[R] Windows BMPs: Why grey background? How to display BMP in R?

[Prof Brian Ripley]

The manual is the source code: we would have to read it to answer your 
questions so you may as well read it yourself.

That driver was written last century by someone no longer active in the R 
project.

On Tue, 8 Feb 2005, Earl F. Glynn wrote:

> "Duncan Murdoch" <murdoch at stats.uwo.ca> wrote in message
> news:3j4i015lan8u9cu1eueuk8h5ghru2gt8hd at 4ax.com...
>> On Tue, 8 Feb 2005 11:35:22 -0600, "Earl F. Glynn"
>> <efg at stowers-institute.org> wrote :
>
>> In what version of R?  I just tried in 2.01 and R-patched, and it was
>> fine.  Maybe the problem is your viewer?
>
> Sorry.
>
> I thought I was using R 2.0.1 but I used a shortcut on my desktop that
> started the older R 2.0.0 -- so I just rediscovered the problem that you've
> already fixed.  With the correct shortcut to R 2.0.1, I am seeing a white
> bmp background.  Sorry to have bothered you with this.
>
> I don't see much information about the bmp driver (from ?bmp).  I noticed
> the BMPs that are created have only 8-bit color depth, which means the
> palette must be stored with the image.  But what is the palette R uses with
> BMPs?  I always use true color (24-bit) bmps in Windows instead of 8-bit
> bmps to avoid palette issues on older 256 color displays.
>
> Microsoft recommended only using 240 of the 256 palette entries, since 16
> were reserved for system colors for older 256 color display monitors (which
> are no longer common) and the Windows palette manager.  I guess R's bmps
> only have 240 colors that will work on all PCs.
>
> So are bmps created under R restricted to a single, fixed 256 color palette?
> (I don't see any color palette parameter to the bmp device.) Is there any
> way to create an R bmp that is hicolor (15 or 16-bit color) or true color
> (24-bit color) to avoid the palette issues of 8-bit bmps?
>
> Thanks for any info about this.
>
> efg
>
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-- 
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