本文主要介绍和大家介绍canvas 实现炫丽的粒子运动效果（粒子生成文字），小编觉得挺不错的，现在分享给大家，也给大家做个参考。一起跟随小编过来看看吧，希望能帮助到大家。
直接上代码 ，不懂可以看代码注释。估计就会看明白大概的思路了。
html 代码
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>canvas 实现炫丽的粒子运动效果-云库前端</title>
<style>
* {
margin: 0;
padding: 0;
}
html,
body {
width: 100%;
height: 100%;
}
canvas {
display: block;
background: #000;
}
body::-webkit-scrollbar{
display: none;
}
.operator-box{
position: fixed;
top: 0;
left: 50%;
border: 1px solid #fff;
background: rgba(255,255,255,0.5);
padding: 20px 10px;
-webkit-transform: translatex(-50%);
transform: translatex(-50%);
}
.back-type,.back-animate{
margin-right: 20px;
}
.flex-box{
display: flex;
justify-content: center;
align-items: center;
}
#input-text{
line-height: 35px;
width: 260px;
height: 35px;
background: rgba(0, 0, 0,0.7);
color: #fff;
font-size: 16px;
border: none;
outline: none;
text-indent: 12px;
box-shadow: inset 0 0 12px 1px rgba(0,0,0,0.7);
}
#input-text::placeholder{
color: #ccc;
line-height: 55px;
height: 55px;
}
select{
-webkit-appearance: none;
-moz-appearance: none;
appearance: none;
border: none;
padding: 0px 20px 0px 6px;
height: 35px;
color: #fff;
text-align: left;
background: rgba(0, 0, 0,0.7) url(data:image/png;base64,ivborw0kggoaaaansuheugaaaauaaaaicayaaaax8tu7aaaaouleq…r4gpgweimaioybcs4c8zdairbq4gignkztqefmi6auqhesapmexiemiwfpaaaaaelftksuqmcc) no-repeat 190px 12px;
background-size: 5px 8px;
box-shadow: inset 0 0 12px 1px rgba(0,0,0,0.7);
}
</style>
</head>
<body>
<p class="operator-box">
<p class="flex-box">
<p class="back-type">散开类型：
<select name="" id="selecttype">
<option value="back">归位</option>
<option value="auto">随机</option>
</select>
</p>
<p class="back-animate">散开效果（对归位有效）：
<select class="back-dynamics" id="selectdynamics">
<option value="spring">dynamics.spring</option>
<option value="bounce">dynamics.bounce</option>
<option value="forcewithgravity">dynamics.forcewithgravity</option>
<option value="gravity">dynamics.gravity</option>
<option value="easeinout">dynamics.easeinout</option>
<option value="easein">dynamics.easein</option>
<option value="easeout">dynamics.easeout</option>
<option value="linear">dynamics.linear</option>
</select>
</p>
<p class="input-box"><input type="text" placeholder="输入汉字后回车" id="input-text"></p>
</p>
</p>
<script src="dynamics.min.js"></script>
<script src="index.js"></script>
<script>
var icircle = new circle();
</script>
</body>
</html>
html 代码不多，只要是几个操作元素。这里一看就明白。不费过多口舌。我们来看看本文的主角 javascript 代码，不过，在看代码前，我们不妨先听听实现这个效果的思路：
首先，我们得先生成一堆群众演员（粒子）；
把每个粒子的相关参数挂到自身的一些属性上，因为第个粒子都会有自己的运动轨迹；
接着得让它们各自运动起来。运动有两种（自由运动和生成文字的运动）；
javascript 代码中使用了三个 canvas 画布，this.icanvas（主场）、this.icanvascalculate（用来计算文字宽度）、this.icanvaspixel（用于画出文字，并从中得到文字对应的像素点的位置坐标）。
this.icanvascalculate 和 this.icanvaspixel 这两个无需在页面中显示出来，只是辅助作用。
下面就献上棒棒的 js 实现代码
function circle() {
var this = this;
this.init();
this.generalrandomparam();
this.drawcircles();
this.ballanimate();
this.getusertext();
// 窗口改变大小后，生计算并获取画面
window.onresize = function(){
this.statew = document.body.offsetwidth;
this.stateh = document.body.offsetheight;
this.icanvasw = this.icanvas.width = this.statew;
this.icanvash = this.icanvas.height = this.stateh;
this.ctx = this.icanvas.getcontext("2d");
}
}
// 初始化
circle.prototype.init = function(){
//父元素宽高
this.statew = document.body.offsetwidth;
this.stateh = document.body.offsetheight;
this.icanvas = document.createelement("canvas");
// 设置canvas 与父元素同宽高
this.icanvasw = this.icanvas.width = this.statew;
this.icanvash = this.icanvas.height = this.stateh;
// 获取 2d 绘画环境
this.ctx = this.icanvas.getcontext("2d");
// 插入到 body 元素中
document.body.appendchild(this.icanvas);
this.icanvascalculate = document.createelement("canvas");
// 用于保存计算文字宽度的画布
this.mctx = this.icanvascalculate.getcontext("2d");
this.mctx.font = "128px 微软雅黑";
this.icanvaspixel = document.createelement("canvas");
this.icanvaspixel.setattribute("style","position:absolute;top:0;left:0;");
this.pctx = null; // 用于绘画文字的画布
// 随机生成圆的数量
this.ballnumber = ramdomnumber(1000, 2000);
// 保存所有小球的数组
this.balls = [];
// 保存动画中最后一个停止运动的小球
this.animte = null;
this.imagedata = null;
this.textwidth = 0; // 保存生成文字的宽度
this.textheight = 150; // 保存生成文字的高度
this.inputtext = ""; // 保存用户输入的内容
this.actioncount = 0;
this.ballactor = []; // 保存生成文字的粒子
this.actornumber = 0; // 保存生成文字的粒子数量
this.backtype = "back"; // 归位
this.backdynamics = ""; // 动画效果
this.isplay = false; // 标识（在生成文字过程中，不能再生成）
}
// 渲染出所有圆
circle.prototype.drawcircles = function () {
for(var i=0;i<this.ballnumber;i++){
this.renderball(this.balls[0]);
}
}
// 获取用户输入文字
circle.prototype.getusertext = function(){
this = this; // 保存 this 指向
ipu = document.getelementbyid("input-text");
ipu.addeventlistener("keydown",function(event){
if(event.which === 13){ // 如果是回车键
ipu.value = ipu.value.trim(); // 去头尾空格
var pat = /[\u4e00-\u9fa5]/; // 中文判断
var ischinese = pat.test(ipu.value);
if(ipu.value.length !=0 && ischinese){
this.inputtext = ipu.value;
}else{
alert("请输入汉字");
return;
}
if(this.isplay){
return
}
this.getanimatetype();
this.gettextpixel();
this.isplay = true;
}
});
}
// 计算文字的宽
circle.prototype.calculatetextwidth = function () {
this.textwidth = this.mctx.measuretext(this.inputtext).width;
}
// 获取文字像素点
circle.prototype.gettextpixel = function () {
if(this.pctx){
this.pctx.clearrect(0,0,this.textwidth,this.textheight);
}
this.calculatetextwidth(this.inputtext);
this.icanvaspixel.width = this.textwidth;
this.icanvaspixel.height = this.textheight;
this.pctx = this.icanvaspixel.getcontext("2d");
this.pctx.font = "128px 微软雅黑";
this.pctx.fillstyle = "#ff0000";
this.pctx.textbaseline = "botom";
this.pctx.filltext(this.inputtext,0,110);
this.imagedata = this.pctx.getimagedata(0,0,this.textwidth,this.textheight).data;
this.gettextpixelposition(this.textwidth,this.textheight);
}
// 获取文字粒子像素点位置
circle.prototype.gettextpixelposition = function (width,height) {
var left = (this.icanvasw - width)/2;
var top = (this.icanvash - height)/2;
var space = 4;
this.actioncount = 0;
for(var i=0;i<this.textheight;i+=space){
for(var j=0;j<this.textwidth;j+=space){
var index = j*space+i*this.textwidth*4;
if(this.imagedata[index] == 255){
if(this.actioncount<this.ballnumber){
this.balls[this.actioncount].status = 1;
this.balls[this.actioncount].targetx = left+j;
this.balls[this.actioncount].targety = top+i;
this.balls[this.actioncount].backx = this.balls[this.actioncount].x;
this.balls[this.actioncount].backy = this.balls[this.actioncount].y;
this.ballactor.push(this.balls[this.actioncount]);
this.actioncount++;
}
}
}
this.actornumber = this.ballactor.length;
}
this.animatetotext();
}
// 粒子运动到指定位置
circle.prototype.animatetotext = function(){
for(var i=0;i<this.actornumber;i++){
dynamics.animate(this.ballactor[i], {
x: this.ballactor[i].targetx,
y: this.ballactor[i].targety
},{
type: dynamics.easein,
duration: 1024,
});
}
settimeout(function(){
this.ballbacktype();
},3000);
}
// 粒子原路返回
circle.prototype.ballbackposition = function(){
for(var i=0;i<this.actornumber;i++){
var ball = this.ballactor[i];
dynamics.animate(ball, {
x: ball.backx,
y: ball.backy
},{
type: dynamics[this.backdynamics],
duration: 991,
complete:this.changestatus(ball)
});
}
}
// 获取类型|动画效果
circle.prototype.getanimatetype = function() {
var selecttype = document.getelementbyid("selecttype");
var selectdynamics = document.getelementbyid("selectdynamics");
this.backtype = selecttype.options[selecttype.options.selectedindex].value;
this.backdynamics = selectdynamics.options[selectdynamics.options.selectedindex].value;
}
// 复位散开
circle.prototype.ballbacktype = function(){
if(this.backtype == "back"){
this.ballbackposition();
}else{
this.ballautoposition();
}
this.ballactor = [];
}
// 随机散开
circle.prototype.ballautoposition = function(ball){
for(var i=0;i<this.actornumber;i++){
this.changestatus(this.ballactor[i])
}
}
// 更改小球状态
circle.prototype.changestatus = function(ball){
ball.status = 0;
if(this.isplay == true){
this.isplay = false;
}
}
// 随机生成每个圆的相关参数
circle.prototype.generalrandomparam = function(){
for(var i=0;i<this.ballnumber;i++){
var ball = {};
ball.size = 1; // 随机生成圆半径
// 随机生成圆心 x 坐标
ball.x = ramdomnumber(0+ball.size, this.icanvasw-ball.size);
ball.y = ramdomnumber(0+ball.size, this.icanvash-ball.size);
ball.speedx = ramdomnumber(-1, 1);
ball.speedy = ramdomnumber(-1, 1);
this.balls.push(ball);
ball.status = 0;
ball.targetx = 0;
ball.targety = 0;
ball.backx = 0;
ball.backy = 0;
}
}
// 改变圆的位置
circle.prototype.changeposition = function(){
for(var i=0;i<this.ballnumber;i++){
if( this.balls[i].status == 0){
this.balls[i].x += this.balls[i].speedx;
this.balls[i].y += this.balls[i].speedy;
}
}
}
// 画圆
circle.prototype.renderball = function(ball){
this.ctx.fillstyle = "#fff";
this.ctx.beginpath(); // 这个一定要加
this.ctx.arc(ball.x, ball.y, ball.size, 0, 2 * math.pi);
this.ctx.closepath(); // 这个一定要加
this.ctx.fill();
}
// 小球碰撞判断
circle.prototype.collision = function(ball){
for(var i=0;i<this.ballnumber;i++){
if(ball.x>this.icanvasw-ball.size || ball.x<ball.size){
if(ball.x>this.icanvasw-ball.size){
ball.x = this.icanvasw-ball.size;
}else{
ball.x = ball.size;
}
ball.speedx = - ball.speedx;
}
if(ball.y>this.icanvash-ball.size || ball.y<ball.size){
if(ball.y>this.icanvash-ball.size){
ball.y = this.icanvash-ball.size;
}else{
ball.y = ball.size;
}
ball.speedy = - ball.speedy;
}
}
}
// 开始动画
circle.prototype.ballanimate = function(){
var this = this;
var animateframe = window.requestanimationframe || window.mozrequestanimationframe || window.webkitrequestanimationframe || window.msrequestanimationframe;
(function move(){
animte = animateframe(move);
this.ctx.clearrect(0, 0, this.icanvasw, this.icanvash);
this.changeposition();
for(var i=0;i<this.ballnumber;i++){
this.collision(this.balls[i]);
this.renderball(this.balls[i]);
}
})();
}
// 生成一个随机数
function ramdomnumber(min, max) {
return math.random() * (max - min) + min;
}
看了代码估计也只是心里炫了一下，也没有让你想把这个东西做出来的欲望，为此我知道必需得让你眼睛心服口服才行。在线 demo： 动感的粒子示例。
人无完人，代码也一样。看起来运行顺畅的代码也或多或少有一些瑕疵，日前这个效果还只支持中文。英文的话，我得再努力一把，不管怎么样，英文后面肯定是会加入来的，只是时间问题了。还有代码中用于标记是否可再次执行生成文字的 属性：this.isplay ，还是一点瑕疵，this.isplay 的状态更改没有准确的在粒子归位的那一瞬间更改，而是提前更改了状态。但这个状态不会影响本例子效果的完整实现。
这个例子中用到了 dynamics.js 库，主要是用到它里面的一些运动函数，让粒子动起来更感人一些，仅此而已。
相关推荐：
用html5中的canvas结合公式绘制粒子运动的教程_html5教程技巧
以上就是canvas实现炫丽的粒子运动效果的详细内容。