Getting started

The deck system

While you can build all your slides in pure C++, you have to recompile each time you want to see an update. This can be frustrating for simple slide creation like text, math and images. To avoid this, you can instead build your presentation fully interactively without having to recompile most of the time.

The deck system splits a presentation in three, by how often you edit each part:

• composition (which content, on which slide, at which position) lives in a deck.yaml file, hot-reloaded while the presentation runs;
• what it animates on lives next to it: tunable parameters for the constants, Lua snippets for the logic, both re-read on save;
• computation (meshes, solves, simulation steps) stays in C++ and is exposed to the deck by registering objects.

Only the last costs a rebuild. Editing the deck, a snippet, a latex definition or a saved camera takes effect on the next frame.

A minimal deck project

#include "slope.h"

using namespace slope;

DeckLoader deck;

int main(int argc, char** argv) {
    deck.init("my_talk", "deck.yaml", argc, argv);

    // C++-defined content, referenced by name in the deck
    deck.registerObject("spot", [](){ return Mesh::Add("spot.obj"); });

    deck.run();
    return 0;
}

with next to it a deck.yaml:

slides:
  - frame:
      - title: My talk
      - latex: it starts \emph{here}
        at: [0.5, 0.6]
  - frame:
      - title: A mesh, from C++
      - object: spot
      - step
      - load: my_key        # content from the latex definitions file

init also loads a latex definitions file (see dynamic latex) and a latex preamble, both hot-reloaded too. Their paths are given at the top of the deck with the latex: and commands: keys; when omitted, the project's latex.json and commands.tex are used if they exist. snippets: names the Lua files the deck animates with, one or several.

latex: my_definitions.json
commands: my_preamble.tex
snippets: snippets.lua
slides:
  - ...

preamble: is latex written straight in the deck, a string or a list of lines, added on top of commands.tex and hot-reloaded with everything else.

preamble:
  - \usepackage{libertine}

Deck settings

config: sets the values used in all frames (like title size, etc...).

config:
  title_scale: 1.5        # scale of title items
  latex_scale: 1.0        # default scale of latex, formula and algo items
  box_roundness: 1.0      # corner radius of boxes
  margin: 0.06            # gap the edge anchors leave, one number or [x, y]
  top: [0.5, 0.1]         # where at: TOP puts an item
  center: [0.5, 0.5]
  bottom: [0.5, 0.9]

What hot reload watches

File	Effect when edited
deck.yaml	slides are recomposed in place
preamble: or config: in the deck	the same, formulas recompiled if the preamble moved
latex definitions file	edited entries are recompiled, and the slides recomposed
latex preamble file	every formula is recompiled
saved camera views	the view is reloaded
views/params.json	tunable parameters are updated
a snippet file	the sections are re-read, and the next frame animates with them

Next: the full deck format, and registering C++ objects.