四、进阶版完整代码
狐七 JavaScriptJqueryExampleHtml2canvas
# css文件glass.css
*{
margin:0;
padding:0;
}
body{
background-image: url('../images/hua.jpg');
background-repeat: no-repeat;
position: absolute;
width: 100%;
height: 100%;
}
#dv{
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
background-color: rgba(0,0,0,0.5);
display: none;
}
#btn{
position:absolute;
top: 100px;
left: 100px;
width: 100px;
height:50px;
background-color:rgba(0,0,0,.9);
border-radius: 8px;
line-height: 50px;
text-align: center;
color: #fff;
cursor: pointer;
font-size: 16px;
}
#mask{
width: 200px;
height:200px;
position: absolute;
top: 0;
left: 0;
background-color: rgba(255,150,0,.5);
cursor: move;
}
#look{
width: 300px;
height:300px;
position: absolute;
bottom: 30px;
right: 30px;
border: 1px solid #f40;
cursor: move;
overflow: hidden;
}
#box{
width: 100%;
height:100%;
}
#jb{
position:absolute;
left: 100px;
top:200px;
width: 100px;
height: 50px;
background-color: rgba(0,0,0,.9);
border-radius: 8px;
line-height: 50px;
text-align: center;
color: #fff;
cursor: pointer;
font-size: 16px;
}
#txt{
position: absolute;
left: 100px;
top: 300px;
width: 100px;
height: 50px;
}
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# index.html
<link rel="stylesheet" href="css/glass.css"/>
<script type="text/javascript" src="libs/jquery.min.js"></script>
<script type="text/javascript" src="libs/html2canvas.js"></script>
<script type="text/javascript" src="js/glass.js"></script>
<body id="bd">
hello world!!
<div id="jb">显示图标</div>
<input type="text" id="txt"/>
<div id="show"></div>
<div id='btn'>放大镜</div>
<div id="dv"><!--遮罩层-->
<div id='box'></div><!--相当于小图-->
<div id="mask"></div><!--跟着鼠标的区域-->
<div id="look">
<div id="move"></div><!--移动的地方-->
</div><!--显示的区域-->
</div>
<script>
$(function(){
$('#dv').glass();
$('#jb').on('click',function(){
var img = document.createElement('img');
img.src = 'images/jb.jpg';
img.width = 100;
img.height = 100;
var leftRandom = Math.random()*1366;
var topRandom = Math.random()*768;
img.style.position = 'absolute';
img.style.left = leftRandom + 'px';
img.style.top = topRandom + 'px';
$('#show').append(img);
})
});
</script>
</body>
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# js文件glass.js
(function($){
$.fn.glass = function(){
var mask = $('#mask');
var box = $('#box');
var look = $('#look');
var move = $('#move');
var btn = $('#btn');
var imgMaxMove;
var maskMaxMove;
var _this = $(this);
//点击按钮
btn.on('click',function(){
move.html('');
takeScreenshot();
_this.css('display','block');
});
//点击屏幕的时候就消除
_this.on('click',function(){
_this.css('display','none');
})
//获取屏幕截图
function takeScreenshot() {
alert('1');
html2canvas($('#bd'), {
allowTaint: true,
taintTest: false,
onrendered: function(canvas) {
canvas.id = 'cv';
var dataUrl = canvas.toDataURL();
var newImg = document.createElement("img");
newImg.src = dataUrl;
newImg.width = 4 * $('#bd').width();
newImg.height = 4* $('#bd').height();
move.width(newImg.width);
move.height(newImg.height);
move.append(newImg);
_this.on('mousemove',function(e){
var left = e.clientX - mask.width() / 2;//横坐标
var top = e.clientY - mask.height() / 2;//纵坐标
//console.log(mask.width());
//设置遮挡层的left和top
var x = left;//margin
var y = top;//margin
x=x<0?0:x;//如果横坐标小于0就设置为0
y=y<0?0:y;//如果纵坐标小于0就设置为0
x=x>box.width()-mask.width()?box.width()-mask.width():x;
y=y>box.height()-mask.height()?box.height()-mask.height():y;
mask.offset({"left":x,"top":y});
//大图的最大的移动距离
imgMaxMove=newImg.width-look.width();
console.log(imgMaxMove);
//遮挡层的最大的移动距离
maskMaxMove=box.width()-mask.width();
console.log(maskMaxMove);
//大图的横向移动的距离
var imgMoveLeft=x*maskMaxMove/imgMaxMove*9;
//大图的纵向移动的距离
var imgMoveTop=y*maskMaxMove/imgMaxMove*9;
move.css("marginLeft",-imgMoveLeft);
move.css("marginTop",-imgMoveTop);
})
},
});
}
}
})(jQuery);
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