<template>
  <div class="water-marker" >
      <div v-waterMarker="{text:'卡洛背心 - 版權(quán)所有',textColor:'rgba(180, 180, 180, 0.4)'}">
        <div class="water-marker-item">測試問題啊測試問題啊測試問題啊測試問題啊測試問題啊測試問題啊</div>
      </div>
  </div>
</template>

<script>
import waterMarker from '../../directive/test/waterMarker'
export default {
  directives: {
    waterMarker
  },
  data(){
    return{
    }
  },
  methods:{
  }
}
</script>

<style lang="scss">
.water-marker{
  height: 300px;
  .water-marker-item{
    line-height: 300px;
  }
}
</style>

function addWaterMarker(str, parentNode, font, textColor) {
  // 水印文字，父元素，字體，文字顏色
  var can = document.createElement('canvas')
  parentNode.appendChild(can)
  can.width = 200
  can.height = 150
  can.style.display = 'none'
  var cans = can.getContext('2d')
  cans.rotate((-20 * Math.PI) / 180)
  cans.font = font || '16px Microsoft JhengHei'
  cans.fillStyle = textColor || 'rgba(180, 180, 180, 0.3)'
  cans.textAlign = 'left'
  cans.textBaseline = 'Middle'
  cans.fillText(str, can.width / 10, can.height / 2)
  parentNode.style.backgroundImage = 'url(' + can.toDataURL('image/png') + ')'
}

const waterMarker = {
  bind: function (el, binding) {
    addWaterMarker(binding.value.text, el, binding.value.font, binding.value.textColor)
  },
}

export default waterMarker