move pointer logic out to own controller

js/controllers/pointer.js

@@ -0,0 +1,118 @@
+/**
+ * Handles hiding of the pointer/cursor when inactive.
+ */
+export default class Pointer {
+
+	constructor( Reveal ) {
+
+		this.Reveal = Reveal;
+
+		// Throttles mouse wheel navigation
+		this.lastMouseWheelStep = 0;
+
+		// Is the mouse pointer currently hidden from view
+		this.cursorHidden = false;
+
+		// Timeout used to determine when the cursor is inactive
+		this.cursorInactiveTimeout = 0;
+
+		this.onDocumentCursorActive = this.onDocumentCursorActive.bind( this );
+		this.onDocumentMouseScroll = this.onDocumentMouseScroll.bind( this );
+
+	}
+
+	/**
+	 * Called when the reveal.js config is updated.
+	 */
+	configure( config, oldConfig ) {
+
+		if( config.mouseWheel ) {
+			document.addEventListener( 'DOMMouseScroll', this.onDocumentMouseScroll, false ); // FF
+			document.addEventListener( 'mousewheel', this.onDocumentMouseScroll, false );
+		}
+		else {
+			document.removeEventListener( 'DOMMouseScroll', this.onDocumentMouseScroll, false ); // FF
+			document.removeEventListener( 'mousewheel', this.onDocumentMouseScroll, false );
+		}
+
+		// Auto-hide the mouse pointer when its inactive
+		if( config.hideInactiveCursor ) {
+			document.addEventListener( 'mousemove', this.onDocumentCursorActive, false );
+			document.addEventListener( 'mousedown', this.onDocumentCursorActive, false );
+		}
+		else {
+			this.showCursor();
+
+			document.removeEventListener( 'mousemove', this.onDocumentCursorActive, false );
+			document.removeEventListener( 'mousedown', this.onDocumentCursorActive, false );
+		}
+
+	}
+
+	/**
+	 * Shows the mouse pointer after it has been hidden with
+	 * #hideCursor.
+	 */
+	showCursor() {
+
+		if( this.cursorHidden ) {
+			this.cursorHidden = false;
+			this.Reveal.getRevealElement().style.cursor = '';
+		}
+
+	}
+
+	/**
+	 * Hides the mouse pointer when it's on top of the .reveal
+	 * container.
+	 */
+	hideCursor() {
+
+		if( this.cursorHidden === false ) {
+			this.cursorHidden = true;
+			this.Reveal.getRevealElement().style.cursor = 'none';
+		}
+
+	}
+
+	/**
+	 * Called whenever there is mouse input at the document level
+	 * to determine if the cursor is active or not.
+	 *
+	 * @param {object} event
+	 */
+	onDocumentCursorActive( event ) {
+
+		this.showCursor();
+
+		clearTimeout( this.cursorInactiveTimeout );
+
+		this.cursorInactiveTimeout = setTimeout( this.hideCursor.bind( this ), this.Reveal.getConfig().hideCursorTime );
+
+	}
+
+	/**
+	 * Handles mouse wheel scrolling, throttled to avoid skipping
+	 * multiple slides.
+	 *
+	 * @param {object} event
+	 */
+	onDocumentMouseScroll( event ) {
+
+		if( Date.now() - this.lastMouseWheelStep > 1000 ) {
+
+			this.lastMouseWheelStep = Date.now();
+
+			let delta = event.detail || -event.wheelDelta;
+			if( delta > 0 ) {
+				this.Reveal.next();
+			}
+			else if( delta < 0 ) {
+				this.Reveal.prev();
+			}
+
+		}
+
+	}
+
+}