Elsie#

Elsie allows you to create slides programmatically using Python. It is a Python library that lets you build SVG slides in a composable way and then render them to PDF. There is no DSL or GUI – presentations created with Elsie are fully programmed with Python.

It was created out of frustration of having to deal with existing tools for creating technically oriented presentations. We believe that creating presentations in a programmable way makes the slide-making process more smooth and reliable.

Quick links

• Installation
• Getting started
• User guide
• Gallery
• API Reference

Elsie example#

import elsie
slides = elsie.SlideDeck()

@slides.slide()
def hello_world(slide):
    import datetime
    slide.box().text(f"Hello from")

    year = str(datetime.datetime.now().year)
    row = slide.box(horizontal=True, p_top=20)
    for i in range(4):
        row.box(width=40, height=40).rect(
          color="black",
          bg_color="black" if i % 2 == 0 else "white"
        ).text(year[i], elsie.TextStyle(color="red"))

slides.render("slides.pdf")

Features#

• Layout model Elsie provides a simple, yet powerful layout model. Rows, columns, padding, text alignment, relative/absolute positioning and many other layout features are included.

• Animations and fragments Reveal your slides gradually using fragments and build complex step-by-step animations in Python. Or draw a fine-tuned SVG image by hand e.g. in Inkscape and let Elsie turn it into an animation using a handy layer-naming convention.

• Source code highlighting Enjoy beautiful code snippets thanks to built-in source code highlighting. Create code walkthroughs using individual line highlighting or arrows pointing to specific code elements.

• Batteries included Leverage familiar SVG features - fonts, colors, dashed line borders. Include PNG/JPG/SVG/ORA images or render Markdown or LaTeX directly into your slides. Build your slides interactively in Jupyter notebooks.

• Familiarity At its heart, Elsie is a streamlined API for creating SVG images, optimized for making presentations. If you know the basics of Python and SVG, you'll be right at home.

The ultimate feature of Elsie is that it allows you to build slides using (an imperative) programming language. You can split a large presentation into several modules/files, parametrize animations or objects that appear often using functions, create arbitrarily complex slides and animations or interactively modify the font, aspect ratio or text color/size of your whole presentation by changing a single line of code.

Every tool has its disadvantages though.

• Elsie provides a rather low-level API. While that means that you can create a slide in almost any way you like, you will sometimes have to roll up your sleeves to achieve your desired goal. However, once you implement it, you can put it inside a function and reuse it the next time, or send us a Pull Request to share the functionality with others.
• Elsie produces PDF slides, so it can only create animations with a single frame per page. If you need 60 FPS animations or GIFs in your presentations, this tool is not for you.
• Elsie is tested only on Linux. If you find a problem on a different platform, do not hesitate to open a GitHub issue.

Comparison to other tools#

• Google slides/PowerPoint These tools are fine if you need to make a bunch of very simple slides quickly, but using them gets very annoying if you need anything more complex. You need to place all items manually, alignment is usually a mess, fragments (animations) are not supported very well. If you need to change some small detail (placement, style, color) of a thing that is repeated on many slides, you pretty much have to go through all the slides and modify them by hand, one by one. Displaying source code with syntax highlighting is notoriously badly supported, so often you have to resort to exporting the highlighted code from carbon.sh or screenshotting it from your IDE, both of which are far from ideal. Also, you can't really use source control (e.g. git) to version your slides, which is a shame.

  However, PowerPoint does allow you to create continuous animations (if you do not export to PDF of course), so if you need that, it might be a good choice. It also has a myriad of other useful features, like tables, charts, shared templates, spell checking, etc.

• LaTeX/Beamer LaTeX has a template called Beamer, which is designed for creating presentation slides. It produces fine-looking text, has good support for syntax highlighting and can be versioned easily. However, in our experience it is not that easy to create custom diagrams and animations using LaTeX, mainly because of its declarative nature (and somewhat confusing syntax). If you can speak fluently in TikZ and you can understand the error messages of pdflatex, you are probably fine. If not, creating slides with complex animations, diagrams and source code snippets might be easier for you in Python.

  While Elsie also has basic support for rendering LaTeX, if your presentation is mostly composed of math formulas, it might be easier to create it in LaTeX directly.

• Reveal.js reveal.js is a great tool for making HTML presentations. It supports syntax highlighting, has good-looking animations and can be versioned. However, it shares some disadvantages of LaTeX/Beamer, which stems from the fact that it is also declarative. Creating an animation that would walk line-by-line through a source code snippet or that would repeatedly display and hide objects in custom fragments is difficult. You can actually use JavaScript to create more complex animations, but it's not integrated very well, and the library itself does not offer you any API to make it easier.

  That being said, if you are fine with declarative description of slides, and you prefer HTML/CSS to Python/SVG, reveal.js is a fine choice.

• Prezi If you like presentations with three or more dimensions, it's a good choice. Otherwise, the disadvantages of PowerPoint also apply here.

• python-pptx python-pptx is an API for building PowerPoint presentations, which is great if you like PowerPoint (or you are forced to use it), because it gives you access to a lot of its features (like tables, charts, slide notes) for free. On the other hand, this also means that you are limited by what can PowerPoint do. Creating complex fragment animations, pretty syntax highlighted source code snippets or LaTeX equations will probably be nigh impossible using this library.

FAQ#

• Why don't you use an existing layout model, e.g. flexbox? We made the layout model tailored for presentations, which might not be so easy with a general layout model. We also couldn't find any usable binding of a standalone and sane layout model in Python. If you know of any, please let us know.

License#

MIT.

Created by Stanislav Böhm and Jakub Beránek.