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| <template>
<div id="watermark">
<canvas id="canvas" height='100%' width='100%'>
你的浏览器不支持canvas,请升级你的浏览器
</canvas>
<canvas id="repeat-watermark" height='100%' width='100%'>
你的浏览器不支持canvas,请升级你的浏览器
</canvas>
</div>
</template>
<script>
export default {
data() {
return {
}
},
component: {
},
async mounted() {
await this.loadWatermark();
await this.getWatermark();
},
methods:{
// 先制作小水印
loadWatermark() {
let canvas = document.getElementById('canvas');
if (!canvas.getContext) return;
// 小画布的宽高
canvas.height = 100;
canvas.width = 100;
let ctx = canvas.getContext('2d');
ctx.clearRect(0,0,160,100); //绘制之前画布清除
ctx.font="20px 黑体";
ctx.rotate(-20*Math.PI/180);
ctx.fillStyle = "rgba(100,100,100,0.1)";
ctx.fillText("刘泽浩", -20, 80);
ctx.rotate('20*Math.PI/180'); //坐标系还原
},
getWatermark() {
// 平铺满整个容器
let crw = document.getElementById('repeat-watermark');
let canvas = document.getElementById('canvas');
if (!crw.getContext) return;
// 整个容器的宽高
let height = document.getElementById('watermark').offsetHeight;
let width= document.getElementById('watermark').offsetWidth;
crw.width = width;
crw.height = height;
let ctxr = crw.getContext("2d");
ctxr.clearRect(0,0,crw.width,crw.height); //清除整个画布 \
//主要是这个API
let pat = ctxr.createPattern(canvas, "repeat"); //在指定的方向上重复指定的元素
ctxr.fillStyle = pat;
ctxr.fillRect(0, 0, crw.width, crw.height);
}
},
}
</script>
<style lang="scss" scoped>
#watermark {
position: relative;
width: 100%;
height: 100%;
}
#repeat-watermark{
position:absolute;
top:0;
z-index:10;
background: #fff;
}
</style>
|