Move example fn widgets into sky/framework/components

sky/examples/fn/widgets/drawer.dart

Index: sky/examples/fn/widgets/drawer.dart
diff --git a/sky/examples/fn/widgets/drawer.dart b/sky/examples/fn/widgets/drawer.dart
deleted file mode 100644
index 8f36d182455a0a51457e73afaca04a52e32f7897..0000000000000000000000000000000000000000
--- a/sky/examples/fn/widgets/drawer.dart
+++ /dev/null
@@ -1,159 +0,0 @@
-part of widgets;
-
-const double _kWidth = 256.0;
-const double _kMinFlingVelocity = 0.4;
-const double _kBaseSettleDurationMS = 246.0;
-const double _kMaxSettleDurationMS = 600.0;
-const Cubic _kAnimationCurve = easeOut;
-
-class DrawerAnimation extends Animation {
-
-  Stream<double> get onPositionChanged => onValueChanged;
-
-  bool get _isMostlyClosed => value <= -_kWidth / 2;
-
-  DrawerAnimation() {
-    value = -_kWidth;
-  }
-
-  void toggle(_) => _isMostlyClosed ? _open() : _close();
-
-  void handleMaskTap(_) => _close();
-
-  void handlePointerDown(_) => stop();
-
-  void handlePointerMove(sky.PointerEvent event) {
-    assert(!isAnimating);
-    value = math.min(0.0, math.max(value + event.dx, -_kWidth));
-  }
-
-  void handlePointerUp(_) {
-    if (!isAnimating)
-      _settle();
-  }
-
-  void handlePointerCancel(_) {
-    if (!isAnimating)
-      _settle();
-  }
-
-  void _open() => _animateToPosition(0.0);
-
-  void _close() => _animateToPosition(-_kWidth);
-
-  void _settle() => _isMostlyClosed ? _close() : _open();
-
-  void _animateToPosition(double targetPosition) {
-    double distance = (targetPosition - value).abs();
-    if (distance != 0) {
-      double targetDuration = distance / _kWidth * _kBaseSettleDurationMS;
-      double duration = math.min(targetDuration, _kMaxSettleDurationMS);
-      animateTo(targetPosition, duration, curve: _kAnimationCurve);
-    }
-  }
-
-  void handleFlingStart(event) {
-    double direction = event.velocityX.sign;
-    double velocityX = event.velocityX.abs() / 1000;
-    if (velocityX < _kMinFlingVelocity)
-      return;
-
-    double targetPosition = direction < 0.0 ? -_kWidth : 0.0;
-    double distance = (targetPosition - value).abs();
-    double duration = distance / velocityX;
-
-    animateTo(targetPosition, duration, curve: linear);
-  }
-}
-
-class Drawer extends Component {
-
-  static Style _style = new Style('''
-    position: absolute;
-    z-index: 2;
-    top: 0;
-    left: 0;
-    bottom: 0;
-    right: 0;
-    box-shadpw: ${Shadow[3]};'''
-  );
-
-  static Style _maskStyle = new Style('''
-    background-color: black;
-    will-change: opacity;
-    position: absolute;
-    top: 0;
-    left: 0;
-    bottom: 0;
-    right: 0;'''
-  );
-
-  static Style _contentStyle = new Style('''
-    background-color: ${Grey[50]};
-    will-change: transform;
-    position: absolute;
-    z-index: 3;
-    width: 256px;
-    top: 0;
-    left: 0;
-    bottom: 0;'''
-  );
-
-  DrawerAnimation animation;
-  List<Node> children;
-
-  Drawer({
-    Object key,
-    this.animation,
-    this.children
-  }) : super(key: key);
-
-  double _position = -_kWidth;
-
-  bool _listening = false;
-
-  void _ensureListening() {
-    if (_listening)
-      return;
-
-    _listening = true;
-    animation.onPositionChanged.listen((position) {
-      setState(() {
-        _position = position;
-      });
-    });
-  }
-
-  Node build() {
-    _ensureListening();
-
-    bool isClosed = _position <= -_kWidth;
-    String inlineStyle = 'display: ${isClosed ? 'none' : ''}';
-    String maskInlineStyle = 'opacity: ${(_position / _kWidth + 1) * 0.25}';
-    String contentInlineStyle = 'transform: translateX(${_position}px)';
-
-    Container mask = new Container(
-      key: 'Mask',
-      style: _maskStyle,
-      inlineStyle: maskInlineStyle
-    )..events.listen('gesturetap', animation.handleMaskTap)
-     ..events.listen('gestureflingstart', animation.handleFlingStart);
-
-    Container content = new Container(
-      key: 'Content',
-      style: _contentStyle,
-      inlineStyle: contentInlineStyle,
-      children: children
-    );
-
-    return new Container(
-      style: _style,
-      inlineStyle: inlineStyle,
-      children: [ mask, content ]
-    )..events.listen('pointerdown', animation.handlePointerDown)
-     ..events.listen('pointermove', animation.handlePointerMove)
-     ..events.listen('pointerup', animation.handlePointerUp)
-     ..events.listen('pointercancel', animation.handlePointerCancel);
-
-  }
-}