docs: function(context){
  		var chart = this;
  		this.canvas = context.canvas;
  
  		this.ctx = context;
  
  		//Variables global to the chart
  		var computeDimension = function(element,dimension)
  		{
  			if (element['offset'+dimension])
  			{
  				return element['offset'+dimension];
  			}
  			else
  			{
  				return document.defaultView.getComputedStyle(element).getPropertyValue(dimension);
  			}
  		};
  
  		var width = this.width = computeDimension(context.canvas,'Width') || context.canvas.width;
  		var height = this.height = computeDimension(context.canvas,'Height') || context.canvas.height;
  
  		this.aspectRatio = this.width / this.height;
  		//High pixel density displays - multiply the size of the canvas height/width by the device pixel ratio, then scale.
  		helpers.retinaScale(this);
  
  		return this;
  	}