R/tweak.R
In nicholasdavies/shmanipulate: Easily manipulate a plot using controls like sliders, drop-down lists and date pickers
Defines functions
tweak
pad_options
realize_control
layout
gridify
slice
get_input_id
parse_slider
parse_control
Documented in
tweak
# Interpret x as control spec
parse_control = function(x)
{
if (inherits(x, "shiny.tag")) {
x
} else if (is.list(x) || (length(x) > 1 && is.character(x))) {
values = unname(x);
choices = as.character(seq_along(x));
names(choices) = if (!is.null(names(x))) names(x) else as.character(x);
list(type = "select", choices = choices, values = values, init = NULL)
} else if (length(x) == 1 && is.logical(x)) {
list(type = "checkbox", init = x)
} else if (length(x) == 1 && is.numeric(x)) {
list(type = "numeric", init = x)
} else if (length(x) == 1 && is.character(x)) {
list(type = "text", init = x)
} else if (length(x) == 1 && inherits(x, "Date")) {
list(type = "date", init = x)
} else if (is.numeric(x)) {
parse_slider(x)
} else {
stop("tweak: cannot interpret control specification ", x);
}
}
# Parse numeric vector of 2, 3, or 4 elements into a list with named elements min, max, init, and by.
parse_slider = function(x)
{
if (length(x) == 2) {
slider = list(type = "slider", min = x[1], max = x[2], init = x[1], by = 0);
} else if (length(x) == 3 && x[1] >= x[2]) {
slider = list(type = "slider", min = x[2], max = x[3], init = x[1], by = 0);
} else if (length(x) == 3) {
slider = list(type = "slider", min = x[1], max = x[2], init = x[1], by = x[3]);
} else if (length(x) == 4) {
slider = list(type = "slider", min = x[2], max = x[3], init = x[1], by = x[4]);
} else {
stop("tweak: malformed slider (expecting 2, 3, or 4 numeric values).");
}
if (slider$min >= slider$max) { stop("tweak: slider max must be greater than min."); }
if (slider$init < slider$min || slider$init > slider$max) { stop("tweak: slider start must be between min and max.") }
if (slider$by < 0) { stop("tweak: slider by must be non-negative."); }
# Set by to something sensible
if (slider$by == 0) {
magnitude = floor(max(log10(abs(c(slider$min, slider$max)))));
slider$by = 10 ^ (magnitude - 2);
}
return (slider)
}
# Search a shiny.tag class object for an inputId
get_input_id = function(x)
{
if (!inherits(x, "shiny.tag")) {
return (NULL)
}
if (x$name %in% c('input', 'select', 'button', 'div') && !is.null(x$attribs$id)) {
return (x$attribs$id)
}
for (xx in x$children) {
result = get_input_id(xx);
if (!is.null(result)) {
return (result)
}
}
return (NULL)
}
# Slice list in quantiles [a/d, b/d)
slice = function(l, a, b, d)
{
n = length(l);
i = (n * a) / d + 1;
j = (n * b) / d + 1;
ind = seq_along(l);
return (l[ind >= i & ind < j])
}
# Put controls in a grid
gridify = function(controls, ncol, position)
{
if (position %in% c("top", "bottom")) {
if (ncol == 1) {
shiny::column(4, controls, offset = 4)
} else if (ncol == 2) {
list(
shiny::column(4, slice(controls, 0, 1, 2), offset = 2),
shiny::column(4, slice(controls, 1, 2, 2))
)
} else if (ncol == 3) {
list(
shiny::column(4, slice(controls, 0, 1, 3)),
shiny::column(4, slice(controls, 1, 2, 3)),
shiny::column(4, slice(controls, 2, 3, 3))
)
} else if (ncol == 4) {
list(
shiny::column(3, slice(controls, 0, 1, 4)),
shiny::column(3, slice(controls, 1, 2, 4)),
shiny::column(3, slice(controls, 2, 3, 4)),
shiny::column(3, slice(controls, 3, 4, 4))
)
} else {
stop("tweak: ncol must be 1, 2, 3, or 4.");
}
} else if (position %in% c("left", "right")) {
shiny::column(4, controls)
}
}
# Lay out plot and controls
layout = function(controls, ncol, position, plot_height)
{
if (position == "top") {
list(
shiny::fluidRow(gridify(controls, ncol, position)),
shiny::fluidRow(shiny::plotOutput("plot", height = plot_height))
)
} else if (position == "bottom") {
list(
shiny::fluidRow(shiny::plotOutput("plot", height = plot_height)),
shiny::fluidRow(gridify(controls, ncol, position))
)
} else if (position == "left") {
shiny::fluidRow(
gridify(controls, ncol, position),
shiny::column(8, shiny::plotOutput("plot", height = plot_height))
)
} else if (position == "right") {
shiny::fluidRow(
shiny::column(8, shiny::plotOutput("plot", height = plot_height)),
gridify(controls, ncol, position)
)
} else {
stop('tweak: position (of controls) must be "top", "bottom", "left", or "right".')
}
}
# Turn control spec into realized shiny tag structure
realize_control = function(name, x)
{
if (inherits(x, "shiny.tag")) {
x
} else if (x$type == "select") {
shiny::selectInput(inputId = name, label = name, choices = x$choices, selected = x$init);
} else if (x$type == "checkbox") {
shiny::checkboxInput(inputId = name, label = name, value = x$init);
} else if (x$type == "numeric") {
shiny::numericInput(inputId = name, label = name, value = x$init);
} else if (x$type == "text") {
shiny::textInput(inputId = name, label = name, value = x$init);
} else if (x$type == "date") {
shiny::dateInput(inputId = name, label = name, value = x$init);
} else if (x$type == "slider") {
shiny::sliderInput(inputId = name, label = name, min = x$min, max = x$max, value = x$init, step = ifelse(x$by == 0, NULL, x$by))
} else {
stop("tweak: unknown control type.");
}
}
# Pad out options list with default values
pad_options = function(options, ...)
{
defaults = list(...);
for (nm in names(defaults)) {
if (is.null(options[[nm]])) {
options[[nm]] = defaults[[nm]];
}
}
return (options)
}
#' Manipulate a plot
#'
#' Easily manipulate a plot using controls like sliders, drop-down lists and
#' date pickers.
#'
#' @param expr an expression that evaluates to a plot using base plotting
#' functions, \code{ggplot}, etc.
#' @param ... variables within the \code{expr} expression to be manipulated.
#' These can be specified in one of two ways:
#' \describe{
#' \item{\strong{The easy way}}{The easy way is to specify the variables
#' to be manipulated as named arguments to \code{tweak}. How you
#' specify the value of each argument determines the default value of the
#' variable and how it is manipulated. Examples for each:
#' \itemize{
#' \item{\code{x = c(min, max)} for a numeric slider between
#' \code{min} and \code{max}; you can optionally provide a
#' starting value before \code{min} and/or a step value after
#' \code{max} (see examples).}
#' \item{\code{y = list(...)} for a fixed set of options
#' in a dropdown menu. If the \code{list} has names, these will
#' be shown. The first element is selected by default. For
#' convenience, a character vector with more than one element
#' will also be interpreted as a dropdown menu.}
#' \item{\code{z = TRUE} or \code{z = FALSE} for a
#' logical value controlled by a checkbox.}
#' \item{\code{foo = "Some text"} for a character
#' string controlled by text input.}
#' \item{\code{bar = 123.456} for a numeric value
#' controlled by text input.}
#' \item{\code{baz = as.Date("2020-01-01")} for a
#' \code{Date} object with a calendar input.}
#' }
#' See below for an example.
#' }
#' \item{\strong{The more flexible way}}{The more flexible way
#' is to specify the variables to be manipulated as input controls
#' using the \code{shiny} package. In this case the names of the
#' arguments are ignored, and the variable names are taken from
#' the \code{inputId} argument to the Shiny input control. An
#' example is below. }
#' }
#' @param options a \code{list} containing further settings:
#' \describe{
#' \item{\code{position}}{where the controls are positioned relative to the
#' plot; either \code{"bottom"} (default), \code{"top"}, \code{"left"}, or
#' \code{"right"}.}
#' \item{\code{ncol}}{if \code{position} is \code{"top"} or \code{"bottom"},
#' the number of columns to distribute controls across; can be \code{1} (default),
#' \code{2}, \code{3}, or \code{4}.}
#' \item{\code{gadget}}{\code{FALSE} (default) to run in a new window, or
#' \code{TRUE} to run as a gadget, i.e. in the RStudio viewer pane.}
#' \item{\code{plot_height}}{Height of the plot in pixels, with \code{400} as
#' the default.}
#' }
#' @param .envir environment in which to evaluate \code{expr}.
#'
#' @export
#' @examples
#' \dontrun{
#' # Specifying controls: the easy way
#' tweak({
#' x = 0:10;
#' plot(A * x^2 + B * x + C,
#' col = if (blue) "blue" else "black",
#' main = plot_title,
#' ylim = c(-5, 10)
#' )
#' },
#' A = c(0, 0.1), # slider from 0 to 0.1
#' B = 1, # numeric text input with starting value 1
#' C = list(one = 1, two = 2, three = 3), # dropdown list with named values
#' plot_title = "Example title", # freeform text input
#' blue = FALSE # checkbox
#' )
#'
#' # Specifying controls: the flexible way
#' library(shiny)
#' library(ggplot2)
#'
#' tweak({
#' dat = data.frame(
#' date = start_date + 0:(n_days - 1),
#' value = start_value * exp(0:(n_days - 1) * growth_rate) +
#' rnorm(n_days, 0, noise)
#' )
#' ggplot(dat) +
#' geom_line(aes(x = date, y = value))
#' },
#' dateInput(inputId = "start_date",
#' label = "Start date", value = "2020-01-01"),
#' numericInput(inputId = "start_value",
#' label = "Starting value", value = 1, min = 0, max = 10, step = 1),
#' sliderInput(inputId = "growth_rate",
#' label = "Growth rate", min = 0, max = 1, value = 0, step = 0.01),
#' numericInput(inputId = "n_days",
#' label = "Number of days", value = 30, min = 1, max = 60, step = 1),
#' sliderInput(inputId = "noise",
#' label = "Noise", min = 0, max = 1, value = 0, step = 0.01)
#' )
#'
#' # Different kinds of numeric sliders
#' tweak({ x = 0:100; plot(A * x^2 + B * x + C, ylim = c(-2000, 2000)) },
#' A = c(0.5, 0, 1), # slider from 0 to 1, with starting value 0.5
#' B = c(0, 10, 0.25), # slider from 0 to 10, with step 0.25
#' C = c(0, -1000, 1000, 50) # slider from -1000 to 1000, starting value 0 and step 50
#' )
#'
#' # tweak plus curve
#' tweak(curve(dbeta(x, alpha, beta), 0, 1), alpha = c(1, 100), beta = c(1, 100))
#'
#' # Quickly explore a numeric data.frame
#' data(quakes)
#' tweak(
#' if (x == y) {
#' hist(quakes[[x]], xlab = x)
#' } else {
#' plot(quakes[[x]], quakes[[y]], xlab = x, ylab = y)
#' },
#' x = names(quakes), y = names(quakes))
#' }
#' @rdname tweak
tweak = function(expr, ..., options = list(), .envir = parent.frame())
{
# Process options
options = pad_options(options,
ncol = 1,
position = "bottom",
gadget = FALSE,
plot_height = "400px"
);
# Read named and unnamed (list) arguments
ellipses = list(...);
args = list();
for (i in seq_along(ellipses)) {
if (!is.null(names(ellipses)) && names(ellipses)[i] != "") {
args = c(args, list(ellipses[[i]]));
names(args)[i] = names(ellipses)[i];
} else {
args = c(args, list(ellipses[[i]]));
names(args)[i] = ""
}
}
# Turn ... arguments into input controls
args = lapply(args, parse_control);
controls = mapply(realize_control, names(args), args, SIMPLIFY = FALSE);
arg_names = unname(sapply(controls, get_input_id));
if (any(is.null(arg_names))) {
stop("tweak: could not find names for all parameters.");
}
# Define page layout
ui = shiny::fluidPage(layout(controls, options$ncol, options$position, options$plot_height));
# Simple server to render plot based on updates to inputs
expr_txt = deparse(substitute(expr));
server = function(input, output, session)
{
output$plot = shiny::renderPlot({
# get server values
args2 = lapply(arg_names, function(name) input[[name]]);
names(args2) = arg_names;
# convert dropdown list values from character to originally specified type
for (i in seq_along(args)) {
if (!inherits(args[[i]], "shiny.tag") && args[[i]]$type == "select") {
args2[[i]] = args[[i]]$values[[as.integer(args2[[i]])]];
}
}
# evaluate plotting command
eval(parse(text = expr_txt), args2, .envir)
});
}
# Run app
if (options$gadget) {
shiny::runGadget(ui, server)
} else {
shiny::shinyApp(ui, server)
}
}
nicholasdavies/shmanipulate documentation built on July 16, 2025, 5:39 p.m.
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Defines functions tweak pad_options realize_control layout gridify slice get_input_id parse_slider parse_control
Documented in tweak
# Interpret x as control spec
parse_control = function(x)
{
if (inherits(x, "shiny.tag")) {
x
} else if (is.list(x) || (length(x) > 1 && is.character(x))) {
values = unname(x);
choices = as.character(seq_along(x));
names(choices) = if (!is.null(names(x))) names(x) else as.character(x);
list(type = "select", choices = choices, values = values, init = NULL)
} else if (length(x) == 1 && is.logical(x)) {
list(type = "checkbox", init = x)
} else if (length(x) == 1 && is.numeric(x)) {
list(type = "numeric", init = x)
} else if (length(x) == 1 && is.character(x)) {
list(type = "text", init = x)
} else if (length(x) == 1 && inherits(x, "Date")) {
list(type = "date", init = x)
} else if (is.numeric(x)) {
parse_slider(x)
} else {
stop("tweak: cannot interpret control specification ", x);
}
}
# Parse numeric vector of 2, 3, or 4 elements into a list with named elements min, max, init, and by.
parse_slider = function(x)
{
if (length(x) == 2) {
slider = list(type = "slider", min = x[1], max = x[2], init = x[1], by = 0);
} else if (length(x) == 3 && x[1] >= x[2]) {
slider = list(type = "slider", min = x[2], max = x[3], init = x[1], by = 0);
} else if (length(x) == 3) {
slider = list(type = "slider", min = x[1], max = x[2], init = x[1], by = x[3]);
} else if (length(x) == 4) {
slider = list(type = "slider", min = x[2], max = x[3], init = x[1], by = x[4]);
} else {
stop("tweak: malformed slider (expecting 2, 3, or 4 numeric values).");
}
if (slider$min >= slider$max) { stop("tweak: slider max must be greater than min."); }
if (slider$init < slider$min || slider$init > slider$max) { stop("tweak: slider start must be between min and max.") }
if (slider$by < 0) { stop("tweak: slider by must be non-negative."); }
# Set by to something sensible
if (slider$by == 0) {
magnitude = floor(max(log10(abs(c(slider$min, slider$max)))));
slider$by = 10 ^ (magnitude - 2);
}
return (slider)
}
# Search a shiny.tag class object for an inputId
get_input_id = function(x)
{
if (!inherits(x, "shiny.tag")) {
return (NULL)
}
if (x$name %in% c('input', 'select', 'button', 'div') && !is.null(x$attribs$id)) {
return (x$attribs$id)
}
for (xx in x$children) {
result = get_input_id(xx);
if (!is.null(result)) {
return (result)
}
}
return (NULL)
}
# Slice list in quantiles [a/d, b/d)
slice = function(l, a, b, d)
{
n = length(l);
i = (n * a) / d + 1;
j = (n * b) / d + 1;
ind = seq_along(l);
return (l[ind >= i & ind < j])
}
# Put controls in a grid
gridify = function(controls, ncol, position)
{
if (position %in% c("top", "bottom")) {
if (ncol == 1) {
shiny::column(4, controls, offset = 4)
} else if (ncol == 2) {
list(
shiny::column(4, slice(controls, 0, 1, 2), offset = 2),
shiny::column(4, slice(controls, 1, 2, 2))
)
} else if (ncol == 3) {
list(
shiny::column(4, slice(controls, 0, 1, 3)),
shiny::column(4, slice(controls, 1, 2, 3)),
shiny::column(4, slice(controls, 2, 3, 3))
)
} else if (ncol == 4) {
list(
shiny::column(3, slice(controls, 0, 1, 4)),
shiny::column(3, slice(controls, 1, 2, 4)),
shiny::column(3, slice(controls, 2, 3, 4)),
shiny::column(3, slice(controls, 3, 4, 4))
)
} else {
stop("tweak: ncol must be 1, 2, 3, or 4.");
}
} else if (position %in% c("left", "right")) {
shiny::column(4, controls)
}
}
# Lay out plot and controls
layout = function(controls, ncol, position, plot_height)
{
if (position == "top") {
list(
shiny::fluidRow(gridify(controls, ncol, position)),
shiny::fluidRow(shiny::plotOutput("plot", height = plot_height))
)
} else if (position == "bottom") {
list(
shiny::fluidRow(shiny::plotOutput("plot", height = plot_height)),
shiny::fluidRow(gridify(controls, ncol, position))
)
} else if (position == "left") {
shiny::fluidRow(
gridify(controls, ncol, position),
shiny::column(8, shiny::plotOutput("plot", height = plot_height))
)
} else if (position == "right") {
shiny::fluidRow(
shiny::column(8, shiny::plotOutput("plot", height = plot_height)),
gridify(controls, ncol, position)
)
} else {
stop('tweak: position (of controls) must be "top", "bottom", "left", or "right".')
}
}
# Turn control spec into realized shiny tag structure
realize_control = function(name, x)
{
if (inherits(x, "shiny.tag")) {
x
} else if (x$type == "select") {
shiny::selectInput(inputId = name, label = name, choices = x$choices, selected = x$init);
} else if (x$type == "checkbox") {
shiny::checkboxInput(inputId = name, label = name, value = x$init);
} else if (x$type == "numeric") {
shiny::numericInput(inputId = name, label = name, value = x$init);
} else if (x$type == "text") {
shiny::textInput(inputId = name, label = name, value = x$init);
} else if (x$type == "date") {
shiny::dateInput(inputId = name, label = name, value = x$init);
} else if (x$type == "slider") {
shiny::sliderInput(inputId = name, label = name, min = x$min, max = x$max, value = x$init, step = ifelse(x$by == 0, NULL, x$by))
} else {
stop("tweak: unknown control type.");
}
}
# Pad out options list with default values
pad_options = function(options, ...)
{
defaults = list(...);
for (nm in names(defaults)) {
if (is.null(options[[nm]])) {
options[[nm]] = defaults[[nm]];
}
}
return (options)
}
#' Manipulate a plot
#'
#' Easily manipulate a plot using controls like sliders, drop-down lists and
#' date pickers.
#'
#' @param expr an expression that evaluates to a plot using base plotting
#' functions, \code{ggplot}, etc.
#' @param ... variables within the \code{expr} expression to be manipulated.
#' These can be specified in one of two ways:
#' \describe{
#' \item{\strong{The easy way}}{The easy way is to specify the variables
#' to be manipulated as named arguments to \code{tweak}. How you
#' specify the value of each argument determines the default value of the
#' variable and how it is manipulated. Examples for each:
#' \itemize{
#' \item{\code{x = c(min, max)} for a numeric slider between
#' \code{min} and \code{max}; you can optionally provide a
#' starting value before \code{min} and/or a step value after
#' \code{max} (see examples).}
#' \item{\code{y = list(...)} for a fixed set of options
#' in a dropdown menu. If the \code{list} has names, these will
#' be shown. The first element is selected by default. For
#' convenience, a character vector with more than one element
#' will also be interpreted as a dropdown menu.}
#' \item{\code{z = TRUE} or \code{z = FALSE} for a
#' logical value controlled by a checkbox.}
#' \item{\code{foo = "Some text"} for a character
#' string controlled by text input.}
#' \item{\code{bar = 123.456} for a numeric value
#' controlled by text input.}
#' \item{\code{baz = as.Date("2020-01-01")} for a
#' \code{Date} object with a calendar input.}
#' }
#' See below for an example.
#' }
#' \item{\strong{The more flexible way}}{The more flexible way
#' is to specify the variables to be manipulated as input controls
#' using the \code{shiny} package. In this case the names of the
#' arguments are ignored, and the variable names are taken from
#' the \code{inputId} argument to the Shiny input control. An
#' example is below. }
#' }
#' @param options a \code{list} containing further settings:
#' \describe{
#' \item{\code{position}}{where the controls are positioned relative to the
#' plot; either \code{"bottom"} (default), \code{"top"}, \code{"left"}, or
#' \code{"right"}.}
#' \item{\code{ncol}}{if \code{position} is \code{"top"} or \code{"bottom"},
#' the number of columns to distribute controls across; can be \code{1} (default),
#' \code{2}, \code{3}, or \code{4}.}
#' \item{\code{gadget}}{\code{FALSE} (default) to run in a new window, or
#' \code{TRUE} to run as a gadget, i.e. in the RStudio viewer pane.}
#' \item{\code{plot_height}}{Height of the plot in pixels, with \code{400} as
#' the default.}
#' }
#' @param .envir environment in which to evaluate \code{expr}.
#'
#' @export
#' @examples
#' \dontrun{
#' # Specifying controls: the easy way
#' tweak({
#' x = 0:10;
#' plot(A * x^2 + B * x + C,
#' col = if (blue) "blue" else "black",
#' main = plot_title,
#' ylim = c(-5, 10)
#' )
#' },
#' A = c(0, 0.1), # slider from 0 to 0.1
#' B = 1, # numeric text input with starting value 1
#' C = list(one = 1, two = 2, three = 3), # dropdown list with named values
#' plot_title = "Example title", # freeform text input
#' blue = FALSE # checkbox
#' )
#'
#' # Specifying controls: the flexible way
#' library(shiny)
#' library(ggplot2)
#'
#' tweak({
#' dat = data.frame(
#' date = start_date + 0:(n_days - 1),
#' value = start_value * exp(0:(n_days - 1) * growth_rate) +
#' rnorm(n_days, 0, noise)
#' )
#' ggplot(dat) +
#' geom_line(aes(x = date, y = value))
#' },
#' dateInput(inputId = "start_date",
#' label = "Start date", value = "2020-01-01"),
#' numericInput(inputId = "start_value",
#' label = "Starting value", value = 1, min = 0, max = 10, step = 1),
#' sliderInput(inputId = "growth_rate",
#' label = "Growth rate", min = 0, max = 1, value = 0, step = 0.01),
#' numericInput(inputId = "n_days",
#' label = "Number of days", value = 30, min = 1, max = 60, step = 1),
#' sliderInput(inputId = "noise",
#' label = "Noise", min = 0, max = 1, value = 0, step = 0.01)
#' )
#'
#' # Different kinds of numeric sliders
#' tweak({ x = 0:100; plot(A * x^2 + B * x + C, ylim = c(-2000, 2000)) },
#' A = c(0.5, 0, 1), # slider from 0 to 1, with starting value 0.5
#' B = c(0, 10, 0.25), # slider from 0 to 10, with step 0.25
#' C = c(0, -1000, 1000, 50) # slider from -1000 to 1000, starting value 0 and step 50
#' )
#'
#' # tweak plus curve
#' tweak(curve(dbeta(x, alpha, beta), 0, 1), alpha = c(1, 100), beta = c(1, 100))
#'
#' # Quickly explore a numeric data.frame
#' data(quakes)
#' tweak(
#' if (x == y) {
#' hist(quakes[[x]], xlab = x)
#' } else {
#' plot(quakes[[x]], quakes[[y]], xlab = x, ylab = y)
#' },
#' x = names(quakes), y = names(quakes))
#' }
#' @rdname tweak
tweak = function(expr, ..., options = list(), .envir = parent.frame())
{
# Process options
options = pad_options(options,
ncol = 1,
position = "bottom",
gadget = FALSE,
plot_height = "400px"
);
# Read named and unnamed (list) arguments
ellipses = list(...);
args = list();
for (i in seq_along(ellipses)) {
if (!is.null(names(ellipses)) && names(ellipses)[i] != "") {
args = c(args, list(ellipses[[i]]));
names(args)[i] = names(ellipses)[i];
} else {
args = c(args, list(ellipses[[i]]));
names(args)[i] = ""
}
}
# Turn ... arguments into input controls
args = lapply(args, parse_control);
controls = mapply(realize_control, names(args), args, SIMPLIFY = FALSE);
arg_names = unname(sapply(controls, get_input_id));
if (any(is.null(arg_names))) {
stop("tweak: could not find names for all parameters.");
}
# Define page layout
ui = shiny::fluidPage(layout(controls, options$ncol, options$position, options$plot_height));
# Simple server to render plot based on updates to inputs
expr_txt = deparse(substitute(expr));
server = function(input, output, session)
{
output$plot = shiny::renderPlot({
# get server values
args2 = lapply(arg_names, function(name) input[[name]]);
names(args2) = arg_names;
# convert dropdown list values from character to originally specified type
for (i in seq_along(args)) {
if (!inherits(args[[i]], "shiny.tag") && args[[i]]$type == "select") {
args2[[i]] = args[[i]]$values[[as.integer(args2[[i]])]];
}
}
# evaluate plotting command
eval(parse(text = expr_txt), args2, .envir)
});
}
# Run app
if (options$gadget) {
shiny::runGadget(ui, server)
} else {
shiny::shinyApp(ui, server)
}
}
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