R help - Mar 2003 - graphics backgrounds from gray to white in png()

Hi,

I'm trying to make a png file of a histogram.  I would like a white
background in the final product but end up producing a gray one, despite
setting what I think are the correct parameters.  Suggestions for how to
properly set a white background would be welcome.

Thanks in advance,

Scot


# for non-lattice
> par("bg"="white")
> par("bg")
[1] "white"

# for lattice
background<-trellis.par.get("background")
background$col<-"white"
trellis.par.set("background",background)
> trellis.par.get("background")
$col
[1] "white"

# produces gray background in png, but white when plotted in active
device
> png(filename = "c:/windows/temp/test.png", width=480, height=640,
+ pointsize = 10, bg="white")
> histogram(rnorm(500))
> dev.off()
windows
      2

Vitals:
> R.version
         _
platform i386-pc-mingw32
arch     i386
os       mingw32
system   i386, mingw32
status
major    1
minor    6.2
year     2003
month    01
day      10
language R


--
  Scot W. McNary  email:smcnary at charm.net

Why are you using lattice for a single plot?

If you use lattice, you should be using trellis.device(), or at least
setting the lattice parameters *after* you open the device.  You set the 
parameters for a screen device (or whatever you had open before).

On Mon, 10 Mar 2003, Scot W McNary wrote:
> 
> 
> Hi,
> 
> I'm trying to make a png file of a histogram.  I would like a white
> background in the final product but end up producing a gray one, despite
> setting what I think are the correct parameters.  Suggestions for how to
> properly set a white background would be welcome.
> 
> Thanks in advance,
> 
> Scot
> 
> 
> # for non-lattice
> > par("bg"="white")
> > par("bg")
> [1] "white"
> 
> # for lattice
> background<-trellis.par.get("background")
> background$col<-"white"
> trellis.par.set("background",background)
> 
> > trellis.par.get("background")
> $col
> [1] "white"
> 
> # produces gray background in png, but white when plotted in active device
> > png(filename = "c:/windows/temp/test.png", width=480,
height=640,
> + pointsize = 10, bg="white")
> > histogram(rnorm(500))
> > dev.off()
> windows
>       2
-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

You need to change the (lattice) background setting AFTER starting the png() 
device (lattice maintains separate settings for different devices). 

If you use png() to start subsequent devices, the same settings will be 
re-used. (The alternative is to use trellis.device(), which is the more 
traditional but not-really-necessary-in-lattice way, in which case by default 
the settings will revert back to the grey background every time a new device 
is started.)

On Monday 10 March 2003 11:48 am, Scot W McNary wrote:
> Hi,
>
> I'm trying to make a png file of a histogram.  I would like a white
> background in the final product but end up producing a gray one, despite
> setting what I think are the correct parameters.  Suggestions for how to
> properly set a white background would be welcome.
>
> Thanks in advance,
>
> Scot
>
>
> # for non-lattice
>
> > par("bg"="white")
> > par("bg")
>
> [1] "white"
>
> # for lattice
> background<-trellis.par.get("background")
> background$col<-"white"
> trellis.par.set("background",background)
>
> > trellis.par.get("background")
>
> $col
> [1] "white"
>
> # produces gray background in png, but white when plotted in active device
>
> > png(filename = "c:/windows/temp/test.png", width=480,
height=640,
>
> + pointsize = 10, bg="white")
>
> > histogram(rnorm(500))
> > dev.off()
>
> windows
>       2
>
> Vitals:
> > R.version
>
>          _
> platform i386-pc-mingw32
> arch     i386
> os       mingw32
> system   i386, mingw32
> status
> major    1
> minor    6.2
> year     2003
> month    01
> day      10
> language R
>
>
> --
>   Scot W. McNary  email:smcnary at charm.net
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help