【JS】代码雨特效
html代码<canvas id="code_rain_canvas" width="1440" height="900"></canvas>
js 代码
window.onload = function() {
//获取画布对象
var canvas = document.getElementById("code_rain_canvas");
//获取画布的上下文
var context = canvas.getContext("2d");
var s = window.screen;
var W = canvas.width = s.width;
var H = canvas.height;
//获取浏览器屏幕的宽度和高度
//var W = window.innerWidth;
//var H = window.innerHeight;
//设置canvas的宽度和高度
canvas.width = W;
canvas.height = H;
//每个文字的字体大小
var fontSize = 12;
//计算列
var colunms = Math.floor(W / fontSize);
//记录每列文字的y轴坐标
var drops = [];
//给每一个文字初始化一个起始点的位置
for (var i = 0; i < colunms; i++) {
drops.push(0);
}
//运动的文字
var str = "WELCOME TO WWW.ITRHX.COM";
//4:fillText(str,x,y);原理就是去更改y的坐标位置
//绘画的函数
function draw() {
context.fillStyle = "rgba(238,238,238,.08)"; //遮盖层
context.fillRect(0, 0, W, H);
//给字体设置样式
context.font = "600 " + fontSize + "pxGeorgia";
//给字体添加颜色
context.fillStyle = ["#33B5E5", "#0099CC", "#AA66CC", "#9933CC", "#99CC00", "#669900", "#FFBB33", "#FF8800", "#FF4444", "#CC0000"]; //randColor();可以rgb,hsl, 标准色，十六进制颜色
//写入画布中
for (var i = 0; i < colunms; i++) {
var index = Math.floor(Math.random() * str.length);
var x = i * fontSize;
var y = drops * fontSize;
context.fillText(str, x, y);
//如果要改变时间，肯定就是改变每次他的起点
if (y >= canvas.height && Math.random() > 0.99) {
drops = 0;
}
drops++;
}
};
function randColor() { //随机颜色
var r = Math.floor(Math.random() * 256);
var g = Math.floor(Math.random() * 256);
var b = Math.floor(Math.random() * 256);
return "rgb(" + r + "," + g + "," + b + ")";
}
draw();
setInterval(draw, 35);
};
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