因为遇到要求给手机调起的摄像头增加一个人像框,所以研究了一下。
这个项目是uniapp开发的手机端,uniapp中右camera组件可以直接实现调用手机的摄像头,但是它仅适用于小程序。
这个方法是参考了网上的案例,根据自己遇到的一些问题进行改进。
主要思路就是调用手机的摄像头数据,将他放到video标签里播放,通过渲染canvas来实现拍摄图片的功能。
话不多上,上代码
<template>
<view class="" style="width: 100vw; height: 100vh; background: #1c1c1c">
<video
:class="
facingMode == 'user'
? 'userVideo cameraViceo'
: 'environemntVideo cameraViceo'
"
object-fit="fill"
></video>
<view
class=""
style="
width: 100vw;
height: 100vh;
background-color: transparent;
opacity: 1;
position: absolute;
top: 0;
left: 0;
z-index: 1;
"
>
<view
class="flex justify-between"
style="
width: 100vw;
height: 100rpx;
padding: 0 20rpx;
box-sizing: border-box;
position: absolute;
top: 0;
left: 0;
z-index: 6;
"
>
<uni-icons
v-if="!imageUrl"
type="back"
color="#fff"
:size="32"
@click="skipBack"
>
</uni-icons>
<uni-icons
v-if="!imageUrl"
type="refreshempty"
color="#fff"
:size="32"
@click="refreshCamera"
>
</uni-icons>
</view>
<view
class="flex justify-center align-center"
style="
width: 100vw;
height: calc(100vh - 240rpx)
position: absolute;
top: 100rpx;
left: 0;
z-index: 1;
"
>
<image
v-if="imageUrl"
:src="imageUrl"
mode="widthFix"
style="width: 100vw"
></image>
</view>
<view
class="flex justify-center align-center"
style="
width: 100vw;
height: 100vh;
position: absolute;
top: 0;
left: 0;
z-index: 3;
"
>
<image
src="@/assets/wens/write/person.png"
mode="widthFix"
style="width: 100vw; margin-top: -200rpx"
></image>
</view>
<view
class="flex justify-center"
style="
width: 100vw;
height: 240rpx;
position: absolute;
bottom: 0;
left: 0;
z-index: 5;
"
>
<view
class=""
style="
position: absolute;
bottom: 88rpx;
left: 68rpx;
color: #fff;
border-radius: 16rpx;
background: #3c3c3c;
border-radius: 50%;
line-height: 1;
padding: 20rpx;
"
>
<uni-icons
v-if="imageUrl"
type="closeempty"
:size="24"
color="#fff"
@click="handleCancelPhoto"
>
</uni-icons>
<uni-icons
v-else
type="loop"
:size="24"
color="#fff"
@click="overturnCamera"
>
</uni-icons>
</view>
<view
v-if="!imageUrl"
class="outer-ring"
style="position: absolute; bottom: 40rpx"
@click="handlePhotographClick"
>
<view class="middle-ring">
<view class="inner-ring"></view>
</view>
</view>
<view
class=""
style="
position: absolute;
bottom: 88rpx;
right: 68rpx;
color: #fff;
background: #3c3c3c;
border-radius: 50%;
line-height: 1;
padding: 20rpx;
"
>
<uni-icons
v-if="imageUrl"
color="#fff"
type="checkmarkempty"
:size="24"
@click="skipBack"
>
</uni-icons>
<uni-icons
v-else
type="images-filled"
color="#fff"
:size="24"
@click="handleAddPhotographClick"
>
</uni-icons>
</view>
</view>
</view>
</view>
</template>
<script>
import uniIcons from "@/components/uni-ui/uni-icons/uni-icons.vue";
export default {
components: {
uniIcons,
},
data() {
return {
// 背景透明的取景框图片
qjkImgSrc: "/static/images/qjk.png",
// 背景透明的头像框图片
qjtxkImgSrc: "/static/images/qjtxk.png",
imageUrl: "",
// 媒体流,用于关闭摄像头
mediaStreamTrack: null,
facingMode: "user",
chooseImageFlag: false,
chooseImageTimer: null,
};
},
watch: {
imageUrl: {
handler(val) {
if (val) {
this.handlePhotographCloseClick();
}
},
},
},
onLoad() {
this.invokingCamera();
},
onShow() {
setTimeout(() => {
if (this.chooseImageFlag) {
if (this.imageUrl) {
this.handlePhotographCloseClick();
} else {
this.handlePhotographCloseClick();
this.invokingCamera();
}
}
}, 1000);
},
onUnload() {
this.handlePhotographCloseClick();
},
methods: {
invokingCamera() {
const self = this;
// 注意本例需要在HTTPS协议网站中运行,新版本Chrome中getUserMedia接口在http下不再支持。
// 老的浏览器可能根本没有实现 mediaDevices,所以我们可以先设置一个空的对象
if (navigator.mediaDevices === undefined) {
navigator.mediaDevices = {};
}
// 一些浏览器部分支持 mediaDevices。我们不能直接给对象设置 getUserMedia
// 因为这样可能会覆盖已有的属性。这里我们只会在没有getUserMedia属性的时候添加它。
if (navigator.mediaDevices.getUserMedia === undefined) {
navigator.mediaDevices.getUserMedia = function (constraints) {
// 首先,如果有getUserMedia的话,就获得它
const getUserMedia =
navigator.getUserMedia ||
navigator.webkitGetUserMedia ||
navigator.mozGetUserMedia;
// 一些浏览器根本没实现它 - 那么就返回一个error到promise的reject来保持一个统一的接口
if (!getUserMedia) {
return Promise.reject(
new Error("getUserMedia is not implemented in this browser")
);
}
// 否则,为老的navigator.getUserMedia方法包裹一个Promise
return new Promise(function (resolve, reject) {
getUserMedia.call(navigator, constraints, resolve, reject);
});
};
}
uni.getSystemInfo({
success: function (res) {
const constraints = {
audio: false,
video: {
// 前置摄像头 - user,后置摄像头 - environment
facingMode: self.facingMode,
// 手机端相当于高
width: Math.max(res.windowWidth, res.windowHeight) - 120,
// 手机端相当于宽
height: Math.min(res.windowWidth, res.windowHeight),
},
};
navigator.mediaDevices
.getUserMedia(constraints)
.then(function (stream) {
self.mediaStreamTrack = stream;
const video = document.querySelector("video");
// 旧的浏览器可能没有srcObject
if ("srcObject" in video) {
video.srcObject = stream;
} else {
// 防止在新的浏览器里使用它,应为它已经不再支持了
video.src = window.URL.createObjectURL(stream);
}
video.onloadedmetadata = function (e) {
video.play();
if (
video.videoWidth == 0 &&
video.videoHeight == 0 &&
video.paused
) {
video.load();
}
};
})
.catch(function (err) {
console.log(err.name + ": " + err.message);
});
},
});
},
refreshCamera() {
if (!this.mediaStreamTrack) {
this.invokingCamera();
this.imageUrl = "";
} else {
this.handlePhotographCloseClick();
this.invokingCamera();
let video = document.querySelector("video");
video.load();
}
},
overturnCamera() {
if (this.facingMode == "user") {
this.facingMode = "environment";
} else {
this.facingMode = "user";
}
this.handlePhotographCloseClick();
this.handleCancelPhoto();
},
handleCancelPhoto() {
if (!this.mediaStreamTrack) {
this.invokingCamera();
this.imageUrl = "";
}
},
handlePhotographCloseClick() {
if (this.mediaStreamTrack) {
// 关闭摄像头
this.mediaStreamTrack.getTracks().forEach(function (track) {
track.stop();
});
this.mediaStreamTrack = null;
}
},
handlePhotographClick() {
const self = this;
const canvas = document.createElement("canvas");
const ctx = canvas.getContext("2d");
const video = document.querySelector("video");
canvas.width = Math.min(video.videoWidth, video.videoHeight);
canvas.height = Math.max(video.videoWidth, video.videoHeight);
ctx.drawImage(video, 0, 0, canvas.width, canvas.height);
// ****** 镜像处理 ******
function getPixel(imageData, row, column) {
const uint8ClampedArray = imageData.data;
const width = imageData.width;
const height = imageData.height;
const pixel = [];
for (let i = 0; i < 4; i++) {
pixel.push(uint8ClampedArray[row * width * 4 + column * 4 + i]);
}
return pixel;
}
function setPixel(imageData, row, column, pixel) {
const uint8ClampedArray = imageData.data;
const width = imageData.width;
const height = imageData.height;
for (let i = 0; i < 4; i++) {
uint8ClampedArray[row * width * 4 + column * 4 + i] = pixel[i];
}
}
const mirrorImageData = ctx.createImageData(canvas.width, canvas.height);
const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
for (let h = 0; h < canvas.height; h++) {
for (let w = 0; w < canvas.width; w++) {
const pixel = getPixel(imageData, h, canvas.width - w - 1);
setPixel(mirrorImageData, h, w, pixel);
}
}
if (this.facingMode == "user") {
ctx.putImageData(mirrorImageData, 0, 0);
} else {
ctx.putImageData(imageData, 0, 0);
}
// ****** 镜像处理 ******
self.$nextTick(() => {
const base64 = canvas.toDataURL("image/jpeg");
self.imageUrl = base64;
self.handlePhotographCloseClick();
});
},
handleAddPhotographClick() {
this.uploadImage();
},
uploadImage: function () {
const self = this;
this.chooseImageFlag = true;
self.handlePhotographCloseClick();
uni.chooseImage({
count: 1, //默认9
sizeType: ["original", "compressed"], //可以指定是原图还是压缩图,默认二者都有
sourceType: ["album"], //从相册选择
success: function (e) {
if (e.tempFiles[0].size < 15 * 1024 * 1024) {
self.imageUrl = e.tempFilePaths[0];
} else {
uni.showToast({
title: "照片大小需小于15M",
icon: "none",
});
}
},
fail: function (e) {
// self.handlePhotographCloseClick();
},
});
},
skipBack() {
if (this.imageUrl) {
sessionStorage.setItem("cameraImg", this.imageUrl);
}
uni.navigateBack();
},
},
};
</script>
<style lang="scss" scoped>
.userVideo {
transform: rotateY(180deg);
-webkit-transform: rotateY(180deg);
/* Safari 和 Chrome */
-moz-transform: rotateY(180deg);
}
.cameraViceo {
width: 100vw;
height: calc(100vh - 240rpx);
}
/deep/ .uni-video-bar {
display: none;
}
/deep/ .uni-video-cover {
display: none;
}
.outer-ring {
width: 160rpx;
height: 160rpx;
border-radius: 50%;
background-color: #3c3c3c;
display: flex;
justify-content: center;
align-items: center;
}
.middle-ring {
width: 130rpx;
height: 130rpx;
border-radius: 50%;
background-color: #000000;
display: flex;
justify-content: center;
align-items: center;
}
.inner-ring {
width: 130rpx;
height: 130rpx;
border-radius: 50%;
background-color: #fff;
}
/deep/ .file-picker__box {
width: 32px !important;
height: 32px !important;
}
</style>
注意:存在三个问题(部分已解决)
1. 在浏览器上ios和Android调用都没问题,但是微信浏览器上ios系统中初次调用摄像头,请求摄像头权限后,会出现视频无显示,无法播放,就算一直重新调用invokingCamera()方法去重新渲染也无效。经研究是由于video宽高均为0,且为暂停状态导致的,不过退出页面,重新进入后又可以正常播放(我猜测是由于这次不需要重新请求摄像头权限)。所以解决方法为,在获取摄像头权限后,视频播放之后,让视频重新加载一次。
这样就解决了ios系统在微信浏览器初次请求摄像头权限后无法显示画面的问题。
2. 由于目前没有单独调取手机相册的api,所以都是两种都有(拍摄、相册),暂时没有方法避免。
3. 由于调用手机相册的功能只有三个监听事件(完成、成功、失败),监听不到取消操作,所以,目前解决方法是右上角增加了刷新图标,刷新一下,画面会重新出现。部分浏览器和机型支持取消操作后会重新调用app.vue里面的内容,所以在onshow生命周期里也写了延时器,会在取消操作1秒后重新加载摄像头(此事件只有部分机型和浏览器支持)。