html2canvas.Preload = function(element, opts){
var options = {
"proxy": "http://html2canvas.appspot.com/"
},
images = [],
pageOrigin = window.location.protocol + window.location.host,
imagesLoaded = 0,
methods,
i,
count = 0,
doc = element.ownerDocument,
domImages = doc.images, // TODO probably should limit it to images present in the element only
imgLen = domImages.length,
link = doc.createElement("a");
opts = opts || {};
options = html2canvas.Util.Extend(opts, options);
element = element || doc.body;
function isSameOrigin(url){
link.href = url;
return ((link.protocol + link.host) === pageOrigin);
}
function getIndex(array,src){
var i, arrLen;
if (array.indexOf){
return array.indexOf(src);
}else{
for(i = 0, arrLen = array.length; i < arrLen; i+=1){
if(this[i] === src) {
return i;
}
}
return -1;
}
}
function start(){
if (images.length === 0 || imagesLoaded === images.length/2){
/*
this.log('Finished loading '+this.imagesLoaded+' images, Started parsing');
this.bodyOverflow = document.getElementsByTagName('body')[0].style.overflow;
document.getElementsByTagName('body')[0].style.overflow = "hidden";
*/
if (typeof options.complete === "function"){
options.complete(images);
}
}
}
function proxyGetImage(url, img){
link.href = url;
url = link.href; // work around for pages with base href="" set
var callback_name,
scriptUrl = options.proxy,
script;
callback_name = 'html2canvas_' + count;
if (scriptUrl.indexOf("?") > -1) {
scriptUrl += "&";
} else {
scriptUrl += "?";
}
scriptUrl += 'url=' + encodeURIComponent(url) + '&callback=' + callback_name;
window[callback_name] = function(a){
if (a.substring(0,6) === "error:"){
images.splice(getIndex(images, url), 2);
start();
}else{
img.onload = function(){
imagesLoaded+=1;
start();
};
img.src = a;
}
delete window[callback_name];
};
count += 1;
script = doc.createElement("script");
script.setAttribute("src", scriptUrl);
script.setAttribute("type", "text/javascript");
window.document.body.appendChild(script);
/*
// enable xhr2 requests where available (no need for base64 / json)
$.ajax({
data:{
xhr2:false,
url:url
},
url: options.proxy,
dataType: "jsonp",
success: function(a){
if (a.substring(0,6) === "error:"){
images.splice(getIndex(images, url), 2);
start();
}else{
img.onload = function(){
imagesLoaded+=1;
start();
};
img.src = a;
}
},
error: function(){
images.splice(getIndex(images, url), 2);
start();
}
});
*/
}
function getImages (el) {
// if (!this.ignoreRe.test(el.nodeName)){
//
var contents = html2canvas.Util.Children(el),
i,
contentsLen = contents.length,
background_image,
src,
img;
for (i = 0; i < contentsLen; i+=1 ){
// var ignRe = new RegExp("("+this.ignoreElements+")");
// if (!ignRe.test(element.nodeName)){
getImages(contents[i]);
// }
}
// }
if (el.nodeType === 1 || el.nodeType === undefined){
background_image = html2canvas.Util.getCSS(el, 'backgroundImage');
if ( background_image && background_image !== "1" && background_image !== "none" ) {
// TODO add multi image background support
if (background_image.substring(0,7) === "-webkit" || background_image.substring(0,3) === "-o-" || background_image.substring(0,4) === "-moz") {
img = html2canvas.Generate.Gradient( background_image, html2canvas.Util.Bounds( el ) );
if ( img !== undefined ){
images.push(background_image);
images.push(img);
imagesLoaded++;
start();
}
} else {
src = html2canvas.Util.backgroundImage(background_image.match(/data:image\/.*;base64,/i) ? background_image : background_image.split(",")[0]);
methods.loadImage(src);
}
/*
if (background_image && background_image !== "1" && background_image !== "none" && background_image.substring(0,7) !== "-webkit" && background_image.substring(0,3)!== "-o-" && background_image.substring(0,4) !== "-moz"){
// TODO add multi image background support
src = html2canvas.Util.backgroundImage(background_image.split(",")[0]);
methods.loadImage(src); */
}
}
}
methods = {
loadImage: function( src ) {
var img;
if ( getIndex(images, src) === -1 ) {
if ( src.match(/data:image\/.*;base64,/i) ) {
//Base64 src
img = new Image();
img.src = src.replace(/url\(['"]{0,}|['"]{0,}\)$/ig, '');
images.push( src );
images.push( img );
imagesLoaded+=1;
start();
}else if ( isSameOrigin( src ) ) {
images.push( src );
img = new Image();
img.onload = function() {
imagesLoaded+=1;
start();
};
img.onerror = function() {
images.splice( getIndex( images, img.src ), 2 );
start();
};
img.src = src;
images.push(img);
}else if ( options.proxy ){
// console.log('b'+src);
images.push( src );
img = new Image();
proxyGetImage( src, img );
images.push( img );
}
}
}
};
// add something to array
images.push('start');
getImages( element );
// load
images
for (i = 0; i < imgLen; i+=1){
var imgSrc = domImages[i].getAttribute( "src" );
if ( imgSrc ) {
methods.loadImage( imgSrc );
}
}
// remove 'start'
images.splice(0, 1);
if ( images.length === 0 ) {
start();
}
return methods;
};