js视频转字符画
2020-12-02 本文已影响0人
蓝不蓝编程
效果图
代码
如下内容另存为index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
* {
padding: 0;
margin: 0;
overflow: hidden;
/* font-size: 0; */
}
canvas,
video {
width: 30%;
height: 30%;
}
</style>
</head>
<body>
<input type="file" id="file" name="file" accept=".mp4,.flv">
</body>
<script src="https://cdn.bootcss.com/flv.js/1.3.3/flv.min.js"></script>
<script>
let fontSize = 9
let $file = document.getElementById('file')
$file.onchange = function () {
let file = $file.files.item(0)
// let reader = new FileReader()
// reader.readAsDataURL(file, 'UTF-8')
// reader.onprogress = function (evt) {
// console.log(`${(evt.loaded / evt.total * 100).toFixed()}%`)
// }
// reader.onload = function (evt) {
document.body.removeChild($file)
// evt.target.result
play(URL.createObjectURL(file), file.name.split('.').pop())
// }
}
function play(url, type) {
if (flvjs.isSupported()) {
let videoElement = document.createElement('video')
videoElement.loop = true
let flvPlayer = flvjs.createPlayer({
type: type,
url: url
})
flvPlayer.attachMediaElement(videoElement)
flvPlayer.load()
flvPlayer.volume = 0.1
flvPlayer.play()
// document.body.appendChild(videoElement)
flvPlayer.on('media_info', function (mediaInfo) {
// 设置canvas
let canvasElement = document.createElement('canvas')
// 不明原因的卡
// canvasElement.onmousewheel = () => { }
let fps = mediaInfo.fps
let canvasWidth = mediaInfo.width
let canvasHeight = mediaInfo.height
let textInfo
let chars = "MMWNKEGD0OLkxdolc;:,'... "
let fontWidth
canvasElement.width = canvasWidth
canvasElement.height = canvasHeight
ctx = canvasElement.getContext('2d')
ctx.font = `${fontSize}px courier new`
ctx.fillStyle = 'black'
ctx.textBaseline = 'middle'
fontWidth = ctx.measureText('A').width
textInfo = {
col: ~~Math.ceil(canvasWidth / fontWidth),
row: canvasHeight / fontSize
}
document.body.appendChild(canvasElement)
draw()
function draw() {
ctx.clearRect(0, 0, canvasWidth, canvasHeight)
ctx.drawImage(videoElement, 0, 0, textInfo.col, textInfo.row)
let strings = getStringData(ctx, textInfo.col, textInfo.row)
ctx.clearRect(0, 0, textInfo.col, textInfo.row)
for (let i = 0, len = strings.length; i < len; i++) {
ctx.fillText(strings[i], 0, fontSize * (i + 0.5), canvasWidth, fontSize)
}
requestAnimationFrame(draw)
}
function getStringData(ctx, width, height) {
let length = textInfo.row * textInfo.col
let strings = []
// 获取一个 fontSize * fontSize 色块的颜色
let imageData = ctx.getImageData(0, 0, width, height)
for (let i = 0; i < length * 4; i += 4) {
let myRed = imageData.data[i]
let myGreen = imageData.data[i + 1]
let myBlue = imageData.data[i + 2]
let myGray = parseInt((myRed + myGreen + myBlue) / 3)
let char = chars[~~(myGray / 255 * chars.length)]
let index = ~~(i / 4 / width)
if (strings[index]) {
strings[index].push(char)
} else {
strings[index] = []
strings[index].push(char)
}
}
return strings
}
})
}
}
</script>
</html>
