| // 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. |
| * |
| * This rectangle uses a left-handed Cartesian coordinate system, with x |
| * directed to the right and y directed down, as per the convention in 2D |
| * computer graphics. |
| * |
| * See also: |
| * [W3C Coordinate Systems Specification](http://www.w3.org/TR/SVG/coords.html#InitialCoordinateSystem). |
| */ |
| 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 x-coordinate of the right edge. */ |
| T get right => left + width; |
| /** The y-coordinate of the bottom edge. */ |
| 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]. |
| * |
| * 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<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<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<T> boundingBox(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 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<T> get topLeft => new Point<T>(this.left, this.top); |
| Point<T> get topRight => new Point<T>(this.left + this.width, this.top); |
| Point<T> get bottomRight => new Point<T>(this.left + this.width, |
| this.top + this.height); |
| Point<T> get bottomLeft => new Point<T>(this.left, |
| this.top + this.height); |
| } |
| |
| |
| /** |
| * A class for representing two-dimensional rectangles whose properties are |
| * immutable. |
| */ |
| class Rectangle<T extends num> 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) { |
| T left = min(a.x, b.x); |
| T width = max(a.x, b.x) - left; |
| T top = min(a.y, b.y); |
| T height = max(a.y, b.y) - top; |
| return new Rectangle<T>(left, top, width, height); |
| } |
| } |
| |
| /** |
| * A class for representing two-dimensional axis-aligned rectangles with mutable |
| * properties. |
| */ |
| class MutableRectangle<T extends num> extends _RectangleBase<T> |
| implements Rectangle<T> { |
| T left; |
| T top; |
| T width; |
| T height; |
| |
| MutableRectangle(this.left, this.top, this.width, this.height); |
| |
| factory MutableRectangle.fromPoints(Point<T> a, Point<T> b) { |
| T left = min(a.x, b.x); |
| T width = max(a.x, b.x) - left; |
| T top = min(a.y, b.y); |
| T height = max(a.y, b.y) - top; |
| return new MutableRectangle<T>(left, top, width, height); |
| } |
| } |