whole_func_string: function (val) {
  			var self = this;
  			console.log("zooming to " + val + "...");
  			self.pix_per_sec = val;
  			self.render();
  		}
func_code_string: function (val) {
  			var self = this;
  			console.log("zooming to " + val + "...");
  			self.pix_per_sec = val;
  			self.render();
  		}
func_documentation_string: change the zoom level and re-render