| // Copyright 2006 The Closure Library Authors. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS-IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| /** |
| * @fileoverview A utility class for representing two-dimensional positions. |
| */ |
| |
| |
| goog.provide('goog.math.Coordinate'); |
| |
| goog.require('goog.math'); |
| |
| |
| |
| /** |
| * Class for representing coordinates and positions. |
| * @param {number=} opt_x Left, defaults to 0. |
| * @param {number=} opt_y Top, defaults to 0. |
| * @struct |
| * @constructor |
| */ |
| goog.math.Coordinate = function(opt_x, opt_y) { |
| /** |
| * X-value |
| * @type {number} |
| */ |
| this.x = goog.isDef(opt_x) ? opt_x : 0; |
| |
| /** |
| * Y-value |
| * @type {number} |
| */ |
| this.y = goog.isDef(opt_y) ? opt_y : 0; |
| }; |
| |
| |
| /** |
| * Returns a new copy of the coordinate. |
| * @return {!goog.math.Coordinate} A clone of this coordinate. |
| */ |
| goog.math.Coordinate.prototype.clone = function() { |
| return new goog.math.Coordinate(this.x, this.y); |
| }; |
| |
| |
| if (goog.DEBUG) { |
| /** |
| * Returns a nice string representing the coordinate. |
| * @return {string} In the form (50, 73). |
| * @override |
| */ |
| goog.math.Coordinate.prototype.toString = function() { |
| return '(' + this.x + ', ' + this.y + ')'; |
| }; |
| } |
| |
| |
| /** |
| * Returns whether the specified value is equal to this coordinate. |
| * @param {*} other Some other value. |
| * @return {boolean} Whether the specified value is equal to this coordinate. |
| */ |
| goog.math.Coordinate.prototype.equals = function(other) { |
| return other instanceof goog.math.Coordinate && |
| goog.math.Coordinate.equals(this, other); |
| }; |
| |
| |
| /** |
| * Compares coordinates for equality. |
| * @param {goog.math.Coordinate} a A Coordinate. |
| * @param {goog.math.Coordinate} b A Coordinate. |
| * @return {boolean} True iff the coordinates are equal, or if both are null. |
| */ |
| goog.math.Coordinate.equals = function(a, b) { |
| if (a == b) { |
| return true; |
| } |
| if (!a || !b) { |
| return false; |
| } |
| return a.x == b.x && a.y == b.y; |
| }; |
| |
| |
| /** |
| * Returns the distance between two coordinates. |
| * @param {!goog.math.Coordinate} a A Coordinate. |
| * @param {!goog.math.Coordinate} b A Coordinate. |
| * @return {number} The distance between {@code a} and {@code b}. |
| */ |
| goog.math.Coordinate.distance = function(a, b) { |
| var dx = a.x - b.x; |
| var dy = a.y - b.y; |
| return Math.sqrt(dx * dx + dy * dy); |
| }; |
| |
| |
| /** |
| * Returns the magnitude of a coordinate. |
| * @param {!goog.math.Coordinate} a A Coordinate. |
| * @return {number} The distance between the origin and {@code a}. |
| */ |
| goog.math.Coordinate.magnitude = function(a) { |
| return Math.sqrt(a.x * a.x + a.y * a.y); |
| }; |
| |
| |
| /** |
| * Returns the angle from the origin to a coordinate. |
| * @param {!goog.math.Coordinate} a A Coordinate. |
| * @return {number} The angle, in degrees, clockwise from the positive X |
| * axis to {@code a}. |
| */ |
| goog.math.Coordinate.azimuth = function(a) { |
| return goog.math.angle(0, 0, a.x, a.y); |
| }; |
| |
| |
| /** |
| * Returns the squared distance between two coordinates. Squared distances can |
| * be used for comparisons when the actual value is not required. |
| * |
| * Performance note: eliminating the square root is an optimization often used |
| * in lower-level languages, but the speed difference is not nearly as |
| * pronounced in JavaScript (only a few percent.) |
| * |
| * @param {!goog.math.Coordinate} a A Coordinate. |
| * @param {!goog.math.Coordinate} b A Coordinate. |
| * @return {number} The squared distance between {@code a} and {@code b}. |
| */ |
| goog.math.Coordinate.squaredDistance = function(a, b) { |
| var dx = a.x - b.x; |
| var dy = a.y - b.y; |
| return dx * dx + dy * dy; |
| }; |
| |
| |
| /** |
| * Returns the difference between two coordinates as a new |
| * goog.math.Coordinate. |
| * @param {!goog.math.Coordinate} a A Coordinate. |
| * @param {!goog.math.Coordinate} b A Coordinate. |
| * @return {!goog.math.Coordinate} A Coordinate representing the difference |
| * between {@code a} and {@code b}. |
| */ |
| goog.math.Coordinate.difference = function(a, b) { |
| return new goog.math.Coordinate(a.x - b.x, a.y - b.y); |
| }; |
| |
| |
| /** |
| * Returns the sum of two coordinates as a new goog.math.Coordinate. |
| * @param {!goog.math.Coordinate} a A Coordinate. |
| * @param {!goog.math.Coordinate} b A Coordinate. |
| * @return {!goog.math.Coordinate} A Coordinate representing the sum of the two |
| * coordinates. |
| */ |
| goog.math.Coordinate.sum = function(a, b) { |
| return new goog.math.Coordinate(a.x + b.x, a.y + b.y); |
| }; |
| |
| |
| /** |
| * Rounds the x and y fields to the next larger integer values. |
| * @return {!goog.math.Coordinate} This coordinate with ceil'd fields. |
| */ |
| goog.math.Coordinate.prototype.ceil = function() { |
| this.x = Math.ceil(this.x); |
| this.y = Math.ceil(this.y); |
| return this; |
| }; |
| |
| |
| /** |
| * Rounds the x and y fields to the next smaller integer values. |
| * @return {!goog.math.Coordinate} This coordinate with floored fields. |
| */ |
| goog.math.Coordinate.prototype.floor = function() { |
| this.x = Math.floor(this.x); |
| this.y = Math.floor(this.y); |
| return this; |
| }; |
| |
| |
| /** |
| * Rounds the x and y fields to the nearest integer values. |
| * @return {!goog.math.Coordinate} This coordinate with rounded fields. |
| */ |
| goog.math.Coordinate.prototype.round = function() { |
| this.x = Math.round(this.x); |
| this.y = Math.round(this.y); |
| return this; |
| }; |
| |
| |
| /** |
| * Translates this box by the given offsets. If a {@code goog.math.Coordinate} |
| * is given, then the x and y values are translated by the coordinate's x and y. |
| * Otherwise, x and y are translated by {@code tx} and {@code opt_ty} |
| * respectively. |
| * @param {number|goog.math.Coordinate} tx The value to translate x by or the |
| * the coordinate to translate this coordinate by. |
| * @param {number=} opt_ty The value to translate y by. |
| * @return {!goog.math.Coordinate} This coordinate after translating. |
| */ |
| goog.math.Coordinate.prototype.translate = function(tx, opt_ty) { |
| if (tx instanceof goog.math.Coordinate) { |
| this.x += tx.x; |
| this.y += tx.y; |
| } else { |
| this.x += Number(tx); |
| if (goog.isNumber(opt_ty)) { |
| this.y += opt_ty; |
| } |
| } |
| return this; |
| }; |
| |
| |
| /** |
| * Scales this coordinate by the given scale factors. The x and y values are |
| * scaled by {@code sx} and {@code opt_sy} respectively. If {@code opt_sy} |
| * is not given, then {@code sx} is used for both x and y. |
| * @param {number} sx The scale factor to use for the x dimension. |
| * @param {number=} opt_sy The scale factor to use for the y dimension. |
| * @return {!goog.math.Coordinate} This coordinate after scaling. |
| */ |
| goog.math.Coordinate.prototype.scale = function(sx, opt_sy) { |
| var sy = goog.isNumber(opt_sy) ? opt_sy : sx; |
| this.x *= sx; |
| this.y *= sy; |
| return this; |
| }; |
| |
| |
| /** |
| * Rotates this coordinate clockwise about the origin (or, optionally, the given |
| * center) by the given angle, in radians. |
| * @param {number} radians The angle by which to rotate this coordinate |
| * clockwise about the given center, in radians. |
| * @param {!goog.math.Coordinate=} opt_center The center of rotation. Defaults |
| * to (0, 0) if not given. |
| */ |
| goog.math.Coordinate.prototype.rotateRadians = function(radians, opt_center) { |
| var center = opt_center || new goog.math.Coordinate(0, 0); |
| |
| var x = this.x; |
| var y = this.y; |
| var cos = Math.cos(radians); |
| var sin = Math.sin(radians); |
| |
| this.x = (x - center.x) * cos - (y - center.y) * sin + center.x; |
| this.y = (x - center.x) * sin + (y - center.y) * cos + center.y; |
| }; |
| |
| |
| /** |
| * Rotates this coordinate clockwise about the origin (or, optionally, the given |
| * center) by the given angle, in degrees. |
| * @param {number} degrees The angle by which to rotate this coordinate |
| * clockwise about the given center, in degrees. |
| * @param {!goog.math.Coordinate=} opt_center The center of rotation. Defaults |
| * to (0, 0) if not given. |
| */ |
| goog.math.Coordinate.prototype.rotateDegrees = function(degrees, opt_center) { |
| this.rotateRadians(goog.math.toRadians(degrees), opt_center); |
| }; |