background colors in image()

Thu, Aug 11, 2005 10:31 AM

Romain,

Thanks for the code. It worked perfectly!

--- Romain Francois <francoisromain at free.fr> wrote:

Le 11.08.2005 00:59, array chip a ??crit :

Thanks for the suggestion! It works in a way that

the

entire graph window is in the background color, is
there a way to only have the plotting area (i.e.

the

area within the axis box in the background color,

but

leave the area outside the axes to be unchanged
(white)?

Thanks!

You need to learn how to use par('usr') and argument
add in image.
demo('graphics') is one way to learn or look at
graph 8 on r graph gallery

R> image(matrix(c(1,2,NA, 1),2, 2))
R> usr <- par('usr')
R> rect(usr[1], usr[3], usr[2], usr[4],
col="cornsilk")
R> image(matrix(c(1,2,NA, 1),2, 2),add=TRUE)

Romain

--- Prof Brian Ripley <ripley at stats.ox.ac.uk>

wrote:

On Wed, 10 Aug 2005, someone needing to conceal

his

real name wrote:

Hi, I am using image() function to plot a matrix

which

has some missing valuies (NA). It looks like, by
default, missing values were drawn in white

color,

How

can I change that into a different color, say a

gray

color? I tried to use bg='gray' argument with no

luck.

Anyone has a suggestion?

They are not drawn in white: in fact they are not
drawn at all, so the 
current background (or if transparent, the canvas)
is what you see.

par(bg="yellow")
image(matrix(c(1,2,NA, 1),2, 2))

works, for example.

-- 
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

-- 
visit the R Graph Gallery :
http://addictedtor.free.fr/graphiques
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background colors in image()

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