服务端渲染canvas动画
更新时间: 2024-12-02 15:14:52
前面已经可以传图片和视频了,今天尝试一下nodejs去渲染canvas动画并传递给客户端
# 思路
服务端安装node-canvas,在服务端渲染好canvas动画,再将canvas.toBuffer()将canvas的图像转成二进制传给客户端,然后客户端将图片渲染出来
效果如下,没有写得太花哨:
# 服务端代码
const express = require('express')
const {createServer} = require('node:http')
const {Server} = require('socket.io')
const { createCanvas } = require('canvas')
const app = express()
const server = createServer(app)
const io = new Server(server,{
cors: {
origin: "*"
}
})
io.on('connection', (socket) => {
const canvas = createCanvas(600, 600)
const ctx = canvas.getContext('2d')
let interval = null
let left = 0
const draw = () => {
ctx.clearRect(0, 0, 600, 600)
ctx.fillRect(left, 100, 20, 20)
left += 2
if(left > 600) {
left = 0
}
socket.emit('img', canvas.toBuffer())
}
draw()
socket.on('start',() => {
if(interval){
clearInterval(interval)
interval = null
}
interval = setInterval(() => {
draw()
},25)
})
socket.on('stop',() => {
if(interval) {
clearInterval(interval)
interval = null
}
})
})
server.listen(3000, () => {
console.log('server running at http://localhost:3000')
})
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
# 客户端代码
<template>
<div class="main">
<button @click="start">开始</button>
<button @click="stop">停止</button>
<div class="img-wrapper">
<img :src="imageSrc" alt="">
</div>
</div>
</template>
<script setup>
import {ref, onMounted} from "vue"
import {io} from "socket.io-client/dist/socket.io.js"
let socket = null
const imageSrc = ref('')
onMounted(() => {
socket = io("http://192.168.2.122:3000")
socket.on('img',(data) => {
const blob = new Blob([data])
imageSrc.value = URL.createObjectURL(blob)
})
})
function start() {
socket.emit('start')
}
function stop() {
socket.emit('stop')
}
</script>
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34