[Rd] tclServiceMode: stop Tcl/Tk from updating

[John Fox]

Dear Duncan,

I hope that some follow-up questions are in order:

In the Rcdmr package, there is a pair of functions for initializing and
completing dialogs:

initializeDialog <- defmacro(window=top, title="", offset=10,
    expr={
        window <- tktoplevel(borderwidth=10)
        tkwm.title(window, title)
        position <- if (is.SciViews()) -1 else commanderPosition() # +PhG
        position <- if (any(position < 0)) "-50+50"
            else paste("+", paste(offset + position, collapse="+"), sep="")
        tkwm.geometry(window, position)
        }
    )

dialogSuffix <- defmacro(window=top, onOK=onOK, rows=1, columns=1,
focus=top,
    bindReturn=TRUE, preventGrabFocus=FALSE, preventDoubleClick=FALSE,
    expr={
        for (row in 0:(rows-1)) tkgrid.rowconfigure(window, row, weight=0)
        for (col in 0:(columns-1)) tkgrid.columnconfigure(window, col,
weight=0)
        .Tcl("update idletasks")
        tkwm.resizable(window, 0, 0)
        if (bindReturn) tkbind(window, "<Return>", onOK)
        if (getRcmdr("double.click") && (!preventDoubleClick))
tkbind(window, "<Double-ButtonPress-1>", onOK)
        tkwm.deiconify(window)
        # focus grabs appear to cause problems for some dialogs
        if (GrabFocus() && (!preventGrabFocus)) tkgrab.set(window)
        tkfocus(focus)
        tkwait.window(window)
        }
    )

(Both of these are "macro-like" in the sense of Thomas Lumley's R-news
article.)

If I understand you correctly, I could improve the R Commander's stability
under windows by putting tclServiceMode(on = FALSE) at the beginning of
initializeDialog(), and tclServiceMode(on = TRUE) at the end of
dialogSuffix(). Is that correct? If so, is there any harm in doing this on
other platforms, or should I test for Windows? Finally, do you mind if I put
tclServiceMode() in the Rcmdr package for the time-being, or would it just
be better to wait for R 2.1.1?

Thanks,
 John

--------------------------------
John Fox
Department of Sociology
McMaster University
Hamilton, Ontario
Canada L8S 4M4
905-525-9140x23604
http://socserv.mcmaster.ca/jfox 
-------------------------------- 

> -----Original Message-----
> From: r-devel-bounces at stat.math.ethz.ch 
> [mailto:r-devel-bounces at stat.math.ethz.ch] On Behalf Of Duncan Murdoch
> Sent: Saturday, April 23, 2005 10:21 AM
> To: r-devel at stat.math.ethz.ch
> Subject: [Rd] tclServiceMode: stop Tcl/Tk from updating
> 
> In Windows, Tcl/Tk programs running under the tcltk package 
> can update too frequently:  for exmaple, we might go through 
> a long sequence of operations to construct a complex display, 
> and in Windows each addition will be shown separately.
> 
> To work around this, I've added a function "tclServiceMode" 
> which serves as an R interface to the "Tcl_SetServiceMode" 
> function in the TCL API.
> Calling "tclServiceMode(on = FALSE)" will stop Tcl/Tk from 
> responding to any events (redraws in particular) until 
> "tclServiceMode(on = TRUE)" is called. As far as I know, 
> events are queued, not lost, when handling is turned off.
> 
> So far this function is only in R-devel, but I'll commit it 
> to R-patched the next chance I get.
> 
> Duncan Murdoch
> 
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