// 页面添加水印效果
const setWatermark = (str: string) => {
  const id = '1.23452384164.123412416';
  if (document.getElementById(id) !== null) document.body.removeChild(<HTMLElement>document.getElementById(id))
  const can = document.createElement('canvas')
  can.width = 200
  can.height = 130
  const cans = <CanvasRenderingContext2D>can.getContext('2d');
  cans.rotate((-20 * Math.PI) / 180)
  cans.font = '12px Vedana'
  cans.fillStyle = 'rgba(200,200,200,0.30)'
  cans.textBaseline = 'middle'
  cans.fillText(str, can.width / 10, can.height / 2)
  const div = document.createElement('div')
  div.id = id
  div.style.pointerEvents = 'none'
  div.style.top = '0px'
  div.style.left = '0px'
  div.style.position = 'fixed'
  div.style.zIndex = '10000000'
  div.style.width = `${document.documentElement.clientWidth}px`
  div.style.height = `${document.documentElement.clientHeight}px`
  div.style.background = `url(${can.toDataURL('image/png')}) left top repeat`
  document.body.appendChild(div)
  return id;
}

/**
 * 页面添加水印效果
 * @method set 设置水印
 * @method del 删除水印
 */
const watermark = {
  // 设置水印
  set: (str: string) => {
    let id = setWatermark(str)
    if (document.getElementById(id) === null) id = setWatermark(str)
  },
  // 删除水印
  del: () => {
    let id = '1.23452384164.123412416';
    if (document.getElementById(id) !== null) document.body.removeChild(<HTMLElement>document.getElementById(id))
  }
}

export default watermark;