Re: [R] locator() via tcltk

From: Prof Brian Ripley <ripley_at_stats.ox.ac.uk>
Date: Sat 04 Jun 2005 - 18:39:33 EST

You have two asynchronous processes here: your R function will return, leaving a Tk widget up. Duncan Murdoch's solution is to give you a function that will retrieve at some future stage the result of the last press (if any) of "Get coordinates" button. Is that what you want?

I think it is more likely you want to wait for the Tk interaction and then return the results, that is use a `modal' widget. If so, take a look at the examples in src/library/tcltk/R/utils.R which are modal and return their results.

On Fri, 3 Jun 2005, Sebastian Luque wrote:

> Hello,
>
> I'm trying to write a function using tcltk to interactively modify a plot
> and gather locator() data. I've read Peter's articles in Rnews, the help
> pages in tcltk, http://bioinf.wehi.edu.au/~wettenhall/RTclTkExamples/,
> plus a post in R-help sometime ago, but haven't found a solution.
> The idea goes something like this:
>
> require(tcltk)
> testplot <- function() {
> getcoords <- function(...) {
> locator(5)
> }
> x <- 1:1000
> y <- rnorm(1000)
> plot(x, y)
> base <- tktoplevel()
> loc.pts <- tkbutton(base, text = "Get coordinates", command = getcoords)
> quit.but <- tkbutton(base, text = "Quit",
> command = function() tkdestroy(base))
> tkpack(loc.pts, quit.but)
> }
>
> I'd like testplot to return the value from getcoords. The "Get
> coordinates" button seems to be correctly calling getcoords, and locator
> is doing its job, but I don't know how to store its value. Any help is
> very much appreciated.

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

______________________________________________
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Received on Sat Jun 04 18:43:40 2005

This archive was generated by hypermail 2.1.8 : Fri 03 Mar 2006 - 03:32:22 EST