R/gotop.R

In lgnbhl/gotop: Scroll Back to Top Icon in Shiny and R Markdown

#' Add scroll up icon
#'
#' @param container A string. The HTML element to which the scroll function will be attached. If no value is given, then the scroll function will be attched to the window.
#' @param appear An integer. The amount of pixels the page must be scrolled down before the gotop icon is displayed.
#' @param scrolltime An integer. A number determining how long the animation will run when scrolling to the top of the page.
#' @param src A string. The CSS classes used to display the gotop icon.
#' @param width An integer. The width of the gotop icon.
#' @param place A string. The location where the gotop icon will be shown. Valid values are 'right' or 'left'.
#' @param color A string. The color of the selected the gotop icon.
#' @param fadein An integer. A number determining how long the animation will run when fading in to opaque.
#' @param fadeout An integer. A number determining how long the animation will run when fading out to transparent.
#' @param opacity decimal Sets the transparency level for the gotop icon, where 1 is not transparent at all, 0.5 is 50 percent see-through and 0 is completely transparent.
#' @param marginX An integer. The percentage amount indicating how far away the gotop icon is from the bottom, left, or right, depending on the value of place.
#' @param marginY An integer. The percentage amount indicating how far away the gotop icon is from the top or bottom, depending on the value of place.
#' @param zIndex An integer. The z-index value.
#' @param use_cdn boolean. TRUE to use a Content Delivery Network (CDN), true by default, or false to use locally stored files.
#'
#' @return Javascript code initializing GoTop with dependencies
#'
#' @examples
#' use_gotop()
#'
#' @importFrom jsonlite toJSON
#' @importFrom htmltools HTML tags tagList
#' @export

use_gotop <- function(
  src = "fas fa-chevron-up",
  width = 45,
  opacity = 0.5,
  place = "right",
  color = "",
  appear = 200,
  scrolltime = 800,
  fadein = 500,
  fadeout = 500,
  marginX = 2,
  marginY = 2,
  container = "",
  zIndex = 9,
  use_cdn = TRUE
){
  options <- list(
    container = container,
    appear = appear,
    scrolltime = scrolltime,
    src = src,
    width = width,
    place = match.arg(arg = place, choices = c("left", "right")),
    color = color,
    fadein = fadein,
    fadeout = fadeout,
    opacity = opacity,
    marginX = marginX,
    marginY = marginY,
    zIndex = zIndex
  )
  
  options <- jsonlite::toJSON(options, auto_unbox = TRUE)
  
  tagList(
    html_dependencies_gotop(use_cdn),
    htmltools::HTML("<div id='goTop'></div>"),
    htmltools::tags$script(
      sprintf(
        "$(function () {
          $('#goTop').goTop(%s);
         });",
        options
      )
    )
  )
}

#' gotop dependencies
#' 
#' Get gotop html dependencies.
#' 
#' @param use_cdn boolean. TRUE to use a Content Delivery Network (CDN), true by default, or false to use locally stored files.
#' 
#' @importFrom htmltools tagList htmlDependency
#' 
#' @rdname gotop-dependencies
#' 
#' @export

html_dependencies_gotop <- function(use_cdn = TRUE) {
  
  jquerygotop <- htmltools::htmlDependency(
    name = "goTop",
    version = "2.0.0",
    src = "",
    script = "assets/jquery.gotop.js",
    package = "gotop"
  )
  
  # fontawesome v 6.5.2
  # https://github.com/rstudio/rmarkdown/tree/master/inst/rmd/h/fontawesome
  if(use_cdn)
    fontawesome_v5_1_0 <- htmltools::htmlDependency(
      name = "fontawesome",
      version = "6.5.2",
      src = c(href = "https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.5.2/css/"),
      stylesheet = c("all.css", "v4-shims.css")
    )
  else 
    fontawesome_v5_1_0 <- htmltools::htmlDependency(
      name = "fontawesome",
      version = "6.5.2",
      src = "",
      stylesheet = c("assets/fontawesome/css/all.css", "assets/fontawesome/css/v4-shims.css"),
      package = "gotop"
    )
  
  htmltools::tagList(fontawesome_v5_1_0, jquerygotop)
}