R help - Sep 2008 - Beginner graphics device questions.

Please forgive me if this has been asked before but I could not readily find an
answer. First, from the example I was able to determine that graphics device
commands such as plot can be redirected using 'png' and 'bmp'
type commands. I tried this and it works as I understand it. The question is how
this graphics device works. If I issue another 'plot' command will it
also be redirected to the 'png' device? Does dev.off essentially reset
the graphics device to the default? Second there is a note that if the name of
the file does not contain %d then every plot will essentially overwrite the
previous plot. So I think I can see how to get 'plot1.bmp',
'plot2.bmp', etc. What if I want a finer control over the name of the
graphics file? What if I want to specify a name? Something like
'plotA.bmp', 'plotB.bmp', etc. ? Would I essentially have to
call 'png' (or 'bmp' etc.) with a file name and then call
dev.off?

Thank you.

Kevin

> On Monday, 08 September 2008, 10:59 (UTC-0700),
> rkevinburton at charter.net wrote:
>  If I issue another 'plot' command will it also be redirected
>  to the 'png' device? 
As long as that png device is the currently active device, yes.
> Does dev.off essentially reset the graphics
>  device to the default? 
It turns off the currently active device, making the next one in the
list active. See what's open using dev.list(). You can also specificy
one of those by doing dev.off(2) etc. 
> Second there is a note that if the name of the
>  file does not contain %d then every plot will essentially overwrite
>  the previous plot. So I think I can see how to get 'plot1.bmp',
>  'plot2.bmp', etc. What if I want a finer control over the name of
the
>  graphics file? 
> What if I want to specify a name? Something like
>  'plotA.bmp', 'plotB.bmp', etc. ? Would I essentially have
to call
>  'png' (or 'bmp' etc.) with a file name and then call
dev.off?
yes, for example bmp(filename="path/if/any/plotA.bmp"). dev.off()
saves that. 

But again, you could then open another plotting more plots with bmp()
or maybe x11() or whatnot and close them explicitly by giving hte
number from dev.list()


for full info 

?dev.off

HTH

m.

-- 
Marianne Promberger
Graduate student in Psychology
http://www.psych.upenn.edu/~mpromber