= DeckTape
Antonin Stefanutti <https://github.com/astefanutti[@astefanutti]>
// Meta
:description: DeckTape is a high-quality PDF exporter for HTML presentation frameworks.
:decktape-version: 3.0.0
// Settings
:idprefix:
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// Aliases
:bullet: &#8201;&#8226;&#8201;
ifdef::env-github[]
:note-caption: :information_source:
:icon-ban: :no_entry_sign:
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:icon-clock: :clock10:
:icon-exclamation: :exclamation:
:icon-exclamation-dim: :grey_exclamation:
:icon-edit: :pencil2:
endif::[]
ifndef::env-github[]
:icons: font
:icon-ban: icon:ban[fw,role=red]
:icon-check: icon:check-square-o[fw,role=green]
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// URIs
:uri-badge-npm: https://img.shields.io/npm/v/decktape.svg
:uri-badge-node: https://img.shields.io/node/v/decktape.svg
:uri-decktape-npm: https://www.npmjs.com/package/decktape
:uri-decktape-release: https://github.com/astefanutti/decktape/releases/latest

:uri-puppeteer: https://github.com/GoogleChrome/puppeteer
:uri-w3c-uievents-key: https://www.w3.org/TR/uievents-key/

:uri-docker: https://www.docker.com
:uri-docker-hub: https://hub.docker.com
:uri-docker-image: https://hub.docker.com/r/astefanutti/decktape
:uri-docker-ref: http://docs.docker.com/engine/reference

:uri-bespokejs: http://markdalgleish.com/projects/bespoke.js
:uri-deckjs: http://imakewebthings.com/deck.js
:uri-dzslides: http://paulrouget.com/dzslides
:uri-flowtimejs: https://marcolago.github.io/flowtime.js/
:uri-impressjs: https://impress.js.org
:uri-inspire: https://inspirejs.org
:uri-nuedeck: https://github.com/twitwi/nuedeck
:uri-pageres: https://github.com/sindresorhus/pageres
:uri-remark: https://remarkjs.com
:uri-revealjs: https://revealjs.com
:uri-rise: https://github.com/damianavila/RISE
:uri-shower: https://shwr.me
:uri-slidy: https://www.w3.org/Talks/Tools/Slidy/
:uri-webslides: https://github.com/jlantunez/webslides

image:{uri-badge-npm}[link="{uri-decktape-npm}"] image:{uri-badge-node}[]

{description}

DeckTape is built on top of {uri-puppeteer}[Puppeteer] which relies on Google Chrome for laying out and rendering Web pages and provides a headless Chrome instance scriptable with a JavaScript API.

DeckTape currently supports the following presentation frameworks out of the box:

{uri-bespokejs}[Bespoke.js]{bullet}
{uri-deckjs}[deck.js]{bullet}
{uri-dzslides}[DZSlides]{bullet}
{uri-flowtimejs}[Flowtime.js]{bullet}
{uri-impressjs}[impress.js]{bullet}
{uri-inspire}[Inspire.js]{bullet}
{uri-nuedeck}[NueDeck]{bullet}
{uri-remark}[remark]{bullet}
{uri-revealjs}[reveal.js]{bullet}
{uri-rise}[RISE]{bullet}
{uri-shower}[Shower]{bullet}
{uri-slidy}[Slidy]{bullet}
{uri-webslides}[WebSlides]

DeckTape also provides a <<generic,generic command>> that works by emulating the end-user interaction, allowing it to be used to convert presentations from virtually any kind of framework.
The generic mode is particularly useful for supporting HTML presentation frameworks that don't expose an API or accessible state.

DeckTape's plugin-based architecture exposes an extension API, making it possible to add support for other frameworks or to tailor existing plugins to your specific needs.

DeckTape can optionally be used to capture screenshots of your slide decks in various resolutions (similar to {uri-pageres}[pageres]).
That can be useful to make sure your presentations are responsive or to create handouts for them.

You can browse some slide deck <<examples,examples>> below that have been exported with DeckTape.

== Install

=== NPM

Install DeckTape globally and run it:

```sh
$ npm install -g decktape
$ decktape
```

Or locally:

```sh
$ npm install decktape
$ `npm bin`/decktape
```

See the <<faq,FAQ>> for troubleshooting / alternatives.

== Usage

[source]
----
$ decktape -h

Usage: decktape [options] [command] <url> <filename>
       decktape version

command      one of: automatic, bespoke, deck, dzslides, flowtime, generic, impress, inspire,
             nuedeck, remark, reveal, shower, slidy, webslides
url          URL of the slides deck
filename     Filename of the output PDF file

Options:
   -s <size>, --size <size>        Size of the slides deck viewport: <width>x<height> (e.g. '1280x720')
   -p <ms>, --pause <ms>           Duration in milliseconds before each slide is exported  [1000]
   --load-pause <ms>               Duration in milliseconds between the page has loaded
                                   and starting to export slides  [0]
   --screenshots                   Capture each slide as an image  [false]
   --screenshots-directory <dir>   Screenshots output directory  [screenshots]
   --screenshots-size <size>       Screenshots resolution, can be repeated  [--size]
   --screenshots-format <format>   Screenshots image format, one of [jpg, png]  [png]
   --slides <range>                Range of slides to be exported, a combination of slide indexes
                                   and ranges (e.g. '1-3,5,8')
   --chrome-path <path>            Path to the Chromium or Chrome executable to run instead of the
                                   bundled Chromium
   --chrome-arg <arg>              Additional argument to pass to the Chrome instance, can be repeated

Defaults to the automatic command.
Iterates over the available plugins, picks the compatible one for presentation at the
specified <url> and uses it to export and write the PDF into the specified <filename>.
----

In addition to the general options listed above, command specific options can be displayed the following way:

 $ decktape <command> -h

== Commands

[#automatic]
=== `automatic`

Iterates over the available link:plugins[], picks the compatible one for presentation at the specified `url` and uses it to export and write the PDF into the specified `filename`.

[#generic]
=== `generic`

Emulates the end-user interaction by pressing the key with the specified `--key` option and iterates over the presentation as long as:

[loweralpha]
. Any change to the DOM is detected by observing mutation events targeting the body element and its subtree nor
. the number of slides exported has reached the specified `--max-slides` option.

The `--key` value must be one of the {uri-w3c-uievents-key}[UI events `KeyboardEvent` key values] and defaults to `ArrowRight`, e.g.:

 $ decktape generic --key=ArrowDown

== Options

=== `--screenshots`

Captures each slide as an image at the `--screenshots-size` resolution, exports it to the `--screenshots-format` image format and writes the output into the `--screenshots-directory` directory.

The `--screenshots-size` option can be set multiple times. For example:

 $ decktape --screenshots --screenshots-size=400x300 --screenshots-size=800x600

=== `--slides`

Exports only the slides specified as a series of slides indexes and ranges, e.g.:

[source,shell]
----
# Capture a single slide
$ decktape --slides 1
# Capture a series of slides
$ decktape --slides 1,3,5
# Capture a range of slides
$ decktape --slides 1-10
# Capture a combination of slides and ranges
$ decktape --slides 1,2,5-10
----

The rendering stops and the file written out after the largest numbered slide is exported.

== Examples

The following slide deck examples have been exported using DeckTape:

[cols="1v,1v,1v"]
|===
|HTML5 Presentation |Framework |Exported PDF

|https://revealjs.com/demo/[Reveal.js Demo]
|reveal.js
|https://astefanutti.github.io/decktape/examples/reveal-js-demo.pdf[reveal-js-demo.pdf] (2.0MB)

|https://tdd.github.io/devoxx-es6-maintenant/[ES6+ maintenant !]
|reveal.js
|https://astefanutti.github.io/decktape/examples/devoxx-es6-maintenant.pdf[devoxx-es6-maintenant.pdf] (2.3MB)

|https://github.com/hakimel/reveal.js/blob/360bc940062711db9b8020ce4e848f6c37014481/test/examples/math.html[reveal.js MathJax example]
|reveal.js
|https://astefanutti.github.io/decktape/examples/reveal-js-mathjax.pdf[reveal-js-mathjax.pdf] (0.3MB)

|https://artificer.jboss.org/slides/general/opensource-getting-involved.html[Getting Involved in Open Source]
|reveal.js
|https://astefanutti.github.io/decktape/examples/opensource-getting-involved.pdf[opensource-getting-involved.pdf] (0.6MB)

|http://astefanutti.github.io/further-cdi[Going Further with CDI]
|Asciidoctor + DZSlides
|https://astefanutti.github.io/decktape/examples/going-further-with-cdi.pdf[going-further-with-cdi.pdf] (2.4MB)

|http://imakewebthings.com/deck.js[Deck.js Modern HTML Presentations]
|deck.js
|https://astefanutti.github.io/decktape/examples/deck-js-presentation.pdf[deck-js-presentation.pdf] (0.5MB)

|https://remarkjs.com[The Official Remark Slideshow]
|remark
|https://astefanutti.github.io/decktape/examples/remark-js-slideshow.pdf[remark-js-slideshow.pdf] (0.15MB)

|https://joshbode.github.io/remark/ansi.html[Coloured Terminal Listings in Remark]
|remark
|https://astefanutti.github.io/decktape/examples/remark-js-coloured-terminal.pdf[remark-js-coloured-terminal.pdf] (0.12MB)

|https://www.w3.org/Talks/Tools/Slidy[HTML Slidy: Slide Shows in HTML and XHTML]
|Slidy
|https://astefanutti.github.io/decktape/examples/html-slidy-presentation.pdf[html-slidy-presentation.pdf] (0.5MB)

|https://inspirejs.org[Inspire.js: Lean, hackable, extensible slide deck framework]
|Inspire.js
|https://astefanutti.github.io/decktape/examples/inspirejs-sample-slideshow.pdf[inspirejs-sample-slideshow.pdf] (1.9MB)

|https://shwr.me[Shower Presentation Engine]
|Shower
|https://astefanutti.github.io/decktape/examples/shower-presentation-engine.pdf[shower-presentation-engine.pdf] (0.6MB)

|http://mikemaccana.github.io/rejectjs2013[Welcome our new ES5 Overloards]
|Bespoke.js
|https://astefanutti.github.io/decktape/examples/new-es5-overloards.pdf[new-es5-overloards.pdf] (0.2MB)

|https://formidable.com/open-source/spectacle/[Spectacle: A ReactJS Presentation Library]
|Spectacle
|https://astefanutti.github.io/decktape/examples/spectacle-reactjs-presentation.pdf[spectacle-reactjs-presentation.pdf] (1.2MB)
|===

== Docker

DeckTape can be executed within a Docker container from the command-line using the {uri-docker-image}[`astefanutti/decktape`] Docker image available on {uri-docker-hub}[Docker Hub]:

 $ docker run astefanutti/decktape -h

For example:

* To convert an online HTML presentation and have it exported into the working directory under the `slides.pdf` filename:
[source,shell,subs=attributes+]
$ docker run --rm -t -v `pwd`:/slides astefanutti/decktape https://revealjs.com/demo/ slides.pdf

* Or, to convert an HTML presentation that's stored on the local file system in the `home` directory:
[source,shell]
$ docker run --rm -t -v `pwd`:/slides -v ~:/home/user astefanutti/decktape /home/user/slides.html slides.pdf

* Or, to convert an HTML presentation that's deployed on the local host:
[source,shell]
$ docker run --rm -t --net=host -v `pwd`:/slides astefanutti/decktape http://localhost:8000 slides.pdf
+
You may have to use `host.docker.internal` instead of `localhost` on macOS and Windows.

You may want to specify a tag corresponding to a released version of DeckTape for the Docker image, e.g. `astefanutti/decktape:{decktape-version}`.

Besides, it is recommended to use the following options from the {uri-docker-ref}/run[`docker run`] command:

{uri-docker-ref}/run/#clean-up-rm[`--rm`]:: DeckTape is meant to be run as a short-term foreground process so that it's not necessary to have the container's file system persisted after DeckTape exits,
{uri-docker-ref}/commandline/run/#mount-volume-v-read-only[`-v`]:: to mount a data volume so that DeckTape can directly write to the local file system.

Alternatively, you can use the {uri-docker-ref}/commandline/cp[`docker cp`] command, e.g.:

[source,shell,subs=attributes+]
----
# Run docker run without the --rm option
$ docker run astefanutti/decktape {uri-revealjs} slides.pdf
# Copy the exported PDF from the latest used container to the local file system
$ docker cp `docker ps -lq`:slides/slides.pdf .
# Finally remove the latest used container
$ docker rm `docker ps -lq`
----

If your presentation relies on fonts installed on the host system, but not in the base Docker container, you can mount your fonts
directory as a volume, e.g. for macOS:

[source]
$ docker run -v "${HOME}/Library/Fonts:/home/node/.local/share/fonts" ...

== FAQ

=== Install

* *_I'm using Arch Linux, is there an AUR package?_*
+
Yes, it is available at https://aur.archlinux.org/packages/nodejs-decktape/.

=== Usage

* *_Is it possible to pass arguments to Chrome?_*
+
Yes, you can use the `--chrome-arg` option, e.g.:
+
[source,shell]
----
$ decktape ... \
  --chrome-arg=--proxy-server="proxy:8080" \
  --chrome-arg=--allow-file-access-from-files
----
+
The list of Chromium flags can be found https://peter.sh/experiments/chromium-command-line-switches/[here].

=== Troubleshooting

* *_No usable sandbox!_*
+
Arch Linux, among other Linux distributions may have the user namespace in the kernel disabled by default. You can verify this by accessing _chrome://sandbox_ in your chrom[e|ium] browser. You can find more about sandboxing, https://chromium.googlesource.com/chromium/src/+/master/docs/linux_sandboxing.md#User-namespaces-sandbox[here]. As a _temporary_ work-around, you can pass `--chrome-arg=--no-sandbox` as a CLI option.

* *_Failed to read the 'rules' property from 'CSSStyleSheet': Cannot access rules_*
+
Starting Chromium 64, accessing CSS rules in a stylesheet loaded from the local filesystem or an external location violates CORS policies.
As some Decktape plugins tweak the CSS rules for better PDF printing, you need to allow access to local files or external stylesheets by setting the `--disable-web-security` flag option, e.g.:
+
[source,shell]
----
$ decktape ... --chrome-arg=--disable-web-security
----

* *_Layout inconsistencies_*
+
Decktape relies on Pupeteer to convert each slide in PDF format. Slight layout inconsistencies can result as part of this transformation. One workaround is to set a specific slide size using the `-s` option. The value of `-s 1024x768` has generally worked well in such situations.
+
* *_Reveal.js slide generation never finishes_*
+
Decktape does not use the built-in PDF support of reveal.js, and instead captures each slide individually. Therefore you must not append `?print-pdf` or load the print stylesheets in any other way when using Decktape.

== Plugin API

{icon-edit}