[R] determining plot location in lattice

[Greg Snow]

Glad I could be of help.

Some possible enhancements that you may want to try:

I would wrap all of that into a function so that the assignments using <<- don't put stuff into the global environment but just change things in the top level functions local environment.

Rather than having the click plot function do a replot I would have your makePlot function export the PLT coordinates to the top level function, then clickPlot would just need to compare to those values without replotting each time (you can have other controls replotting if desired).

--
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111

> -----Original Message-----
> From: Sundar Dorai-Raj [mailto:sundar.dorai-raj at pdf.com]
> Sent: Saturday, November 08, 2008 9:17 AM
> To: Greg Snow
> Cc: r-help at r-project.org
> Subject: Re: [R] determining plot location in lattice
>
> Hi, Greg,
>
> Thanks again for your reply. I looked at TkIdentify which lead me to
> "plt", which with RSiteSearch("grid plt") lead me to gridBase::gridPLT.
> Here's my solution:
>
>
> stopifnot(require(tkrplot),
>            require(lattice),
>            require(gridBase))
> makePlot <- function() {
>    print(xyplot(1 ~ 1))
>    if(click) {
>      trellis.focus(highlight = FALSE)
>      plt <- gridPLT()
>      out <- ((x < plt[1] || x > plt[2]) ||
>              (y < plt[3] || y > plt[4]))
>      cat(if(out) "outside" else "inside", "\n")
>    }
> }
> clickPlot <- function(x, y) {
>    width  <- as.numeric(tclvalue(tkwinfo("reqwidth", img)))
>    height <- as.numeric(tclvalue(tkwinfo("reqheight", img)))
>    x <<- as.numeric(x)/width
>    y <<- 1 - as.numeric(y)/height
>    click <<- TRUE
>    tkrreplot(img)
>    click <<- FALSE
> }
> x <- y <- -1
> click <- FALSE
> tt <- tktoplevel()
> img <- tkrplot(tt, makePlot)
> tkbind(img, "<1>", clickPlot)
> tkpack(img)
> tkwm.resizable(tt, 0, 0)
>
>
> Greg Snow said the following on 11/7/2008 8:23 PM:
> > As far as R is concerned, the plot in tkrplot is being written to a
> file and therefore is not interactive.  So functions like grid.locator
> and trellis.focus are not going to work.
> >
> > You need to use the Tk commands to determine where the mouse is and
> where a click occurred, then this needs to be converted to the
> coordinates of the trellis plot.  There are some examples of the first
> part in the TeachingDemos package, eg TkBrush, TkIdentify, TkApprox,
> and a couple of others (also the play.sudoku function in the Sudoku
> package).  These all work with base graphics rather than trellis/grid
> so will not help with the 2nd part.  Possibly something in the grid
> package can tell you the coordinates of the various viewports (but you
> need to save this information before the end of the plotting command
> because the information will probably be lost when the plot finishes).
> >
> > Hope this helps,
> >
> > --
> > Gregory (Greg) L. Snow Ph.D.
> > Statistical Data Center
> > Intermountain Healthcare
> > greg.snow at imail.org
> > 801.408.8111
> >
> >
> >> -----Original Message-----
> >> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> >> project.org] On Behalf Of Sundar Dorai-Raj
> >> Sent: Friday, November 07, 2008 12:43 PM
> >> To: r-help at r-project.org
> >> Subject: [R] determining plot location in lattice
> >>
> >> Hi,
> >>
> >> I'm dealing with a lattice plot inserted into a tk widget and would
> >> like
> >> to know when a user has clicked on the plot area of a plot (i.e.
> inside
> >> the axes). For example,
> >>
> >> library(tkrplot)
> >> library(lattice)
> >> tt <- tktoplevel()
> >> makePlot <- function() print(xyplot(1 ~ 1))
> >> printCoords <- function(x, y) print(c(x, y))
> >> img <- tkrplot(tt, makePlot)
> >> tkbind(img, "<1>", printCoords)
> >> tkpack(img)
> >>
> >> I would like to know when a user clicks inside the axes, but don't
> know
> >> how to determine where the plot region is. Essentially, this comes
> down
> >> to answering the following question: Assuming the entire plot is on
> a
> >> unit square, what are the coordinates of the plotting area?
> >>
> >> This question is may seem unrelated to tkrplot, but outside of this
> >> context I may not get answers that work. I have been playing with
> both
> >> lattice::trellis.focus and grid::grid.locator to no avail.
> >>
> >> Thanks,
> >>
> >> --sundar
> >>
> >> ______________________________________________
> >> R-help at r-project.org mailing list
> >> https://stat.ethz.ch/mailman/listinfo/r-help
> >> PLEASE do read the posting guide http://www.R-project.org/posting-
> >> guide.html
> >> and provide commented, minimal, self-contained, reproducible code.