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ShowOff Presentation Software

ShowOff is a Sinatra web app that reads simple configuration files for a presentation. It is sort of like a Keynote web app engine - think S5 + Slidedown. I am using it to do all my talks in 2010, because I have a deep hatred in my heart for Keynote and yet it is by far the best in the field.

The idea is that you setup your markdown slide files in section subdirectories and then startup the showoff server in that directory. It will read in your showoff.json file for which sections go in which order and then will give you a URL to present from.

It can:

  • show simple text

  • show images

  • show syntax highlighted code

  • bullets with incremental advancing

  • re-enact command line interactions

  • call up a menu of sections/slides at any time to jump around

  • execute Javascript, Coffeescript or Ruby live and display results

  • do simple transitions (instant, fade, slide in)

  • show a pre-show slideshow while you wait to start

It might will can:

  • show a timer - elapsed / remaining

  • perform simple animations of images moving between keyframes

  • show synchronized, hidden notes on another browser (like an iphone)

  • show audience questions / comments (twitter or direct)

  • let audience members go back / catch up as you talk

  • let audience members vote on sections (?)

  • broadcast itself on Bonjour

  • let audience members download slides, code samples or other supplementary material

  • let you write on the slide with your mouse, madden-style via canvas

  • automatically resize text to fit screen [see Alex's shrink.js]

Some of the nice things are that you can easily version control it, you can easily move sections between presentations, and you can rearrange or remove sections easily.


ShowOff is meant to be run in a ShowOff formatted repository - that means that it has a showoff.json file and a number of sections (subdirectories) with markdown files for the slides you're presenting.

$ gem install showoff
$ git clone (showoff-repo)
$ cd (showoff-repo)
$ showoff serve

If you run 'showoff' in the example subdirectory of ShowOff itself, it will show an example presentation, so you can see what it's like.

You can also run 'showoff serve' inside a section subdirectory. If there is no showoff.json file then it will make its best guess, creating a presentation from all `.md` files in alphabetical order in the given (or current) directory.

Slide Format

You can break your slides up into sections of however many subdirectories deep you need. ShowOff will recursively check all the directories mentioned in your showoff.json file for any markdown files (.md). Each markdown file can have any number of slides in it, separating each slide with the '!SLIDE' keyword and optional slide styles.

For example, if you run 'showoff create my_new_pres' it will create a new starter presentation for you with one .md file at one/ which will have the following contents:


# My Presentation #

!SLIDE bullets incremental transition=fade

# Bullet Points #

* first point
* second point
* third point

That represents two slides, the first contains just a large title, and the second is faded into view showing the title and three bullets that are then incrementally shown. In order for ShowOff to see those slides, your showoff.json file needs to look something like this:

  "name": "Something",
  "description": "Example Presentation",
  "sections": [

If you have multiple sections in your talk, you can make this json array include all the sections you want to show in which order you want to show them.

Instead of a hash, you can use a plain string as an entry in the `sections` section of `showoff.json`.

And if that plain string starts with '#' then it is interpreted not as a filename, but as markdown. This is used for inserting interstitial slides or notes – for instance, Alex Chaffee's [Ruby Notes]( uses it to insert lab instructions between lecture slide sections, which may vary from venue to venue.

If you want to keep the ability to emit an HTML document from your Markdown source file – say, for a TextMate preview or a GitHub rendering – you can use angle brackets around the `!SLIDE` keyword and styles, e.g.

<!SLIDE bullets incremental transition=fade>

Some useful styles for each slide are:

  • center - centers images on a slide

  • full-page - allows an image to take up the whole slide

  • bullets - sizes and separates bullets properly (fits up to 5, generally)

  • smbullets - sizes and separates more bullets (smaller, closer together)

  • subsection - creates a different background for titles

  • command - monospaces h1 title slides

  • commandline - for pasted commandline sections (needs leading '$' for commands, then output on subsequent lines)

  • code - monospaces everything on the slide

  • incremental - can be used with 'bullets' and 'commandline' styles, will incrementally update elements on arrow key rather than switch slides

  • small - make all slide text 80%

  • smaller - make all slide text 70%

  • execute - on Javascript, Coffeescript and Ruby highlighted code slides, you can click on the code to execute it and display the results on the slide

Check out the example directory included to see examples of most of these.

Transitions can be supplied through the use of transition=tname on the !SLIDE definition, where tname is one of the following supported transitions:

  • blindX

  • blindY

  • blindZ

  • cover

  • curtainX

  • curtainY

  • fade

  • fadeZoom

  • growX

  • growY

  • none (this is the default)

  • scrollUp

  • scrollDown

  • scrollLeft

  • scrollRight

  • scrollHorz

  • scrollVert

  • shuffle

  • slideX

  • slideY

  • toss

  • turnUp

  • turnDown

  • turnLeft

  • turnRight

  • uncover

  • wipe

  • zoom

The transitions are provided by jQuery Cycle plugin. See to view the effects and for how to add custom effects.

You can manage the presentation with the following keys:

  • space, cursor right: next slide

  • shift-space, cursor left: previous slide

  • d: debug mode

  • c, t: table of contents (vi)

  • f: toggle footer

  • z, ?: toggle help

  • p: toggle preshow

Showing plain old markdown

If a markdown file has no !SLIDE keywords, then showoff will treat every line beginning with a single hash – i.e. every H1 – as a new slide in “bullets” style. Remember that you can't specify classes or transitions in this mode, and as soon as you add one !SLIDE you need them everywhere.


If you want to show a slideshow while you wait to speak, you can run a preshow. Add a _preshow directory to your project (I use a symlink, so I don't have to add all the images into Git), put a bunch of images in the _preshow directory and optionally add a preshow.json file that provides descriptions for any of the images. If you then press 'p' at the beginning of your presentation, it will prompt you for a number of minutes until you start. Then it will count down the time until then, flipping through your pictures to entertain the audience in the meantime. Press 'p' again to stop, or wait until the timer runs out.

Custom JavaScript

To insert custom JavaScript into your presentation you can either place it into a file (with extension .js) into the root directory of your presentation or you can embed a <script> element directly into your slides. This JavaScript will be executed—as usually—as soon as it is loaded.

If you want to trigger some JavaScript as soon as a certain page is shown or when you switch to the next or previous slide, you can bind a callback to a custom event:

  • showoff:show will be triggered as soon as you enter a page

  • showoff:next will be triggered when you switch to the next page

  • showoff:incr will be triggered when you advance to the next increment on the page

  • showoff:prev will be triggered when you switch to the previous page

These events are triggered on the “div.content” child of the slide, so you must add a custom and unique class to your SLIDE to identify it:

!SLIDE custom_and_unique_class
# 1st Example h1
// bind to custom event
$(".custom_and_unique_class").bind("showoff:show", function (event) {
  // animate the h1
  var h1 = $("h1");
    .slideUp(300, function () { $(this).css({textDecoration: "line-through"}); })

This will bind an event handler for showoff:show to your slide. The h1-element will be animated, as soon as this event is triggered on that slide.

If you bind an event handler to the custom events showoff:next or showoff:prev, you can prevent the default action (that is switching to the appropriate slide) by calling *event.preventDefault()*:

!SLIDE prevent_default
# 2nd Example h1
$(".prevent_default").bind("showoff:next", function (event) {
  var h1 = $("h1");
  if (h1.css("text-decoration") === "none") {
    h1.css({textDecoration: "line-through"})

This will bind an event handler for showoff:next to your slide. When you press the right arrow key the first time, the h1-element will be decorated. When you press the right array key another time, you will switch to the next slide.

The same applies to the showoff:prev event, of course.

Custom Stylesheets

To insert custom Stylesheets into your presentation you can either place it into a file (with extension .css) into the root directory of your presentation or you can embed a <link> element directly into your slides. This stylesheet will be applied as soon as it is loaded.

The content generated by the slide is wrapped with a div with the class .content like this.

<div ref="intro/01_slide/1" class="content" style="margin-top: 210px;">
<h1>jQuery &amp; Sinatra</h1>
<h2>A Classy Combination</h2>

This makes the .content tag a perfect place to add additional styling if that is your preference. An example of adding some styling is here.

.content {
  color: black;
  font-family: helvetica, arial;
h1, h2 {
  color: rgb(79, 180, 226);
  font-family: Georgia;
.content::after {
  position: absolute;
  right: 120px;
  bottom: 120px;
  content: url(jay_small.png);

Note that the example above uses CSS3 styling with ::after and the content -attribute to add an image to the slides.

Language highlighting

Showoff uses shjs to highlight code blocks. If you begin a code block with three @-signs followed by a programming language name, that line will be stripped and the rest of the block will become sparkly and colorful.

@@@ ruby
10.times { puts "Whee!" }

Custom Ruby Files

If you want to have executable Ruby code on your slides you must set the environment variable ENV. This can be done with



# On Heroku
heroku config:add SHOWOFF_EVAL_RUBY=1

If you need supporting libraries when you evaluate the code. You can do this by putting Ruby files (*.rb) into the root directory of the presentation then they will be required when the presentation loads.

Presenter Notes

Add a line that starts with .notes:

.notes my notes here

Toggle presenter notes with the n key while in the presentation.

Editor integration

The “add slide” feature can allow you to add the necessary boilerplate from your editor. If you are using vim, you can

!showoff add -t code Check This Code

And your buffer will get

# Check This Code #
    @@@ Ruby

added where your cursor was. Binding this to a keybinding can allow you to add new slides quickly.

Command Line Interface

showoff command_name [command-specific options] [--] arguments...
  • Use the command help to get a summary of commands

  • Use the command help command_name to get a help for command_name

  • Use -- to stop command line argument processing; useful if your arguments have dashes in them



Add a new slide at the end in a given dir


Create new showoff presentation


Shows list of commands or help for one command


Setup your presentation to serve on Heroku


Setup your presentation to serve on GitHub Pages


Serves the showoff presentation in the current directory (or a given dir)


Generate static version of presentation

showoff add [title]

Add a new slide at the end in a given dir


  • new

Outputs or creates a new slide. With -d and -n, a new slide is created in the given dir, numbered to appear as the last slide in that dir (use -u to avoid numbering). Without those, outputs the slide markdown to stdout (useful for shelling out from your editor). You may also specify a source file to use for a code slide.

options for add

These options are specified after the command.

-d, --dir=dir

Slide dir (where to put a new slide file)

-n, --name=basename

Slide name (name of the new slide file)

-s, --source=path to file

Include code from the given file as the slide body

-t, --style, --type=valid showoff style/type

Slide Type/Style ( default: title)

-u, --nonumber

Dont number the slide, use the given name verbatim

showoff create dir_name

Create new showoff presentation


  • init

This command helps start a new showoff presentation by setting up the proper directory structure for you. It takes the directory name you would like showoff to create for you.

options for create

These options are specified after the command.

-d, --slidedir=arg

sample slide directory name ( default: one)

-n, --nosamples

Dont create sample slides

showoff help [command]

Shows list of commands or help for one command

showoff heroku heroku_name

Setup your presentation to serve on Heroku

Creates the Gemfile and file needed to push a showoff pres to heroku. It will then run heroku create for you to register the new project on heroku and add the remote for you. Then all you need to do is commit the new created files and run git push heroku to deploy.

showoff github

Generates a static version of your site and puts it in a gh-pages branch for static serving on GitHub.

options for github

These options are specified after the command.

-f, --force

force overwrite of existing Gemfile/.gems and files if they exist

-g, --dotgems

Use older-style .gems file instead of bundler-style Gemfile

-p, --password=arg

add password protection to your heroku site

showoff serve

Serves the showoff presentation in the current directory

options for serve

These options are specified after the command.

-f, --pres_file=arg

Presentation file (default: showoff.json)

-h, --host=arg

Host or ip to run on ( default: localhost)

-p, --port=arg

Port on which to run ( default: 9090)

showoff static name

Generate static version of presentation

PDF Output

Showoff can produce a PDF version of your presentation. To do this, you must install a few things first:

gem install pdfkit

You'll then need to install a version of wkhtmltopdf available at the wkhtmltopdf repo (or brew install wkhtmltopdf on a mac) and make sure that wkhtmltopdf is in your path:

export $PATH="/location/to/my/wkhtmltopdf/0.9.9:$PATH"

Then restart showoff, and navigate to /pdf (e.g. localhost/pdf) of your presentation and a PDF will be generated with the browser.


ZSH completion

You can complete commands and options in ZSH, by installing a script:

mkdir -p $HOME/.zsh/Completion
cp script/_showoff $HOME/.zsh/Completion
echo 'fpath=(~/.zsh/Completion $fpath)' >> $HOME/.zshrc

bash completion

You can complete commands for showoff by putting the following in your .bashrc (or whatever you use when starting bash):

complete -F get_showoff_commands
function get_showoff_commands()
    if [ -z $2 ] ; then
        COMPREPLY=(`showoff help -c`)
        COMPREPLY=(`showoff help -c $2`)

Real World Usage

So far, ShowOff has been used in the following presentations (and many others):

If you use it for something, please let me know so I can add it.

Editor Support

Future Plans

I really want this to evolve into a dynamic presentation software server, that gives the audience a lot of interaction into the presentation - helping them decide dynamically what the content of the presentation is, ask questions without interupting the presenter, etc. I want the audience to be able to download a dynamically generated PDF of either the actual talk that was given, or all the available slides, plus supplementary material. And I want the presenter (me) to be able to push each presentation to Heroku or GitHub pages for archiving super easily.

Why Not S5 or Slidy or Slidedown?

S5 and Slidy are really cool, and I was going to use them, but mainly I wanted something more dynamic. I wanted Slidy + Slidedown, where I could write my slideshows in a structured format in sections, where the sections could easily be moved around and between presentations and could be written in Markdown. I also like the idea of having interactive presentation system and didn't need half the features of S5/Slidy (style based print view, auto-scaling, themes, etc).


  • Ruby (duh)

  • Sinatra (and thus Rack)

  • BlueCloth

  • Nokogiri

  • json

  • GLI gem

  • Firefox or Chrome to present

  • PDFKit (optional, for generating PDF of presentation)


See the CONTRIB.txt file for how to contribute to this project


the best damn presentation software a developer could ever love




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