Move Point and Rect over to dart:math, to be re-exported by dart:html.

sdk/lib/math/rectangle.dart

+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+part of dart.math;
+
+/**
+ * A base class for representing two-dimensional axis-aligned rectangles.
+ */
+abstract class RectangleBase<T extends num> {
+  const RectangleBase();
+
+  /**
+   * The x-coordinate of the left edge.
+   */
+  T get left;
+  /**
+   * The y-coordinate of the top edge.
+   */
+  T get top;
+  /** The `width` of the rectangle. */
+  T get width;
+  /** The `height` of the rectangle. */
+  T get height;
+
+  /**
+   * The number of units `right` of the origin where this rectangle's bottom
+   * right corner can be found.
+   */
+  T get right => left + width;
+  /**
+   * The number of units below the origin where this rectangle's bottom
+   * right corner can be found.
+   */
+  T get bottom => top + height;
+
+  String toString() {
+    return 'Rectangle ($left, $top) $width x $height';
+  }
+
+  bool operator ==(other) {
+    if (other is !Rectangle) return false;
+    return left == other.left && top == other.top && width == other.width &&
+        height == other.height;
+  }
+
+  int get hashCode => _JenkinsSmiHash.hash4(left.hashCode, top.hashCode,
+      width.hashCode, height.hashCode);
+
+  /**
+   * Computes the intersection of `this` and [other].
+   *
+   * Returns null if there is no intersection.
+   */
+  Rectangle<T> intersection(Rectangle<T> other) {
+    var x0 = max(left, other.left);
+    var x1 = min(left + width, other.left + other.width);
+
+    if (x0 <= x1) {
+      var y0 = max(top, other.top);
+      var y1 = min(top + height, other.top + other.height);
+
+      if (y0 <= y1) {
+        return new Rectangle<T>(x0, y0, x1 - x0, y1 - y0);
+      }
+    }
+    return null;
+  }
+
+
+  /**
+   * Returns true if `this` intersects [other].
+   */
+  bool intersects(Rectangle other) {
+    return (left <= other.left + other.width && other.left <= left + width &&
+        top <= other.top + other.height && other.top <= top + height);
+  }
+
+  /**
+   * Returns a new rectangle which completely contains `this` and [other].
+   */
+  Rectangle<T> union(Rectangle<T> other) {
+    var right = max(this.left + this.width, other.left + other.width);
+    var bottom = max(this.top + this.height, other.top + other.height);
+
+    var left = min(this.left, other.left);
+    var top = min(this.top, other.top);
+
+    return new Rectangle<T>(left, top, right - left, bottom - top);
+  }
+
+  /**
+   * Tests whether `this` entirely contains [another].
+   */
+  bool contains(Rectangle another) {
+    return left <= another.left &&
+           left + width >= another.left + another.width &&
+           top <= another.top &&
+           top + height >= another.top + another.height;
+  }
+
+  /**
+   * Tests whether `this` entirely contains a point.
+   */
+  bool containsPoint(Point another) {
+    return another.x >= left &&
+           another.x <= left + width &&
+           another.y >= top &&
+           another.y <= top + height;
+  }
+
+  Rectangle<int> ceil() => new Rectangle<int>(left.ceil(), top.ceil(),
+      width.ceil(), height.ceil());
+  Rectangle<int> floor() => new Rectangle<int>(left.floor(), top.floor(),
+      width.floor(), height.floor());
+  Rectangle<int> round() => new Rectangle<int>(left.round(), top.round(),
+      width.round(), height.round());
+
+  /**
+   * Truncates coordinates to integers and returns the result as a new
+   * rectangle.
+   */
+  Rectangle<int> truncate() => new Rectangle<int>(left.toInt(), top.toInt(),
+      width.toInt(), height.toInt());
+
+  Point<T> get topLeft => new Point<T>(this.left, this.top);
+  Point<T> get bottomRight => new Point<T>(this.left + this.width,
+      this.top + this.height);
+
+  static List<T> _calculateVerticesFromPoints(Point<T> a, Point<T> b) {
+    var left;
+    var width;
+    if (a.x < b.x) {
+      left = a.x;
+      width = b.x - left;
+    } else {
+      left = b.x;
+      width = a.x - left;
+    }
+    var top;
+    var height;
+    if (a.y < b.y) {
+      top = a.y;
+      height = b.y - top;
+    } else {
+      top = b.y;
+      height = a.y - top;
+    }
+    return [left, top, width, height];
+  }
+}
+
+
+/**
+ * A class for representing two-dimensional rectangles whose properties are
+ * immutable.
+ */
+class Rectangle<T> extends RectangleBase<T> {
+  final T left;
+  final T top;
+  final T width;
+  final T height;
+
+  const Rectangle(this.left, this.top, this.width, this.height);
+
+  factory Rectangle.fromPoints(Point<T> a, Point<T> b) {
+    var list = RectangleBase._calculateVerticesFromPoints(a, b);
+    return new Rectangle<T>(list[0], list[1], list[2], list[3]);
+  }
+}