[R] feedback on writing r extensions

[Scott Harrison]

Hi, 


To whom should I send feedback/edits concerning the
Writing R Extensions web page? 


http://cran.r-project.org/doc/manuals/R-exts.html 


Scott

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Re: [R] fidelity of generated raster images (R and perl)

[Scott Harrison]

Wrap-up:
Different solutions were proposed for turning a matrix
into a bitmap.
Henrik Bengtsson [EMAIL PROTECTED]
R.classes bundle from
 (http://www.maths.lth.se/help/R/R.classes/)
MonochromeImage
R.classes is still not compatible with
2.0.0 (minor modification to DESCRIPTION etc
 are needed) so you have use R v1.9.1 to try the below.
img - MonochromeImage(1-bits) # 1=white, 0=black
image(img)
plot(img)
persp(img, phi=60, theta=150)
write(img, foo.pbm) # Write directly
Martin Maechler [EMAIL PROTECTED]
I think the most typical alternative is to use image()
[EMAIL PROTECTED]
Maybe use the write.pnm() function in the pixmap package
Another package you could explore is rimage, which looks relevant.
For the sake of being conventional and minimizing dependencies,
I had good success with the image() function.  It is very nice to know
there are other approaches if I need to optimize/customize what
I am doing more for this.
(As usual) learned a few more things about 'R' from the examples
provided by others.  Most grateful for your help.
Regards,
Scott
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[R] fidelity of generated raster images (R and perl)

[Scott Harrison]

Hi:
Goal: use R to turn a matrix of 1's and 0's
 into a corresponding image (e.g. png)
 of black and white pixels.
Why R: Yes, I can do this more efficiently and precisely
   with a perl module like Image::PBM.  Been there,
   done that many times, etc.  (Just humor me.
   I'm trying to do this with R for a number of reasons.)
Problem: Difficult to get a perfect rasterization.  There can
   be appended or removed pixel columns or pixel rows
   depending on plot region dimensions.  I witness this
   with both R version 1.8.1 and R version 2.0.
print($out bitmap('/usr/local/mycrow/tmp/out.png', type = 'png256', 
height = .(int($height*68/64)/64)., width = 
.(int($width*69/64)/64)., res = 64, pointsize=0)\n);
print($out 'par(mar=c(0,0,0,0))'.\n);
my $width1 = $width-1;
my $height1 = $height-1;
print($out END);
plot.new()
plot.window(c(0,$width1),c(0,$height1))
rect(m[,1], m[,2], m[,1], m[,2], col=black, border=black)

There are alternatives to rect (plot with type=p, pch=., etc)
and I have also tried png() instead of bitmap().  (I do prefer
bitmap so this can run without x11.)
I am guessing that R's internal region calculations are
vector based, which generally makes sense for most statistical
plots.  However, I do have some ideas for R and the presentation
of cellular automata results.
Any tips out there?  (Is it just a matter of height=50px to
overcome the inches default, etc?).
Regards,
Scott
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