Merge pull request #760 from Hixie/move-pointer-fixes

Cleanup for the Pointer changes.

packages/flutter/lib/src/gestures/drag.dart

@@ -25,8 +25,7 @@ typedef void GesturePanEndCallback(Offset velocity);
 typedef void _GesturePolymorphicUpdateCallback<T>(T delta);
 
 bool _isFlingGesture(Offset velocity) {
-  if (velocity == null)
-    return false;
+  assert(velocity != null);
   double velocitySquared = velocity.dx * velocity.dx + velocity.dy * velocity.dy;
   return velocitySquared > kMinFlingVelocity * kMinFlingVelocity
       && velocitySquared < kMaxFlingVelocity * kMaxFlingVelocity;

packages/flutter/lib/src/gestures/events.dart

@@ -193,8 +193,8 @@ class PointerAddedEvent extends PointerEvent {
     PointerDeviceKind kind: PointerDeviceKind.touch,
     Point position: Point.origin,
     bool obscured: false,
-    double pressureMin: 0.0,
-    double pressureMax: 0.0,
+    double pressureMin: 1.0,
+    double pressureMax: 1.0,
     double distance: 0.0,
     double distanceMax: 0.0,
     double radiusMin: 0.0,
@@ -224,8 +224,8 @@ class PointerRemovedEvent extends PointerEvent {
     int pointer: 0,
     PointerDeviceKind kind: PointerDeviceKind.touch,
     bool obscured: false,
-    double pressureMin: 0.0,
-    double pressureMax: 0.0,
+    double pressureMin: 1.0,
+    double pressureMax: 1.0,
     double distanceMax: 0.0,
     double radiusMin: 0.0,
     double radiusMax: 0.0
@@ -251,9 +251,9 @@ class PointerDownEvent extends PointerEvent {
     Point position: Point.origin,
     int buttons: 0,
     bool obscured: false,
-    double pressure: 0.0,
-    double pressureMin: 0.0,
-    double pressureMax: 0.0,
+    double pressure: 1.0,
+    double pressureMin: 1.0,
+    double pressureMax: 1.0,
     double distanceMax: 0.0,
     double radiusMajor: 0.0,
     double radiusMinor: 0.0,
@@ -293,9 +293,9 @@ class PointerMoveEvent extends PointerEvent {
     int buttons: 0,
     bool down: false,
     bool obscured: false,
-    double pressure: 0.0,
-    double pressureMin: 0.0,
-    double pressureMax: 0.0,
+    double pressure: 1.0,
+    double pressureMin: 1.0,
+    double pressureMax: 1.0,
     double distance: 0.0,
     double distanceMax: 0.0,
     double radiusMajor: 0.0,
@@ -335,8 +335,8 @@ class PointerUpEvent extends PointerEvent {
     Point position: Point.origin,
     int buttons: 0,
     bool obscured: false,
-    double pressureMin: 0.0,
-    double pressureMax: 0.0,
+    double pressureMin: 1.0,
+    double pressureMax: 1.0,
     double distance: 0.0,
     double distanceMax: 0.0,
     double radiusMin: 0.0,
@@ -369,8 +369,8 @@ class PointerCancelEvent extends PointerEvent {
     Point position: Point.origin,
     int buttons: 0,
     bool obscured: false,
-    double pressureMin: 0.0,
-    double pressureMax: 0.0,
+    double pressureMin: 1.0,
+    double pressureMax: 1.0,
     double distance: 0.0,
     double distanceMax: 0.0,
     double radiusMin: 0.0,

packages/flutter_sprites/lib/src/node.dart

@@ -769,10 +769,10 @@ class Node {
   ///       }
   ///
   ///       bool handleEvent(SpriteBoxEvent event) {
-  ///         if (event.type == 'pointerdown) {
+  ///         if (event.type == PointerDownEvent) {
   ///           opacity = 0.5;
   ///         }
-  ///         else if (event.type == 'pointerup') {
+  ///         else if (event.type == PointerUpEvent) {
   ///           opacity = 1.0;
   ///         }
   ///         return true;

packages/flutter_sprites/lib/src/sprite_box.dart

@@ -187,13 +187,11 @@ class SpriteBox extends RenderBox {
     }
   }
 
-  void handleEvent(InputEvent event, _SpriteBoxHitTestEntry entry) {
+  void handleEvent(PointerEvent event, _SpriteBoxHitTestEntry entry) {
     if (!attached)
       return;
 
-    if (event is PointerInputEvent) {
-
-      if (event.type == 'pointerdown') {
+    if (event is PointerDownEvent) {
       // Build list of event targets
       if (_eventTargets == null) {
         _eventTargets = <Node>[];
@@ -225,7 +223,7 @@ class SpriteBox extends RenderBox {
       // Check if this event should be dispatched
       if (node.handleMultiplePointers || event.pointer == node._handlingPointer) {
         // Dispatch event
-          bool consumedEvent = node.handleEvent(new SpriteBoxEvent(new Point(event.x, event.y), event.type, event.pointer));
+        bool consumedEvent = node.handleEvent(new SpriteBoxEvent(new Point(event.x, event.y), event.runtimeType, event.pointer));
         if (consumedEvent == null || consumedEvent)
           break;
       }
@@ -233,12 +231,10 @@ class SpriteBox extends RenderBox {
 
     // De-register pointer for nodes that doesn't handle multiple pointers
     for (Node node in targets) {
-        if (event.type == 'pointerup' || event.type == 'pointercancel') {
+      if (event is PointerUpEvent || event is PointerCancelEvent)
         node._handlingPointer = null;
     }
   }
-    }
-  }
 
   bool hitTest(HitTestResult result, { Point position }) {
     result.add(new _SpriteBoxHitTestEntry(this, position));
@@ -531,13 +527,13 @@ class SpriteBoxEvent {
   ///     }
   final Point boxPosition;
 
-  /// The type of event, there are currently four valid types, 'pointerdown', 'pointermoved', 'pointerup', and
-  /// 'pointercancel'.
+  /// The type of event, there are currently four valid types, PointerDownEvent, PointerMoveEvent, PointerUpEvent, and
+  /// PointerCancelEvent.
   ///
-  ///     if (event.type == 'pointerdown') {
+  ///     if (event.type == PointerDownEvent) {
   ///       // Do something!
   ///     }
-  final String type;
+  final Type type;
 
   /// The id of the pointer. Each pointer on the screen will have a unique pointer id.
   ///

packages/flutter_sprites/lib/src/virtual_joystick.dart

@@ -31,18 +31,18 @@ class VirtualJoystick extends NodeWithSize {
   Paint _paintControl;
 
   bool handleEvent(SpriteBoxEvent event) {
-    if (event.type == "pointerdown") {
+    if (event.type == PointerDownEvent) {
       _pointerDownAt = event.boxPosition;
       actions.stopAll();
       _isDown = true;
     }
-    else if (event.type == "pointerup" || event.type == "pointercancel") {
+    else if (event.type == PointerUpEvent || event.type == PointerCancelEvent) {
       _pointerDownAt = null;
       _value = Point.origin;
       ActionTween moveToCenter = new ActionTween((a) => _handlePos = a, _handlePos, _center, 0.4, Curves.elasticOut);
       actions.run(moveToCenter);
       _isDown = false;
-    } else if (event.type == "pointermove") {
+    } else if (event.type == PointerMoveEvent) {
       Offset movedDist = event.boxPosition - _pointerDownAt;
 
       _value = new Point(