Thanks Simon, this works really well.

Thanks Ken also for the information on the pnm utilities, but at the moment I did not have time to figure out how to get and install them. The R function is more practical for me.

Denis
Le 08-06-05 à 10:15, Simon Urbanek a écrit :


On Jun 5, 2008, at 7:36 AM, Denis Chabot wrote:

Hi,

a bit frivolous, I know, but I thought of adding a small picture of each species of fish onto the upper right corner of plots dealing with metabolic rate of several species of fish.

The only information I could find about doing this involved a package named pixmap. But from what I understand, I must first make the picture of each fish (diverse original formats, gif, jpeg, pdf) into a pnm format.

How do I manage this on Mac OS X? I had never come across this format before.


IMHO the simplest solution is to save your image(s) into uncompressed TIFFs (e.g. open the image in Preview and Save As.. , Format: TIFF , Compression: None). The you can use this simple function to read TIFFs into pixmaps:

read.tiff = function(con, ...) {
   if (is.character(con)) {
       con = file(con, "rb")
       on.exit(close(con))
   }
 sig = readBin(con, 1L, 1, 2)
 if (sig != 0x4949 && sig != 0x4d4d) stop("Invalid signature")
 end = if (sig == 0x4949) "little" else "big"
if (readBin(con, 1L, 1, 2, endian=end) != 42) stop("Invalid signature")
 o = readBin(con, 1L, 1, 4, endian=end)
 data = readBin(con, 1L, o - 8, 1, signed=FALSE, endian=end)
 ifds = readBin(con, 1L, 1, 2, endian=end)
 info = list()
 for (i in 1:ifds) {
   tag = readBin(con, 1L, 6, 2, endian=end)
   if (tag[1] == 257) info$height = tag[5]
   if (tag[1] == 256) info$width = tag[5]
if (tag[1] == 259 && tag[5] != 1) stop("compressed TIFFs are not supported")
 }
if (is.null(info$width)||is.null(info$height)) stop("missing width/ height tags")
 res = array(data/255, dim=c(3, info$width, info$height))
 z = pixmapRGB(0, ncol = dim(res)[2], nrow = dim(res)[3], ...)
 [EMAIL PROTECTED] = t(res[1, , ])
 [EMAIL PROTECTED] = t(res[2, , ])
 [EMAIL PROTECTED] = t(res[3, , ])
 z
}

Cheers,
Simon


I have seen another way using grImport to import postscript vector graphics. Does anyone here know if this will also work if I transform my original pictures and drawings into postscript format (which obvisouly won't be vector based)?

Thanks,

Denis Chabot

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