Wenn ich exif.js zum Parsen des Bildes verwende, weiß ich nicht, warum das hochgeladene PNG-Format einen schwarzen Hintergrund hat
Posten Sie den Code direkt unten
<code>/**
* 上传多张图片
* @method uploadImg
* @params url:上传图片请求的服务器端的文件的地址,
* @params container:图片上传之后渲染到哪个父盒子,
* @params maxCount:最多可上传的数目,
* @params maxMb:上传的大小MB
* @params fileInput:上传图片的文件域
* @params scale:图片的缩放比例 大小
* @params name:参数名称
* @params success:上传成功之后执行的回调函数
* @params error:上传失败之后执行的回调函数
* @params warn:不符合上传条件时执行的回调函数
* @return 元素对象.uploadImg(Objext)
*/
(function($){
$.fn.extend({
uploadImg:function(opt){
var up=new UploadImg(opt,this);
}
});
function UploadImg(option,self){
var _defaults={
url:"",
container:self,
maxCount:3,
maxMb:2,
fileInput:$(self).find(".fileImg"),
scale:0.8,
name:"img",
success:function(data,idx){
},
error:function(msg){
alertBox(msg,1,"关 闭","",cancelAlert);
},
warn:function(msg){
alertBox(msg,1,"关 闭","",cancelAlert);
}
};
this.opt=$.extend({},_defaults,option);
this.init(self);
}
UploadImg.prototype={
init:function(self){
var _this=this;
var liIndex=0;
// 给文件域绑定事件
_this.opt.fileInput.on('change',function(){
var files=this.files?this.files:null,
_tar=files[0],
maxSize=_this.opt.maxMb*1024*1024,
reg=/\.(jpg)|(jpeg)|(gif)|(png)$/i,
err="",
html="";
if(!(reg.test(_tar.name))){
err="请上传jpg/jpeg/gif/png格式的图片";
}else{
if(_tar.size>maxSize){
err="图片尺寸超出限制，请上传低于"+_this.opt.maxMb+"M的图片";
}
}
if(err){
_this.opt.warn && _this.opt.warn(err);
return;
}
liIndex++;
html='<li class="upload-img upload-loading">'
+'<img src="">'
+'<a href="javascript:void(0)" class="upload_delete" title="删除"></a>'
+'</li>';
$(html).prependTo($(_this.opt.container));
_this.getCount(liIndex);
// 上传图片
_this.zipImg({
files:files,
scale:_this.opt.scale,
callback:function(tar){
if(tar.constructor!='Array'){
tar=[tar];
}
_this.submit(tar,liIndex,self);
}
})
})
// 关闭
$(_this.opt.container).on('click','.upload_delete',function(){
liIndex-=1;
$(this).parents('li.upload-img').remove();
_this.getCount(liIndex);
})
},
//压缩图片方法
zipImg: function(cfg){
/*
* cfg.files input对象触发onchange时候的files
* cfg.scale 压缩比例
* cfg.callback 压缩成功后的回调
*/
var _this = this;
var options = cfg;
[].forEach.call(options.files, function(v, k){
var fr = new FileReader();
fr.onload= function(e) {
var oExif = EXIF.readFromBinaryFile(new BinaryFile(e.target.result)) || {};
var $img = document.createElement('img');
$img.onload = function(){
_this.fixDirect().fix($img, oExif, options.callback,options.scale);
};
if(typeof(window.URL) != 'undefined'){
$img.src = window.URL.createObjectURL(v);
}else{
$img.src = e.target.result;
}
};
//fr.readAsDataURL(v);
fr.readAsBinaryString(v);
});
},
//调整图片方向
fixDirect: function(){
var r = {};
r.fix = function(img, a, callback,scale) {
var n = img.naturalHeight,
i = img.naturalWidth,
c = 1024,
o = document.createElement("canvas"),
s = o.getContext("2d");
a = a || {};
//o.width = o.height = c;
//debugger;
if(n > c || i > c){
o.width = o.height = c;
}else{
o.width = i;
o.height = n;
}
a.Orientation = a.Orientation || 1;
r.detectSubSampling(img) && (i /= 2, n /= 2);
var d, h;
i > n ? (d = c, h = Math.ceil(n / i * c)) : (h = c, d = Math.ceil(i / n * c));
// var g = c / 2,
var g = Math.max(o.width,o.height)/2,
l = document.createElement("canvas");
if(n > c || i > c){
l.width = g, l.height = g;
}else{
l.width = i;
l.height = n;
d = i;
h =n;
}
//l.width = g, l.height = g;
var m = l.getContext("2d"), u = r.detect(img, n) || 1;
s.save();
r.transformCoordinate(o, d, h, a.Orientation);
var isUC = navigator.userAgent.match(/UCBrowser[\/]?([\d.]+)/i);
if (isUC && $.os.android){
s.drawImage(img, 0, 0, d, h);
}else{
for (var f = g * d / i, w = g * h / n / u, I = 0, b = 0; n > I; ) {
for (var x = 0, C = 0; i > x; )
m.clearRect(0, 0, g, g), m.drawImage(img, -x, -I), s.drawImage(l, 0, 0, g, g, C, b, f, w), x += g, C += f;
I += g, b += w
}
}
s.restore();
a.Orientation = 1;
img = document.createElement("img");
img.onload = function(){
a.PixelXDimension = img.width;
a.PixelYDimension = img.height;
//e(img, a);
};
callback && callback(o.toDataURL("image/jpeg", scale).substring(22));//压缩图片
};
r.detect = function(img, a) {
var e = document.createElement("canvas");
e.width = 1;
e.height = a;
var r = e.getContext("2d");
r.drawImage(img, 0, 0);
for(var n = r.getImageData(0, 0, 1, a).data, i = 0, c = a, o = a; o > i; ) {
var s = n[4 * (o - 1) + 3];
0 === s ? c = o : i = o, o = c + i >> 1
}
var d = o / a;
return 0 === d ? 1 : d
};
r.detectSubSampling = function(img) {
var a = img.naturalWidth, e = img.naturalHeight;
if (a * e > 1048576) {
var r = document.createElement("canvas");
r.width = r.height = 1;
var n = r.getContext("2d");
return n.drawImage(img, -a + 1, 0), 0 === n.getImageData(0, 0, 1, 1).data[3]
}
return !1;
};
r.transformCoordinate = function(img, a, e, r) {
switch (r) {
case 5:
case 6:
case 7:
case 8:
img.width = e, img.height = a;
break;
default:
img.width = a, img.height = e
}
var n = img.getContext("2d");
switch (r) {
case 2:
n.translate(a, 0), n.scale(-1, 1);
break;
case 3:
n.translate(a, e), n.rotate(Math.PI);
break;
case 4:
n.translate(0, e), n.scale(1, -1);
break;
case 5:
n.rotate(.5 * Math.PI), n.scale(1, -1);
break;
case 6:
n.rotate(.5 * Math.PI), n.translate(0, -e);
break;
case 7:
n.rotate(.5 * Math.PI), n.translate(a, -e), n.scale(-1, 1);
break;
case 8:
n.rotate(-.5 * Math.PI), n.translate(-a, 0)
}
};
return r;
},
getCount:function(idx){
var _this=this,
size=$(_this.opt.container).find('li.upload-img').size(),
$uploadLi=$(_this.opt.fileInput).parents("li");
if(idx>=_this.opt.maxCount){
$uploadLi.hide();
}else{
$uploadLi.show();
}
},
submit:function(files,idx,t){
var _this=this,
files=files[0],
param={},
url=_this.opt.url;
param[_this.opt.name]=files;
$.ajax({
url:url,
type:"post",
data:param,
success:function(data){
data=JSON.parse(data);
_this.opt.success && _this.opt.success(data,idx);
$(t).find("li").eq(0).removeClass('upload-loading').find('img').attr('src',data.url);
},
error:function(data){
_this.opt.error && _this.opt.error(data.msg);
}
})
}
}
})(jQuery);</code>Das beim Komprimieren von Bildern verwendete EXIF wird zur Verarbeitung der hochgeladenen Bilder im PNG-Format verwendet. Bitte helfen Sie mir. ! !
Sie können es auch direkt herunterladen und ausführen, vor allem weil das transparente PNG, auf das Sie stoßen, beim Synthetisieren einen schwarzen Hintergrund hat! Der Zweck besteht darin, den schwarzen Hintergrund zu entfernen! !
<code>git clone https://github.com/Shoestrong/uploadimg.git</code>
Zusätzlicher Punkt: Ich habe gerade entdeckt, dass es beim Hochladen von PNG ein Problem mit der Größe gibt, bitte lösen Sie es übrigens! !
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