From 02ab96dc5f6f256b23f91bf9b534f6cd43ceea8f Mon Sep 17 00:00:00 2001
From: arrix <arrixzhou@gmail.com>
Date: Tue, 6 Aug 2013 10:34:13 +0800
Subject: [PATCH] passes z-index8 non-positioned element with opactiy < 1

The MDN article Understanding_z_index/Stacking_and_float is wrong about this
---
 src/Parse.js    | 1 +
 src/Renderer.js | 8 +++++---
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/Parse.js b/src/Parse.js
index 5ad7b1d..488b38e 100644
--- a/src/Parse.js
+++ b/src/Parse.js
@@ -331,6 +331,7 @@ _html2canvas.Parse = function (images, options) {
     stack.zIndex = newContext = h2czContext(zIndex);
     newContext.isPositioned = isPositioned;
     newContext.isFloated = isFloated;
+    newContext.opacity = opacity;
 
     if (zIndex !== 'auto' || opacity < 1) {
       newContext.ownStacking = true;
diff --git a/src/Renderer.js b/src/Renderer.js
index 1d039c9..d516229 100644
--- a/src/Renderer.js
+++ b/src/Renderer.js
@@ -48,10 +48,12 @@ _html2canvas.Renderer = function(parseQueue, options){
 
         // positioned after static
         context[zi].forEach(function(v) {
-          if (v.node.zIndex.isFloated) {
-            floated.push(v);
-          } else if (v.node.zIndex.isPositioned) {
+          if (v.node.zIndex.isPositioned || v.node.zIndex.opacity < 1) {
+            // http://www.w3.org/TR/css3-color/#transparency
+            // non-positioned element with opactiy < 1 should be stacked as if it were a positioned element with ‘z-index: 0’ and ‘opacity: 1’.
             positioned.push(v);
+          } else if (v.node.zIndex.isFloated) {
+            floated.push(v);
           } else {
             nonPositioned.push(v);
           }