写在前面的话：最近要配合项目输出带水印的图片，之前的实现的方式是调uniapp封装好的相机，然后在图片输出的时候用canvas,把水印绘制上去，但是老感觉没有水印相机看着舒服.改成了现在的这种方式。
1.相机实现
水印相机实现有两种方式，在小程序端可以用camera来实现，但在安卓端不支持camera，使用uniapp的live-pusher来实现相机。
而live-pusher推荐使用nvue来做，好处是
- nvue也可一套代码编译多端。
- nvue的cover-view比vue的cover-view更强大，在视频上绘制元素更容易。如果只考虑App端的话，不用cover-view，任意组件都可以覆盖组件，因为nvue没有层级问题。
- 若需要视频内嵌在swiper里上下滑动（类抖音、映客首页模式），App端只有nvue才能实现 当然nvue相比vue的坏处是css写法受限，如果只开发微信小程序，不考虑App，那么使用vue页面也是一样的。
- App平台：使用
<live-pusher/>组件，打包 App 时必须勾选 manifest.json->App 模块权限配置->LivePusher(直播推流) 模块。
上代码！
<template>
<view class="live-camera" :style="{ width: windowWidth, height: windowHeight }">
<view class="preview" :style="{ width: windowWidth, height: windowHeight }">
<live-pusher
id="livePusher"
ref="livePusher"
class="livePusher"
mode="FHD"
beauty="0"
whiteness="0"
:aspect="aspect"
min-bitrate="1000"
audio-quality="16KHz"
device-position="back"
:auto-focus="true"
:muted="true"
:enable-camera="true"
:enable-mic="false"
:zoom="false"
@statechange="statechange"
:style="{ width: windowWidth, height: windowHeight }"
></live-pusher>
<!--这里修改水印的样式-->
<cover-view class="remind">
<text class="remind-text" style="">{{ message }}</text>
<text class="remind-text" style="">经度：1002.32</text>
<text class="remind-text" style="">纬度：1002.32</text>
</cover-view>
</view>
<view class="menu">
<!--底部菜单区域背景-->
<cover-image class="menu-mask" src="/static/live-camera/bar.png"></cover-image>
<!--返回键-->
<cover-image class="menu-back" @tap="back" src="/static/live-camera/back.png"></cover-image>
<!--快门键-->
<cover-image class="menu-snapshot" @tap="snapshot" src="/static/live-camera/shutter.png"></cover-image>
<!--反转键-->
<cover-image class="menu-flip" @tap="flip" src="/static/live-camera/flip.png"></cover-image>
</view>
</view>
</template>
<script>
let _this = null;
export default {
data() {
return {
dotype: 'watermark',
message: '水印相机', //水印内容
poenCarmeInterval: null, //打开相机的轮询
aspect: '2:3', //比例
windowWidth: '', //屏幕可用宽度
windowHeight: '', //屏幕可用高度
camerastate: false, //相机准备好了
livePusher: null, //流视频对象
snapshotsrc: null //快照
};
},
onLoad(e) {
_this = this;
if (e.dotype != undefined) this.dotype = e.dotype;
this.initCamera();
},
onReady() {
this.livePusher = uni.createLivePusherContext('livePusher', this);
this.startPreview(); //开启预览并设置摄像头
this.poenCarme();
},
methods: {
//轮询打开
poenCarme() {
//#ifdef APP-PLUS
if (plus.os.name == 'Android') {
this.poenCarmeInterval = setInterval(function () {
console.log(_this.camerastate);
if (!_this.camerastate) _this.startPreview();
}, 2500);
}
//#endif
},
//初始化相机
initCamera() {
uni.getSystemInfo({
success: function (res) {
_this.windowWidth = res.windowWidth;
_this.windowHeight = res.windowHeight;
let zcs = _this.aliquot(_this.windowWidth, _this.windowHeight);
_this.aspect = _this.windowWidth / zcs + ':' + _this.windowHeight / zcs;
console.log('画面比例：' + _this.aspect);
}
});
},
//整除数计算
aliquot(x, y) {
if (x % y == 0) return y;
return this.aliquot(y, x % y);
},
//开始预览
startPreview() {
this.livePusher.startPreview({
success: (a) => {
console.log(a);
}
});
},
//停止预览
stopPreview() {
this.livePusher.stopPreview({
success: (a) => {
_this.camerastate = false; //标记相机未启动
}
});
},
//状态
statechange(e) {
//状态改变
console.log(e);
if (e.detail.code == 1007) {
_this.camerastate = true;
} else if (e.detail.code == -1301) {
_this.camerastate = false;
}
},
//返回
back() {
uni.navigateBack();
},
//抓拍
snapshot() {
this.livePusher.snapshot({
success: (e) => {
_this.snapshotsrc = e.message.tempImagePath;
_this.stopPreview();
_this.setImage();
uni.navigateBack();
}
});
},
//反转
flip() {
this.livePusher.switchCamera();
},
//设置
setImage() {
let pages = getCurrentPages();
let prevPage = pages[pages.length - 2]; //上一个页面
//直接调用上一个页面的setImage()方法，把数据存到上一个页面中去
prevPage.$vm.setImage({ path: _this.snapshotsrc, dotype: this.dotype });
}
}
};
</script>
<style lang="scss">
.live-camera {
justify-content: center;
align-items: center;
.preview {
justify-content: center;
align-items: center;
.remind {
position: absolute;
bottom: 180rpx;
left: 20rpx;
width: 130px;
z-index: 100;
.remind-text {
color: #dddddd;
font-size: 40rpx;
text-shadow: #fff 1px 0 0, #fff 0 1px 0, #fff -1px 0 0, #fff 0 -1px 0;
}
}
}
.menu {
position: absolute;
left: 0;
bottom: 0;
width: 750rpx;
height: 180rpx;
z-index: 98;
align-items: center;
justify-content: center;
.menu-mask {
position: absolute;
left: 0;
bottom: 0;
width: 750rpx;
height: 180rpx;
z-index: 98;
}
.menu-back {
position: absolute;
left: 30rpx;
bottom: 50rpx;
width: 80rpx;
height: 80rpx;
z-index: 99;
align-items: center;
justify-content: center;
}
.menu-snapshot {
width: 130rpx;
height: 130rpx;
z-index: 99;
}
.menu-flip {
position: absolute;
right: 30rpx;
bottom: 50rpx;
width: 80rpx;
height: 80rpx;
z-index: 99;
align-items: center;
justify-content: center;
}
}
}
</style>
2.水印图片绘制
图片水印返回上一页用<canvas>添加水印
<template>
<view class="page">
<view style="height: 80rpx;"></view>
<navigator class="buttons" url="../camera/watermark/watermark"><button type="primary">打开定制水印相机</button></navigator>
<view style="height: 80rpx;"></view>
<view>拍摄结果预览图，见下方</view>
<image class="preview" :src="imagesrc" mode="aspectFit" style="width:710rpx:height:710rpx;margin: 20rpx;"></image>
<canvas id="canvas-clipper" canvas-id="canvas-clipper" type="2d" :style="{width: canvasSiz.width+'px',height: canvasSiz.height+'px',position: 'absolute',left:'-500000px',top: '-500000px'}" />
</view>
</template>
<script>
var _this;
export default {
data() {
return {
windowWidth:'',
windowHeight:'',
imagesrc: null,
canvasSiz:{
width:188,
height:273
}
};
},
onLoad() {
_this= this;
this.init();
},
methods: {
//设置图片
setImage(e) {
console.log(e);
//显示在页面
//this.imagesrc = e.path;
if(e.dotype =='idphoto'){
_this.zjzClipper(e.path);
}else if(e.dotype =='watermark'){
_this.watermark(e.path);
}else{
_this.savePhoto(e.path);
}
},
//添加照片水印
watermark(path){
uni.getImageInfo({
src: path,
success: function(image) {
console.log(image);
_this.canvasSiz.width =image.width;
_this.canvasSiz.height =image.height;
//担心尺寸重置后还没生效，故做延迟
setTimeout(()=>{
let ctx = uni.createCanvasContext('canvas-clipper', _this);
ctx.drawImage(
path,
0,
0,
image.width,
image.height
);
//具体位置如需和相机页面上一致还需另外做计算，此处仅做大致演示
ctx.setFillStyle('white');
ctx.setFontSize(40);
ctx.fillText('live-camera', 20, 100);
//再来加个时间水印
var now = new Date();
var time= now.getFullYear()+'-'+now.getMonth()+'-'+now.getDate()+' '+now.getHours()+':'+now.getMinutes()+':'+now.getMinutes();
ctx.setFontSize(30);
ctx.fillText(time, 20, 140);
ctx.draw(false, () => {
uni.canvasToTempFilePath(
{
destWidth: image.width,
destHeight: image.height,
canvasId: 'canvas-clipper',
fileType: 'jpg',
success: function(res) {
_this.savePhoto(res.tempFilePath);
}
},
_this
);
});
},500)
}
});
},
//保存图片到相册，方便核查
savePhoto(path){
this.imagesrc = path;
//保存到相册
uni.saveImageToPhotosAlbum({
filePath: path,
success: () => {
uni.showToast({
title: '已保存至相册',
duration: 2000
});
}
});
},
//初始化
init(){
let _this = this;
uni.getSystemInfo({
success: function(res) {
_this.windowWidth = res.windowWidth;
_this.windowHeight = res.windowHeight;
}
});
}
}
};
</script>
<style lang="scss">
.page {
width: 750rpx;
justify-content: center;
align-items: center;
flex-direction:column;
display: flex;
.buttons {
width: 600rpx;
}
}
</style>