<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>canvas字母喷射效果</title>
<style>
*{
margin:0;
padding:0;
}
body{
background:#000000;
overflow:hidden;
}
</style>
</head>
<body>
<canvas id=canvas></canvas>
<script>
//页面命名空间 命名空间就是对象 需要用到this
var Canvas={};
Canvas.anim={
//初始化
init:function(){
var canvas=document.getElementById("canvas");
this.ctx=canvas.getContext("2d");//画笔，创建2d空间，加this相当于全局变量
canvas.width=window.innerWidth;
canvas.height=window.innerHeight;
this.letters="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
this.cw=canvas.width;
this.ch=canvas.height;
this.particles=[];
},
//执行动画
render:function(){
//粒子的属性
var particle={
//显示的位置random为随机数0-1
x:this.cw/2,
y:this.ch,
character:this.letters[Math.floor(Math.random()*this.letters.length)],
//速度值
xSpeed: (Math.random()*20)-10,
ySpeed: (Math.random()*20)-10
}
this.particles.push(particle);
this.drawParticles();
},
//绘制字母
drawParticles: function(){
this.fadeCanvas();
var particleCount=this.particles.length;
var c=this.ctx;
for(var i=0;i<particleCount;i++){
var particle=this.particles[i];
c.font="12px sans-serif";
c.fillStyle="#ffffff";
c.fillText(particle.character,particle.x,particle.y);
particle.x += particle.xSpeed;
particle.y += particle.ySpeed;
// 驶近Y轴
particle.y *= 0.97;
}
},
//清除画布
fadeCanvas: function(){
this.ctx.fillStyle = "rgba(0,0,0,0.5)";
this.ctx.fillRect(0,0,this.cw,this.ch);
}
};
Canvas.anim.init();
setInterval(function(){
Canvas.anim.render();
},13);
</script>
</body>
</html>
加入绘制字母
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>canvas字母喷射</title>
<style>
*{
padding: 0px;
margin: 0px;
}
#canvas{
background-color:#000;
}
</style>
<body>
<canvas id="canvas"></canvas>
</body>
<script>
// 页面命名空间
var Canvas = {}
Canvas.anim = {
// 初始化
init: function(){
var canvas = document.getElementById("canvas");
this.ctx = canvas.getContext("2d");
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
this.cw = canvas.width;
this.ch = canvas.height;
// 随机字母
this.letters = "QWERTYUIOPLKJHGFDSAZXCVBNM";
// 位置
this.particles = [];
},
// 执行动画
rander: function(){
// 显示的位置
var particle = {
x: this.cw/2,
y: this.ch,
// 随机字母
character: this.letters[Math.floor(Math.random()*this.letters.length)],
// 速度值
xSpeed: (Math.random()*20)-10,
ySpeed: (Math.random()*20)-10
}
this.particles.push(particle);
this.drawParticles();
},
// 绘制字母
drawParticles: function(){
this.fadeCanvas();
var c = this.ctx;
// 喷射字母
var particleCount = this.particles.length;
for(var i=0;i<particleCount;i++){
var particle = this.particles[i];
c.font = "12px";
c.fillStyle = "#ffffff";
c.fillText(particle.charact