add exception for wikimedia math images

Readability-readerable.js

@@ -29,9 +29,11 @@ var REGEXPS = {
 };
 
 function isNodeVisible(node) {
-  // Have to null-check node.style to deal with SVG and MathML nodes.
-  return (!node.style || node.style.display != "none") && !node.hasAttribute("hidden")
-    && (!node.hasAttribute("aria-hidden") || node.getAttribute("aria-hidden") != "true");
+  // Have to null-check node.style and node.className.indexOf to deal with SVG and MathML nodes.
+  return (!node.style || node.style.display != "none")
+  && !node.hasAttribute("hidden")
+  //check for "fallback-image" so that wikimedia math images are displayed
+  && (!node.hasAttribute("aria-hidden") || node.getAttribute("aria-hidden") != "true" || (node.className && node.className.indexOf && node.className.indexOf("fallback-image") !== -1));
 }
 
 /**

Readability.js

@@ -1796,9 +1796,11 @@ Readability.prototype = {
   },
 
   _isProbablyVisible: function(node) {
+    // Have to null-check node.style and node.className.indexOf to deal with SVG and MathML nodes.
     return (!node.style || node.style.display != "none")
       && !node.hasAttribute("hidden")
-      && (!node.hasAttribute("aria-hidden") || node.getAttribute("aria-hidden") != "true");
+      //check for "fallback-image" so that wikimedia math images are displayed
+      && (!node.hasAttribute("aria-hidden") || node.getAttribute("aria-hidden") != "true" || (node.className && node.className.indexOf && node.className.indexOf("fallback-image") !== -1));
   },
 
   /**

test/test-pages/wikipedia-3/expected-metadata.json

@@ -0,0 +1,8 @@
+{
+  "title": "Hermitian matrix - Wikipedia",
+  "byline": null,
+  "dir": "ltr",
+  "excerpt": "In mathematics, a Hermitian matrix (or self-adjoint matrix) is a complex square matrix that is equal to its own conjugate transpose—that is, the element in the i-th row and j-th column is equal to the complex conjugate of the element in the j-th row and i-th column, for all indices i and j:",
+  "siteName": null,
+  "readerable": true
+}