Touying (投影 in chinese, /tóuyǐng/, meaning projection) is a powerful and efficient package for creating presentation slides in Typst. Partial code is inherited from Polylux. Therefore, many concepts and APIs remain consistent with Polylux.

Touying provides an object-oriented programming (OOP) style syntax, allowing the simulation of “global variables” through a global singleton. This makes it easy to write themes. Touying does not rely on counter and locate to implement #pause, resulting in better performance.

If you like it, consider giving a star on GitHub. Touying is a community-driven project, feel free to suggest any ideas and contribute.

Document

Read the document to learn all about Touying.

This documentation is powered by Docusaurus. We will maintain English and Chinese versions of the documentation for Touying, and for each major version, we will maintain a documentation copy. This allows you to easily refer to old versions of the Touying documentation and migrate to new versions.

Special Features

1. #pause and #meanwhile Marks document

#slide[
  First
  
  #pause
  
  Second

  #meanwhile

  Third

  #pause

  Fourth
]

2. Dewdrop Theme Navigation Bar document

3. touying-equation Math Equation Animation document

4. touying-reducer Cetz and Fletcher Animations document

5. #show: slides Style and #slide[..] Style

6. Semi-transparent Cover Mode document

Quick start

Before you begin, make sure you have installed the Typst environment. If not, you can use the Web App or the Typst LSP and Typst Preview plugins for VS Code.

To use Touying, you only need to include the following code in your document:

#import "@preview/touying:0.3.2": *

#let s = themes.simple.register(aspect-ratio: "16-9")
#let (init, slides) = utils.methods(s)
#show: init

#let (slide,) = utils.slides(s)
#show: slides


= Title

== First Slide

Hello, Touying!

#pause

Hello, Typst!

It’s simple. Congratulations on creating your first Touying slide! 🎉

Tip: You can use Typst syntax like #import "config.typ": * or #include "content.typ" to implement Touying’s multi-file architecture.

Warning: The comma in #let (slide,) = utils.slides(s) is necessary for the unpacking syntax.

More Complex Examples

In fact, Touying provides various styles for writing slides. For example, the above example uses first-level and second-level titles to create new slides. However, you can also use the #slide[..] format to access more powerful features provided by Touying.

#import "@preview/touying:0.3.2": *
#import "@preview/cetz:0.2.1"
#import "@preview/fletcher:0.4.2" as fletcher: node, edge

// cetz and fletcher bindings for touying
#let cetz-canvas = touying-reducer.with(reduce: cetz.canvas, cover: cetz.draw.hide.with(bounds: true))
#let fletcher-diagram = touying-reducer.with(reduce: (arr, ..args) => fletcher.diagram(..args, ..arr))

// Register university theme
// You can remove the theme registration or replace other themes
// it can still work normally
#let s = themes.university.register(aspect-ratio: "16-9")

// Global information configuration
#let s = (s.methods.info)(
  self: s,
  title: [Title],
  subtitle: [Subtitle],
  author: [Authors],
  date: datetime.today(),
  institution: [Institution],
)

// Extract methods
#let (init, slides, touying-outline, alert) = utils.methods(s)
#show: init

#show strong: alert

// Extract slide functions
#let (slide,) = utils.slides(s)
#show: slides

= Animation

== Simple Animation

#slide[
  We can use `#pause` to #pause display something later.

  #pause
  
  Just like this.

  #meanwhile
  
  Meanwhile, #pause we can also use `#meanwhile` to #pause display other content synchronously.
]


== Complex Animation

#slide(repeat: 3, self => [
  #let (uncover, only, alternatives) = utils.methods(self)

  At subslide #self.subslide, we can

  use #uncover("2-")[`#uncover` function] for reserving space,

  use #only("2-")[`#only` function] for not reserving space,

  #alternatives[call `#only` multiple times \u{2717}][use `#alternatives` function #sym.checkmark] for choosing one of the alternatives.
])


== Math Equation Animation

#slide[
  Touying equation with `pause`:

  #touying-equation(`
    f(x) &= pause x^2 + 2x + 1  \
         &= pause (x + 1)^2  \
  `)

  #meanwhile

  Here, #pause we have the expression of $f(x)$.
  
  #pause

  By factorizing, we can obtain this result.
]


== CeTZ Animation

#slide[
  CeTZ Animation in Touying:

  #cetz-canvas({
    import cetz.draw: *
    
    rect((0,0), (5,5))

    (pause,)

    rect((0,0), (1,1))
    rect((1,1), (2,2))
    rect((2,2), (3,3))

    (pause,)

    line((0,0), (2.5, 2.5), name: "line")
  })
]


== Fletcher Animation

#slide[
  Fletcher Animation in Touying:

  #fletcher-diagram(
    node-stroke: .1em,
    node-fill: gradient.radial(blue.lighten(80%), blue, center: (30%, 20%), radius: 80%),
    spacing: 4em,
    edge((-1,0), "r", "-|>", `open(path)`, label-pos: 0, label-side: center),
    node((0,0), `reading`, radius: 2em),
    edge((0,0), (0,0), `read()`, "--|>", bend: 130deg),
    pause,
    edge(`read()`, "-|>"),
    node((1,0), `eof`, radius: 2em),
    pause,
    edge(`close()`, "-|>"),
    node((2,0), `closed`, radius: 2em, extrude: (-2.5, 0)),
    edge((0,0), (2,0), `close()`, "-|>", bend: -40deg),
  )
]


= Others

== Side-by-side

#slide[
  First column.
][
  Second column.
]


== Setting

#slide(setting: body => {
  set text(fill: blue)
  body
})[
  This slide has blue text.
]


== Multiple Pages

#slide[
  #lorem(200)
]


// appendix by freezing last-slide-number
#let s = (s.methods.appendix)(self: s)
#let (slide,) = utils.slides(s)

== Appendix

#slide[
  Please pay attention to the current slide number.
]

Acknowledgements

Thanks to…

• @andreasKroepelin for the polylux package
• @Enivex for the metropolis theme
• @drupol for the university theme
• @ntjess for contributing to fit-to-height, fit-to-width and cover-with-rect