Typing your presentation
Thanks to the editors and preview embedded in this page, this tutorial does not require you to have access to the slipshow compiler on your machine. However, we encourage you to have it, to not just read, but actually create the presentation this tutorial is describing. It is even better if you modify it to make it your own!
Introduction
Slipshow is a compiler from a source file to a source language to a slipshow presentation, so you simply write a text file to describe your presentation. This makes it portable, lightweight and lets you use your favorite text editor instead of forcing you into one. It has also drawbacks: it can be less visual than other solutions such as “power-point” style presentations.
When you turn your source file into a presentation (you compile the presentation), the file created is actually an html file: the format used to describe websites. So, even if it is a local file, you need to open it with a web browser with javascript enabled: most web browsers will work. An important thing to know is that (unless special setup) the file is fully self-contained: it can be viewed offline, and if you want to send your presentation to someone, you just need to send them the file. It is also highly portable: it will work on any OS with a web browser (virtually all of them!).
In this tutorial, you will create your first slipshow presentation. It is entirely self-contained, and introduces both the usage, the syntax and the different features of slipshow. The Anatomy of a Slipshow presentation is a good complementary read, both can be read in any order.
A minimal example
We start by considering a simple but complete example. This allows us to cover the basic usage of the tools, the basic syntax, and the basic features of slipshow. The next parts of the tutorial will build on this example to explain the more advanced workflows!
To start, copy the following lines in a file, named for instance
prime-numbers.md:
Note
The extension of the file (.md) is for markdown. Many editors will
open files with such extension in a special mode that will help you read and
write it. Slipshow’s syntax is an extension of markdown.
Compiling and viewing your presentation
The file that we just created is the source for a minimal prime-numbers. In
order to get the presentation itself, we need to compile it, using the
slipshow tool.
In a terminal, issue the following command:
$ slipshow serve prime-numbers.md
Visit http://localhost:8080 to view your presentation, with auto-reloading on file changes.
This serve command creates a file with the same name as the input
name, but a different extension: prime-numbers.html. The .md file
is the one you’ll use to modify the presentation, and the one you’ll share
with another author of the presentation. The .html file is the one
you’ll use to view or do your presentation, or to share with someone
interested in viewing the presentation.
Moreover, the flag command will propagate any saved changes in the
input file, and “live-reload” the presentation served at the address
http://localhost:8080. It is very useful when writing your
presentation. When you only want to generate the html file once, use
compile instead.
On the slipshow preview, you should see the familiar format for slide-based presentations (4:3 rectangle with black borders). Click on it to be sure you have the window focused, and hit the Right arrow key (or equivalently, the Down arrow key) to step through the presentation! Right now, it has only two steps: the initial one, and the last one.
Try to make a modification in prime-numbers.md and save the file. The
preview should refresh automatically with the new content!
Also, type s: this opens the speaker view, with a timer, notes you might want to add, and a synced view of the presentation.
Note
The speaker view is disabled in the slipshow previews embedded in this tutorial.
The syntax used
Slipshow uses an extension of Markdown for its main syntax. So, having already seen Markdown is a good start when using slipshow. Fortunately, Markdown is very simple! And is already widely used. I’ll link to some great resources to learn Markdown, but you can also follow along this tutorial first and come back to them later.
The Learn Markdown in 60 seconds is from CommonMark, the organization that proposed a well-defined specification for Markdown. They also have a 10-minute tutorial to learn but also train!
The slipshow markup is defined in Markup. In this tutorial, let’s only focus on the syntax used in the example.
Pauses
The fifth line is the first one that is not regular markdown:
{pause}
This line won’t appear as is in the rendered presentation. In fact, any
content inside curly braces {...} is considered “metadata” and will be
interpreted in specific ways, but not displayed in the presentation.
The purpose of this line is to inform the slipshow engine that the presentation should “pause” here. Indeed, when opening the presentation, only the title and the first paragraph were shown. The rest of the presentation was shown only after the “right” key was pressed.
Blocks
Following the {pause} keyword, we have the following content:
{.definition}
A **prime number** is a number divisible by exactly two integers: 1, and itself.
The meaning should be clear from the rendered presentation: this is a
“definition” block. As you can see, we use the “metadata” syntax once again: the
{.definition} part is not rendered, but is used to describe the content. In
this case, there is a . followed by a word: such syntax is used for add a
“class” to an element, an information which is used only to alter the rendering
of an element.
There are several classes available. To describe blocks, in addition to the
“definition” block, you can chose from .theorem, .proof, .alert, and
.block.
Note
Blocks support the display of a title. You can provide the title in the
metadata: {.definition title="Prime numbers"}. Try it in the example!
If your block includes multiple paragraphs or elements, just indent all those
elements using >. For instance, try the following in the examples:
{.definition}
> A **prime number** is a number divisible by exactly two integers: 1, and itself.
>
> We consider 1 not to be a prime number, as it is divisible only by one integer.
Your presentation as a papyrus
In this minimal example, we haven’t yet touched the core of slipshow’s typed presentations. But we are close to that!
Let’s expand our basic example with the fact and proof that there are infinitely many prime numbers. This is one of the first important fact to know!
Append the following lines to the example file. (If you are dissatisfied with the proof, feel free to improve it 🙂.)
{pause}
{.theorem}
There are infinitely many prime numbers.
{pause .proof}
> Suppose there are finitely many prime numbers.
>
> Let's write $p_0, p_1, \dots, p_{n-1}$ a list of all prime numbers. We define:
>
> ```math
> P = \prod_{i=0}^{n-1}p_i, \quad
> N = P + 1.
> ```
>
> {pause}
>
> Let $p$ be a prime divisor of $N$. We claim that:
>
> ```math
> \forall i, p\neq p_i
> ```
> {pause}
> Indeed,
>
> ```math
> p \text{ divides } N \land\ p\text{ divides } P \implies p\text{ divides } 1
> ```
>
> So $p$ is a prime that is not part of the $p_i$, a contradiction. {pause}
> **Therefore, there must exists infinitely many prime numbers.**
Let’s look at the updated rendering of the presentation: What you see is quite disappointing. There is too many content for the space available, and the last part of the proof overflows and is invisible. Most presentations would solve this problem by creating a new slide, but slipshow does it very differently, which is what makes it unique!
Note
Slipshow supports several ways of grouping. Instead of >, you can enclose the proof with ---. In this case, it would become:
{.theorem}
There are infinitely many prime numbers.
{pause .proof}
---
Suppose there are finitely many prime numbers.
[...]
**Therefore, there must exists infinitely many prime numbers.**
---
The problem of uncovering new content
Recall the problem here. There is too much content for the space we have: the proof of the infinity of prime numbers overflow through the bottom end!
The usual answer from traditional slideshow programs are to create a new slide to hold the new content. But that does not come without problems. For instance, what to put in this new slide? Obviously, we don’t want to put only the overflown content in the new slide: this content should be seen in some context, that you want to have on screen.
So, one way would be to duplicate some content from the previous slide on the second slide. This works reasonably well, but is often difficult to follow for the viewer: it takes cognitive load to distinguish between what is new and what is just duplicated content in a new slide.
Moreover, it is also a problem for the author: duplicated content means duplicated work when, for instance, rewording the duplicated content.
Slipshow’s way
Slipshow’s solution is to, instead of clearing the whole screen and duplicating some content, just “scroll” the window down to get more space for the new content, hiding only what you do not need anymore!
Let’s focus on our specific case here. We don’t have enough space for the whole proof, but we do not need to see the presentation title, nor the (kind of useless) rhetorical question. However, we do want to keep the “prime number” definition, as long as possible, and the theorem statement as well, of course.
So what we want to do is to “scroll” (I also like the idea of a papyrus being unrolled), until the definition is at the top of the screen. We need two things for that:
Be able to refer to a part of your presentation (in our case, the definition),
Tell the slipshow engine when to move the screen (in our case: when we start displaying the proof),
Tell the slipshow engine where to move the screen (in our case: such that the definition is on top).
Unsurprisingly, all these information are put in the metadatas parts of slipshow
syntax: everything enclosed in {}.
Be able to refer to a part of your presentation
For the first point, slipshow uses a system of ids. An id is just a string
without space, that must be unique amongst all ids. In order to assign an id to
a block, one must add the id prepended with a # inside the metadata of the
block. For instance, let’s add the prime-def id to the definition. The
source should look like this now:
{.definition #prime-def}
A **prime number** is a number divisible by exactly two integers: 1, and itself.
Tell the engine when to move the screen
For the second point, we use an action metadata kind. Such metadata
should only be grouped with a pause metadata. It says that a specific action
must be taken when stepping through this pause.
Tell the engine where to move the screen
For the third point, slipshow has several commands to move the screen. In our
case, we want to put something on top of the screen, so we use up keyword.
Putting everything together
So, we want to add up=prime-def to the
pause associated to the proof. The modified source should look like this:
{.definition #prime-def}
A **prime number** is a number divisible by exactly two integers: 1, and itself.
[...]
{pause .proof up=prime-def}
> Suppose there are finitely many prime numbers.
> [...]
Try the rendered version of this new source: by getting rid of anything not useful, there is enough space in the screen to display the definition, theorem statement and whole proof!
The source is still readable, the flow is not broken, and the presentation is easy to follow for the viewer.
Note
The main instructions to move the window are up to put some element on
top of the screen, down to put it at the bottom, and center to center
it.
If no id is given, the instruction is considered to apply on the element
itself. For instance, down without id is a useful command,
that we could have used on the proof element.
Note
It is not always best to remove everything that you don’t need. For instance, in the example above, suppose that you continue by giving an example of a very big prime number. Technically, you could start fresh, the example does not need the proof to be on screen. However, for any viewer that is a little bit late, it is very good to keep at least the end of the proof visible, in order to let them finish their note-taking and catch up with the presentation.
Note
Don’t go too fast! The more textual content you have, the slowest you should go. Think about how long it would have taken you to write all this on a whiteboard.
Making your presentation live
The previous sections cover most of the first phase of making a presentation: the preparation. Slipshow has also several important features regarding the presentation in itself!
Using the speaker view
You can open the speaker view with the s keybinding. The speaker view has a
timer and a clock, speaker notes (filled using the speaker-note action) and
a mirror of your main presentation. It’s disabled in the previews in this tutorial.
Writing on the screen
One of the goal of slipshow is to make digital presentations “less bad” compared to the blackboard ones.
One of the great features of blackboards is that you can write on them while explaining, doodle, make arrows all over the place. To try to do something similar, the slipshow rendering engine allows you to write on your presentation, using the tools present on the top left of your presentation.
The best is still to use the shortcuts:
w to write,
h to highlight,
e to erase,
x to go back to a normal cursor,
X to clear all annotations.
See Drawing your presentation and Record and replay drawings for more information on drawing, and in particular for recording your drawings beforehand and replaying them during the presentation!
Using the table of content
Press t during a presentation to open the table of content, with fast jump to any part of your presentation!
Moving freely
During a presentation, it is important to not be too tied to the original program. You can move the window freely, using the i, j, k and l keys. Change the “zoom” factor using the z and Z keys.
What next?
Congratulation, you’ve finished the tutorial for typed presentations! There are however many more things to learn:
Typed presentations are great but some part of your presentation might benefit from being handwritten. The Drawing your presentation is explaining how to do that.
We only briefly touched on the syntax. When you face new situations, you’ll quickly need a more thorough presentation of Slipshow’s syntax.
While predefined actions such as
pauseorupcan bring you quite far, if you want more custom animations it is nice to know how to write your own scripts.