From 7f6239e987d6d0fb16037c93f183f6b36c3acc02 Mon Sep 17 00:00:00 2001
From: Jake Howard <git@theorangeone.net>
Date: Thu, 13 Aug 2015 14:04:18 +0100
Subject: [PATCH] Moved old functions into object

---
 parallax.js | 33 ++++++++++++++++++++++++++-------
 1 file changed, 26 insertions(+), 7 deletions(-)

diff --git a/parallax.js b/parallax.js
index eb03a2a..a25347b 100644
--- a/parallax.js
+++ b/parallax.js
@@ -1,20 +1,39 @@
 var Parallax = {
-    initialise: function() {
-
+    initialise: function(createEvents) {
+        $(this.ident).each(function(){
+            // Calculate Offset
+            inset = $(this).attr('parallax-inset');
+            image_height = $(this).height();
+            range = image_height / inset;
+            $(this).attr('parallax-offset', range / 2);
+        });
+        console.log("Parallax Initialised.");
+        if (createEvents) {this.createEvents();}
+        this.calculate();
     },
     calculate: function() {
+        window_top = $(window).scrollTop();
+        window_bottom = window_top + $(window).height();
+        $(this.ident).each(function(){
+            if (!is_on_screen(this) || !$(this).attr('parallax-offset') != false) { return; }
+            element = $(this);
+            center_pos = (element.offset().top - $(window).scrollTop()) + (element.height() / 2);
+            perc = -(0.5 - ((window_top - center_pos) / window_bottom));
 
+            pos = Math.round((perc * element.attr('parallax-offset')) * 100) / 100;
+            element.css('background-position',"0px " + pos + "px");
+        });
     },
-    events: function() {
-
+    createEvents: function() {
+        $(window).scroll(function() { Parallax.calculate(); });
+        $(window).resize(function() { Parallax.initialise(); })
     },
     ident: '.parallax'
 }
 
 function is_on_screen(elm) {
-
-    var vpH = $(window).height(), // Viewport Height
-        st = $(window).scrollTop(), // Scroll Top
+    var vpH = $(window).height(),
+        st = $(window).scrollTop(),
         y = $(elm).offset().top,
         elementHeight = $(elm).height();
     return ((y < (vpH + st)) && (y > (st - elementHeight)));