samples/pop_pop_win: now based on StageXL

samples/pop_pop_win/lib/src/canvas/square_element.dart

-part of pop_pop_win.canvas;
-
-class SquareElement extends Thing {
-  static const int _size = 80;
-
-  static const List<String> _balloonBits = const['balloon_pieces_a.png',
-                                                 'balloon_pieces_b.png',
-                                                 'balloon_pieces_c.png',
-                                                 'balloon_pieces_d.png'];
-
-  static const List<String> _numberMap = const["game_board_center",
-                                               "number_one", "number_two",
-                                               "number_three", "number_four",
-                                               "number_five", "number_six",
-                                               "number_seven", "number_eight"];
-
-  final int x, y;
-
-  SquareState _lastDrawingState;
-
-  SquareElement(this.x, this.y): super(_size, _size) {
-    MouseManager.setClickable(this, true);
-  }
-
-  void update() {
-    if (_lastDrawingState != _squareState) {
-      _lastDrawingState = _squareState;
-      invalidateDraw();
-    }
-  }
-
-  void drawOverride(CanvasRenderingContext2D ctx) {
-    var textureName;
-    switch (_lastDrawingState) {
-      case SquareState.hidden:
-        textureName = _getHiddenTexture();
-        break;
-      case SquareState.flagged:
-        textureName = 'balloon_tagged_frozen.png';
-        break;
-      case SquareState.revealed:
-        final prefix = _numberMap[_adjacentCount];
-        textureName = '$prefix.png';
-        break;
-      case SquareState.bomb:
-        textureName = 'crater_b.png';
-        break;
-      case SquareState.safe:
-        textureName = 'balloon_tagged_bomb.png';
-        break;
-    }
-
-    _textureData.drawTextureKeyAt(ctx, textureName);
-  }
-
-  String toString() => 'Square at [$x, $y]';
-
-  String _getHiddenTexture() {
-    assert(_lastDrawingState == SquareState.hidden);
-    if (_game.state == GameState.lost) {
-      final index = (x + y) % _balloonBits.length;
-      return _balloonBits[index];
-    } else {
-      return 'balloon.png';
-    }
-  }
-
-  SquareState get _squareState => _game.getSquareState(x, y);
-
-  int get _adjacentCount => _game.field.getAdjacentCount(x, y);
-
-  BoardElement get _board {
-    final BoardElement p = this.parent;
-    return p;
-  }
-
-  TextureData get _textureData => _board._textureData;
-
-  Game get _game => _board._game;
-}