feat: Add PDF export options

[gquintana]

Add options described in https://github.com/hakimel/reveal.js/#pdf-export

[ggrossetie]

You need to use lowercase:

Suggested change

	|:revealjs_pdfSeparateFragments:
	|:revealjs_pdfseparatefragments:

See: 134bf3d

[gquintana]

There are already revealjs_parallaxBackgroundHorizontal, revealjs_showNotes, etc. most options are revealjs_camelCaseOption. The only exceptions are revealjs_minscale and revealjs_maxscale. It doesn't make sense to me lowercase the option.
Are you sure you want me to change this?

[ggrossetie]

There are already revealjs_parallaxBackgroundHorizontal, revealjs_showNotes, etc. most options are revealjs_camelCaseOption. The only exceptions are revealjs_minscale and revealjs_maxscale. It doesn't make sense to me lowercase the option.

It has changed recently, now all the attributes are lowercased (on master).

Are you sure you want me to change this?

Yes.

Although uppercase characters are permitted in an attribute entry (the place where an attribute is defined), the attribute name is converted to lowercase before being stored. The attribute name in an attribute reference is also converted to lowercase before the attribute is resolved. For example, URI, Uri and uRI are all treated as uri. (See issue #509 for a proposed change to this restriction). A best practice is to only use lowercase for letters in the name and avoid starting the name with a number.

https://asciidoctor.org/docs/user-manual/#attribute-restrictions

In short, you can define :revealjs_camelCaseOption: in your document but the attribute name will be converted to revealjs_camelcaseoption. So in the template we must use lowercase.
To avoid confusion, we also use lowercase in the documentation.

[gquintana]

@Mogztter On the branch master, it's still camel case, there's something I don't understand? Your link is pointing to asciidoctor manual, not asciidoctor-reveal.js.

[ggrossetie]

Do you have a link where it's still in camel case? Here's what I get on the master branch:

asciidoctor-reveal.js/templates/document.html.slim

Lines 128 to 244 in 45a0232

	Reveal.initialize({
	// Display presentation control arrows
	controls: #{to_boolean(attr 'revealjs_controls', true)},
	// Help the user learn the controls by providing hints, for example by
	// bouncing the down arrow when they first encounter a vertical slide
	controlsTutorial: #{to_boolean(attr 'revealjs_controlstutorial', true)},
	// Determines where controls appear, "edges" or "bottom-right"
	controlsLayout: '#{attr 'revealjs_controlslayout', 'bottom-right'}',
	// Visibility rule for backwards navigation arrows; "faded", "hidden"
	// or "visible"
	controlsBackArrows: '#{attr 'revealjs_controlsbackarrows', 'faded'}',
	// Display a presentation progress bar
	progress: #{to_boolean(attr 'revealjs_progress', true)},
	// Display the page number of the current slide
	slideNumber: #{to_valid_slidenumber(attr 'revealjs_slidenumber', false)},
	// Control which views the slide number displays on
	showSlideNumber: '#{attr 'revealjs_showslidenumber', 'all'}',
	// Push each slide change to the browser history
	history: #{to_boolean(attr 'revealjs_history', false)},
	// Enable keyboard shortcuts for navigation
	keyboard: #{to_boolean(attr 'revealjs_keyboard', true)},
	// Enable the slide overview mode
	overview: #{to_boolean(attr 'revealjs_overview', true)},
	// Vertical centering of slides
	center: #{to_boolean(attr 'revealjs_center', true)},
	// Enables touch navigation on devices with touch input
	touch: #{to_boolean(attr 'revealjs_touch', true)},
	// Loop the presentation
	loop: #{to_boolean(attr 'revealjs_loop', false)},
	// Change the presentation direction to be RTL
	rtl: #{to_boolean(attr 'revealjs_rtl', false)},
	// Randomizes the order of slides each time the presentation loads
	shuffle: #{to_boolean(attr 'revealjs_shuffle', false)},
	// Turns fragments on and off globally
	fragments: #{to_boolean(attr 'revealjs_fragments', true)},
	// Flags whether to include the current fragment in the URL,
	// so that reloading brings you to the same fragment position
	fragmentInURL: #{to_boolean(attr 'revealjs_fragmentinurl', false)},
	// Flags if the presentation is running in an embedded mode,
	// i.e. contained within a limited portion of the screen
	embedded: #{to_boolean(attr 'revealjs_embedded', false)},
	// Flags if we should show a help overlay when the questionmark
	// key is pressed
	help: #{to_boolean(attr 'revealjs_help', true)},
	// Flags if speaker notes should be visible to all viewers
	showNotes: #{to_boolean(attr 'revealjs_shownotes', false)},
	// Global override for autolaying 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
	autoPlayMedia: #{attr 'revealjs_autoplaymedia', 'null'},
	// 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: #{attr 'revealjs_autoslide', 0},
	// Stop auto-sliding after user input
	autoSlideStoppable: #{to_boolean(attr 'revealjs_autoslidestoppable', true)},
	// Use this method for navigation when auto-sliding
	autoSlideMethod: #{attr 'revealjs_autoslidemethod', 'Reveal.navigateNext'},
	// 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: #{attr 'revealjs_defaulttiming', 120},
	// Enable slide navigation via mouse wheel
	mouseWheel: #{to_boolean(attr 'revealjs_mousewheel', false)},
	// Hides the address bar on mobile devices
	hideAddressBar: #{to_boolean(attr 'revealjs_hideaddressbar', true)},
	// Opens links in an iframe preview overlay
	// Add `data-preview-link` and `data-preview-link="false"` to customise each link
	// individually
	previewLinks: #{to_boolean(attr 'revealjs_previewlinks', false)},
	// Transition style (e.g., none, fade, slide, convex, concave, zoom)
	transition: '#{attr 'revealjs_transition', 'slide'}',
	// Transition speed (e.g., default, fast, slow)
	transitionSpeed: '#{attr 'revealjs_transitionspeed', 'default'}',
	// Transition style for full page slide backgrounds (e.g., none, fade, slide, convex, concave, zoom)
	backgroundTransition: '#{attr 'revealjs_backgroundtransition', 'fade'}',
	// Number of slides away from the current that are visible
	viewDistance: #{attr 'revealjs_viewdistance', 3},
	// Parallax background image (e.g., "'https://s3.amazonaws.com/hakim-static/reveal-js/reveal-parallax-1.jpg'")
	parallaxBackgroundImage: '#{attr 'revealjs_parallaxbackgroundimage', ''}',
	// Parallax background size in CSS syntax (e.g., "2100px 900px")
	parallaxBackgroundSize: '#{attr 'revealjs_parallaxbackgroundsize', ''}',
	// Number of pixels to move the parallax background per slide
	// - Calculated automatically unless specified
	// - Set to 0 to disable movement along an axis
	parallaxBackgroundHorizontal: #{attr 'revealjs_parallaxbackgroundhorizontal', 'null'},
	parallaxBackgroundVertical: #{attr 'revealjs_parallaxbackgroundvertical', 'null'},
	// The display mode that will be used to show slides
	display: '#{attr 'revealjs_display', 'block'}',
	// 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: #{attr 'revealjs_width', 960},
	height: #{attr 'revealjs_height', 700},
	// Factor of the display size that should remain empty around the content
	margin: #{attr 'revealjs_margin', 0.1},
	// Bounds for smallest/largest possible scale to apply to content
	minScale: #{attr 'revealjs_minscale', 0.2},
	maxScale: #{attr 'revealjs_maxscale', 1.5},
	// Optional libraries used to extend on reveal.js
	dependencies: [
	{ src: '#{revealjsdir}/lib/js/classList.js', condition: function() { return !document.body.classList; } },
	#{(document.attr? 'source-highlighter', 'highlightjs') ? "{ src: '#{revealjsdir}/plugin/highlight/highlight.js', async: true, callback: function() { hljs.initHighlightingOnLoad(); } }," : nil}
	#{(attr? 'revealjs_plugin_zoom', 'disabled') ? "" : "{ src: '#{revealjsdir}/plugin/zoom-js/zoom.js', async: true }," }
	#{(attr? 'revealjs_plugin_notes', 'disabled') ? "" : "{ src: '#{revealjsdir}/plugin/notes/notes.js', async: true }," }
	#{(attr? 'revealjs_plugin_marked', 'enabled') ? "{ src: '#{revealjsdir}/plugin/markdown/marked.js', condition: function() { return !!document.querySelector( '[data-markdown]' ); } }," : "" }
	#{(attr? 'revealjs_plugin_markdown', 'enabled') ? "{ src: '#{revealjsdir}/plugin/markdown/markdown.js', condition: function() { return !!document.querySelector( '[data-markdown]' ); } }," : "" }
	#{(attr? 'revealjs_plugin_pdf', 'enabled') ? "{ src: '#{revealjsdir}/plugin/print-pdf/print-pdf.js', async: true }," : "" }
	#{(attr? 'revealjs_plugins') ? File.read(attr('revealjs_plugins', '')) : ""}
	],
	#{(attr? 'revealjs_plugins_configuration') ? File.read(attr('revealjs_plugins_configuration', '')) : ""}

Your link is pointing to asciidoctor manual, not asciidoctor-reveal.js.

Yes but Asciidoctor Reveal.js is using Asciidoctor to resolve attributes so we must comply with the above rule.

[gquintana]

Here https://raw.githubusercontent.com/asciidoctor/asciidoctor-reveal.js/master/README.adoc
The documentation doesn't match the code indeed.
I changed casing.

[ggrossetie]

Oh I see... technically it works because revealjs_camelCaseOption will be resolved to revealjs_camelcaseoption.

@obilodeau Do you have an opinion? Should we also use lowercase in the documentation?

[obilodeau]

Yeah, at first I created a commit that fixed the case for all the doc but then I realized: why bother? It worked for people before and it will continue working. If attributes ever become case-sensitive then we will fix it and in the meantime, it is more readable than without casing.

[ggrossetie]

Suggested change

	|:revealjs_pdfMaxPagesPerSlide:
	|:revealjs_pdfmaxpagesperslide:

[ggrossetie]

Suggested change

	pdfSeparateFragments: #{to_boolean(attr 'revealjs_pdfSeparateFragments', true)},
	pdfSeparateFragments: #{to_boolean(attr 'revealjs_pdfseparatefragments', true)},

[ggrossetie]

Suggested change

	pdfMaxPagesPerSlide: #{attr 'revealjs_pdfMaxPagesPerSlide', 1},
	pdfMaxPagesPerSlide: #{attr 'revealjs_pdfmaxpagesperslide', 1},

[ggrossetie]

Tests are failing because the expected output changed: https://travis-ci.org/asciidoctor/asciidoctor-reveal.js/jobs/616847269?utm_medium=notification&utm_source=github_status

Ideally we should also add tests on this new feature to make sure that pdfMaxPagesPerSlide has the correct value when revealjs_pdfmaxpagesperslide is defined. Same thing applies for pdfSeparateFragments.

[ggrossetie]

👍