Controlling Animations

Methods

‘Lottie’ offers several methods for controlling various aspects of animations, and ‘shinyLottie’ provides options for calling these methods when initialising the animation or updating them at a later point. The table below documents the most common methods:

Method	lottie_animation() argument	‘shinyLottie’ Function
Loop	loop	lottie_setLoop()
Autoplay	autoplay	lottie_play(), lottie_pause(), and lottie_stop()
Speed	speed	lottie_setSpeed()
Direction	direction	lottie_setDirection()
Play Segments	playSegments	lottie_playSegments(), lottie_goToAndStop(), and lottie_goToAndPlay()
Set Subframe Rendering	setSubFrame	lottie_setSubFrame()
Destroy	N/A	lottie_destroy()

To demonstrate this, the example below initialises an animation using lottie_animation() with a speed value of 2, causing the animation to play twice as fast as normal. We can then use a reactive event, triggered by clicking the button, to update the speed to a value of 0.5 (causing it to play twice as slow as normal) using lottie_setSpeed().

library(shiny)
library(shinyLottie)

ui <- fluidPage(
  include_lottie(),
  lottie_animation(
    path = "shinyLottie/example.json",
    name = "my_animation",
    speed = 2
  ),
  actionButton("updateSpeed", "Set Speed to 0.5")
)

server <- function(input, output, session) {
  observeEvent(input$updateSpeed, {
    lottie_setSpeed(speed = 0.5, name = "my_animation")
  })
}

shinyApp(ui, server)

Note that when calling lottie_setSpeed(), we reference the name of the animation we wish to target (in this case, "my_animation"). This is consistent across virtually all ‘shinyLottie’ functions, allowing for fine control over the animations in your ‘shiny’ app (i.e. being able to update the speed of a single animation, rather than all animations). Alternatively, the default default name value of "all" can be used to target all animations in the app.

Finally, if you want to call a ‘Lottie’ method for which ‘shinyLottie’ does not provide a function for, this can be achieved using lottie_callMethod().

Properties

‘Lottie’ animations have a number of properties that can be queried during runtime. The example below demonstrates how to query the ‘playCount’ property of an animation using lottie_getProperty().

library(shiny)
library(shinyLottie)

ui <- fluidPage(
  include_lottie(),
  lottie_animation(
    path = "shinyLottie/example.json",
    name = "my_animation"
  ),
  actionButton("getProperty", "Update Play Count"),
  textOutput("playCountOutput")
)

server <- function(input, output, session) {
  observeEvent(input$getProperty, {
    lottie_getProperty(name = "my_animation", property = "playCount")
  })

  observe({
    req(input$playCount)
    output$playCountOutput <- renderText({
      paste("Play Count:", input$playCount)
    })
  })
}

 shinyApp(ui, server)