// Copyright 2007 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 sizes.
 * @author brenneman@google.com (Shawn Brenneman)
 */


goog.provide('goog.math.Size');



/**
 * Class for representing sizes consisting of a width and height. Undefined
 * width and height support is deprecated and results in compiler warning.
 * @param {number} width Width.
 * @param {number} height Height.
 * @struct
 * @constructor
 */
goog.math.Size = function(width, height) {
  /**
   * Width
   * @type {number}
   */
  this.width = width;

  /**
   * Height
   * @type {number}
   */
  this.height = height;
};


/**
 * Compares sizes for equality.
 * @param {goog.math.Size} a A Size.
 * @param {goog.math.Size} b A Size.
 * @return {boolean} True iff the sizes have equal widths and equal
 *     heights, or if both are null.
 */
goog.math.Size.equals = function(a, b) {
  if (a == b) {
    return true;
  }
  if (!a || !b) {
    return false;
  }
  return a.width == b.width && a.height == b.height;
};


/**
 * @return {!goog.math.Size} A new copy of the Size.
 */
goog.math.Size.prototype.clone = function() {
  return new goog.math.Size(this.width, this.height);
};


if (goog.DEBUG) {
  /**
   * Returns a nice string representing size.
   * @return {string} In the form (50 x 73).
   * @override
   */
  goog.math.Size.prototype.toString = function() {
    return '(' + this.width + ' x ' + this.height + ')';
  };
}


/**
 * @return {number} The longer of the two dimensions in the size.
 */
goog.math.Size.prototype.getLongest = function() {
  return Math.max(this.width, this.height);
};


/**
 * @return {number} The shorter of the two dimensions in the size.
 */
goog.math.Size.prototype.getShortest = function() {
  return Math.min(this.width, this.height);
};


/**
 * @return {number} The area of the size (width * height).
 */
goog.math.Size.prototype.area = function() {
  return this.width * this.height;
};


/**
 * @return {number} The perimeter of the size (width + height) * 2.
 */
goog.math.Size.prototype.perimeter = function() {
  return (this.width + this.height) * 2;
};


/**
 * @return {number} The ratio of the size's width to its height.
 */
goog.math.Size.prototype.aspectRatio = function() {
  return this.width / this.height;
};


/**
 * @return {boolean} True if the size has zero area, false if both dimensions
 *     are non-zero numbers.
 */
goog.math.Size.prototype.isEmpty = function() {
  return !this.area();
};


/**
 * Clamps the width and height parameters upward to integer values.
 * @return {!goog.math.Size} This size with ceil'd components.
 */
goog.math.Size.prototype.ceil = function() {
  this.width = Math.ceil(this.width);
  this.height = Math.ceil(this.height);
  return this;
};


/**
 * @param {!goog.math.Size} target The target size.
 * @return {boolean} True if this Size is the same size or smaller than the
 *     target size in both dimensions.
 */
goog.math.Size.prototype.fitsInside = function(target) {
  return this.width <= target.width && this.height <= target.height;
};


/**
 * Clamps the width and height parameters downward to integer values.
 * @return {!goog.math.Size} This size with floored components.
 */
goog.math.Size.prototype.floor = function() {
  this.width = Math.floor(this.width);
  this.height = Math.floor(this.height);
  return this;
};


/**
 * Rounds the width and height parameters to integer values.
 * @return {!goog.math.Size} This size with rounded components.
 */
goog.math.Size.prototype.round = function() {
  this.width = Math.round(this.width);
  this.height = Math.round(this.height);
  return this;
};


/**
 * Scales this size by the given scale factors. The width and height are scaled
 * by {@code sx} and {@code opt_sy} respectively.  If {@code opt_sy} is not
 * given, then {@code sx} is used for both the width and height.
 * @param {number} sx The scale factor to use for the width.
 * @param {number=} opt_sy The scale factor to use for the height.
 * @return {!goog.math.Size} This Size object after scaling.
 */
goog.math.Size.prototype.scale = function(sx, opt_sy) {
  var sy = goog.isNumber(opt_sy) ? opt_sy : sx;
  this.width *= sx;
  this.height *= sy;
  return this;
};


/**
 * Uniformly scales the size to perfectly cover the dimensions of a given size.
 * If the size is already larger than the target, it will be scaled down to the
 * minimum size at which it still covers the entire target. The original aspect
 * ratio will be preserved.
 *
 * This function assumes that both Sizes contain strictly positive dimensions.
 * @param {!goog.math.Size} target The target size.
 * @return {!goog.math.Size} This Size object, after optional scaling.
 */
goog.math.Size.prototype.scaleToCover = function(target) {
  var s = this.aspectRatio() <= target.aspectRatio() ?
      target.width / this.width :
      target.height / this.height;

  return this.scale(s);
};


/**
 * Uniformly scales the size to fit inside the dimensions of a given size. The
 * original aspect ratio will be preserved.
 *
 * This function assumes that both Sizes contain strictly positive dimensions.
 * @param {!goog.math.Size} target The target size.
 * @return {!goog.math.Size} This Size object, after optional scaling.
 */
goog.math.Size.prototype.scaleToFit = function(target) {
  var s = this.aspectRatio() > target.aspectRatio() ?
      target.width / this.width :
      target.height / this.height;

  return this.scale(s);
};