R help - Sep 2005 - grid.locator

If I do:

library(lattice)
x <- 1:10
xyplot(x ~ x)
grid.locator()

and click on 2,2 say the I get this:
> grid.locator()
$x
[1] 201native

$y
[1] 476native

How do I get the user coordinates of the graph?

(If I did not use lattice/grid I could have just done:

plot(x ~ x)
locator()

and it would have worked as expected.)

Hi


Gabor Grothendieck wrote:
> If I do:
> 
> library(lattice)
> x <- 1:10
> xyplot(x ~ x)

After the lattice plot, you are back at the top-level grid viewport.

> grid.locator()
> 
> and click on 2,2 say the I get this:
> 
> 
>>grid.locator()
> 
> $x
> [1] 201native
> 
> $y
> [1] 476native

grid.locator() by default gives you the click in "native" coordinates.
The "native" coordinates for the top-level viewport depend on the 
device;  on-screen it is pixel-based.

> How do I get the user coordinates of the graph?

Look up the lattice function trellis.focus().

Paul

> (If I did not use lattice/grid I could have just done:
> 
> plot(x ~ x)
> locator()
> 
> and it would have worked as expected.)
> 
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-- 
Dr Paul Murrell
Department of Statistics
The University of Auckland
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Auckland
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paul at stat.auckland.ac.nz
http://www.stat.auckland.ac.nz/~paul/

Thanks.  Following the example there worked.

I suggest adding trellis.focus to the See Also in ?grid.locator


On 9/25/05, Paul Murrell <p.murrell at auckland.ac.nz>
wrote:
> Hi
>
>
> Gabor Grothendieck wrote:
> > If I do:
> >
> > library(lattice)
> > x <- 1:10
> > xyplot(x ~ x)
>
>
> After the lattice plot, you are back at the top-level grid viewport.
>
>
> > grid.locator()
> >
> > and click on 2,2 say the I get this:
> >
> >
> >>grid.locator()
> >
> > $x
> > [1] 201native
> >
> > $y
> > [1] 476native
>
>
> grid.locator() by default gives you the click in "native"
coordinates.
> The "native" coordinates for the top-level viewport depend on the
> device;  on-screen it is pixel-based.
>
>
> > How do I get the user coordinates of the graph?
>
>
> Look up the lattice function trellis.focus().
>
> Paul
>
>
> > (If I did not use lattice/grid I could have just done:
> >
> > plot(x ~ x)
> > locator()
> >
> > and it would have worked as expected.)