先看效果
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<head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title>
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<body style="background-color: #000;padding: 0; margin: 0;"><canvas id="canvas"></canvas>
</body><script>let cvs = document.querySelector('canvas');let ctx = cvs.getContext('2d');function init() {cvs.width = window.innerWidth * devicePixelRatio;cvs.height = window.innerHeight * devicePixelRatio;console.log(cvs.width);console.log(cvs.height);}init()let fontsize = 20 * devicePixelRatio;ctx.fillStyle="#000"let columCount = Math.floor(cvs.width/fontsize);//获取列let charIndex = new Array(columCount).fill(0);function draw() {ctx.fillStyle='rgba(0,0,0,0.1)'ctx.fillRect(0,0,cvs.width,cvs.height)ctx.fillStyle='#6be445'ctx.textBaseline='top'for (let i = 0; i < columCount; i++) {let x = i *fontsize;let y = charIndex[i] *fontsize;ctx.fillText(getRandomText(),x,y)if(y>cvs.height && Math.random()>0.99){charIndex[i] = 0;}else{charIndex[i]++}}}draw()function getRandomText() {let str = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';return str[Math.floor(Math.random()*str.length)]}setInterval(draw, 50);</script>
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