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html5 canvas壓縮上傳圖檔,jquery+html5+canvas實作圖檔 預覽 壓縮 上傳

javascirpt(function($){

$.fn.extend({

aiiUpload:function(obj)

{

if(typeof obj !="object")

{

alert(‘參數錯誤‘);

return;

}

var imageWidth,imageHeight;

var base64;

var file_num=0;

var fileInput=$(this);

var fileInputId=fileInput.attr(‘id‘);

createDoc(‘#‘+fileInputId,obj.method,obj.action);

$(‘#aii_file‘).change(function(){

if(test(this.value)==false)

{

alert(‘格式錯誤‘);

return;

}

var objUrl = getObjectURL(this.files[0]);

if (objUrl)

{

imgBefore(objUrl,file_num);

render(objUrl,obj.max_h,obj.max_w,file_num);

file_num++;

}

});

}

});

function createDoc(objID,form_method,form_action)

{

var element=$(objID);

element.append(‘

‘).append(‘‘);

}

function test(value)

{

var regexp=new RegExp("(.JPEG|.jpeg|.JPG|.jpg|.GIF|.gif|.BMP|.bmp|.PNG|.png)$",‘g‘);

return regexp.test(value);

}

function render(src,MaximgW,MaximgH,idnum)

{

var image=new Image();

image.οnlοad=function()

{

var canvas=document.getElementById(‘canvas‘);

if(image.width>image.height)

{

imageWidth=MaximgW;

imageHeight=MaximgH*(image.height/image.width);

}

else if(image.width

{

imageHeight=MaximgH;

imageWidth=MaximgW*(image.width/image.height);

}

else

{

imageWidth=MaximgW;

imageHeight=MaximgH;

}

canvas.width=imageWidth;

canvas.height=imageHeight;

var con=canvas.getContext(‘2d‘);

con.clearRect(0,0,canvas.width,canvas.height);

con.drawImage(image,0,0,imageWidth,imageHeight);

base64=canvas.toDataURL(‘image/jpeg‘,0.5).substr(22);

add_doc(base64,idnum);

}

image.src=src;

};

//建立一個可存取到該file的url

function getObjectURL(file) {

var url = null ;

if (window.createObjectURL!=undefined) { // basic

url = window.createObjectURL(file) ;

} else if (window.URL!=undefined) { // mozilla(firefox)

url = window.URL.createObjectURL(file) ;

} else if (window.webkitURL!=undefined) { // webkit or chrome

url = window.webkitURL.createObjectURL(file) ;

}

return url ;

}

//預覽

function imgBefore(objUrl,idnum)

{

var li=‘

html5 canvas壓縮上傳圖檔,jquery+html5+canvas實作圖檔 預覽 壓縮 上傳

$(‘.viewList‘).append(li);

var img=$(‘#aiiImg_‘+idnum);

//預覽圖檔居中 填滿 代碼

console.log(‘asdfasdfasdf‘);

img.load(function(){

var imgw=img.width(),

imgh=img.height();

console.log(imgw);

console.log(imgh);

if(imgw>imgh)

{

img.css(‘height‘,‘100%‘);

img.css(‘width‘,‘auto‘);

img.css(‘marginLeft‘,-(img.width()-img.height())/2+‘px‘);

}

else if(imgw

{

img.css(‘width‘,‘100%‘);

img.css(‘height‘,‘auto‘);

img.css(‘marginTop‘,-(img.height()-img.width())/2+‘px‘);

}

});

}

function add_doc (base,idnum)

{

$(‘#aii_upload_form‘).append(‘‘);

}

})(jQuery);

function img_remove(element)

{

var num=$(element).prev().attr(‘idnum‘);

$(element).parent().remove();

$(‘#f_‘+num).remove();

console.log(‘asdf‘);

}