Skip to content

update graphics component without redrawing whole plot

3 messages · iuhz7j202 at sneakemail.com, Ken Knoblauch, Brian Ripley

Original
iuhz7j202 at sneakemail.com
# 
Hi,

I know that interactive graphics aren't R's strongpoint, but I have a question for this list:

Are there any devices/packages available for R on Mac OS that let you move a single element in a plot without redrawing the whole plot? 

I have a complex simulation running in R (with networks and cumulative summary stats), and I want to be able to make small updates to the graphics as the simulation runs. Each tick only a very few of the many graphics elements need to be changed. With standard R plotting this slows the simulation down excessively and 'flickers' the whole graphics window throughout. 

The grid package lets you shift individual elements, but I've tried it in X11(), quartz() and Cairo() devices and in every case it still redraws whole plot. quartz() seems to be the fastest, but also the most flickery.

As a quick example of what I'm talking about, here is some code:

  library(ggplot2)
  qplot(1:5,1:5)
  for(i in 1:30){
    grid.gedit(gPath("geom_point"),x=unit((1:5/5)/i,"npc"))
  }

This should shift the five points in the plot smoothly to the left, but the redrawing of the whole background etc makes it difficult to see what's going on.

Any ideas would be greatly appreciated.

Many thanks,

Peter
Ken Knoblauch
# 
<iuhz7j202 <at> sneakemail.com> writes:
....
Now about something like

 library(ggplot2)
  qplot(1:5,1:5)
  for(i in 1:30){
    grid.gedit(gPath("geom_point"),x=unit((1:5/5)/i,"npc"))
    Sys.sleep(0.1)
  }

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Brian Ripley
    

    

      
      #
    

  


  

      
That still redraws, and it flickers visibly on my (latest model with 
nVidia graphics) MacBook Air (on both quartz() and X11()).

R graphics devices use an 'ink and paper' model, so it is impossible 
to remove (or move) elements.  All you can do is repaint background on 
sections of the plot and redraw there.  It can be done much more 
smoothly than that example in base graphics, at least.

We expect to have a double-buffered X11 device soon (it is delayed by 
event-loop issues) and that will probably not flicker so visibly (the 
windows() device is double-buffered and does not).

        
On Fri, 20 Feb 2009, Ken Knoblauch wrote: