function addWaterMarker(str, parentNode, font, textColor) {
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