reveal.js writer: better handling of options.

Previously it was impossible to specify false values for
options that default to true; setting the option to false
just caused the portion of the template setting the option
to be omitted.

Now we prepopulate all the variables with their default
values, including them unconditionally and allowing them
to be overridden.

1 files changed, 70 insertions, 128 deletions

diff --git a/data/templates/default.revealjs b/data/templates/default.revealjs
index 8a77674dd..203983522 100644
--- a/data/templates/default.revealjs
+++ b/data/templates/default.revealjs
@@ -90,256 +90,198 @@ $endif$
       // Full list of configuration options available at:
       // https://revealjs.com/config/
       Reveal.initialize({
-$if(center)$
-        // Determines whether slide content should be vertically centered
-        center: $center$,
-$endif$      
-$if(controls)$
         // Display controls in the bottom right corner
         controls: $controls$,
-$endif$
-$if(controlsTutorial)$
+
         // Help the user learn the controls by providing hints, for example by
         // bouncing the down arrow when they first encounter a vertical slide
         controlsTutorial: $controlsTutorial$,
-$endif$
-$if(controlsLayout)$
+
         // Determines where controls appear, "edges" or "bottom-right"
         controlsLayout: '$controlsLayout$',
-$endif$
-$if(controlsBackArrows)$
+
         // Visibility rule for backwards navigation arrows; "faded", "hidden"
         // or "visible"
         controlsBackArrows: '$controlsBackArrows$',
-$endif$
-$if(progress)$
+
         // Display a presentation progress bar
         progress: $progress$,
-$endif$
-$if(slideNumber)$
+
         // Display the page number of the current slide
         slideNumber: $slideNumber$,
-$endif$
-$if(showSlideNumber)$
+
         // 'all', 'print', or 'speaker'
         showSlideNumber: '$showSlideNumber$',
-$endif$
+
         // Add the current slide number to the URL hash so that reloading the
         // page/copying the URL will return you to the same slide
-        hash: $if(hash)$$hash$$else$true$endif$,
-$if(hashOneBasedIndex)$
+        hash: $hash$,
+
         // Start with 1 for the hash rather than 0
         hashOneBasedIndex: $hashOneBasedIndex$,
-$endif$
-$if(history)$
+
+        // Flags if we should monitor the hash and change slides accordingly
+        respondToHashChanges: $respondToHashChanges$,
+
         // Push each slide change to the browser history
         history: $history$,
-$endif$
-$if(keyboard)$
+
         // Enable keyboard shortcuts for navigation
         keyboard: $keyboard$,
-$endif$
-$if(overview)$
+
         // Enable the slide overview mode
         overview: $overview$,
-$endif$
-$if(center)$
+
+        // Disables the default reveal.js slide layout (scaling and centering)
+        // so that you can use custom CSS layout
+        disableLayout: false,
+
         // Vertical centering of slides
         center: $center$,
-$endif$
-$if(touch)$
+
         // Enables touch navigation on devices with touch input
         touch: $touch$,
-$endif$
-$if(loop)$
+
         // Loop the presentation
         loop: $loop$,
-$endif$
-$if(rtl)$
+
         // Change the presentation direction to be RTL
         rtl: $rtl$,
-$endif$
-$if(navigationMode)$
+
         // see https://revealjs.com/vertical-slides/#navigation-mode
         navigationMode: '$navigationMode$',
-$endif$
-$if(shuffle)$
+
         // Randomizes the order of slides each time the presentation loads
         shuffle: $shuffle$,
-$endif$
-$if(fragments)$
+
         // Turns fragments on and off globally
         fragments: $fragments$,
-$endif$
-$if(fragmentInURL)$
+
         // Flags whether to include the current fragment in the URL,
         // so that reloading brings you to the same fragment position
         fragmentInURL: $fragmentInURL$,
-$endif$
-$if(embedded)$
+
         // Flags if the presentation is running in an embedded mode,
         // i.e. contained within a limited portion of the screen
         embedded: $embedded$,
-$endif$
-$if(help)$
+
         // Flags if we should show a help overlay when the questionmark
         // key is pressed
         help: $help$,
-$endif$
-$if(pause)$
-       // Flags if it should be possible to pause the presentation (blackout)
-       pause: $pause$,
-$endif$
-$if(showNotes)$
+
+        // Flags if it should be possible to pause the presentation (blackout)
+        pause: $pause$,
+
         // Flags if speaker notes should be visible to all viewers
         showNotes: $showNotes$,
-$endif$
-$if(autoPlayMedia)$
-        // Global override for autoplaying embedded media (video/audio/iframe)
-        // - null: Media will only autoplay if data-autoplay is present
-        // - true: All media will autoplay, regardless of individual setting
-        // - false: No media will autoplay, regardless of individual setting
+
+        // Global override for autoplaying embedded media (null/true/false)
         autoPlayMedia: $autoPlayMedia$,
-$endif$
-$if(preloadIframes)$
-        // Global override for preloading lazy-loaded iframes
-        // - null: Iframes with data-src AND data-preload will be loaded when within
-        //   the viewDistance, iframes with only data-src will be loaded when visible
-        // - true: All iframes with data-src will be loaded when within the viewDistance
-        // - false: All iframes with data-src will be loaded only when visible
+
+        // Global override for preloading lazy-loaded iframes (null/true/false)
         preloadIframes: $preloadIframes$,
-$endif$
-$if(autoSlide)$
+
         // Number of milliseconds between automatically proceeding to the
         // next slide, disabled when set to 0, this value can be overwritten
         // by using a data-autoslide attribute on your slides
         autoSlide: $autoSlide$,
-$endif$
-$if(autoSlideStoppable)$
+
         // Stop auto-sliding after user input
         autoSlideStoppable: $autoSlideStoppable$,
-$endif$
-$if(autoSlideMethod)$
+
         // Use this method for navigation when auto-sliding
         autoSlideMethod: $autoSlideMethod$,
-$endif$
-$if(defaultTiming)$
+
         // Specify the average time in seconds that you think you will spend
         // presenting each slide. This is used to show a pacing timer in the
         // speaker view
         defaultTiming: $defaultTiming$,
-$endif$
-$if(totalTime)$
-        // Specify the total time in seconds that is available to
-        // present.  If this is set to a nonzero value, the pacing
-        // timer will work out the time available for each slide,
-        // instead of using the defaultTiming value
-        totalTime: $totalTime$,
-$endif$
-$if(minimumTimePerSlide)$
-        // Specify the minimum amount of time you want to allot to
-        // each slide, if using the totalTime calculation method.  If
-        // the automated time allocation causes slide pacing to fall
-        // below this threshold, then you will see an alert in the
-        // speaker notes window
-        minimumTimePerSlide: $minimumTimePerSlide$,
-$endif$
-$if(mouseWheel)$
+
         // Enable slide navigation via mouse wheel
         mouseWheel: $mouseWheel$,
-$endif$
-$if(rollingLinks)$
-        // Apply a 3D roll to links on hover
-        rollingLinks: $rollingLinks$,
-$endif$
-$if(hideInactiveCursor)$
+
+        // The display mode that will be used to show slides
+        display: '$display$',
+
         // Hide cursor if inactive
         hideInactiveCursor: $hideInactiveCursor$,
-$endif$
-$if(hideCursorTime)$
+
         // Time before the cursor is hidden (in ms)
         hideCursorTime: $hideCursorTime$,
-$endif$
-$if(hideAddressBar)$
-        // Hides the address bar on mobile devices
-        hideAddressBar: $hideAddressBar$,
-$endif$
-$if(previewLinks)$
+
         // Opens links in an iframe preview overlay
         previewLinks: $previewLinks$,
-$endif$
-$if(transition)$
-        // Transition style
-        transition: '$transition$', // none/fade/slide/convex/concave/zoom
-$endif$
-$if(transitionSpeed)$
-        // Transition speed
-        transitionSpeed: '$transitionSpeed$', // default/fast/slow
-$endif$
-$if(backgroundTransition)$
+
+        // Transition style (none/fade/slide/convex/concave/zoom)
+        transition: '$transition$',
+
+        // Transition speed (default/fast/slow)
+        transitionSpeed: '$transitionSpeed$',
+
         // Transition style for full page slide backgrounds
-        backgroundTransition: '$backgroundTransition$', // none/fade/slide/convex/concave/zoom
-$endif$
-$if(viewDistance)$
+        // (none/fade/slide/convex/concave/zoom)
+        backgroundTransition: '$backgroundTransition$',
+
         // Number of slides away from the current that are visible
         viewDistance: $viewDistance$,
-$endif$
-$if(mobileViewDistance)$
+
         // Number of slides away from the current that are visible on mobile
         // devices. It is advisable to set this to a lower number than
         // viewDistance in order to save resources.
         mobileViewDistance: $mobileViewDistance$,
-$endif$
 $if(parallaxBackgroundImage)$
+
         // Parallax background image
         parallaxBackgroundImage: '$parallaxBackgroundImage$', // e.g. "'https://s3.amazonaws.com/hakim-static/reveal-js/reveal-parallax-1.jpg'"
 $else$
 $if(background-image)$
+
        // Parallax background image
        parallaxBackgroundImage: '$background-image$', // e.g. "'https://s3.amazonaws.com/hakim-static/reveal-js/reveal-parallax-1.jpg'"
 $endif$
 $endif$
 $if(parallaxBackgroundSize)$
+
         // Parallax background size
         parallaxBackgroundSize: '$parallaxBackgroundSize$', // CSS syntax, e.g. "2100px 900px"
 $endif$
 $if(parallaxBackgroundHorizontal)$
+
         // Amount to move parallax background (horizontal and vertical) on slide change
         // Number, e.g. 100
         parallaxBackgroundHorizontal: $parallaxBackgroundHorizontal$,
 $endif$
 $if(parallaxBackgroundVertical)$
+
         parallaxBackgroundVertical: $parallaxBackgroundVertical$,
 $endif$
 $if(width)$
+
         // The "normal" size of the presentation, aspect ratio will be preserved
         // when the presentation is scaled to fit different resolutions. Can be
         // specified using percentage units.
         width: $width$,
 $endif$
 $if(height)$
+
         height: $height$,
 $endif$
 $if(margin)$
+
         // Factor of the display size that should remain empty around the content
         margin: $margin$,
 $endif$
 $if(minScale)$
+
         // Bounds for smallest/largest possible scale to apply to content
         minScale: $minScale$,
 $endif$
 $if(maxScale)$
+
         maxScale: $maxScale$,
 $endif$
-$if(zoomKey)$
-        // Modifier key used to click-zoom to part of the slide
-        zoomKey: '$zoomKey$',
-$endif$
-$if(display)$
-        // The display mode that will be used to show slides
-        display: '$display$',
-$endif$
 $if(mathjax)$
+
         math: {
           mathjax: '$mathjaxurl$',
           config: 'TeX-AMS_HTML-full',