From bd1e82d19af43294df240f33a738e8d1bc293444 Mon Sep 17 00:00:00 2001
From: Hakim El Hattab <hakim.elhattab@gmail.com>
Date: Mon, 20 May 2019 11:24:05 +0200
Subject: [PATCH] new API methods for getting horizontal/vertical slides, force
 linear navigation for one-dimensional decks

---
 README.md    | 11 ++++++++-
 js/reveal.js | 64 ++++++++++++++++++++++++++++++++++++++++++++++------
 2 files changed, 67 insertions(+), 8 deletions(-)

diff --git a/README.md b/README.md
index 7bd33c64..283801f2 100644
--- a/README.md
+++ b/README.md
@@ -629,6 +629,15 @@ Reveal.getProgress();       // (0 == first slide, 1 == last slide)
 Reveal.getSlides();         // Array of all slides
 Reveal.getTotalSlides();    // Total number of slides
 
+// Returns an array with all horizontal/vertical slides in the deck
+Reveal.getHorizontalSlides();
+Reveal.getVerticalSlides();
+
+// Checks if the presentation contains two or more
+// horizontal/vertical slides
+Reveal.hasHorizontalSlides();
+Reveal.hasVerticalSlides();
+
 // Returns the speaker notes for the current slide
 Reveal.getSlideNotes();
 
@@ -640,7 +649,7 @@ Reveal.isPaused();
 Reveal.isAutoSliding();
 
 // Returns the top-level DOM element
-getRevealElement(); // <div class="reveal">...</div>
+Reveal.getRevealElement(); // <div class="reveal">...</div>
 ```
 
 ### Custom Key Bindings
diff --git a/js/reveal.js b/js/reveal.js
index cd51ccac..08412bc3 100644
--- a/js/reveal.js
+++ b/js/reveal.js
@@ -3337,7 +3337,7 @@
 			}
 
 			// Flag if there are ANY vertical slides, anywhere in the deck
-			if( dom.wrapper.querySelectorAll( '.slides>section>section' ).length ) {
+			if( hasVerticalSlides() ) {
 				dom.wrapper.classList.add( 'has-vertical-slides' );
 			}
 			else {
@@ -3345,7 +3345,7 @@
 			}
 
 			// Flag if there are ANY horizontal slides, anywhere in the deck
-			if( dom.wrapper.querySelectorAll( '.slides>section' ).length > 1 ) {
+			if( hasHorizontalSlides() ) {
 				dom.wrapper.classList.add( 'has-horizontal-slides' );
 			}
 			else {
@@ -4468,7 +4468,44 @@
 	 */
 	function getSlides() {
 
-		return toArray( dom.wrapper.querySelectorAll( SLIDES_SELECTOR + ':not(.stack)' ));
+		return toArray( dom.wrapper.querySelectorAll( SLIDES_SELECTOR + ':not(.stack)' ) );
+
+	}
+
+	/**
+	 * Returns a list of all horizontal slides in the deck. Each
+	 * vertical stack is included as one horizontal slide in the
+	 * resulting array.
+	 */
+	function getHorizontalSlides() {
+
+		return toArray( dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) );
+
+	}
+
+	/**
+	 * Returns all vertical slides that exist within this deck.
+	 */
+	function getVerticalSlides() {
+
+		return toArray( dom.wrapper.querySelectorAll( '.slides>section>section' ) );
+
+	}
+
+	/**
+	 * Returns true if there are at least two horizontal slides.
+	 */
+	function hasHorizontalSlides() {
+
+		return getHorizontalSlides().length > 1;
+	}
+
+	/**
+	 * Returns true if there are at least two vertical slides.
+	 */
+	function hasVerticalSlides() {
+
+		return getVerticalSlides().length > 1;
 
 	}
 
@@ -5183,6 +5220,10 @@
 			return false;
 		}
 
+		// Use linear navigation if we're configured to OR if
+		// the presentation is one-dimensional
+		var useLinearMode = config.navigationMode === 'linear' || !hasHorizontalSlides() || !hasVerticalSlides();
+
 		var triggered = false;
 
 		// 1. User defined key bindings
@@ -5255,7 +5296,7 @@
 				if( firstSlideShortcut ) {
 					slide( 0 );
 				}
-				else if( !isOverview() && config.navigationMode === 'linear' ) {
+				else if( !isOverview() && useLinearMode ) {
 					navigatePrev();
 				}
 				else {
@@ -5267,7 +5308,7 @@
 				if( lastSlideShortcut ) {
 					slide( Number.MAX_VALUE );
 				}
-				else if( !isOverview() && config.navigationMode === 'linear' ) {
+				else if( !isOverview() && useLinearMode ) {
 					navigateNext();
 				}
 				else {
@@ -5276,7 +5317,7 @@
 			}
 			// K, UP
 			else if( keyCode === 75 || keyCode === 38 ) {
-				if( !isOverview() && config.navigationMode === 'linear' ) {
+				if( !isOverview() && useLinearMode ) {
 					navigatePrev();
 				}
 				else {
@@ -5285,7 +5326,7 @@
 			}
 			// J, DOWN
 			else if( keyCode === 74 || keyCode === 40 ) {
-				if( !isOverview() && config.navigationMode === 'linear' ) {
+				if( !isOverview() && useLinearMode ) {
 					navigateNext();
 				}
 				else {
@@ -5944,6 +5985,15 @@
 		// Returns the speaker notes string for a slide, or null
 		getSlideNotes: getSlideNotes,
 
+		// Returns an array with all horizontal/vertical slides in the deck
+		getHorizontalSlides: getHorizontalSlides,
+		getVerticalSlides: getVerticalSlides,
+
+		// Checks if the presentation contains two or more
+		// horizontal/vertical slides
+		hasHorizontalSlides: hasHorizontalSlides,
+		hasVerticalSlides: hasVerticalSlides,
+
 		// Returns the previous slide element, may be null
 		getPreviousSlide: function() {
 			return previousSlide;