R devel - Jan 1998 - Default device instead of ``No graphics device is active''

in RHOME/src/ :
	grep DevInit */*.[ch]
reveals only a few calls such as

	if(!DevInit) error("No graphics device is active\n");

(in graphics/graphics.c  and  main/par.c).

Couldn't we startup a default device instead of having the error message?

The Default device would be

	Unix, interactive:	x11
	Unix, batch:		postscript
	
	Win,  interactive:	windows
	Win,  batch:		postscript ??

	Mac,  interactive:	macintosh
	Mac,  batch:		postscript  ????

[ one could even  define

	default.device <- x11		
  in Rprofile.unix, etc.

 and have the same .First function  
	(which could be moved out of profile to base

  .First <- function() if(interactive()) default.device()
]

-- If I remember properly, this is also  how S4 behaves..

Martin
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Martin Maechler <maechler@stat.math.ethz.ch> writes:
> Couldn't we startup a default device instead of having the error
message?
Very good idea!
> The Default device would be
> 
> 	Unix, interactive:	x11
or: "none" (or "printer"???) if DISPLAY not set, or maybe
customizable
(sometimes you really don't want it, e.g. when connected to Auckland
from Europe...)
>   .First <- function() if(interactive()) default.device()
Actually, it might be a better idea to use this to *get rid* of the
initial graphics startup. I, for one, tend to get annoyed at seeing
the window popup, even when what I am trying to do has nothing to do
with graphics. Having to place it manually doesn't help...

While we're at this, how about making it possible to override the
printer and device orientation in print.plot() and save.plot()?

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk)             FAX: (+45) 35327907

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On Mon, 12 Jan 1998, Martin Maechler wrote:
> in RHOME/src/ :
> 	grep DevInit */*.[ch]
> reveals only a few calls such as
> 
> 	if(!DevInit) error("No graphics device is active\n");
> 
> (in graphics/graphics.c  and  main/par.c).
> 
> Couldn't we startup a default device instead of having the error
message?
yes, though I think the default device for batch processing should do
nothing or just emit warnings -- if postscript() is the default then you
might overwrite the previous contents of an output file. At least if it is
going to be postscript() it should use a unique file name. 

It should be relatively easy to define a none() device that does
absolutely nothing (a simple but inefficient one would be
postscript("/dev/null") under Unix)

	-thomas

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