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| <!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0" name="viewport">
<title>移动端图片压缩上传demo</title>
<style>
* {margin: 0;padding: 0;}
li {list-style-type: none;}
a,input {outline: none;-webkit-tap-highlight-color: rgba(0, 0, 0, 0);}
canvas {width: 100%;border: 1px solid
.touch {background-color:
.img-list {margin: 10px 5px;}
.img-list img {position: relative;display: inline-block;width: 100px;height: 100px;margin: 5px 5px 20px 5px;border: 1px solid rgb(100, 149, 198);background:
</style>
</head>
<body>
<ul class="img-list"></ul>
<a id="upload"><input type="file" id="choose" onclick="fileChooser(this,'1')" accept="image/*" multiple></a>
<script type="text/javascript" src="../js/jquery.main.js"></script>
<script>
var fileData = "";
function fileChooser(fileInp, sss) {
console.log(fileInp);
console.log(sss);
fileInp.onchange = function() {
if(!this.files.length) return;
var files = Array.prototype.slice.call(this.files);
files.forEach(function(file, i) {
if(!/\/(?:jpeg|png|gif)/i.test(file.type)) return;
var reader = new FileReader();
//获取图片大小
var size = file.size / 1024 > 1024 ? (~~(10 * file.size / 1024 / 1024)) / 10 + "MB" : ~~(file.size / 1024) + "KB";
console.log("上传图片大小：" + size);
console.log("图片名称:" + file.name);
console.log("图片类型:" + file.type);
reader.onload = function() {
var result = this.result;
var img = new Image();
img.src = result;
//如果图片大小小于100kb，则直接上传
var maxsize = 100 * 1024;
if(result.length <= maxsize) {
img = null;
console.log(result); //结果
$(".img-list").html("<img src='"+result+"'>");
return;
}
//图片加载完毕之后进行压缩，然后上传
if(img.complete) {
callback();
} else {
img.onload = callback;
}
function callback() {
var data = compress(img);
console.log(data); //结果
$(".img-list").html("<img src='"+data+"'>");
img = null;
}
};
reader.readAsDataURL(file);
})
};
}
//使用canvas对大图片进行压缩
function compress(img) {
//用于压缩图片的canvas
var canvas = document.createElement("canvas");
var ctx = canvas.getContext('2d');
//瓦片canvas
var tCanvas = document.createElement("canvas");
var tctx = tCanvas.getContext("2d");
var initSize = img.src.length;
var width = img.width;
var height = img.height;
//如果图片大于四百万像素，计算压缩比并将大小压至400万以下
var ratio;
if((ratio = width * height / 4000000) > 1) {
ratio = Math.sqrt(ratio);
width /= ratio;
height /= ratio;
} else {
ratio = 1;
}
canvas.width = width;
canvas.height = height;
//铺底色
ctx.fillStyle = "#fff";
ctx.fillRect(0, 0, canvas.width, canvas.height);
//如果图片像素大于100万则使用瓦片绘制
var count;
if((count = width * height / 1000000) > 1) {
count = ~~(Math.sqrt(count) + 1); //计算要分成多少块瓦片
// 计算每块瓦片的宽和高
var nw = ~~(width / count);
var nh = ~~(height / count);
tCanvas.width = nw;
tCanvas.height = nh;
for(var i = 0; i < count; i++) {
for(var j = 0; j < count; j++) {
tctx.drawImage(img, i * nw * ratio, j * nh * ratio, nw * ratio, nh * ratio, 0, 0, nw, nh);
ctx.drawImage(tCanvas, i * nw, j * nh, nw, nh);
}
}
} else {
ctx.drawImage(img, 0, 0, width, height);
}
//进行最小压缩
var ndata = canvas.toDataURL('image/jpeg', 0.1);
console.log('压缩前：' + initSize);
console.log('压缩后：' + ndata.length);
console.log('压缩率：' + ~~(100 * (initSize - ndata.length) / initSize) + "%");
tCanvas.width = tCanvas.height = canvas.width = canvas.height = 0;
return ndata;
}
</script>
</body>
</html>
|
