R help - Sep 2003 - lattice, trellis.device, dev.off() within a condition (seems t o be a bug)

Hi,

I have a strange issue under W2K;
consider these two code extracts:

1)

	if(condition a){
	trellis.device(png,filename = filename_a,...
	xyplot(...
	dev.off()	
	}

2) 

	if(condition a){
	trellis.device(png,filename = filename_a,...
	xyplot(...
	}
	dev.off()	



In 1), The png file is generated, but empty; in 2), where I've taken the
dev.off clause out of the condition block, my plot is fine

I've also tried following without success:

	if(condition a){
	trellis.device(png,filename = filename_a,...
	xyplot(...
	}
	if(condition a){
	dev.off()	
	}

Is there a way to get a list of all open devices in order to close them
outsid the condition blocks ??

Thanks for your help,

Marc Mamin

Marc Mamin wrote:
> Hi,
> 
> I have a strange issue under W2K;
> consider these two code extracts:
> 
> 1)
> 
> 	if(condition a){
> 	trellis.device(png,filename = filename_a,...
> 	xyplot(...
> 	dev.off()	
> 	}
> 
> 2) 
> 
> 	if(condition a){
> 	trellis.device(png,filename = filename_a,...
> 	xyplot(...
> 	}
> 	dev.off()	
> 
> 
> 
> In 1), The png file is generated, but empty; in 2), where I've taken
the
> dev.off clause out of the condition block, my plot is fine
> 
> I've also tried following without success:
> 
> 	if(condition a){
> 	trellis.device(png,filename = filename_a,...
> 	xyplot(...
> 	}
> 	if(condition a){
> 	dev.off()	
> 	}
> 
> Is there a way to get a list of all open devices in order to close them
> outsid the condition blocks ??
> 
Try wrapping the xyplot call in a print() call.

e.g.

if(condition a) {
   trellis.device(...)
   print(xyplot(...))
   dev.off()
}

This is FAQ 7.24.

-sd