write.image {imageio} | R Documentation |
Reading and writing of various types of image file as pixmap objects, using netpbm to do the hard work
img <- read.image(filename,fformat=NULL,opts="",...) write.image(img,filename,fformat=NULL,opts="",...)
filename |
Name of the image file. |
img |
Object of class pixmap |
opts |
Command-line options passed to the netpbm program used |
... |
Extra arguments to be passed to read.pnm or
write.pnm |
fformat |
Code for the file format to read or write. Valid
values are png , jpg , tiff . On unix systems,
read.image also accepts fformat=auto , this is used
as the default. The fformat=auto option does not work
under MicroSoft Windows, so a default of "png" is used.
|
read.image
reads a large variety of image types, returning an
object of class pixmap
.
write.image
writes an object of class pixmap
to
a file in one of several common image file formats.
Both read.image
and write.image
work by using
read.pnm
or
write.pnm
to move the data between R and a temporary
file. Programs in the netpbm package are used to convert from temporary
file to the desired format or vice versa. You therefore need to have
netpbm installed for either of these programs to work. For Windows, you
can obtain this from http://gnuwin32.sourceforge.net/. With most
unixes and Linux distributions you will find it packaged for your
distribution. If not, you can get it at
http://netpbm.sourceforge.net/.
The imageio
package does not check for the presence of netpbm when installed. We
hope to fix this in a subsequent release.
Hugh C. Pumphrey H.C.Pumphrey@ed.ac.uk