Merge pull request #492 from jessetan/raf-scroll

Debounce scroll and resize through rAF

Author: ericholscher

js/theme.js

@@ -29,16 +29,21 @@ function ThemeNav () {
                 // Set scroll monitor
                 self.win.on('scroll', function () {
                     if (!self.linkScroll) {
-                        self.winScroll = true;
+                        if (!self.winScroll) {
+                            self.winScroll = true;
+                            requestAnimationFrame(function() { self.onScroll(); });
+                        }
                     }
                 });
-                setInterval(function () { if (self.winScroll) self.onScroll(); }, 25);
 
                 // Set resize monitor
                 self.win.on('resize', function () {
-                    self.winResize = true;
+                    if (!self.winResize) {
+                        self.winResize = true;
+                        requestAnimationFrame(function() { self.onResize(); });
+                    }
                 });
-                setInterval(function () { if (self.winResize) self.onResize(); }, 25);
+
                 self.onResize();
             });
         };
@@ -166,3 +171,33 @@ module.exports.ThemeNav = ThemeNav();
 if (typeof(window) != 'undefined') {
     window.SphinxRtdTheme = { StickyNav: module.exports.ThemeNav };
 }
+
+
+// requestAnimationFrame polyfill by Erik Möller. fixes from Paul Irish and Tino Zijdel
+// https://gist.github.com/paulirish/1579671
+// MIT license
+
+(function() {
+    var lastTime = 0;
+    var vendors = ['ms', 'moz', 'webkit', 'o'];
+    for(var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {
+        window.requestAnimationFrame = window[vendors[x]+'RequestAnimationFrame'];
+        window.cancelAnimationFrame = window[vendors[x]+'CancelAnimationFrame']
+                                   || window[vendors[x]+'CancelRequestAnimationFrame'];
+    }
+
+    if (!window.requestAnimationFrame)
+        window.requestAnimationFrame = function(callback, element) {
+            var currTime = new Date().getTime();
+            var timeToCall = Math.max(0, 16 - (currTime - lastTime));
+            var id = window.setTimeout(function() { callback(currTime + timeToCall); },
+              timeToCall);
+            lastTime = currTime + timeToCall;
+            return id;
+        };
+
+    if (!window.cancelAnimationFrame)
+        window.cancelAnimationFrame = function(id) {
+            clearTimeout(id);
+        };
+}());