From d56fc820db7007b6cc9ab5b98e2ba268f8304ee3 Mon Sep 17 00:00:00 2001
From: Peter Dietrich <peter.dietrich@smartpixelmedia.de>
Date: Thu, 19 Jul 2012 17:41:52 +0200
Subject: [PATCH] If no heading is in view, uses fallback

---
 scripts/setup.js | 73 +++++++++++++++++++++++++++++++-----------------
 1 file changed, 47 insertions(+), 26 deletions(-)

diff --git a/scripts/setup.js b/scripts/setup.js
index 23ef869..49695dc 100644
--- a/scripts/setup.js
+++ b/scripts/setup.js
@@ -26,33 +26,54 @@
 })(jQuery);
 
 (function ($) {
-	//Add current view's highlighting to the navigation 
-	$(window).scroll(function() {
-		//console.log("They see me scrollin, they hatin");
+    //Add current view's highlighting to the navigation
+    
+    /** helper for highlighting */
+    function highlightNav(navLinks,id)
+    {
+        navLinks.filter('[href="/#'+id+'"]').addClass("active");
+    }
 
-		//clear highlighting
-		var navLinks=$('.site-navigation a')
-		navLinks.removeClass("active");
+    $(window).scroll(function() {
+        //console.log("They see me scrollin, they hatin");
 
-		//calc current viewport
-		var viewTop = $(window).scrollTop();
-		var viewBottom = viewTop + $(window).height();
+        //clear highlighting
+        var navLinks = $('.site-navigation a');
+        navLinks.removeClass("active");
 
-		//for all h1 and h2 elements, check if they are visible
-		//performance tweak: stop each() after the first element is found to be behind view
-		$('h1, h2').each(function(i,e) {
-				//get element position;
-				var eTop = $(e).offset().top;
-				var eBottom = eTop + $(e).height();
-				if (eTop >= viewTop) {
-					if (eBottom <= viewBottom) {
-						//filter cached navLinks
-						navLinks.filter('[href="/#'+e.id+'"]').addClass("active");
-					} else {
-						//console.log("Start skipping test with "+e.id);
-						return false;
-					}
-				}
-		});
-	});
+        //calc current viewport
+        var viewTop = $(window).scrollTop();
+        var viewBottom = viewTop + $(window).height();
+
+        //for all h1 and h2 elements, check if they are visible
+        //performance tweak: stop each() after the first element is found to be behind view
+        var previous = "";
+        var foundOne = false;
+        var fallback = "";
+        $('h1, h2').each(function(i,e) {
+            //get element position;
+            var eTop = $(e).offset().top;
+            var eBottom = eTop + $(e).height();
+            var id=e.id;
+
+            if (eTop >= viewTop) {
+                //if we are passed the view and no heading was highlighted yet, store previous one as fallback
+                if (! foundOne) {
+                    fallback=previous;
+                }
+                if (eBottom <= viewBottom) {
+                    highlightNav(navLinks, id);
+                    foundOne = true;
+                } else {
+                    return false; //break the each(), the rest is below
+                }
+            }
+            previous=id;
+        });
+        //no h1/h2 is in the viewport, so highlight the last one above
+        if (! foundOne) {
+            highlightNav(navLinks, fallback);
+        }
+    });
 })(jQuery);
+