[argyllcms] Re: targen: creating combined channel steps
- From: Klaus Karcher <lists@xxxxxxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Sat, 11 Apr 2009 01:45:24 +0200
Jörg Koch wrote:
Hello,
as I'm trying to generate test patches for characterization. In which
way can combined channel steps be created with targen (e.g. in RGB, 52
red-green (yellow) steps in order from 0 to 100, blue always 0)?
maybe the quickest way is to use Octave
<http://www.gnu.org/software/octave/> or R <http://www.r-project.org/>
In R you can create the table with one line of code:
> yellow <- data.frame(RGB_R=0:51*100/51, RGB_G=0:51*100/51, RGB_B=0)
you can use the built in function write.table() to write it to a text
file and add the CGATS header manually or you can use e.g. my simple
writeCgats() function:
> writeCgats(yellow, "yellow.ti1", id=TRUE)
Here is the writeCgats() function:
---8<---
function(dframe, file, id=FALSE, dec=".") {
if(id==TRUE) {
na <- c("SAMPLE_ID",names(dframe))
nc <- ncol(dframe)+1
} else {
na <- names(dframe)
nc <- ncol(dframe)
}
header <- list("R",
c("CREATED", paste("\"",
format(Sys.time(), usetz = TRUE), "\"", sep="")),
c("NUMBER_OF_FIELDS", nc),
"BEGIN_DATA_FORMAT",
na,
"END_DATA_FORMAT",
c("NUMBER_OF_SETS", nrow(dframe)),
"BEGIN_DATA")
write(header[[1]],file, sep="\t")
for (i in 2:length(header))
write(header[[i]],file, sep="\t", ncolumns=1000,append=TRUE)
write.table(format(dframe, digits=5),
file = file, append = TRUE, quote = FALSE, sep = "\t",
eol = "\n", na = "NA", dec = dec, row.names = id,
col.names = FALSE, qmethod = "escape")
write("END_DATA", file, append=TRUE)
}
--->8---
Klaus
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