Hello R-Help, I want to be able to read in a raster image, plot it with grid.raster or rasterImage and save the image with one pixel per a pixel element from my array. Saved preferably in a common image format.
The real goal of my question is to eventually read in images with text on them, manipulate them with my controlled functions, save them without changing the image dimensions, and perform OCR outside R. I have read The R Journal article on raster images (http://journal.r-project.org/archive/2011-1/RJournal_2011-1_Murrell.pdf) and have experimented with some of the par() variables with no success. There are some arguments in gird.raster that elude me currently on how to use them. These include, vjust, hjust, default.units, gp and vp. Perhaps these are what I need to use but I am getting nowhere without more documentation. Here is the basic code I've used to experiment with making this work. The end result I'm hoping for would be an image exactly like the one I've read in (Rlogo.jpg for this small example). I turned off dev.copy lines because I'm not sure on the guidelines for file writing functions. Thanks, Hans Thompson Forgive me If I made any mistakes following posting guidelines. ####START##### library(jpeg) library(grid) img <- readJPEG(system.file("img", "Rlogo.jpg", package="jpeg")) grid.raster(img, interpolate =F) #turnon next line for output. Don't want to accidentally write any unwanted files. #dev.copy(tiff, "outputimage.tiff") dev.off() #or using package = "graphics" but not perfered. library(graphics) plot( c(0, dim(img)[2]), c(0, dim(img)[1]), type = "n", xlab = "", ylab = "") rasterImage(img, 0, 0, dim(img)[2], dim(img)[1]) #dev.copy(tiff, "outputfile2.tiff") dev.off() ##STOP## ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
