fix overview rendering issues in latest chrome #1649

css/reveal.css

@@ -1059,6 +1059,8 @@ body {
     visibility: visible;
     outline: 10px solid rgba(150, 150, 150, 0.1);
     outline-offset: 10px; }
+  .reveal.overview .backgrounds .slide-background.stack {
+    overflow: visible; }
 
 .reveal.overview .slides section,
 .reveal.overview-deactivating .slides section {
@@ -1070,10 +1072,6 @@ body {
   -webkit-transition: none;
           transition: none; }
 
-.reveal.overview-animated .slides {
-  -webkit-transition: -webkit-transform 0.4s ease;
-          transition: transform 0.4s ease; }
-
 /*********************************************
  * RTL SUPPORT
  *********************************************/

css/reveal.scss

@@ -1101,6 +1101,10 @@ body {
 		outline: 10px solid rgba(150,150,150,0.1);
 		outline-offset: 10px;
 	}
+
+	.backgrounds .slide-background.stack {
+		overflow: visible;
+	}
 }
 
 // Disable transitions transitions while we're activating
@@ -1115,10 +1119,6 @@ body {
 	transition: none;
 }
 
-.reveal.overview-animated .slides {
-	transition: transform 0.4s ease;
-}
-
 
 /*********************************************
  * RTL SUPPORT

js/reveal.js

@@ -1797,6 +1797,10 @@
 			updateProgress();
 			updateParallax();
 
+			if( isOverview() ) {
+				updateOverview();
+			}
+
 		}
 
 	}
@@ -2012,11 +2016,14 @@
 	 */
 	function updateOverview() {
 
+		var vmin = Math.min( window.innerWidth, window.innerHeight );
+		var scale = Math.max( vmin / 5, 150 ) / vmin;
+
 		transformSlides( {
 			overview: [
+				'scale('+ scale +')',
 				'translateX('+ ( -indexh * overviewSlideWidth ) +'px)',
-				'translateY('+ ( -indexv * overviewSlideHeight ) +'px)',
-				'translateZ('+ ( window.innerWidth < 400 ? -1000 : -2500 ) +'px)'
+				'translateY('+ ( -indexv * overviewSlideHeight ) +'px)'
 			].join( ' ' )
 		} );