最近需要项目需要实现弹幕,网上参考了各种方法,最后觉得transform+transition实现的效果在移动设备上性能最好,在iphone6和红米4上测试,看不到卡顿的感觉。用jquery的animate动画在移动设备上有明显的卡顿。
1.首先创建弹幕区域
<div class="barrage">
<div class="mask">
“
</div>
</div>
<input type="text" ng-model="data.comment"/>
<button ng-click="addDanmu()">说两句</button >
2.css
.webPage .barrage{width:100%;height:22%;position: absolute; bottom: 50px; background-color: transparent;pointer-events: none;}
.webPage .barrage .mask{width:100%;height:100%;background:transparent;z-index:100;}
注:以上html,css根据自己需求来即可
3.js
$scope.data = {comment:''};
$scope.danmuCount = 5; //最大弹幕行数
$scope.danmus = ['1545466666还是','9777777','哈哈哈哈哈','对企业读完后环球网好齐齐哈','42115我我我5','556噢噢噢噢45','54哦','54545646','666但近段时间66','56565','454465465565', '1545466666还是','9777777','哈哈哈哈哈','对企业读完后环球网好齐齐哈','42115我我我5','556噢噢噢噢45','54哦','54545646','666但近段时间66','56565','454465465565']; //弹幕数据源
//创建弹幕区域
$scope.createDanmuContent = function () {
var height = 1 / $scope.danmuCount * 100 + '%';
for (var i = 0; i < $scope.danmuCount; i++) {
var item = '<div style="width: 100%; height: '+height+'"></div>';
$('.mask').append(item);
}
$scope.createDanmu ();
};
//开始弹幕绘制
$scope.createDanmu = function () {
var maxCount = 0;
if ($scope.danmus.length > $scope.danmuCount) {
maxCount = $scope.danmuCount;
} else {
maxCount = $scope.danmus.length;
}
var _left = window.screen.width;
for (var i = 0; i < maxCount; i++) {
var _lable = $("<p style='margin: 0;position: absolute;opacity:1;display:table;left: "+_left + 'px'+';color:'+$scope.getRandomColor()+"'>"+$scope.danmus[i]+"</p>");
$(".mask div").each(function () {
//检测该区域是否绘制了弹幕
if ($scope.checkDanmu($(this))) {
$(this).append(_lable);
$scope.moveArray(i);
i--;
return false;
}
});
}
$scope.init_barrage();
};
//将数组第一位放到最后一位,(因弹幕池内容太少,所以没删除已显示的弹幕)
$scope.moveArray = function (i) {
var temp = $scope.danmus[i];
$scope.danmus.splice(i,1);
$scope.danmus.push(temp);
}
//判断content区域有没有弹幕
$scope.checkDanmu = function (el) {
return el.find('p').length == 0 ? true : false;
};
//获取随机颜色
$scope.getRandomColor = function () {
return '#' + (function(h){
return new Array(7 - h.length).join("0") + h
})((Math.random() * 0x1000000 << 0).toString(16))
};
//初始化弹幕参数
$scope.init_barrage = function () {
$(".mask div p").show().each(function() {
var _moveLeft = window.screen.width+$(this).width();
var time = 100000 / $(this).width() + 5000;//弹幕滑动时间
$scope.addCssAnimate($(this),_moveLeft,time);
});
};
//添加弹幕动画
$scope.addCssAnimate = function (el,_moveLeft,time) {
el.css({
'transform':'translateX('+-_moveLeft+'px)',
'transition':'all '+time+'ms'+ ' linear',
'-webkit-transform':'translateX('+-_moveLeft+'px)',
'-webkit-transition':'all '+time+'ms'+ ' linear',
'-moz-transform':'translateX('+-_moveLeft+'px)',
'-moz-transition':'all '+time+'ms'+ ' linear',
'-ms-transform':'translateX('+-_moveLeft+'px)',
'-ms-transition':'all '+time+'ms'+ ' linear'
});
//当动画执行完毕后,将弹幕移到原处,更换弹幕文字,重新开始执行动画,相当于对原本弹幕的复用
$timeout(function () {
//判断弹幕池是否还有内容,如果没有则移除弹幕
if ($scope.danmus.length > 0) {
el.css({
'transform':'translateX(0px)',
'transition':'all 0ms linear',
'-webkit-transform':'translateX(0px)',
'-webkit-transition':'all 0ms linear',
'-moz-transform':'translateX(0px)',
'-moz-transition':'all 0ms linear',
'-ms-transform':'translateX(0px)',
'-ms-transition':'all 0ms linear'
});
$scope.resetAnimate(el);
} else {
el.remove();
}
},time);
};
//更换弹幕内容,重新开始弹幕动画
$scope.resetAnimate = function (el) {
el.html($scope.danmus[0]);
$scope.moveArray(0);
var _moveLeft = el.width() + screen.width;
var time = 100000 / el.width() + 5000;
$scope.addCssAnimate(el,_moveLeft,time);
};
//评论,添加弹幕
$scope.addDanmu = function () {
var text = $scope.data.comment;
if(text == ""){
return;
}
$scope.danmus.unshift(text);
};
$scope.createDanmuContent();