README.md

In RinteRface/waypointer: Scrolling Callbacks for 'Shiny'

waypointer

Simple animated waypoints for shiny.

• waypointer
• Installation
• Guide
• Methods
• Arguments
• Examples

Installation

# install.packages("remotes")
remotes::install_github("RinteRface/waypointer")

Guide

1. Place use_waypointer() anywhere in your ui.
2. Create a waypoint with new method, giving it at least the id of the element to watch.
3. Start the waypoint with the start method.
4. Watch the waypoint with the get_direction method.

Methods

Note that the get_* family of methods return character vectors and not the waypoint, unlike others.

1. new - create a waypoint.
2. start - start watching the waypoint.
3. enable - enable the waypoint (enabled by default)
4. disable - disable the waypoint.
5. destroy - destroy the waypoint.
6. animate - animate the waypoint, see ?.init for the full list.
7. get_direction - returns the direction in which the user scrolls passed the waypoint (up or down)
8. get_triggered - returns TRUE if the waypoint has been triggered previously, and FALSE otherwise.

Arguments

All the arguments are passed to the new method, at the expection of animation which can also be passed to the animate method.

• dom_id - Id of element to watch.
• animate - Set to TRUE to automatically animate when the waypoint is triggered.
• animation - Name of animation, defaults to shake.
• offset - By default, the handler is triggered when the top of an element hits the top of the viewport. The offset changes the location of that trigger point.
• horizontal - When horizontal is set to true, all of this changes to the horizontal axis and the get_direction method will return left or right.
• id - Id of waypoint. When used you can replace the get_* family of methods to traditional shiny inputs, e.g. if the id of the waypoint is set to myInput then you can obtain the direction in your shiny server with input$myInput_direction.

Examples

Create a waypoint with waypoint$new() passing at least the id of the element to observe as dom_id (first argument). Note that technically the get_* family of methods are inputs, you therefore may need to use shiny::req where needed (see below).

library(shiny)
library(waypointer)

ui <- fluidPage(
    use_waypointer(),
    div(
        h1("Scroll down"), 
        style = "min-height:90vh"
    ),
    verbatimTextOutput("result"),
    plotOutput("plot"),
    div(style = "min-height:90vh")
)

server <- function(input, output, session) {

    w <- Waypoint$
        new("plot", offset = "20%")$
        start()

    output$result <- renderPrint({
        w$get_direction()
    })

    output$plot <- renderPlot({

        req(w$going_down())

        # show if scrolling down
        if(w$going_down())
            hist(runif(100))
    })

}

shinyApp(ui, server)

Note that in the above we use the get_direction method to get the direction in which the user is scrolling, relative to the given dom_id. However if you provide an id when initialising the waypoint then you can use the traditional way of accessing callbacks: input$id_direction. The example below would then look like:

library(shiny)
library(waypointer)

ui <- fluidPage(
    use_waypointer(),
    div(
        h1("Scroll down"), 
        style = "min-height:90vh"
    ),
    verbatimTextOutput("result"),
    plotOutput("plot"),
    div(style = "min-height:90vh")
)

server <- function(input, output, session) {

    w <- Waypoint$
        new("plot", offset = "20%", id = "myWaypoint")$
        start()

    output$result <- renderPrint({
        w$get_direction()
    })

    output$plot <- renderPlot({

        req(input$myWaypoint_direction)

        # show if scrolling down
        if(input$myWaypoint_direction == "down")
            hist(runif(100))
    })

}

shinyApp(ui, server)

You can also animate the waypoint, setting animate to TRUE will automatically animate the waypoint when is triggered.

library(shiny)
library(waypointer)

ui <- fluidPage(
    use_waypointer(),
    div(
        "Scroll!", 
        style = "min-height:90vh"
    ),
    verbatimTextOutput("result"),
    plotOutput("plot"),
    div(style = "min-height:90vh")
)

server <- function(input, output, session) {

    w <- Waypoint$
        new(
      "plot", 
      offset = "20%", 
      animate = TRUE, 
      id = "waypoint"
    )$
        start()

    output$result <- renderPrint({
        input$waypoint_direction
    })

    output$plot <- renderPlot({

        req(input$waypoint_direction)

        if(input$waypoint_direction == "down")
            hist(runif(100))
    })

}

shinyApp(ui, server)

Otherwise you may use the animate method to manually trigger the animation.

library(shiny)
library(waypointer)

ui <- fluidPage(
    use_waypointer(),
    div(
        "Scroll!", 
        style = "min-height:90vh"
    ),
    verbatimTextOutput("result"),
    plotOutput("plot"),
    div(style = "min-height:90vh")
)

server <- function(input, output, session) {

    w <- Waypoint$
        new("plot", offset = "20%")$
        start()

    output$result <- renderPrint({
        w$get_direction()
    })

    output$plot <- renderPlot({

        req(w$get_direction())

        hist(runif(100))
    w$animate()
    })

}

shinyApp(ui, server)

RinteRface/waypointer documentation built on Feb. 2, 2020, 7:46 p.m.