canvas如何实现弹幕效果
短信预约 -IT技能 免费直播动态提醒
这篇文章主要介绍canvas如何实现弹幕效果，文中介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们一定要看完！
代码如下
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<canvas >你的浏览器不支持canvas</canvas>
</body>
<script class="lazy" data-src="http://www.jq22.com/jquery/jquery-1.10.2.js"></script>
<script>
(function ($) {
function Barrager(dom) {
this.canvas = dom.get(0);
this.ctx = this.canvas.getContext("2d");
this.msgs = new Array(300);//缓冲池，长度越大，屏幕上显示的就越多
this.width = 1280;//canvas分辨率1280*720
this.height = 720;
this.canvas.width=this.width;//上边的两步可以省略，直接在这里赋值
this.canvas.height=this.height;
this.font = "30px 黑体";//字体和字体大小
this.ctx.font=this.font;
//颜色数组，在绘制过程中随机从这里取出颜色
this.colorArr=["Olive","OliveDrab","Orange","OrangeRed","Orchid","PaleGoldenRod","PaleGreen","PaleTurquoise","PaleVioletRed","PapayaWhip","PeachPuff","Peru","Pink","Plum","PowderBlue","Purple","Red","RosyBrown","RoyalBlue","SaddleBrown","Salmon","SandyBrown","SeaGreen","SeaShell","Sienna","Silver","SkyBlue"];
this.interval = "";
this.draw = function () {//绘制方法
if (this.interval != "")return;
var _this=this;
this.interval = setInterval(function () {//每隔20毫秒重新绘制一次，间隔最好小于40，要不然效果就跟播放图片差不多
//1，清除屏幕
_this.ctx.clearRect(0, 0, _this.width, _this.height);
_this.ctx.save();
//2，循环缓冲区域，把没有设置Left，Top，Speed，Color先赋值，赋值的就改变left值（产生移动效果），left值小于200就会从缓冲区移除
for (var i = 0; i < _this.msgs.length; i++) {
if (!(_this.msgs[i] == null || _this.msgs[i] == "" || typeof(_this.msgs[i]) == "undefined")) {
if(_this.msgs[i].L==null || typeof(_this.msgs[i].L)=="undefined"){
_this.msgs[i].L=_this.width;
_this.msgs[i].T=parseInt(Math.random() * 700);
_this.msgs[i].S=parseInt(Math.random() * (10 - 4) + 4);
_this.msgs[i].C=_this.colorArr[Math.floor(Math.random() * _this.colorArr.length)];
}else{
if(_this.msgs[i].L<-200){
_this.msgs[i]=null;
}else {
_this.msgs[i].L=parseInt(_this.msgs[i].L-_this.msgs[i].S);
_this.ctx.fillStyle =_this.msgs[i].C;
_this.ctx.fillText(_this.msgs[i].msg,_this.msgs[i].L,_this.msgs[i].T);
_this.ctx.restore();
}
}
}
}
}, 20);
};
//添加数据，数据格式[{"msg":"nihao"}]
this.putMsg = function (datas) {//循环缓冲区，把位置是空的装填上数据
for (var j = 0; j < datas.length; j++) {
for (var i = 0; i < this.msgs.length; i++) {
if (this.msgs[i] == null || this.msgs[i] == "" || typeof(this.msgs[i]) == "undefined") {
this.msgs[i] = datas[j];
break;
}
}
}
this.draw();
};
this.clear = function () {//清除定时器，清除屏幕，清空缓冲区
clearInterval(this.interval);
this.interval="";
this.ctx.clearRect(0, 0, this.width, this.height);
this.ctx.save();
for(var i=0;i<this.msgs.length;i++){
this.msgs[i]=null;
}
};
}
$.fn.barrager = function (para) {
if (typeof(para)=="string") {
try{
var api = $(this).data('barrager_api');
api[para].apply(api);
}catch (e){}
} else if (typeof para == 'object' || !para) {
$this = $(this);
if ($this.data('barrager_api') != null && $this.data('barrager_api') != ''){
var api = $this.data('barrager_api');
api.putMsg(para);
}else{
var api = new Barrager($this);
$this.data('barrager_api', api);
api.putMsg(para);
}
} else {
$.error('Method ' + method + ' does not exist on jQuery.slidizle');
}
return this;
}
})(jQuery);
</script>
<script>
// $('canvas').barrager([{"msg":"这是我发的。。。哈哈哈"}]);// 发送弹幕
$('canvas').barrager([{"msg":"看着不错。。。。"},{"msg":"哈哈哈。。。。"},{"msg":"不错不错。。"},{"msg":"真好看。。。。"}]);//多条发送方式
// $('canvas').barrager("clear"); //清除/关闭弹幕
</script>
</html>以上是“canvas如何实现弹幕效果”这篇文章的所有内容，感谢各位的阅读！希望分享的内容对大家有帮助，更多相关知识，欢迎关注编程网行业资讯频道！
免责声明：
① 本站未注明“稿件来源”的信息均来自网络整理。其文字、图片和音视频稿件的所属权归原作者所有。本站收集整理出于非商业性的教育和科研之目的，并不意味着本站赞同其观点或证实其内容的真实性。仅作为临时的测试数据，供内部测试之用。本站并未授权任何人以任何方式主动获取本站任何信息。
② 本站未注明“稿件来源”的临时测试数据将在测试完成后最终做删除处理。有问题或投稿请发送至: 邮箱/279061341@qq.com QQ/279061341
