docs: function (prop, value) {
        this.lowerCanvasEl[prop] = value;
        this.lowerCanvasEl.style[prop] = value + 'px';
  
        if (this.upperCanvasEl) {
          this.upperCanvasEl[prop] = value;
          this.upperCanvasEl.style[prop] = value + 'px';
        }
  
        if (this.wrapperEl) {
          this.wrapperEl.style[prop] = value + 'px';
        }
  
        this[prop] = value;
  
        this.calcOffset();
        this.renderAll();
  
        return this;
      }