don't process pseudo elements for hidden elements; cleanup pseudo elements after render

src/Core.js

@@ -14,6 +14,14 @@ function h2clog(a) {
 
 _html2canvas.Util = {};
 
+_html2canvas.Util.isElementVisible = function (element) {
+  return (
+      _html2canvas.Util.getCSS( element, 'display' ) !== "none" && 
+      _html2canvas.Util.getCSS( element, 'visibility' ) !== "hidden" && 
+      !element.hasAttribute( "data-html2canvas-ignore" )
+    );
+};
+
 _html2canvas.Util.trimText = (function(native){ 
   return function(input){
     if(native) { return native.apply( input ); }

src/Parse.js

@@ -170,7 +170,7 @@ _html2canvas.Parse = function (images, options) {
         textList.forEach(function(word, index) {
           if (/.*[\u4E00-\u9FA5].*$/.test(word)) {
             word = word.split("");
-            word.unshift(index, 1)
+            word.unshift(index, 1);
             textList.splice.apply(textList, word);
           }
         });

src/Preload.js

@@ -212,10 +212,12 @@ _html2canvas.Preload = function( options ) {
          */
   }
 
-
-
   var uid = 0, injectStyle;
   function injectPseudoElements(el) {
+    if(!_html2canvas.Util.isElementVisible(el)) {
+      return;
+    }
+
     var before = getPseudoElement(el, ':before'),
     after = getPseudoElement(el, ':after');
     if(!before && !after) {
@@ -258,6 +260,17 @@ _html2canvas.Preload = function( options ) {
     }
   }
 
+  function cleanupPseudoElements(){
+    if(!injectStyle) { 
+      return; 
+    }
+    injectStyle.parentNode.removeChild(injectStyle);
+    injectStyle = undefined;
+
+    [].slice.apply(element.all || element.getElementsByTagName('*'))
+      .forEach(removePseudoElements);
+  }
+
   function getPseudoElement(el, which) {
     var elStyle = window.getComputedStyle(el, which);
     if(!elStyle || !elStyle.content) { return; }
@@ -380,19 +393,14 @@ _html2canvas.Preload = function( options ) {
         }
       }
 
-      if(injectStyle) {
-        injectStyle.parentNode.removeChild(injectStyle);
-        injectStyle = undefined;
-
-        [].slice.apply(element.all || element.getElementsByTagName('*'))
-          .forEach(removePseudoElements);
-      }
+      cleanupPseudoElements();
     },
 
     renderingDone: function() {
       if (timeoutTimer) {
         window.clearTimeout(timeoutTimer);
       }
+      cleanupPseudoElements();
     }
   };