tools/dom/templates/html/impl/impl_DOMRect.darttemplate

// 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 $LIBRARYNAME;

$(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS implements Rectangle$IMPLEMENTS {

  // NOTE! All code below should be common with RectangleBase.
   String toString() {
    return 'Rectangle ($left, $top) $width x $height';
  }

  bool operator ==(other) =>
      other is Rectangle &&
      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].
   *
   * The intersection of two axis-aligned rectangles, if any, is always another
   * axis-aligned rectangle.
   *
   * Returns the intersection of this and `other`, or null if they don't
   * intersect.
   */
  Rectangle$NULLABLE intersection(Rectangle 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(x0, y0, x1 - x0, y1 - y0);
      }
    }
    return null;
  }


  /**
   * Returns true if `this` intersects [other].
   */
  bool intersects(Rectangle<num> 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 boundingBox(Rectangle 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(left, top, right - left, bottom - top);
  }

  /**
   * Tests whether `this` entirely contains [another].
   */
  bool containsRectangle(Rectangle<num> another) {
    return left <= another.left &&
           left + width >= another.left + another.width &&
           top <= another.top &&
           top + height >= another.top + another.height;
  }

  /**
   * Tests whether [another] is inside or along the edges of `this`.
   */
  bool containsPoint(Point<num> another) {
    return another.x >= left &&
           another.x <= left + width &&
           another.y >= top &&
           another.y <= top + height;
  }

  Point get topLeft => new Point(this.left, this.top);
  Point get topRight => new Point(this.left + this.width, this.top);
  Point get bottomRight => new Point(this.left + this.width,
      this.top + this.height);
  Point get bottomLeft => new Point(this.left,
      this.top + this.height);

  $!MEMBERS}

/**
 * This is the [Jenkins hash function][1] but using masking to keep
 * values in SMI range.
 *
 * [1]: http://en.wikipedia.org/wiki/Jenkins_hash_function
 *
 * Use:
 * Hash each value with the hash of the previous value, then get the final
 * hash by calling finish.
 *
 *     var hash = 0;
 *     for (var value in values) {
 *       hash = JenkinsSmiHash.combine(hash, value.hashCode);
 *     }
 *     hash = JenkinsSmiHash.finish(hash);
 */
class _JenkinsSmiHash {
  // TODO(11617): This class should be optimized and standardized elsewhere.

  static int combine(int hash, int value) {
    hash = 0x1fffffff & (hash + value);
    hash = 0x1fffffff & (hash + ((0x0007ffff & hash) << 10));
    return hash ^ (hash >> 6);
  }

  static int finish(int hash) {
    hash = 0x1fffffff & (hash + ((0x03ffffff & hash) <<  3));
    hash = hash ^ (hash >> 11);
    return 0x1fffffff & (hash + ((0x00003fff & hash) << 15));
  }

  static int hash2(a, b) => finish(combine(combine(0, a), b));

  static int hash4(a, b, c, d) =>
      finish(combine(combine(combine(combine(0, a), b), c), d));
}