R/dlg_input.tcltkGUI.R

In svDialogstcltk: 'SciViews' - Standard Dialog Boxes using Tcl/Tk

#' A Tcl/Tk version of the {svDialogs} input a string or value dialog box
#'
#' Prompt for some data in a modal dialog box.
#'
#' @param message The message to display in the dialog box. Use `\\n` for
#' line break, or provide a vector of character strings, one for each line.
#' @param default The default value in the text box. Single string or `NULL`.
#' @param ... Not used yet.
#' @param gui The 'gui' object concerned by this dialog box.
#'
#' @return The string the user wrote in the dialog box.
#' @export
#' @rdname dlg_input
#' @method dlg_input tcltkGUI
#' @seealso [svDialogs::dlg_input()]
#' @keywords misc
#' @concept Modal dialog box
#' @examples
#' library(svDialogstcltk) # Tcl/Tk dialog boxes are now used by default
#' \dontrun{
#' # Ask something...
#' user <- dlg_input("Who are you?", Sys.info()["user"])$res
#' if (!length(user)) {# The user clicked the 'cancel' button
#'   cat("OK, you prefer to stay anonymous!\n")
#' } else {
#'   cat("Hello", user, "\n")
#' }
#' }
dlg_input.tcltkGUI <- function(message = "Enter a value", default = "", ...,
gui = .GUI) {
  gui$setUI(args = list(message = message, default = default), widgets = "tcltkGUI")
  # A simple text input box
  # This dialog box is always modal
  # Return either a string, or character(0) if 'Cancel' clicked
  # Do we have access to ttk widgets?
  if (as.character(tcl("info", "tclversion")) < "8.5") {
    ttklabel <- tklabel
    ttkbutton <- tkbutton
    ttkentry <- tkentry
    ttkframe <- tkframe
  }
  inbox <- tktoplevel()
  tkwm.withdraw(inbox)

  # Construct the dialog box
  tktitle(inbox) <- "Question"

  # The message
  wlabel <- ttklabel(inbox, text = gui$args$message)
  tkgrid(wlabel, sticky = "w", padx = 5, pady = 5)

  # The text entry
  varText <- tclVar(gui$args$default)
  wtext <- ttkentry(inbox, width = "50", textvariable = varText)
  tkgrid(wtext, padx = 5, pady = 5)

  # The buttons
  onOk <- function() {
    tkdestroy(inbox)
  }
  onCancel <- function() {
    tkdestroy(inbox)
    # Change the text to @@@@@Cancelled!@@@@@ in varText
    tclvalue(varText) <- "@@@@@Cancelled!@@@@@"
  }
  butFrame <- ttkframe(inbox)
  wbutOK <- ttkbutton(butFrame, text = "OK", width = "12", command = onOk,
    default = "active")
  wbutCancel <- ttkbutton(butFrame, text = "Cancel", width = "12",
    command = onCancel)
  if (.Platform$OS.type == "windows") {
    tkgrid(wbutOK, wbutCancel, sticky = "w", padx = 5)
  } else {
    tkgrid(wbutCancel, wbutOK, sticky = "w", padx = 5)
  }
  tkgrid(butFrame, pady = 5)

  # Other event bindings
  tkwm.protocol(inbox, "WM_DELETE_WINDOW", onCancel)
  tkbind(inbox, "<Return>", onOk)
  tkbind(inbox, "<KeyPress-Escape>", onCancel)
  .Tcl("update idletasks")
  tkselection.range(wtext, "0", "100000")
  tkicursor(wtext, as.character(nchar(gui$args$default)))

  # Center the window on screen
  W <- as.integer(tclvalue(tcl("winfo", "screenwidth", inbox)))
  H <- as.integer(tclvalue(tcl("winfo", "screenheight", inbox)))
  X <- as.integer(tclvalue(tcl("winfo", "width", inbox)))
  Y <- as.integer(tclvalue(tcl("winfo", "height", inbox)))
  X0 <- W/2 - X/2 - as.integer(tclvalue(tcl("winfo", "vrootx", inbox)))
  Y0 <- H/2 - Y/2 - as.integer(tclvalue(tcl("winfo", "vrooty", inbox)))
  pos <- paste("+", round(X0), "+", round(Y0), sep = "")
  tkwm.geometry(inbox, pos)

  # Do not allow to resize the window
  tkwm.resizable(inbox, 0, 0)
  # Show it now and wait for it is destroyed
  tkwm.deiconify(inbox)
  # Make sure the window is always on top
  try(tcl("wm", "attributes", inbox, topmost = 1), silent = TRUE)
  # Focus now inside the entry widget
  tkfocus(wtext)
  # Wait for the window to be destroyed
  tkwait.window(inbox)
  # Get the value
  res <- tclvalue(varText)
  # Check if the user cancelled the dialog box
  if (res == "@@@@@Cancelled!@@@@@")
    res <- character(0)
  gui$setUI(res = res, status = NULL)
  return(invisible(gui))
}