R help - Jan 2009 - Can I add a point to a pointsGrob from an xyplot without redrawing ?

Hi:

I am a newbie using grid and lattice.
I want to update a xyplot without redrawing and I was wondering if there is
a way of adding a point to a pointsGrob ?

For example, take the example from the "R Graphics Book"  page
218-219:
grid.newpage()
angle <- seq(0, 2*pi, length=21)[-21]
x <- cos(angle)
y <- sin(angle)
xyplot( y ~ x, aspect = 1)

Lets say I take the pointsGrob below:

getNames()
  [1] "GRID.rect.748"     "plot1.xlab"       
"plot1.ylab"
"GRID.segments.749"
  [5] "GRID.segments.750" "GRID.text.751"    
"GRID.segments.752"
"GRID.text.753"
  [9] "GRID.segments.754" "GRID.points.755"  
"GRID.rect.756"
pg = grid.get("GRID.points", grep=TRUE)
pg
   points[GRID.points.755]

Is there a way I can add a point to pg (or "GRID.points.755") to
update the
xyplot without redrawing all the points ?
If redrawing is obligatory,  is there way of redrawing the least elements of
the xyplot ?

Searched for a long time but could not find anything, even if this seems
like a fairly basic operation.
I guess this may well go against the grid's package "philosophy"
or
"architecture" ?

       Thanks.

               Daniel.

	[[alternative HTML version deleted]]

Hi Daniel,
>> Is there a way I can add a point to pg (or "GRID.points.755")
to update
>> the
>> xyplot without redrawing all the points ?
I think you want to look at ?grid.edit to do this.

grid.edit(yourGROB, redraw = FALSE)

HTH, Mark.



Daniel Kornhauser-3 wrote:
> 
> Hi:
> 
> I am a newbie using grid and lattice.
> I want to update a xyplot without redrawing and I was wondering if there
> is
> a way of adding a point to a pointsGrob ?
> 
> For example, take the example from the "R Graphics Book"  page
218-219:
> grid.newpage()
> angle <- seq(0, 2*pi, length=21)[-21]
> x <- cos(angle)
> y <- sin(angle)
> xyplot( y ~ x, aspect = 1)
> 
> Lets say I take the pointsGrob below:
> 
> getNames()
>   [1] "GRID.rect.748"     "plot1.xlab"       
"plot1.ylab"
> "GRID.segments.749"
>   [5] "GRID.segments.750" "GRID.text.751"    
"GRID.segments.752"
> "GRID.text.753"
>   [9] "GRID.segments.754" "GRID.points.755"  
"GRID.rect.756"
> pg = grid.get("GRID.points", grep=TRUE)
> pg
>    points[GRID.points.755]
> 
> Is there a way I can add a point to pg (or "GRID.points.755") to
update
> the
> xyplot without redrawing all the points ?
> If redrawing is obligatory,  is there way of redrawing the least elements
> of
> the xyplot ?
> 
> Searched for a long time but could not find anything, even if this seems
> like a fairly basic operation.
> I guess this may well go against the grid's package
"philosophy" or
> "architecture" ?
> 
>        Thanks.
> 
>                Daniel.
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> 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.
> 
> 
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