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using yscrollcommand in tkcanvas crashes R (PR#13231)

3 messages · Sundar Dorai-Raj, Greg Snow, Paul Roebuck

Original
Sundar Dorai-Raj
# 
Full_Name: Sundar Dorai-Raj
Version: 2.8.0
OS: Windows
Submission from: (NULL) (76.220.41.126)


The following code crashes R:

library(tcltk)
tt <- tktoplevel()
tc <- tkcanvas(tt, yscrollcommand = function(...) tkset(ts, ...))
R version 2.8.0 (2008-10-20) 
i386-pc-mingw32 

locale:
LC_COLLATE=English_United States.1252;LC_CTYPE=English_United
States.1252;LC_MONETARY=English_United
States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252

attached base packages:
[1] tcltk     stats     graphics  grDevices utils     datasets  methods  
[8] base
Greg Snow
# 
I don't know if this is the case here or not, but putting in scrollbars and scrolling can be a bit tricky.  It usually works best to create the canvas without a scroll command, then create the scrollbar(s), then use tkconfig to go back and add the scroll command to the canvas after the scrollbar has been created and placed.

Hope this helps,

--
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111
Paul Roebuck
#
On Thu, 30 Oct 2008 sundar.dorai-raj at pdf.com wrote:

            

      
      
      
    

        
Here's a portion of the code I wrote for a package that
contains a scrollable canvas, if it helps you any.


.RDEnv <- new.env(hash=TRUE)                   # Private environment

rdenv <- function() {
    return(.RDEnv)
}


scrollframe_create <- function(parent) {
    stopifnot(is.tkwin(parent))

    frame <- tkframe(parent,
                     class="ScrollFrame")
    xscroll <- tkscrollbar(frame,
                           orient="horizontal",
                           command=function(...) tkxview(vport, ...))
    yscroll <- tkscrollbar(frame,
                           orient="vertical",
                           command=function(...) tkyview(vport, ...))
    vport <- tkcanvas(frame,
                      xscrollcommand=function(...) tkset(xscroll, ...),
                      yscrollcommand=function(...) tkset(yscroll, ...))

    pady <- paste("0", tclvalue(tkwinfo.reqheight(xscroll)))
    tkpack(yscroll, side="right", fill="y", pady=pady)
    tkpack(xscroll, side="bottom", fill="x")
    tkpack(vport, side="left", fill="both", expand=TRUE)

    int.frame <- tkframe(vport,
                         borderwidth=4,
                         relief="groove")
    tkcreate(vport, "window", "0 0", anchor="nw", window=int.frame$ID)
    tkbind(int.frame, "<Configure>", function() scrollframe_resize(int.frame))

    ## Save this so items can be put in it
    assign("interior.frame", int.frame, envir=rdenv())

    return(frame)
}


scrollframe_resize <- function(iframe) {
    stopifnot(tclvalue(tkwinfo.class(iframe)) == "Frame")

    w <- tkwinfo.width(iframe)
    h <- tkwinfo.height(iframe)

    vport <- tkwinfo.parent(iframe)
    stopifnot(tclvalue(tkwinfo.class(vport)) == "Canvas")
    bbox <- tkbbox(vport, "all")

    tkconfigure(vport,
                width=w,
                height=h,
                scrollregion=bbox,
                xscrollincrement="0.1i",
                yscrollincrement="0.1i")
}


scrollframe_interior <- function() {
    return(get("interior.frame", envir=rdenv()))
}


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SIGSIG -- signature too long (core dumped)