Reusable animations

Sometimes, you want to split an animation across several slides. In this case, you reveal the first steps, switch to another slide to explain or show something else, then come back and continue the same animation from where it stopped. Every window re-displays the earlier steps in their fully-revealed, static state and animates only the steps it is responsible for.

The render-animation function allows to write an animation sequence once and then rendered wherever you need it, either in full or one window of steps at a time.

#let render-animation(
  ..int-or-range,
  from: 1,
  to: none,
  body,
)

Argument

int-or-range
int | array

Positional step numbers naming the window this call renders. A render window is contiguous by nature, so a list is taken as its span.

Some examples:

#render-animation(3, 4, body) // renders global steps 3 through 4
#render-animation(2, 4, body) // renders global steps 2 through 4 (the span of the list)
#render-animation(3, body)    // renders global step 3 to the last step
#render-animation(body)       // renders the whole animation

Warning

Because a render window is contiguous, you cannot, for instance, resume steps 2 and 4 while skipping 3 on one slide.

Argument

from – default: 1
int

The subslide number from which the content will be revealed. The default value is 1, meaning that the content will be visible from the first subslide.

Argument

to – default: none
int | none

The subslide number until which the content will be revealed. If set to none, the content will be visible until the last subslide. The default value is none.

Argument

body
content

The reusable animated block.

Note

Out-of-range values are clamped to the animation’s real length.

// Example
#let derivation = [
  We start from the identity.
  #pause
  Apply the substitution $u = x^2$.
  #pause
  Integrate term by term.
  #pause
  And simplify the result.
]

== Reusable animations - Main animation

// Render the first two steps of the derivation, then pause to explain them.
#render-animation(1, 2, derivation)

== Reusable animations - A side note

The chain rule states that $(f compose g)' = (f' compose g) dot g'$.

== Reusable animations - Back to main animation

// Render the rest of the derivation, starting from step 3.
#render-animation(from: 3, derivation)

Note

render-animation works by briefly re-pointing Slydekit’s shared subslide clock while it renders body, so packages that read that clock (CeTZ / Fletcher via #reveal, #anim-label, …) resume correctly too. In handout: true mode each window collapses to a single page showing its final state.