Clear the crop box
function clear() {
    if (this.cropped && !this.disabled) {
      assign(this.cropBoxData, {
        left: 0,
        top: 0,
        width: 0,
        height: 0
      });
      this.cropped = false;
      this.renderCropBox();
      this.limitCanvas(true, true); // Render canvas after crop box rendered

      this.renderCanvas();
      removeClass(this.dragBox, CLASS_MODAL);
      addClass(this.cropBox, CLASS_HIDDEN);
    }

    return this;
  }