imageWidget.image.resolve(ImageUtil.createLocalImageConfiguration(
-                    context,
-                    size: imageWidget.width != null && imageWidget.height != null
-                        ? new Size(imageWidget.width.Value, imageWidget.height.Value)
+                this.widget.image.resolve(ImageUtils.createLocalImageConfiguration(
+                    this.context,
+                    size: this.widget.width != null && this.widget.height != null
+                        ? new Size(this.widget.width.Value, this.widget.height.Value)
-            _updateSourceStream(newStream);
+            D.assert(newStream != null);
+            this._updateSourceStream(newStream);
-            setState(() => { _imageInfo = imageInfo; });
+            this.setState(() => { this._imageInfo = imageInfo; });
-            if ((_imageStream == null ? null : _imageStream.key) == (newStream == null ? null : newStream.key))
+            if (this._imageStream?.key == newStream?.key) {
+            }
-            if (_isListeningToStream && _imageStream != null)
-                _imageStream.removeListener(_handleImageChanged);
+            if (this._isListeningToStream) {
+                this._imageStream.removeListener(this._handleImageChanged);
+            }
-            if (!((Image) widget).gaplessPlayback) {
-                setState(() => { _imageInfo = null; });
+            if (!this.widget.gaplessPlayback) {
+                this.setState(() => { this._imageInfo = null; });
+            }
-                _imageStream = newStream;
-                if (_isListeningToStream && _imageStream != null)
-                    _imageStream.addListener(_handleImageChanged);
+            this._imageStream = newStream;
+            if (this._isListeningToStream) {
+                this._imageStream.addListener(this._handleImageChanged);
-            if (_isListeningToStream)
+            if (this._isListeningToStream) {
-            _imageStream.addListener(_handleImageChanged);
-            _isListeningToStream = true;
+            }
+
+            this._imageStream.addListener(this._handleImageChanged);
+            this._isListeningToStream = true;
-            if (!_isListeningToStream)
+            if (!this._isListeningToStream) {
-            _imageStream.removeListener(_handleImageChanged);
-            _isListeningToStream = false;
+            }
+
+            this._imageStream.removeListener(this._handleImageChanged);
+            this._isListeningToStream = false;
+        public override void dispose() {
+            D.assert(this._imageStream != null);
+            this._stopListeningToStream();
+            base.dispose();
+        }
+
+
-            var imageWidget = (Image) widget;
-                null,
-                _imageInfo == null ? null : _imageInfo.image,
-                _imageInfo == null ? 1.0 : _imageInfo.scale,
-                imageWidget.color,
-                imageWidget.colorBlendMode,
-                imageWidget.fit,
-                imageWidget.centerSlice,
-                imageWidget.width,
-                imageWidget.height,
-                imageWidget.alignment,
-                imageWidget.repeat
+                image: this._imageInfo?.image,
+                width: this.widget.width,
+                height: this.widget.height,
+                scale: this._imageInfo?.scale ?? 1.0,
+                color: this.widget.color,
+                colorBlendMode: this.widget.colorBlendMode,
+                fit: this.widget.fit,
+                alignment: this.widget.alignment,
+                repeat: this.widget.repeat,
+                centerSlice: this.widget.centerSlice,
+                invertColors: this._invertColors,
+                filterMode: this.widget.filterMode
+        }
+
+        public override void debugFillProperties(DiagnosticPropertiesBuilder description) {
+            base.debugFillProperties(description);
+            description.add(new DiagnosticsProperty<ImageStream>("stream", this._imageStream));
+            description.add(new DiagnosticsProperty<ImageInfo>("pixels", this._imageInfo));
         }
     }
 }

Runtime/widgets/scroll_activity.cs

 
         public readonly double? motionStartDistanceThreshold;
 
-        DateTime _lastNonStationaryTimestamp;
+        TimeSpan _lastNonStationaryTimestamp;
 
         bool _retainMomentum;
 
             this._del = value;
         }
 
-        void _maybeLoseMomentum(double offset, DateTime? timestamp) {
+        void _maybeLoseMomentum(double offset, TimeSpan? timestamp) {
             if (this._retainMomentum &&
                 offset == 0.0 &&
                 (timestamp == null ||
         }
 
-        double _adjustForScrollStartThreshold(double offset, DateTime? timestamp) {
+        double _adjustForScrollStartThreshold(double offset, TimeSpan? timestamp) {
             if (timestamp == null) {
                 return offset;
             }

Runtime/widgets/scroll_notification.mixin.njk

 using System.Collections.Generic;
-using UIWidgets.rendering;
+using Unity.UIWidgets.rendering;
-namespace UIWidgets.widgets {
+namespace Unity.UIWidgets.widgets {
 {% macro ViewportNotificationMixin(with) %} 
     public abstract class ViewportNotificationMixin{{with}} : {{with}} {
         public int depth {

Tests/Editor/CanvasAndLayers.cs

 
         private int _selected;
 
-        private PaintingBinding _paintingBinding;
-
         private ImageStream _stream;
 
         private RenderTexture _renderTexture;
 
         void OnGUI() {
             this._selected = EditorGUILayout.Popup("test case", this._selected, this._optionStrings);
+            if (this._selected == 3) {
+                using (this._windowAdapter.getScope()) {
+                    if (GUI.Button(new UnityEngine.Rect(20, 50, 100, 20), "Image 1")) {
+                        LoadImage(
+                            "http://a.hiphotos.baidu.com/image/h%3D300/sign=10b374237f0e0cf3bff748fb3a47f23d/adaf2edda3cc7cd90df1ede83401213fb80e9127.jpg");
+                    }
-            if (_selected == 3) {
-                if (GUI.Button(new UnityEngine.Rect(20, 50, 100, 20), "Image 1")) {
-                    LoadImage(
-                        "http://a.hiphotos.baidu.com/image/h%3D300/sign=10b374237f0e0cf3bff748fb3a47f23d/adaf2edda3cc7cd90df1ede83401213fb80e9127.jpg");
-                }
-
-                if (GUI.Button(new UnityEngine.Rect(20, 150, 100, 20), "Image 2")) {
-                    LoadImage(
-                        "http://a.hiphotos.baidu.com/image/pic/item/cf1b9d16fdfaaf519b4aa960875494eef11f7a47.jpg");
-                }
+                    if (GUI.Button(new UnityEngine.Rect(20, 150, 100, 20), "Image 2")) {
+                        LoadImage(
+                            "http://a.hiphotos.baidu.com/image/pic/item/cf1b9d16fdfaaf519b4aa960875494eef11f7a47.jpg");
+                    }
-                if (GUI.Button(new UnityEngine.Rect(20, 250, 100, 20), "Image 3")) {
-                    LoadImage(
-                        "http://a.hiphotos.baidu.com/image/pic/item/2f738bd4b31c8701c1e721dd2a7f9e2f0708ffbc.jpg");
+                    if (GUI.Button(new UnityEngine.Rect(20, 250, 100, 20), "Image 3")) {
+                        LoadImage(
+                            "http://a.hiphotos.baidu.com/image/pic/item/2f738bd4b31c8701c1e721dd2a7f9e2f0708ffbc.jpg");
+                    }
                 }
             }
 
         private void OnEnable() {
             this._windowAdapter = new EditorWindowAdapter(this);
             this._windowAdapter.OnEnable();
-
-            this._paintingBinding = new PaintingBinding(this._windowAdapter);
-            this._paintingBinding.initInstances();
         }
 
         void createRenderTexture() {
 
         private void LoadImage(string url) {
             Dictionary<string, string> headers = new Dictionary<string, string>();
-            NetworkImage networkImage = new NetworkImage(url, headers);
+            NetworkImage networkImage = new NetworkImage(url, headers: headers);
             ImageConfiguration imageConfig = new ImageConfiguration();
             _stream = networkImage.resolve(imageConfig);
         }
         }
 
         void drawImageRect() {
-            if (_stream == null || _stream.completer == null || _stream.completer._currentImgae == null) {
+            if (_stream == null || _stream.completer == null || _stream.completer.currentImage == null) {
                 return;
             }
 
             };
 
             canvas.drawImageRect(
-                _stream.completer._currentImgae.image.texture,
+                _stream.completer.currentImage.image,
                 Rect.fromLTWH(100, 50, 250, 250),
                 paint
             );

Tests/Editor/EditableTextWiget.cs

     {
         private WindowAdapter windowAdapter;
 
-        private PaintingBinding paintingBinding;
-
         private Widget root;
 
         private Widget image;
         }
 
         private void OnEnable() {
-            this.paintingBinding = new PaintingBinding(null);
-            paintingBinding.initInstances();
             this.windowAdapter = new EditorWindowAdapter(this);
             this.windowAdapter.OnEnable();
             this.root = new Container(

Tests/Editor/Widgets.cs

     public class Widgets : EditorWindow {
         private WindowAdapter windowAdapter;
 
-        private PaintingBinding paintingBinding;
-
         private readonly Func<Widget>[] _options;
 
         private readonly string[] _optionStrings;
         }
 
         private void OnEnable() {
-            this.paintingBinding = new PaintingBinding(null);
-            paintingBinding.initInstances();
             this.windowAdapter = new EditorWindowAdapter(this);
             this.windowAdapter.OnEnable();
         }
 
         Widget localImage() {
             var image = widgets.Image.file(
-                localImagePath
+                localImagePath,
+                filterMode: FilterMode.Bilinear
             );
 
             return image;

Runtime/async/coroutine.cs.meta

 fileFormatVersion: 2
-guid: d54df7319b8ca49cf9aba74db3698508
+guid: edd74736642e341e29510a7e3dafb5f6
 MonoImporter:
   externalObjects: {}
   serializedVersion: 2

Runtime/async/coroutine.cs

+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using RSG;
+using Unity.UIWidgets.foundation;
+using Unity.UIWidgets.ui;
+using UnityEngine;
+
+namespace Unity.UIWidgets.async {
+    public class UIWidgetsCoroutine {
+        _WaitforSecondsProcessor _waitProcessor;
+        _WaitForCoroutineProcessor _waitForCoroutine;
+        _WaitForAsyncOPProcessor _waitForAsyncOPProcessor;
+
+        readonly IEnumerator _routine;
+        readonly Window _window;
+        readonly IDisposable _unhook;
+        readonly bool _isBackground;
+
+        internal volatile object lastResult;
+        internal volatile Exception lastError;
+        internal bool isDone;
+
+        readonly Promise<object> _promise = new Promise<object>();
+        public IPromise<object> promise => this._promise;
+
+        internal UIWidgetsCoroutine(IEnumerator routine, Window window, bool isBackground = false) {
+            D.assert(routine != null);
+            D.assert(window != null);
+
+            this._routine = routine;
+            this._window = window;
+
+            if (isBackground && BackgroundCallbacks.getInstance() != null) {
+                this._unhook = BackgroundCallbacks.getInstance().addCallback(this._moveNext);
+            } else {
+                this._unhook = this._window.onUpdate(this._moveNext);
+            }
+
+            this._isBackground = isBackground;
+        }
+
+        void _moveNext() {
+            D.assert(!this.isDone);
+
+            var lastError = this.lastError;
+            if (lastError != null) {
+                this._unhook.Dispose();
+
+                this.isDone = true;
+                this.lastResult = null;
+                if (this._isBackground) {
+                    Timer.runInMain(() => { this._window.run(() => { this._promise.Reject(lastError); }); });
+                } else {
+                    this._promise.Reject(lastError);
+                }
+
+                return;
+            }
+
+            bool hasNext;
+            try {
+                hasNext = this._processIEnumeratorRecursive(this._routine);
+            }
+            catch (Exception ex) {
+                this.stop(ex);
+                return;
+            }
+
+            if (!hasNext && !this.isDone) {
+                this._unhook.Dispose();
+
+                this.isDone = true;
+                D.assert(this.lastError == null);
+                if (this._isBackground) {
+                    Timer.runInMain(() => { this._window.run(() => { this._promise.Resolve(this.lastResult); }); });
+                } else {
+                    this._promise.Resolve(this.lastResult);
+                }
+            }
+        }
+
+        bool _processIEnumeratorRecursive(IEnumerator child) {
+            D.assert(child != null);
+
+            if (child.Current is IEnumerator nestedEnumerator) {
+                return this._processIEnumeratorRecursive(nestedEnumerator) || child.MoveNext();
+            }
+
+            if (child.Current is UIWidgetsCoroutine nestedCoroutine) {
+                if (this._isBackground) {
+                    throw new Exception("nestedCoroutine is not supported in Background Coroutine");
+                }
+
+                this._waitForCoroutine.set(nestedCoroutine);
+                return this._waitForCoroutine.moveNext(child, this);
+            }
+
+            if (child.Current is UIWidgetsWaitForSeconds waitForSeconds) {
+                if (this._isBackground) {
+                    throw new Exception("waitForSeconds is not supported in Background Coroutine");
+                }
+
+                this._waitProcessor.set(waitForSeconds);
+                return this._waitProcessor.moveNext(child);
+            }
+
+            if (child.Current is AsyncOperation waitForAsyncOP) {
+                if (this._isBackground) {
+                    throw new Exception("asyncOperation is not supported in Background Coroutine");
+                }
+
+                this._waitForAsyncOPProcessor.set(waitForAsyncOP);
+                return this._waitForAsyncOPProcessor.moveNext(child);
+            }
+
+            this.lastResult = child.Current;
+            return child.MoveNext();
+        }
+
+        public void stop() {
+            this.stop(null);
+        }
+
+        internal void stop(Exception ex) {
+            if (this.lastError == null) {
+                this.lastError = ex ?? new CoroutineCanceledException();
+            }
+        }
+    }
+
+    struct _WaitforSecondsProcessor {
+        UIWidgetsWaitForSeconds _current;
+        double _targetTime;
+
+        public void set(UIWidgetsWaitForSeconds yieldStatement) {
+            if (this._current != yieldStatement) {
+                this._current = yieldStatement;
+                this._targetTime = Timer.timeSinceStartup + yieldStatement.waitTime;
+            }
+        }
+
+        public bool moveNext(IEnumerator enumerator) {
+            if (this._targetTime <= Timer.timeSinceStartup) {
+                this._current = null;
+                this._targetTime = 0;
+                return enumerator.MoveNext();
+            }
+
+            return true;
+        }
+    }
+
+    struct _WaitForCoroutineProcessor {
+        UIWidgetsCoroutine _current;
+
+        public void set(UIWidgetsCoroutine routine) {
+            if (this._current != routine) {
+                this._current = routine;
+            }
+        }
+
+        public bool moveNext(IEnumerator enumerator, UIWidgetsCoroutine parent) {
+            if (this._current.isDone) {
+                var current = this._current;
+                this._current = null;
+
+                if (current.lastError != null) {
+                    parent.stop(current.lastError);
+                    return false;
+                }
+
+                parent.lastResult = current.lastResult;
+                return enumerator.MoveNext();
+            }
+
+            return true;
+        }
+    }
+
+    struct _WaitForAsyncOPProcessor {
+        AsyncOperation _current;
+
+        public void set(AsyncOperation operation) {
+            if (this._current != operation) {
+                this._current = operation;
+            }
+        }
+
+        public bool moveNext(IEnumerator enumerator) {
+            if (this._current.isDone) {
+                this._current = null;
+                return enumerator.MoveNext();
+            }
+
+            return true;
+        }
+    }
+
+    public static class Coroutine {
+        public static UIWidgetsCoroutine startCoroutine(this Window owner, IEnumerator routine) {
+            return new UIWidgetsCoroutine(routine, owner);
+        }
+
+        public static UIWidgetsCoroutine startBackgroundCoroutine(this Window owner, IEnumerator routine) {
+            return new UIWidgetsCoroutine(routine, owner, isBackground: true);
+        }
+    }
+
+    public class CoroutineCanceledException : Exception {
+    }
+
+    public class UIWidgetsWaitForSeconds {
+        public double waitTime { get; }
+
+        public UIWidgetsWaitForSeconds(float time) {
+            this.waitTime = time;
+        }
+    }
+
+    internal class WindowCallbacks {
+        readonly LinkedList<VoidCallback> _callbackList;
+        readonly Window _window;
+
+        public WindowCallbacks() {
+            this._callbackList = new LinkedList<VoidCallback>();
+        }
+
+        public void update() {
+            var callbackList = this._callbackList.ToArray();
+            foreach (var callback in callbackList) {
+                try {
+                    callback();
+                }
+                catch (Exception ex) {
+                    Debug.LogError("Failed to execute callback in WindowCallbacks: " + ex);
+                }
+            }
+        }
+
+        public IDisposable onUpdate(VoidCallback callback) {
+            var node = this._callbackList.AddLast(callback);
+
+            return new _CallbackDisposable(this, node);
+        }
+
+        class _CallbackDisposable : IDisposable {
+            readonly WindowCallbacks _parent;
+            readonly LinkedListNode<VoidCallback> _node;
+
+            public _CallbackDisposable(WindowCallbacks parent, LinkedListNode<VoidCallback> node) {
+                this._parent = parent;
+                this._node = node;
+            }
+
+            public void Dispose() {
+                this._parent._callbackList.Remove(this._node);
+            }
+        }
+    }
+
+    internal class BackgroundCallbacks : IDisposable {
+        static BackgroundCallbacks _instance;
+
+        public static BackgroundCallbacks getInstance() {
+#if UNITY_WEBGL
+            return null;   
+#endif
+            if (_instance == null) {
+                _instance = new BackgroundCallbacks(2);
+            }
+
+            return _instance;
+        }
+
+        readonly LinkedList<_CallbackNode> _callbackList;
+        readonly ManualResetEvent _event;
+
+        readonly Thread[] _threads;
+        volatile bool _aborted = false;
+
+        public BackgroundCallbacks(int threadCount = 1) {
+            this._callbackList = new LinkedList<_CallbackNode>();
+            this._event = new ManualResetEvent(false);
+
+            this._threads = new Thread[threadCount];
+            for (var i = 0; i < this._threads.Length; i++) {
+                this._threads[i] = new Thread(this._threadLoop);
+                this._threads[i].Start();
+            }
+        }
+
+        public void Dispose() {
+            foreach (var t in this._threads) {
+                this._aborted = true;
+                this._event.Set();
+                t.Join();
+            }
+
+            this._callbackList.Clear();
+        }
+
+        void _threadLoop() {
+            while (true) {
+                if (this._aborted) {
+                    break;
+                }
+
+                LinkedListNode<_CallbackNode> node;
+                lock (this._callbackList) {
+                    node = this._callbackList.First;
+                    if (node != null) {
+                        this._callbackList.Remove(node);
+                    }
+                }
+
+                if (node == null) {
+                    this._event.WaitOne();
+                    this._event.Reset();
+                    continue;
+                }
+
+                var callbackNode = node.Value;
+                D.assert(!callbackNode.isDone);
+
+                try {
+                    callbackNode.callback();
+                }
+                catch (Exception ex) {
+                    Debug.LogError("Failed to execute callback in BackgroundCallbacks: " + ex);
+                }
+
+                if (!callbackNode.isDone) {
+                    lock (this._callbackList) {
+                        this._callbackList.AddLast(node);
+                    }
+                }
+            }
+        }
+
+        public IDisposable addCallback(VoidCallback callback) {
+            var node = new _CallbackNode {callback = callback};
+            lock (this._callbackList) {
+                this._callbackList.AddLast(node);
+            }
+
+            this._event.Set();
+
+            return new _CallbackDisposable(node);
+        }
+
+        class _CallbackDisposable : IDisposable {
+            readonly _CallbackNode _node;
+
+            public _CallbackDisposable(_CallbackNode node) {
+                this._node = node;
+            }
+
+            public void Dispose() {
+                this._node.isDone = true;
+            }
+        }
+
+        class _CallbackNode {
+            public VoidCallback callback;
+            public volatile bool isDone;
+        }
+    }
+}

Runtime/ui/painting/GifDecoder.cs

+using System;
+using System.IO;
+using System.Text;
+
+namespace Unity.UIWidgets.ui {
+    // from https://github.com/avianbc/NGif/blob/master/Components/GifDecoder.cs
+    // https://gist.github.com/devunwired/4479231
+    // No DISPOSAL_PREVIOUS as its not actually widely used.
+    public class GifDecoder : IDisposable {
+        /**
+         * File read status: No errors.
+         */
+        public const int STATUS_OK = 0;
+
+        /**
+         * File read status: Error decoding file (may be partially decoded)
+         */
+        public const int STATUS_FORMAT_ERROR = 1;
+
+        /**
+         * File read status: Unable to open source.
+         */
+        public const int STATUS_OPEN_ERROR = 2;
+
+        // max decoder pixel stack size
+        const int MAX_STACK_SIZE = 4096;
+
+        // input stream
+        Stream _inStream;
+
+        /**
+        * Global status code of GIF data parsing
+        */
+        int _status;
+
+        // Global File Header values and parsing flags
+        volatile int _width; // full image width
+        volatile int _height; // full image height
+        bool _gctFlag; // global color table used
+        int _gctSize; // size of global color table
+        volatile int _loopCount = 1; // iterations; 0 = repeat forever
+
+        int[] _gct; // global color table
+        int[] _lct; // local color table
+        int[] _act; // active color table
+
+        int _bgIndex; // background color index
+        int _bgColor; // background color
+        int _lastBgColor; // previous bg color
+        int _pixelAspect; // pixel aspect ratio
+
+        bool _lctFlag; // local color table flag
+        bool _interlace; // interlace flag
+        int _lctSize; // local color table size
+
+        int _ix, _iy, _iw, _ih; // current image rectangle
+        int _lix, _liy, _liw, _lih; // last image rect
+        int[] _image; // current frame
+
+        byte[] _block = new byte[256]; // current data block
+        int _blockSize = 0; // block size
+
+        // last graphic control extension info
+        int _dispose = 0;
+
+        // 0=no action; 1=leave in place; 2=restore to bg; 3=restore to prev
+        int _lastDispose = 0;
+        bool _transparency = false; // use transparent color
+        int _delay = 0; // delay in milliseconds
+        int _transIndex; // transparent color index
+
+        // LZW decoder working arrays
+        short[] _prefix;
+        byte[] _suffix;
+        byte[] _pixelStack;
+        byte[] _pixels;
+
+        volatile GifFrame _currentFrame; // frames read from current file
+        volatile int _frameCount;
+        volatile bool _done;
+
+        public class GifFrame {
+            public byte[] bytes;
+            public int delay;
+        }
+
+        public int frameWidth => this._width;
+
+        public int frameHeight => this._height;
+
+        public GifFrame currentFrame => this._currentFrame;
+
+        public int frameCount => this._frameCount;
+
+        public int loopCount => this._loopCount;
+
+        public bool done => this._done;
+
+        void _setPixels() {
+            // fill in starting image contents based on last image's dispose code
+            if (this._lastDispose > 0) {
+                var n = this._frameCount - 1;
+                if (n > 0) {
+                    if (this._lastDispose == 2) {
+                        // fill last image rect area with background color 
+                        var fillcolor = this._transparency ? 0 : this._lastBgColor;
+                        for (var i = 0; i < this._lih; i++) {
+                            var line = i + this._liy;
+                            if (line >= this._height) {
+                                continue;
+                            }
+
+                            line = this._height - line - 1;
+                            var dx = line * this._width + this._lix;
+                            var endx = dx + this._liw;
+                            while (dx < endx) {
+                                this._image[dx++] = fillcolor;
+                            }
+                        }
+                    }
+                }
+            }
+
+            // copy each source line to the appropriate place in the destination
+            int pass = 1;
+            int inc = 8;
+            int iline = 0;
+            for (int i = 0; i < this._ih; i++) {
+                int line = i;
+                if (this._interlace) {
+                    if (iline >= this._ih) {
+                        pass++;
+                        switch (pass) {
+                            case 2:
+                                iline = 4;
+                                break;
+                            case 3:
+                                iline = 2;
+                                inc = 4;
+                                break;
+                            case 4:
+                                iline = 1;
+                                inc = 2;
+                                break;
+                        }
+                    }
+
+                    line = iline;
+                    iline += inc;
+                }
+
+                line += this._iy;
+                if (line >= this._height) {
+                    continue;
+                }
+
+                var sx = i * this._iw;
+                line = this._height - line - 1;
+                var dx = line * this._width + this._ix;
+                var endx = dx + this._iw;
+
+                for (; dx < endx; dx++) {
+                    var c = this._act[this._pixels[sx++] & 0xff];
+                    if (c != 0) {
+                        this._image[dx] = c;
+                    }
+                }
+            }
+        }
+
+        /**
+         * Reads GIF image from stream
+         *
+         * @param BufferedInputStream containing GIF file.
+         * @return read status code (0 = no errors)
+         */
+        public int read(Stream inStream) {
+            this._init();
+            if (inStream != null) {
+                this._inStream = inStream;
+                this._readHeader();
+            } else {
+                this._status = STATUS_OPEN_ERROR;
+            }
+
+            return this._status;
+        }
+
+        public void Dispose() {
+            if (this._inStream != null) {
+                this._inStream.Dispose();
+                this._inStream = null;
+            }
+        }
+
+        /**
+         * Decodes LZW image data into pixel array.
+         * Adapted from John Cristy's ImageMagick.
+         */
+        void _decodeImageData() {
+            const int NullCode = -1;
+            int npix = this._iw * this._ih;
+            int available,
+                clear,
+                code_mask,
+                code_size,
+                end_of_information,
+                in_code,
+                old_code,
+                bits,
+                code,
+                count,
+                i,
+                datum,
+                data_size,
+                first,
+                top,
+                bi,
+                pi;
+
+            if ((this._pixels == null) || (this._pixels.Length < npix)) {
+                this._pixels = new byte[npix]; // allocate new pixel array
+            }
+
+            if (this._prefix == null) {
+                this._prefix = new short[MAX_STACK_SIZE];
+            }
+
+            if (this._suffix == null) {
+                this._suffix = new byte[MAX_STACK_SIZE];
+            }
+
+            if (this._pixelStack == null) {
+                this._pixelStack = new byte[MAX_STACK_SIZE + 1];
+            }
+
+            //  Initialize GIF data stream decoder.
+
+            data_size = this._read();
+            clear = 1 << data_size;
+            end_of_information = clear + 1;
+            available = clear + 2;
+            old_code = NullCode;
+            code_size = data_size + 1;
+            code_mask = (1 << code_size) - 1;
+            for (code = 0; code < clear; code++) {
+                this._prefix[code] = 0;
+                this._suffix[code] = (byte) code;
+            }
+
+            //  Decode GIF pixel stream.
+
+            datum = bits = count = first = top = pi = bi = 0;
+
+            for (i = 0; i < npix;) {
+                if (top == 0) {
+                    if (bits < code_size) {
+                        //  Load bytes until there are enough bits for a code.
+                        if (count == 0) {
+                            // Read a new data block.
+                            count = this._readBlock();
+                            if (count <= 0) {
+                                break;
+                            }
+
+                            bi = 0;
+                        }
+
+                        datum += (this._block[bi] & 0xff) << bits;
+                        bits += 8;
+                        bi++;
+                        count--;
+                        continue;
+                    }
+
+                    //  Get the next code.
+
+                    code = datum & code_mask;
+                    datum >>= code_size;
+                    bits -= code_size;
+
+                    //  Interpret the code
+
+                    if ((code > available) || (code == end_of_information))
+                        break;
+                    if (code == clear) {
+                        //  Reset decoder.
+                        code_size = data_size + 1;
+                        code_mask = (1 << code_size) - 1;
+                        available = clear + 2;
+                        old_code = NullCode;
+                        continue;
+                    }
+
+                    if (old_code == NullCode) {
+                        this._pixelStack[top++] = this._suffix[code];
+                        old_code = code;
+                        first = code;
+                        continue;
+                    }
+
+                    in_code = code;
+                    if (code == available) {
+                        this._pixelStack[top++] = (byte) first;
+                        code = old_code;
+                    }
+
+                    while (code > clear) {
+                        this._pixelStack[top++] = this._suffix[code];
+                        code = this._prefix[code];
+                    }
+
+                    first = this._suffix[code] & 0xff;
+
+                    //  Add a new string to the string table,
+
+                    if (available >= MAX_STACK_SIZE) {
+                        break;
+                    }
+
+                    this._pixelStack[top++] = (byte) first;
+                    this._prefix[available] = (short) old_code;
+                    this._suffix[available] = (byte) first;
+                    available++;
+                    if (((available & code_mask) == 0)
+                        && (available < MAX_STACK_SIZE)) {
+                        code_size++;
+                        code_mask += available;
+                    }
+
+                    old_code = in_code;
+                }
+
+                //  Pop a pixel off the pixel stack.
+
+                top--;
+                this._pixels[pi++] = this._pixelStack[top];
+                i++;
+            }
+
+            for (i = pi; i < npix; i++) {
+                this._pixels[i] = 0; // clear missing pixels
+            }
+        }
+
+        /**
+         * Returns true if an error was encountered during reading/decoding
+         */
+        bool _error() {
+            return this._status != STATUS_OK;
+        }
+
+        /**
+         * Initializes or re-initializes reader
+         */
+        void _init() {
+            this._status = STATUS_OK;
+            this._currentFrame = null;
+            this._frameCount = 0;
+            this._done = false;
+            this._gct = null;
+            this._lct = null;
+        }
+
+        /**
+         * Reads a single byte from the input stream.
+         */
+        int _read() {
+            int curByte = 0;
+            try {
+                curByte = this._inStream.ReadByte();
+            }
+            catch (IOException) {
+                this._status = STATUS_FORMAT_ERROR;
+            }
+
+            return curByte;
+        }
+
+        /**
+         * Reads next variable length block from input.
+         *
+         * @return number of bytes stored in "buffer"
+         */
+        int _readBlock() {
+            this._blockSize = this._read();
+            int n = 0;
+            if (this._blockSize > 0) {
+                try {
+                    int count = 0;
+                    while (n < this._blockSize) {
+                        count = this._inStream.Read(this._block, n, this._blockSize - n);
+                        if (count == -1) {
+                            break;
+                        }
+
+                        n += count;
+                    }
+                }
+                catch (IOException) {
+                }
+
+                if (n < this._blockSize) {
+                    this._status = STATUS_FORMAT_ERROR;
+                }
+            }
+
+            return n;
+        }
+
+        /**
+         * Reads color table as 256 RGB integer values
+         *
+         * @param ncolors int number of colors to read
+         * @return int array containing 256 colors (packed ARGB with full alpha)
+         */
+        int[] _readColorTable(int ncolors) {
+            int nbytes = 3 * ncolors;
+            int[] tab = null;
+            byte[] c = new byte[nbytes];
+            int n = 0;
+            try {
+                n = this._inStream.Read(c, 0, c.Length);
+            }
+            catch (IOException) {
+            }
+
+            if (n < nbytes) {
+                this._status = STATUS_FORMAT_ERROR;
+            } else {
+                tab = new int[256]; // max size to avoid bounds checks
+                int i = 0;
+                int j = 0;
+                while (i < ncolors) {
+                    int r = c[j++] & 0xff;
+                    int g = c[j++] & 0xff;
+                    int b = c[j++] & 0xff;
+                    tab[i++] = (int) (0xff000000 | (r << 16) | (g << 8) | b);
+                }
+            }
+
+            return tab;
+        }
+
+        /**
+         * Main file parser.  Reads GIF content blocks.
+         */
+        public int nextFrame() {
+            // read GIF file content blocks
+            bool done = false;
+            while (!(done || this._error())) {
+                int code = this._read();
+                switch (code) {
+                    case 0x2C: // image separator
+                        this._readImage();
+                        done = true;
+                        break;
+
+                    case 0x21: // extension
+                        code = this._read();
+                        switch (code) {
+                            case 0xf9: // graphics control extension
+                                this._readGraphicControlExt();
+                                break;
+
+                            case 0xff: // application extension
+                                this._readBlock();
+
+                                var appBuilder = new StringBuilder();
+                                for (int i = 0; i < 11; i++) {
+                                    appBuilder.Append((char) this._block[i]);
+                                }
+
+                                String app = appBuilder.ToString();
+                                if (app.Equals("NETSCAPE2.0")) {
+                                    this._readNetscapeExt();
+                                } else {
+                                    this._skip(); // don't care
+                                }
+
+                                break;
+
+                            default: // uninteresting extension
+                                this._skip();
+                                break;
+                        }
+
+                        break;
+
+                    case 0x3b: // terminator
+                        this._done = true;
+                        done = true;
+                        break;
+
+                    case 0x00: // bad byte, but keep going and see what happens
+                        break;
+
+                    default:
+                        this._status = STATUS_FORMAT_ERROR;
+                        break;
+                }
+            }
+
+            return this._status;
+        }
+
+        /**
+         * Reads Graphics Control Extension values
+         */
+        void _readGraphicControlExt() {
+            this._read(); // block size
+            int packed = this._read(); // packed fields
+            this._dispose = (packed & 0x1c) >> 2; // disposal method
+            if (this._dispose == 0) {
+                this._dispose = 1; // elect to keep old image if discretionary
+            }
+
+            this._transparency = (packed & 1) != 0;
+            this._delay = this._readShort() * 10; // delay in milliseconds
+            this._transIndex = this._read(); // transparent color index
+            this._read(); // block terminator
+        }
+
+        /**
+         * Reads GIF file header information.
+         */
+        void _readHeader() {
+            var idBuilder = new StringBuilder();
+            for (int i = 0; i < 6; i++) {
+                idBuilder.Append((char) this._read());
+            }
+
+            var id = idBuilder.ToString();
+            if (!id.StartsWith("GIF")) {
+                this._status = STATUS_FORMAT_ERROR;
+                return;
+            }
+
+            this._readLSD();
+            if (this._gctFlag && !this._error()) {
+                this._gct = this._readColorTable(this._gctSize);
+                this._bgColor = this._gct[this._bgIndex];
+            }
+        }
+
+        /**
+         * Reads next frame image
+         */
+        void _readImage() {
+            this._ix = this._readShort(); // (sub)image position & size
+            this._iy = this._readShort();
+            this._iw = this._readShort();
+            this._ih = this._readShort();
+
+            int packed = this._read();
+            this._lctFlag = (packed & 0x80) != 0; // 1 - local color table flag
+            this._interlace = (packed & 0x40) != 0; // 2 - interlace flag
+            // 3 - sort flag
+            // 4-5 - reserved
+            this._lctSize = 2 << (packed & 7); // 6-8 - local color table size
+
+            if (this._lctFlag) {
+                this._lct = this._readColorTable(this._lctSize); // read table
+                this._act = this._lct; // make local table active
+            } else {
+                this._act = this._gct; // make global table active
+                if (this._bgIndex == this._transIndex) {
+                    this._bgColor = 0;
+                }
+            }
+
+            int save = 0;
+            if (this._transparency) {
+                save = this._act[this._transIndex];
+                this._act[this._transIndex] = 0; // set transparent color if specified
+            }
+
+            if (this._act == null) {
+                this._status = STATUS_FORMAT_ERROR; // no color table defined
+            }
+
+            if (this._error()) {
+                return;
+            }
+
+            this._decodeImageData(); // decode pixel data
+            this._skip();
+
+            if (this._error()) {
+                return;
+            }
+
+            // create new image to receive frame data
+            //		image =
+            //			new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB_PRE);
+
+            this._image = this._image ?? new int[this._width * this._height];
+
+            this._setPixels(); // transfer pixel data to image
+
+            var bytes = new byte[this._width * this._height * sizeof(int)];
+            Buffer.BlockCopy(this._image, 0, bytes, 0, bytes.Length);
+            this._currentFrame = new GifFrame {bytes = bytes, delay = this._delay};
+            this._frameCount++;
+
+            if (this._transparency) {
+                this._act[this._transIndex] = save;
+            }
+
+            this._resetFrame();
+        }
+
+        /**
+         * Reads Logical Screen Descriptor
+         */
+        void _readLSD() {
+            // logical screen size
+            this._width = this._readShort();
+            this._height = this._readShort();
+
+            // packed fields
+            int packed = this._read();
+            this._gctFlag = (packed & 0x80) != 0; // 1   : global color table flag
+            // 2-4 : color resolution
+            // 5   : gct sort flag
+            this._gctSize = 2 << (packed & 7); // 6-8 : gct size
+
+            this._bgIndex = this._read(); // background color index
+            this._pixelAspect = this._read(); // pixel aspect ratio
+        }
+
+        /**
+         * Reads Netscape extenstion to obtain iteration count
+         */
+        void _readNetscapeExt() {
+            do {
+                this._readBlock();
+                if (this._block[0] == 1) {
+                    // loop count sub-block
+                    int b1 = this._block[1] & 0xff;
+                    int b2 = this._block[2] & 0xff;
+                    this._loopCount = (b2 << 8) | b1;
+                }
+            } while (this._blockSize > 0 && !this._error());
+        }
+
+        /**
+         * Reads next 16-bit value, LSB first
+         */
+        int _readShort() {
+            // read 16-bit value, LSB first
+            return this._read() | (this._read() << 8);
+        }
+
+        /**
+         * Resets frame state for reading next image.
+         */
+        void _resetFrame() {
+            this._lastDispose = this._dispose;
+            this._lix = this._ix;
+            this._liy = this._iy;
+            this._liw = this._iw;
+            this._lih = this._ih;
+            this._lastBgColor = this._bgColor;
+            this._lct = null;
+        }
+
+        /**
+         * Skips variable length blocks up to and including
+         * next zero length block.
+         */
+        void _skip() {
+            do {
+                this._readBlock();
+            } while ((this._blockSize > 0) && !this._error());
+        }
+    }
+}

Runtime/ui/painting/GifDecoder.cs.meta

+fileFormatVersion: 2
+guid: 657b3aa341be94fc09e9c79dcc086f75
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Runtime/ui/painting/codec.cs

+using System;
+using RSG;
+using Unity.UIWidgets.foundation;
+using UnityEngine;
+
+namespace Unity.UIWidgets.ui {
+    public class FrameInfo {
+        public Image image;
+        public TimeSpan duration;
+    }
+
+    public interface Codec : IDisposable {
+        int frameCount { get; }
+        int repetitionCount { get; }
+        IPromise<FrameInfo> getNextFrame();
+    }
+
+    public class ImageCodec : Codec {
+        Image _image;
+
+        public ImageCodec(Image image) {
+            D.assert(image != null);
+            this._image = image;
+        }
+
+        public int frameCount => 1;
+
+        public int repetitionCount => 0;
+
+        public IPromise<FrameInfo> getNextFrame() {
+            D.assert(this._image != null);
+
+            return Promise<FrameInfo>.Resolved(new FrameInfo {
+                duration = TimeSpan.Zero,
+                image = this._image
+            });
+        }
+
+        public void Dispose() {
+            if (this._image != null) {
+                this._image.Dispose();
+                this._image = null;
+            }
+        }
+    }
+
+
+    public static class CodecUtils {
+        public static IPromise<Codec> getCodec(byte[] bytes) {
+            if (GifCodec.isGif(bytes)) {
+                return Promise<Codec>.Resolved(new GifCodec(bytes));
+            }
+
+            var texture = new Texture2D(2, 2);
+            texture.LoadImage(bytes);
+            return Promise<Codec>.Resolved(new ImageCodec(new Image(texture)));
+        }
+
+        public static IPromise<Codec> getCodec(Texture2D texture) {
+            return Promise<Codec>.Resolved(new ImageCodec(new Image(texture)));
+        }
+    }
+}

Runtime/ui/painting/codec.cs.meta

+fileFormatVersion: 2
+guid: a76c61db5ad8a4faf9c0667883dce90d
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
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Runtime/ui/painting/codec_gif.cs

+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.IO;
+using RSG;
+using Unity.UIWidgets.async;
+using Unity.UIWidgets.foundation;
+using UnityEngine;
+using Timer = Unity.UIWidgets.async.Timer;
+
+namespace Unity.UIWidgets.ui {
+    public class GifCodec : Codec {
+        public static bool isGif(byte[] bytes) {
+            return bytes != null && bytes.Length >= 3 && bytes[0] == 'G' && bytes[1] == 'I' && bytes[2] == 'F';
+        }
+
+        public class FrameData {
+            public FrameInfo frameInfo;
+            public GifDecoder.GifFrame gifFrame;
+        }
+
+        readonly List<Promise<FrameData>> _frames;
+        volatile int _width;
+        volatile int _height;
+        volatile int _frameCount;
+        volatile int _repetitionCount;
+        volatile bool _isDone;
+        volatile int _frameIndex;
+        readonly UIWidgetsCoroutine _coroutine;
+
+        public GifCodec(byte[] bytes) {
+            D.assert(bytes != null);
+            D.assert(isGif(bytes));
+
+            this._frames = new List<Promise<FrameData>>();
+            this._width = 0;
+            this._height = 0;
+            this._frameCount = 0;
+            this._repetitionCount = 0;
+            this._isDone = false;
+            this._frameIndex = 0;
+
+            this._coroutine = Window.instance.startBackgroundCoroutine(
+                this._startDecoding(bytes, Window.instance));
+        }
+
+        IEnumerator _startDecoding(byte[] bytes, Window window) {
+            var bytesStream = new MemoryStream(bytes);
+
+            var gifDecoder = new GifDecoder();
+            if (gifDecoder.read(bytesStream) != GifDecoder.STATUS_OK) {
+                throw new Exception("Failed to decode gif.");
+            }
+
+            this._width = gifDecoder.frameWidth;
+            this._height = gifDecoder.frameHeight;
+
+            int i = 0;
+            while (true) {
+                yield return null;
+
+                if (gifDecoder.nextFrame() != GifDecoder.STATUS_OK) {
+                    throw new Exception("Failed to decode gif.");
+                }
+                if (gifDecoder.done) {
+                    break;
+                }
+
+                var frameData = new FrameData {
+                    gifFrame = gifDecoder.currentFrame,
+                };
+
+                Promise<FrameData> frame;
+
+                lock (this._frames) {
+                    if (i < this._frames.Count) {
+                    } else {
+                        D.assert(this._frames.Count == i);
+                        this._frames.Add(new Promise<FrameData>());
+                    }
+
+                    frame = this._frames[i];
+                }
+
+                Timer.runInMain(() => { window.run(() => { frame.Resolve(frameData); }); });
+
+                i++;
+            }
+
+            D.assert(gifDecoder.frameCount == i);
+            this._frameCount = gifDecoder.frameCount;
+            this._repetitionCount = gifDecoder.loopCount;
+            this._isDone = true;
+        }
+
+        public int frameCount => this._frameCount;
+
+        public int repetitionCount => this._repetitionCount - 1;
+
+
+        void _nextFrame() {
+            this._frameIndex++;
+
+            if (this._isDone && this._frameIndex >= this._frameCount) {
+                this._frameIndex = 0;
+            }
+        }
+
+        public IPromise<FrameInfo> getNextFrame() {
+            Promise<FrameData> frame;
+
+            lock (this._frames) {
+                if (this._frameIndex == this._frames.Count) {
+                    this._frames.Add(new Promise<FrameData>());
+                } else {
+                    D.assert(this._frameIndex < this._frames.Count);
+                }
+
+                frame = this._frames[this._frameIndex];
+            }
+
+
+            return frame.Then(frameData => {
+                this._nextFrame();
+
+                if (frameData.frameInfo != null) {
+                    return frameData.frameInfo;
+                }
+
+                var tex = new Texture2D(this._width, this._height, TextureFormat.BGRA32, false);
+                tex.LoadRawTextureData(frameData.gifFrame.bytes);
+                tex.Apply();
+
+                frameData.frameInfo = new FrameInfo {
+                    image = new Image(tex),
+                    duration = TimeSpan.FromMilliseconds(frameData.gifFrame.delay)
+                };
+                frameData.gifFrame = null; // dispose gifFrame
+
+                return frameData.frameInfo;
+            });
+        }
+
+        public void Dispose() {
+            this._coroutine.stop();
+        }
+    }
+}

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