support for background transition overrides

css/reveal.css

@@ -1308,7 +1308,7 @@ body {
 
 
 /*********************************************
- * 
+ * PER-SLIDE BACKGROUNDS
  *********************************************/
 
 .reveal>.backgrounds {
@@ -1345,7 +1345,8 @@ body {
 	}
 
 /* Linear sliding transition style */
-.reveal[data-background-transition=linear]>.backgrounds .slide-background {
+.reveal[data-background-transition=linear]>.backgrounds .slide-background,
+.reveal>.backgrounds .slide-background[data-background-transition=linear] {
 	opacity: 1;
 
 	-webkit-backface-visibility: hidden;
@@ -1359,14 +1360,16 @@ body {
 	     -o-transition-duration: 800ms;
 	        transition-duration: 800ms;
 }
-	.reveal[data-background-transition=linear]>.backgrounds .slide-background.past {
+	.reveal[data-background-transition=linear]>.backgrounds .slide-background.past,
+	.reveal>.backgrounds .slide-background.past[data-background-transition=linear] {
 		-webkit-transform: translate(-100%, 0);
 		   -moz-transform: translate(-100%, 0);
 		    -ms-transform: translate(-100%, 0);
 		     -o-transform: translate(-100%, 0);
 		        transform: translate(-100%, 0);
 	}
-	.reveal[data-background-transition=linear]>.backgrounds .slide-background.future {
+	.reveal[data-background-transition=linear]>.backgrounds .slide-background.future,
+	.reveal>.backgrounds .slide-background.future[data-background-transition=linear] {
 		-webkit-transform: translate(100%, 0);
 		   -moz-transform: translate(100%, 0);
 		    -ms-transform: translate(100%, 0);
@@ -1374,14 +1377,16 @@ body {
 		        transform: translate(100%, 0);
 	}
 
-	.reveal[data-background-transition=linear]>.backgrounds .slide-background>.slide-background.past {
+	.reveal[data-background-transition=linear]>.backgrounds .slide-background>.slide-background.past,
+	.reveal>.backgrounds .slide-background>.slide-background.past[data-background-transition=linear] {
 		-webkit-transform: translate(0, -100%);
 		   -moz-transform: translate(0, -100%);
 		    -ms-transform: translate(0, -100%);
 		     -o-transform: translate(0, -100%);
 		        transform: translate(0, -100%);
 	}
-	.reveal[data-background-transition=linear]>.backgrounds .slide-background>.slide-background.future {
+	.reveal[data-background-transition=linear]>.backgrounds .slide-background>.slide-background.future,
+	.reveal>.backgrounds .slide-background>.slide-background.future[data-background-transition=linear] {
 		-webkit-transform: translate(0, 100%);
 		   -moz-transform: translate(0, 100%);
 		    -ms-transform: translate(0, 100%);

js/reveal.js

@@ -274,7 +274,8 @@ var Reveal = (function(){
 				backgroundSize: slide.getAttribute( 'data-background-size' ),
 				backgroundColor: slide.getAttribute( 'data-background-color' ),
 				backgroundRepeat: slide.getAttribute( 'data-background-repeat' ),
-				backgroundPosition: slide.getAttribute( 'data-background-position' )
+				backgroundPosition: slide.getAttribute( 'data-background-position' ),
+				backgroundTransition: slide.getAttribute( 'data-background-transition' )
 			};
 
 			var element = document.createElement( 'div' );
@@ -295,6 +296,7 @@ var Reveal = (function(){
 			if( data.backgroundColor ) element.style.backgroundColor = data.backgroundColor;
 			if( data.backgroundRepeat ) element.style.backgroundRepeat = data.backgroundRepeat;
 			if( data.backgroundPosition ) element.style.backgroundPosition = data.backgroundPosition;
+			if( data.backgroundTransition ) element.setAttribute( 'data-background-transition', data.backgroundTransition );
 
 			container.appendChild( element );