using System; using RSG; using Unity.UIWidgets.animation; using Unity.UIWidgets.foundation; using Unity.UIWidgets.gestures; using Unity.UIWidgets.painting; using Unity.UIWidgets.physics; using Unity.UIWidgets.scheduler; using Unity.UIWidgets.ui; namespace Unity.UIWidgets.widgets { public interface ScrollActivityDelegate { AxisDirection axisDirection { get; } double setPixels(double pixels); void applyUserOffset(double delta); void applyUserScrollOffset(double delta); void goIdle(); void goBallistic(double velocity); } public abstract class ScrollActivity { public ScrollActivity(ScrollActivityDelegate del) { this._del = del; } public ScrollActivityDelegate del { get { return this._del; } } ScrollActivityDelegate _del; public void updateDelegate(ScrollActivityDelegate value) { D.assert(this._del != value); this._del = value; } public virtual void resetActivity() { } public virtual void dispatchScrollStartNotification(ScrollMetrics metrics, BuildContext context) { new ScrollStartNotification(metrics: metrics, context: context).dispatch(context); } public virtual void dispatchScrollUpdateNotification(ScrollMetrics metrics, BuildContext context, double scrollDelta) { new ScrollUpdateNotification(metrics: metrics, context: context, scrollDelta: scrollDelta) .dispatch(context); } public virtual void dispatchOverscrollNotification(ScrollMetrics metrics, BuildContext context, double overscroll) { new OverscrollNotification(metrics: metrics, context: context, overscroll: overscroll).dispatch(context); } public virtual void dispatchScrollEndNotification(ScrollMetrics metrics, BuildContext context) { new ScrollEndNotification(metrics: metrics, context: context).dispatch(context); } public virtual void applyNewDimensions() { } public abstract bool shouldIgnorePointer { get; } public abstract bool isScrolling { get; } public abstract double velocity { get; } public virtual void dispose() { this._del = null; } public override string ToString() { return Diagnostics.describeIdentity(this); } } public class IdleScrollActivity : ScrollActivity { public IdleScrollActivity(ScrollActivityDelegate del) : base(del) { } public override void applyNewDimensions() { this.del.goBallistic(0.0); } public override bool shouldIgnorePointer { get { return false; } } public override bool isScrolling { get { return false; } } public override double velocity { get { return 0.0; } } } public interface ScrollHoldController { void cancel(); } public class HoldScrollActivity : ScrollActivity, ScrollHoldController { public HoldScrollActivity( ScrollActivityDelegate del = null, VoidCallback onHoldCanceled = null ) : base(del) { this.onHoldCanceled = onHoldCanceled; } public readonly VoidCallback onHoldCanceled; public override bool shouldIgnorePointer { get { return false; } } public override bool isScrolling { get { return false; } } public override double velocity { get { return 0.0; } } public void cancel() { this.del.goBallistic(0.0); } public override void dispose() { if (this.onHoldCanceled != null) { this.onHoldCanceled(); } base.dispose(); } } public class ScrollDragController : Drag { public ScrollDragController( ScrollActivityDelegate del = null, DragStartDetails details = null, VoidCallback onDragCanceled = null, double? carriedVelocity = null, double? motionStartDistanceThreshold = null ) { D.assert(del != null); D.assert(details != null); D.assert( motionStartDistanceThreshold == null || motionStartDistanceThreshold > 0.0, "motionStartDistanceThreshold must be a positive number or null" ); this._del = del; this._lastDetails = details; this._retainMomentum = carriedVelocity != null && carriedVelocity != 0.0; this._lastNonStationaryTimestamp = details.sourceTimeStamp; this._offsetSinceLastStop = motionStartDistanceThreshold == null ? (double?) null : 0.0; this.onDragCanceled = onDragCanceled; this.carriedVelocity = carriedVelocity; this.motionStartDistanceThreshold = motionStartDistanceThreshold; } public ScrollActivityDelegate del { get { return this._del; } } ScrollActivityDelegate _del; public readonly VoidCallback onDragCanceled; public readonly double? carriedVelocity; public readonly double? motionStartDistanceThreshold; TimeSpan _lastNonStationaryTimestamp; bool _retainMomentum; double? _offsetSinceLastStop; public static readonly TimeSpan momentumRetainStationaryDurationThreshold = new TimeSpan(0, 0, 0, 0, 20); public static readonly TimeSpan motionStoppedDurationThreshold = new TimeSpan(0, 0, 0, 0, 50); const double _bigThresholdBreakDistance = 24.0; bool _reversed { get { return AxisUtils.axisDirectionIsReversed(this.del.axisDirection); } } public void updateDelegate(ScrollActivityDelegate value) { D.assert(this._del != value); this._del = value; } void _maybeLoseMomentum(double offset, TimeSpan? timestamp) { if (this._retainMomentum && offset == 0.0 && (timestamp == null || timestamp - this._lastNonStationaryTimestamp > momentumRetainStationaryDurationThreshold)) { this._retainMomentum = false; } } double _adjustForScrollStartThreshold(double offset, TimeSpan? timestamp) { if (timestamp == null) { return offset; } if (offset == 0.0) { if (this.motionStartDistanceThreshold != null && this._offsetSinceLastStop == null && timestamp - this._lastNonStationaryTimestamp > motionStoppedDurationThreshold) { this._offsetSinceLastStop = 0.0; } return 0.0; } else { if (this._offsetSinceLastStop == null) { return offset; } else { this._offsetSinceLastStop += offset; if (this._offsetSinceLastStop.Value.abs() > this.motionStartDistanceThreshold) { this._offsetSinceLastStop = null; if (offset.abs() > _bigThresholdBreakDistance) { return offset; } else { return Math.Min( this.motionStartDistanceThreshold.Value / 3.0, offset.abs() ) * offset.sign(); } } else { return 0.0; } } } } public void update(DragUpdateDetails details) { D.assert(details.primaryDelta != null); this._lastDetails = details; double offset = details.primaryDelta.Value; if (details.isScroll) { if (offset == 0.0) { return; } if (this._reversed) { offset = -offset; } this.del.applyUserScrollOffset(offset); return; } if (offset != 0.0) { this._lastNonStationaryTimestamp = details.sourceTimeStamp; } this._maybeLoseMomentum(offset, details.sourceTimeStamp); offset = this._adjustForScrollStartThreshold(offset, details.sourceTimeStamp); if (offset == 0.0) { return; } if (this._reversed) { offset = -offset; } this.del.applyUserOffset(offset); } public void end(DragEndDetails details) { D.assert(details.primaryVelocity != null); double velocity = -details.primaryVelocity.Value; if (this._reversed) { velocity = -velocity; } this._lastDetails = details; if (this._retainMomentum && velocity.sign() == this.carriedVelocity.Value.sign()) { velocity += this.carriedVelocity.Value; } this.del.goBallistic(velocity); } public void cancel() { this.del.goBallistic(0.0); } public virtual void dispose() { this._lastDetails = null; if (this.onDragCanceled != null) { this.onDragCanceled(); } } public object lastDetails { get { return this._lastDetails; } } object _lastDetails; public override string ToString() { return Diagnostics.describeIdentity(this); } } public class DragScrollActivity : ScrollActivity { public DragScrollActivity( ScrollActivityDelegate del, ScrollDragController controller ) : base(del) { this._controller = controller; } ScrollDragController _controller; public override void dispatchScrollStartNotification(ScrollMetrics metrics, BuildContext context) { object lastDetails = this._controller.lastDetails; D.assert(lastDetails is DragStartDetails); new ScrollStartNotification(metrics: metrics, context: context, dragDetails: (DragStartDetails) lastDetails) .dispatch(context); } public override void dispatchScrollUpdateNotification(ScrollMetrics metrics, BuildContext context, double scrollDelta) { object lastDetails = this._controller.lastDetails; D.assert(lastDetails is DragUpdateDetails); new ScrollUpdateNotification(metrics: metrics, context: context, scrollDelta: scrollDelta, dragDetails: (DragUpdateDetails) lastDetails).dispatch(context); } public override void dispatchOverscrollNotification(ScrollMetrics metrics, BuildContext context, double overscroll) { object lastDetails = this._controller.lastDetails; D.assert(lastDetails is DragUpdateDetails); new OverscrollNotification(metrics: metrics, context: context, overscroll: overscroll, dragDetails: (DragUpdateDetails) lastDetails).dispatch(context); } public override void dispatchScrollEndNotification(ScrollMetrics metrics, BuildContext context) { object lastDetails = this._controller.lastDetails; new ScrollEndNotification( metrics: metrics, context: context, dragDetails: lastDetails as DragEndDetails ).dispatch(context); } public override bool shouldIgnorePointer { get { return true; } } public override bool isScrolling { get { return true; } } public override double velocity { get { return 0.0; } } public override void dispose() { this._controller = null; base.dispose(); } public override string ToString() { return $"{Diagnostics.describeIdentity(this)}({this._controller})"; } } public class BallisticScrollActivity : ScrollActivity { public BallisticScrollActivity( ScrollActivityDelegate del, Simulation simulation, TickerProvider vsync ) : base(del) { this._controller = AnimationController.unbounded( debugLabel: this.GetType().ToString(), vsync: vsync ); this._controller.addListener(this._tick); this._controller.animateWith(simulation).Then(() => this._end()); } public override double velocity { get { return this._controller.velocity; } } readonly AnimationController _controller; public override void resetActivity() { this.del.goBallistic(this.velocity); } public override void applyNewDimensions() { this.del.goBallistic(this.velocity); } void _tick() { if (!this.applyMoveTo(this._controller.value)) { this.del.goIdle(); } } protected bool applyMoveTo(double value) { return this.del.setPixels(value) == 0.0; } void _end() { if (this.del != null) { this.del.goBallistic(0.0); } } public override void dispatchOverscrollNotification( ScrollMetrics metrics, BuildContext context, double overscroll) { new OverscrollNotification(metrics: metrics, context: context, overscroll: overscroll, velocity: this.velocity).dispatch(context); } public override bool shouldIgnorePointer { get { return true; } } public override bool isScrolling { get { return true; } } public override void dispose() { this._controller.dispose(); base.dispose(); } public override string ToString() { return $"{Diagnostics.describeIdentity(this)}({this._controller})"; } } public class DrivenScrollActivity : ScrollActivity { public DrivenScrollActivity( ScrollActivityDelegate del, double from, double to, TimeSpan duration, Curve curve, TickerProvider vsync ) : base(del) { D.assert(duration > TimeSpan.Zero); D.assert(curve != null); this._completer = new Promise(); this._controller = AnimationController.unbounded( value: from, debugLabel: this.GetType().ToString(), vsync: vsync ); this._controller.addListener(this._tick); this._controller.animateTo(to, duration: duration, curve: curve) .Then(() => this._end()); } readonly Promise _completer; readonly AnimationController _controller; public IPromise done { get { return this._completer; } } public override double velocity { get { return this._controller.velocity; } } void _tick() { if (this.del.setPixels(this._controller.value) != 0.0) { this.del.goIdle(); } } void _end() { if (this.del != null) { this.del.goBallistic(this.velocity); } } public override void dispatchOverscrollNotification( ScrollMetrics metrics, BuildContext context, double overscroll) { new OverscrollNotification(metrics: metrics, context: context, overscroll: overscroll, velocity: this.velocity).dispatch(context); } public override bool shouldIgnorePointer { get { return true; } } public override bool isScrolling { get { return true; } } public override void dispose() { this._completer.Resolve(); this._controller.dispose(); base.dispose(); } public override string ToString() { return $"{Diagnostics.describeIdentity(this)}({this._controller})"; } } }