function prepare(source) {
    const item = rederive(source, {});
    if (item.stroke && item.strokeOpacity !== 0 || item.fill && item.fillOpacity !== 0) {
      return {
        ...item,
        strokeOpacity: 1,
        stroke: '#000',
        fillOpacity: 0
      };
    }
    return item;
  }
Prepare item before drawing into canvas (setting stroke and opacity)
@param {object} source item to be prepared
@returns prepared item