之前用Jcrop实现头像上传的功能的时候。有个缺点，是先把原始图片上传，再在页面上显示出来，供用户截取。这么以来不管用户是否保存修改头像的操作，都会执行一个上传操作并保存图片。
改进：把上传的图片转成base64格式的图片显示在页面上，仅当用户截取头像点击保存的时候再执行上传操作。
效果：
1.gif
直接上代码
index.html
<html lang="en" style="overflow-x:visible;">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1" />
<meta name="description" content="">
<meta name="keywords" content="">
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<link rel="stylesheet" type="text/css" href="./css/self_container.css">
<link rel="stylesheet" type="text/css" href="./css/self_bootstrap.css">
<link rel="stylesheet" type="text/css" href="./css/jquery.Jcrop.min.css">
</head>
<body style="overflow-x:visible;">
<div class="self_container">
<div class="content-wrapper" style="min-height: 800px;">
<div class="col-md-9">
<div class="panel panel-default panel-col">
<div class="panel-heading">
头像设置</div>
<div class="panel-body">
<form id=form1 style="display: block" enctype="multipart/form-data" class="form-horizontal" method="post">
<div class="form-group">
<div class="col-md-2 control-label">
<b>
当前头像</b>
</div>
<div class="controls col-md-8 controls">
<img src="./img/avatar.jpg">
</div>
</div>
<div class="form-group">
<div class="col-md-2 control-label">
</div>
<div class="controls col-md-8 controls">
<p class="help-block">
仅支持上传JPG格式的文件。
</p>
</div>
</div>
<div class="form-group">
<div class="col-md-2 control-label">
</div>
<div class="controls col-md-8 controls">
<a id="upload-picture-btn" class="btn btn-primary webuploader-container" >
<div class="webuploader-pick">
上传新头像</div>
<div id="" style="position: absolute; top: 6px; width: 70px; height: 20px; overflow: hidden; bottom: auto; right: auto;">
<input id="avatar1" type="file" name="avatar" class="webuploader-element-invisible" accept="image/png,image/jpg,image/jpeg,imge/bmp,image/gif">
<label style="opacity: 0; width: 100%; height: 100%; display: block; cursor: pointer; background: rgb(255, 255, 255);">
</label>
</div>
</a>
</div>
</div>
</form>
<form id="form2" style="display: none;" action="" method="post">
<div class="form-group clearfix">
<div class="col-md-offset-2 col-md-8 controls">
<img id="cropbox" class="img-responsive" src="" >
<div class="help-block">
提示：请选择图片裁剪区域。</div>
</div>
</div>
<div class="form-group">
<div class="col-md-offset-2 col-md-8 controls">
<a class="btn btn-fat btn-primary" id="upload-avatar-btn" data-url="/settings/avatar/crop" data-goto-url="/settings/avatar">
保存
<input id="commit" type="button" value="保存" style="position: absolute; left: 10px; width: 55px; height: 35px; top:0px; opacity: 0;" />
</a>
</div>
<div class="col-md-offset-2 col-md-8 controls">
<a id="upload-picture-btn" class="btn btn-primary webuploader-container" >
<div class="webuploader-pick">
重新选择图片</div>
</a>
</div>
</div>
<input type="hidden" id="x" name="x" />
<input type="hidden" id="y" name="y" />
<input type="hidden" id="w" name="w" />
<input type="hidden" id="h" name="h" />
</form>
</div>
</div>
</div>
</div>
</div>
<script type="text/javascript" src="./js/jquery-2.2.3.min.js"></script>
<script type="text/javascript" src="./js/jquery.Jcrop.min.js"></script>
<script type="text/javascript">
(function(){
$("#avatar1").change(function() {
var img = $(".img-responsive");
var reader = new FileReader();
reader.readAsDataURL(this.files[0]);
reader.onload = function (e) {
img.attr('src',this.result);
$("#form1").css('display','none');
$("#form2").css('display','block');
$('.img-responsive').Jcrop({
boxWidth:600,
boxHeight:300,
aspectRatio: 1,
onSelect: updateCoords,
});
}
});
$(".webuploader-pick").click(function() {
location.reload();
});
})()
$("#commit").click(function(){
var avatarForm = document.getElementById('form2');
var formData = new FormData(avatarForm);
$(".img-responsive").each(function(){
var blob = dataURItoBlob(this.src); // 上一步中的函数
formData.append("avatar", blob, 'avatar.jpg');
});
$.ajax({
url: 'upload.php',
type: 'post',
processData: false,
contentType: false,
// dataType: 'json',
data: formData,
success: function(data){
location.reload();
},
error: function(){
alert("error");
}
});
})
function dataURItoBlob(base64Data) {
var byteString;
if (base64Data.split(',')[0].indexOf('base64') >= 0)
byteString = atob(base64Data.split(',')[1]);
else
byteString = unescape(base64Data.split(',')[1]);
var mimeString = base64Data.split(',')[0].split(':')[1].split(';')[0];
var ia = new Uint8Array(byteString.length);
for (var i = 0; i < byteString.length; i++) {
ia[i] = byteString.charCodeAt(i);
}
return new Blob([ia], {type:mimeString});
}
function updateCoords(c)
{
$('#x').val(c.x);
$('#y').val(c.y);
$('#w').val(c.w);
$('#h').val(c.h);
};
function checkCoords()
{
if (parseInt($('#w').val())) return true;
alert('Please select a crop region then press submit.');
return false;
};
</script>
</body>
</html>
upload.php
<?php
if ($_SERVER['REQUEST_METHOD']=="POST") {
// 保存图片
$image = $_FILES['avatar'];
if($image['error'] == UPLOAD_ERR_OK){
$dest='img/avatar_crop.jpg';
move_uploaded_file($image['tmp_name'],$dest);
}
$targ_w = $targ_h = 160;
$jpeg_quality = 90;
$src = 'img/avatar_crop.jpg';
$img_r = imagecreatefromjpeg($src);
$dst_r = ImageCreateTrueColor( $targ_w, $targ_h );
imagecopyresampled($dst_r, $img_r, 0, 0, $_POST['x'], $_POST['y'], $targ_w, $targ_h, $_POST['w'], $_POST['h']);
imagejpeg($dst_r, 'img/avatar.jpg', $jpeg_quality);
echo "success";
}