Home | History | Annotate | Download | only in base 
      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 'use strict';
      6 
      7 /**
      8  * @fileoverview 2D bounding box computations.
      9  */
     10 base.require('base.gl_matrix');
     11 base.require('base.rect');
     12 
     13 base.exportTo('base', function() {
     14 
     15   /**
     16    * Tracks a 2D bounding box.
     17    * @constructor
     18    */
     19   function BBox2() {
     20     this.isEmpty_ = true;
     21     this.min_ = undefined;
     22     this.max_ = undefined;
     23   };
     24 
     25   BBox2.prototype = {
     26     __proto__: Object.prototype,
     27 
     28     reset: function() {
     29       this.isEmpty_ = true;
     30       this.min_ = undefined;
     31       this.max_ = undefined;
     32     },
     33 
     34     get isEmpty() {
     35       return this.isEmpty_;
     36     },
     37 
     38     addBBox2: function(bbox2) {
     39       if (bbox2.isEmpty)
     40         return;
     41       this.addVec2(bbox2.min_);
     42       this.addVec2(bbox2.max_);
     43     },
     44 
     45     clone: function() {
     46       var bbox = new BBox2();
     47       bbox.addBBox2(this);
     48       return bbox;
     49     },
     50 
     51     /**
     52      * Adds x, y to the range.
     53      */
     54     addXY: function(x, y) {
     55       if (this.isEmpty_) {
     56         this.max_ = vec2.create();
     57         this.min_ = vec2.create();
     58         vec2.set(this.max_, x, y);
     59         vec2.set(this.min_, x, y);
     60         this.isEmpty_ = false;
     61         return;
     62       }
     63       this.max_[0] = Math.max(this.max_[0], x);
     64       this.max_[1] = Math.max(this.max_[1], y);
     65       this.min_[0] = Math.min(this.min_[0], x);
     66       this.min_[1] = Math.min(this.min_[1], y);
     67     },
     68 
     69     /**
     70      * Adds value_x, value_y in the form [value_x,value_y] to the range.
     71      */
     72     addVec2: function(value) {
     73       if (this.isEmpty_) {
     74         this.max_ = vec2.create();
     75         this.min_ = vec2.create();
     76         vec2.set(this.max_, value[0], value[1]);
     77         vec2.set(this.min_, value[0], value[1]);
     78         this.isEmpty_ = false;
     79         return;
     80       }
     81       this.max_[0] = Math.max(this.max_[0], value[0]);
     82       this.max_[1] = Math.max(this.max_[1], value[1]);
     83       this.min_[0] = Math.min(this.min_[0], value[0]);
     84       this.min_[1] = Math.min(this.min_[1], value[1]);
     85     },
     86 
     87     addQuad: function(quad) {
     88       this.addVec2(quad.p1);
     89       this.addVec2(quad.p2);
     90       this.addVec2(quad.p3);
     91       this.addVec2(quad.p4);
     92     },
     93 
     94     get minVec2() {
     95       if (this.isEmpty_)
     96         return undefined;
     97       return this.min_;
     98     },
     99 
    100     get maxVec2() {
    101       if (this.isEmpty_)
    102         return undefined;
    103       return this.max_;
    104     },
    105 
    106     get sizeAsVec2() {
    107       if (this.isEmpty_)
    108         throw new Error('Empty BBox2 has no size');
    109       var size = vec2.create();
    110       vec2.subtract(size, this.max_, this.min_);
    111       return size;
    112     },
    113 
    114     get size() {
    115       if (this.isEmpty_)
    116         throw new Error('Empty BBox2 has no size');
    117       return {width: this.max_[0] - this.min_[0],
    118         height: this.max_[1] - this.min_[1]};
    119     },
    120 
    121     get width() {
    122       if (this.isEmpty_)
    123         throw new Error('Empty BBox2 has no width');
    124       return this.max_[0] - this.min_[0];
    125     },
    126 
    127     get height() {
    128       if (this.isEmpty_)
    129         throw new Error('Empty BBox2 has no width');
    130       return this.max_[1] - this.min_[1];
    131     },
    132 
    133     toString: function() {
    134       if (this.isEmpty_)
    135         return 'empty';
    136       return 'min=(' + this.min_[0] + ',' + this.min_[1] + ') ' +
    137           'max=(' + this.max_[0] + ',' + this.max_[1] + ')';
    138     },
    139 
    140     asRect: function() {
    141       return base.Rect.FromXYWH(
    142           this.min_[0],
    143           this.min_[1],
    144           this.max_[0] - this.min_[0],
    145           this.max_[1] - this.min_[1]);
    146     }
    147   };
    148 
    149   return {
    150     BBox2: BBox2
    151   };
    152 
    153 });
    154