[R-gui] MainFrame Tk BWidget

[Enrique Bengoechea]

Thanks a lot for your two detailed answers, I'm going to try with your clues and will tell whether it works, although the crashes obtained by James are not very encouraging!

Regards,

Enrique





James Wettenhall <wettenhall at wehi.edu.au> on 20/04/2004 16:34:31

To:    Peter Dalgaard <p.dalgaard at biostat.ku.dk>
cc:    Enrique Bengoechea/CSPF at PCOMINT, <r-sig-gui at stat.math.ethz.ch>

Subject:    Re: [R-gui] MainFrame Tk BWidget

Enrique,

Have a look at the BWidget demos that come with ActiveTcl.

For your amusement, here are my efforts to totally confuse
myself about the MainFrame widget.  Does it require "." as a
parent?  What difference does having a menu make?
Three cases below.
(1) A MainFrame widget with no menu and with parent tt
(2) A MainFrame widget with a menu and with parent tt
(3) A MainFrame widget with a menu and with parent .

(1) A MainFrame widget with no menu and with parent tt
library(tcltk)
tt <- tktoplevel()
tclRequire("BWidget")
mainFrame <- tkwidget(tt,"MainFrame")
tkdestroy(mainFrame) # Optional
tkdestroy(tt)
# Notes:  No problems with Case (1).  :)


(2) A MainFrame widget with a menu and with parent tt
library(tcltk)
tt <- tktoplevel()
tclRequire("BWidget")
exit <- function()
{
  tkdestroy(mainFrame)
  tkdestroy(tt)
}
mainMenu <-
  paste("\"&File\" all file 0 ",
  "{{command \"E&xit\" {} \"Exit Case 2\" {}",
  "-command \"",.Tcl.callback(exit),"\"}}")
mainFrame <- tkwidget(tt,"MainFrame",menu=mainMenu)
tkpack(mainFrame)

# Notes:  Now I can crash my R session by typing
# either of tkdestroy(tt) or tkdestroy(mainFrame)
# or clicking "Exit" in the File menu.
# The following DOESN'T crash my R session and
# appears to destroy the menu (and frame?):

tkcmd("MainFrame::_destroy",mainFrame)

# But then tkdestroy(tt) still crashes my R session.
# Now if instead of tkdestroy(tt), I click on the
# close button at the top-right-hand corner of tt,
# (after doing MainFrame::_destroy), I get this:

Application Error
Error: can't read "_widget(.1.1,top)": no such element in array
can't read "_widget(.1.1,top)": no such element in array
can't read "_widget(.1.1,top)": no such element in array
    while executing
"$_widget($path,top) configure -menu {}"
    (procedure "MainFrame::_destroy" line 6)
    invoked from within
"MainFrame::_destroy .1.1"
    (command bound to event)

# Note that the menu option of BWidget::MainFrame is described
# as "read-only".  Is that a clue?



(3) A MainFrame widget with a menu and with parent .
library(tcltk)
tkwm.deiconify(".")
tclRequire("BWidget")
exit <- function()
{
  tkcmd("MainFrame::_destroy",mainFrame)
  tkwm.withdraw(".")
}
mainMenu <-
  paste("\"&File\" all file 0 ",
  "{{command \"E&xit\" {} \"Exit Case 3\" {}",
  "-command \"",.Tcl.callback(exit),"\"}}")
mainFrame <- tkwidget(.TkRoot,"MainFrame",menu=mainMenu)
tkpack(mainFrame)

# Notes: Using the Tk root window "." is ugly
# because if you destroy it then I think you have to
# restart R or at least reload the tcltk package.  The
# exit function used here simply hides the "."
# window.  It doesn't really destroy anything.


Well, maybe that will give others some clues in order to
go further...

Regards,
James