code: function() {
  			var self = this;
  			//self.pointLocationArr = [];
  			if (self.cxt) {
  				self.cxt.clearRect(0, 0, self.CW, self.CH);
  				self.draw(self.cxt, self.pointLocationArr, [], {
  					X: 0,
  					Y: 0
  				});
  			}
  		}
docs: 清除图形