Calculates the bounding box of a KineticJS path

kineticjsbbox.js

/* This file is in the public domain. Peter O., 2012. http://upokecenter.dreamhosters.com 
    Public domain dedication: http://creativecommons.org/publicdomain/zero/1.0/legalcode  */

/* NOTE: Currently supports lines only */

function RectAccum(){
 this.left=0;
 this.top=0;
 this.right=0;
 this.bottom=0;
 this.startX=true;
 this.startY=true;
}
RectAccum.prototype={
width:function(){
return this.right-this.left
},
height:function(){
return this.bottom-this.top
},
addX:function(x){
this.left=(this.startX) ? x : Math.min(x,this.left);
this.right=(this.startX) ? x : Math.max(x,this.right);
this.startX=false;
},
addY:function(y){
this.top=(this.startY) ? y : Math.min(y,this.top);
this.bottom=(this.startY) ? y : Math.max(y,this.bottom);
this.startY=false;
},
addXY:function(x,y){
 this.addX(x); this.addY(y);
}
}


function getPathDimensions(path){
  var data=path.dataArray;
  var ra=new RectAccum();
  for(var i=0;i<data.length;i++){
   switch(data[i].command){
    case "L":
     ra.addXY(data[i].start.x,data[i].start.y);
     ra.addXY(data[i].points[0],data[i].points[1]);
     break;
   }
  }
  return {left:ra.left,top:ra.top,width:ra.width(),height:ra.height()}
}