Move sky/examples to sky/sdk/lib/example, and code changes to support that change. Fixes T277.

sky/examples/game/lib/sprite_box.dart

Index: sky/examples/game/lib/sprite_box.dart
diff --git a/sky/examples/game/lib/sprite_box.dart b/sky/examples/game/lib/sprite_box.dart
deleted file mode 100644
index f3020316b9017cf292328d31ddffb5c288acba67..0000000000000000000000000000000000000000
--- a/sky/examples/game/lib/sprite_box.dart
+++ /dev/null
@@ -1,381 +0,0 @@
-part of sprites;
-
-/// Options for setting up a [SpriteBox].
-///
-///  * [nativePoints], use the same points as the parent [Widget].
-///  * [letterbox], use the size of the root node for the coordinate system, constrain the aspect ratio and trim off
-///  areas that end up outside the screen.
-///  * [stretch], use the size of the root node for the coordinate system, scale it to fit the size of the box.
-///  * [scaleToFit], similar to the letterbox option, but instead of trimming areas the sprite system will be scaled
-///  down to fit the box.
-///  * [fixedWidth], uses the width of the root node to set the size of the coordinate system, this option will change
-///  the height of the root node to fit the box.
-///  * [fixedHeight], uses the height of the root node to set the size of the coordinate system, this option will change
-///  the width of the root node to fit the box.
-enum SpriteBoxTransformMode {
-  nativePoints,
-  letterbox,
-  stretch,
-  scaleToFit,
-  fixedWidth,
-  fixedHeight,
-}
-
-class SpriteBox extends RenderBox {
-
-  // Member variables
-
-  // Root node for drawing
-  NodeWithSize _rootNode;
-
-  // Tracking of frame rate and updates
-  double _lastTimeStamp;
-  int _numFrames = 0;
-  double _frameRate = 0.0;
-
-  // Transformation mode
-  SpriteBoxTransformMode _transformMode;
-
-  /// The transform mode used by the [SpriteBox].
-  SpriteBoxTransformMode get transformMode => _transformMode;
-
-  // Cached transformation matrix
-  Matrix4 _transformMatrix;
-
-  List<Node> _eventTargets;
-
-  // Setup
-
-  /// Creates a new SpriteBox with a node as its content, by default uses letterboxing.
-  ///
-  /// The [rootNode] provides the content of the node tree, typically it's a custom subclass of [NodeWithSize]. The
-  /// [mode] provides different ways to scale the content to best fit it to the screen. In most cases it's preferred to
-  /// use a [SpriteWidget] that automatically wraps the SpriteBox.
-  ///
-  ///     var spriteBox = new SpriteBox(myNode, SpriteBoxTransformMode.fixedHeight);
-  SpriteBox(NodeWithSize rootNode, [SpriteBoxTransformMode mode = SpriteBoxTransformMode.letterbox]) {
-    assert(rootNode != null);
-    assert(rootNode._spriteBox == null);
-
-    // Setup root node
-    _rootNode = rootNode;
-
-    // Assign SpriteBox reference to all the nodes
-    _addSpriteBoxReference(_rootNode);
-
-    // Setup transform mode
-    _transformMode = mode;
-
-    _scheduleTick();
-  }
-
-  void _addSpriteBoxReference(Node node) {
-    node._spriteBox = this;
-    for (Node child in node._children) {
-      _addSpriteBoxReference(child);
-    }
-  }
-
-  // Properties
-
-  /// The root node of the node tree that is rendered by this box.
-  ///
-  ///     var rootNode = mySpriteBox.rootNode;
-  NodeWithSize get rootNode => _rootNode;
-
-  void performLayout() {
-    size = constraints.constrain(Size.infinite);
-    _invalidateTransformMatrix();
-    _callSpriteBoxPerformedLayout(_rootNode);
-  }
-
-  // Event handling
-
-  void _addEventTargets(Node node, List<Node> eventTargets) {
-    List children = node.children;
-    int i = 0;
-
-    // Add childrens that are behind this node
-    while (i < children.length) {
-      Node child = children[i];
-      if (child.zPosition >= 0.0) break;
-      _addEventTargets(child, eventTargets);
-      i++;
-    }
-
-    // Add this node
-    if (node.userInteractionEnabled) {
-      eventTargets.add(node);
-    }
-
-    // Add children in front of this node
-    while (i < children.length) {
-      Node child = children[i];
-      _addEventTargets(child, eventTargets);
-      i++;
-    }
-  }
-
-  void handleEvent(Event event, _SpriteBoxHitTestEntry entry) {
-    if (event is PointerEvent) {
-
-      if (event.type == 'pointerdown') {
-        // Build list of event targets
-        if (_eventTargets == null) {
-          _eventTargets = [];
-          _addEventTargets(_rootNode, _eventTargets);
-        }
-
-        // Find the once that are hit by the pointer
-        List<Node> nodeTargets = [];
-        for (int i = _eventTargets.length - 1; i >= 0; i--) {
-          Node node = _eventTargets[i];
-
-          // Check if the node is ready to handle a pointer
-          if (node.handleMultiplePointers || node._handlingPointer == null) {
-            // Do the hit test
-            Point posInNodeSpace = node.convertPointToNodeSpace(entry.localPosition);
-            if (node.isPointInside(posInNodeSpace)) {
-              nodeTargets.add(node);
-              node._handlingPointer = event.pointer;
-            }
-          }
-        }
-
-        entry.nodeTargets = nodeTargets;
-      }
-
-      // Pass the event down to nodes that were hit by the pointerdown
-      List<Node> targets = entry.nodeTargets;
-      for (Node node in targets) {
-        // 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));
-          if (consumedEvent == null || consumedEvent) break;
-        }
-      }
-
-      // De-register pointer for nodes that doesn't handle multiple pointers
-      for (Node node in targets) {
-        if (event.type == 'pointerup' || event.type == 'pointercancel') {
-          node._handlingPointer = null;
-        }
-      }
-    }
-  }
-
-  bool hitTest(HitTestResult result, { Point position }) {
-    result.add(new _SpriteBoxHitTestEntry(this, position));
-    return true;
-  }
-
-  // Rendering
-
-  /// The transformation matrix used to transform the root node to the space of the box.
-  ///
-  /// It's uncommon to need access to this property.
-  ///
-  ///     var matrix = mySpriteBox.transformMatrix;
-  Matrix4 get transformMatrix {
-    // Get cached matrix if available
-    if (_transformMatrix != null) {
-      return _transformMatrix;
-    }
-
-    _transformMatrix = new Matrix4.identity();
-
-    // Calculate matrix
-    double scaleX = 1.0;
-    double scaleY = 1.0;
-    double offsetX = 0.0;
-    double offsetY = 0.0;
-
-    double systemWidth = rootNode.size.width;
-    double systemHeight = rootNode.size.height;
-
-    switch(_transformMode) {
-      case SpriteBoxTransformMode.stretch:
-        scaleX = size.width/systemWidth;
-        scaleY = size.height/systemHeight;
-        break;
-      case SpriteBoxTransformMode.letterbox:
-        scaleX = size.width/systemWidth;
-        scaleY = size.height/systemHeight;
-        if (scaleX > scaleY) {
-          scaleY = scaleX;
-          offsetY = (size.height - scaleY * systemHeight)/2.0;
-        } else {
-          scaleX = scaleY;
-          offsetX = (size.width - scaleX * systemWidth)/2.0;
-        }
-        break;
-      case SpriteBoxTransformMode.scaleToFit:
-        scaleX = size.width/systemWidth;
-        scaleY = size.height/systemHeight;
-        if (scaleX < scaleY) {
-          scaleY = scaleX;
-          offsetY = (size.height - scaleY * systemHeight)/2.0;
-        } else {
-          scaleX = scaleY;
-          offsetX = (size.width - scaleX * systemWidth)/2.0;
-        }
-        break;
-      case SpriteBoxTransformMode.fixedWidth:
-        scaleX = size.width/systemWidth;
-        scaleY = scaleX;
-        systemHeight = size.height/scaleX;
-        rootNode.size = new Size(systemWidth, systemHeight);
-        break;
-      case SpriteBoxTransformMode.fixedHeight:
-        scaleY = size.height/systemHeight;
-        scaleX = scaleY;
-        systemWidth = size.width/scaleY;
-        rootNode.size = new Size(systemWidth, systemHeight);
-        break;
-      case SpriteBoxTransformMode.nativePoints:
-        break;
-      default:
-        assert(false);
-        break;
-    }
-
-    _transformMatrix.translate(offsetX, offsetY);
-    _transformMatrix.scale(scaleX, scaleY);
-
-    return _transformMatrix;
-  }
-
-  void _invalidateTransformMatrix() {
-    _transformMatrix = null;
-    _rootNode._invalidateToBoxTransformMatrix();
-  }
-
-  void paint(RenderCanvas canvas) {
-    canvas.save();
-
-    // Move to correct coordinate space before drawing
-    canvas.concat(transformMatrix.storage);
-
-    // Draw the sprite tree
-    _rootNode._visit(canvas);
-
-    canvas.restore();
-  }
-
-  // Updates
-
-  int _animationId = 0;
-
-  void _scheduleTick() {
-    _animationId = scheduler.requestAnimationFrame(_tick);
-  }
-
-  void _tick(double timeStamp) {
-
-      // Calculate the time between frames in seconds
-    if (_lastTimeStamp == null) _lastTimeStamp = timeStamp;
-    double delta = (timeStamp - _lastTimeStamp) / 1000;
-    _lastTimeStamp = timeStamp;
-
-    // Count the number of frames we've been running
-    _numFrames += 1;
-
-    _frameRate = 1.0/delta;
-
-    // Print frame rate
-    if (_numFrames % 60 == 0) print("delta: $delta fps: $_frameRate");
-
-    _callUpdate(_rootNode, delta);
-    _scheduleTick();
-  }
-
-  void _callUpdate(Node node, double dt) {
-    node.update(dt);
-    for (Node child in node.children) {
-      if (!child.paused) {
-        _callUpdate(child, dt);
-      }
-    }
-  }
-
-  void _callSpriteBoxPerformedLayout(Node node) {
-    node.spriteBoxPerformedLayout();
-    for (Node child in node.children) {
-      _callSpriteBoxPerformedLayout(child);
-    }
-  }
-
-  // Hit tests
-
-  /// Finds all nodes at a position defined in the box's coordinates.
-  ///
-  /// Use this method with caution. It searches the complete node tree to locate the nodes, which can be slow if the
-  /// node tree is large.
-  ///
-  ///     List nodes = mySpriteBox.findNodesAtPosition(new Point(50.0, 50.0));
-  List<Node> findNodesAtPosition(Point position) {
-    assert(position != null);
-
-    List<Node> nodes = [];
-
-    // Traverse the render tree and find objects at the position
-    _addNodesAtPosition(_rootNode, position, nodes);
-
-    return nodes;
-  }
-
-  _addNodesAtPosition(Node node, Point position, List<Node> list) {
-    // Visit children first
-    for (Node child in node.children) {
-      _addNodesAtPosition(child, position, list);
-    }
-    // Do the hit test
-    Point posInNodeSpace = node.convertPointToNodeSpace(position);
-    if (node.isPointInside(posInNodeSpace)) {
-      list.add(node);
-    }
-  }
-}
-
-class _SpriteBoxHitTestEntry extends BoxHitTestEntry {
-  List<Node> nodeTargets;
-  _SpriteBoxHitTestEntry(RenderBox target, Point localPosition) : super(target, localPosition);
-}
-
-/// An event that is passed down the node tree when pointer events occur. The SpriteBoxEvent is typically handled in
-/// the handleEvent method of [Node].
-class SpriteBoxEvent {
-
-  /// The position of the event in box coordinates.
-  ///
-  /// You can use the convertPointToNodeSpace of [Node] to convert the position to local coordinates.
-  ///
-  ///     bool handleEvent(SpriteBoxEvent event) {
-  ///       Point localPosition = convertPointToNodeSpace(event.boxPosition);
-  ///       if (event.type == 'pointerdown') {
-  ///         // Do something!
-  ///       }
-  ///     }
-  final Point boxPosition;
-
-  /// The type of event, there are currently four valid types, 'pointerdown', 'pointermoved', 'pointerup', and
-  /// 'pointercancel'.
-  ///
-  ///     if (event.type == 'pointerdown') {
-  ///       // Do something!
-  ///     }
-  final String type;
-
-  /// The id of the pointer. Each pointer on the screen will have a unique pointer id.
-  ///
-  ///     if (event.pointer == firstPointerId) {
-  ///       // Do something
-  ///     }
-  final int pointer;
-
-  /// Creates a new SpriteBoxEvent, typically this is done internally inside the SpriteBox.
-  ///
-  ///     var event = new SpriteBoxEvent(new Point(50.0, 50.0), 'pointerdown', 0);
-  SpriteBoxEvent(this.boxPosition, this.type, this.pointer);
-}