Dear R-help
I want to display an image file in a new plot frame.
SVG is my preferred format, but I can also consider
PNG, GIF, JPEG, TIFF, and PPM (from ImageMagick).
By way of background (although not material to this
posting), the image file is generated by a call to
'dot' (part of the 'Graphviz' suite) after the required
.dot file has been produced using hand-crafted R code.
I have reduced my options to the following. Any
corrections, suggestions, or comments would be most
welcome.
I realize the list is quite long, but if the feedback
converges, I will refine the material below and add it
to a new page on the R-wiki.
# HEATH WARNING: none of this code has been run
# ---------------------------------
x11() # open another plot frame as required (UNIX-alikes)
plot.new()
# SVG (hypothetical code)
# ---------------------------------
# SVG is not supported in this context (it would
# appear)
library(?????)
svg <- read.svg(file = "my.svg") # hypothetical call
plot(svg)
# PNG, JPEG, GIF, TIFF, PPM
# ---------------------------------
# package 'EBImage' is an image processing toolkit
# -- the package requires ImageMagick 6.2.4 or
# better
library(EBImage)
g <- system.file("images", "my.gif", package = "EBImage")
gif <- readImage(g)
display(gif)
# similarly for "my.png", "my.jpg", "my.ppm", and
# "my.tiff", depending on the capabilities of the
# 'ImageMagick' installation you have
# PNG, JPG, TIFF
# ---------------------------------
# package 'rgdal' -- requires system library and
# headers for the 'GDAL' geospatial data library
library(rgdal)
p <- system.file("my.png", package = "rgdal")
h <- GDAL.open(p) # returns a file handle
getDriverLongName(getDriver(h)) # should report "Portable Network Graphics"
displayDataset(h)
GDAL.close(h)
# note that recent versions of 'ReadImages' (see
# the JPEG section) will also read PNG [is the call
# still 'read.jpg'? -- or is it now 'read.png'?]
# JPEG
# ---------------------------------
# package 'rimage' provides functions for
# processing images and for reading JPEG files --
# this package requires system libraries and
# headers for 'libjpeg' and 'fftw-2'
#
# package 'ReadImages' is essentially a subset of
# 'rimage' and does not require 'fftw-2'
library(ReadImages) # subset of package 'rimage'
j <- system.file("data", "my.jpg", package = "ReadImages")
jpeg <- read.jpeg(j)
plot(jpeg)
library(rimage)
j <-system.file("data", "my.jpg", package = "rimage")
jpeg <- read.jpeg(j)
plot(jpeg)
# GIF
# ---------------------------------
# package 'caTools' provides a number of utility
# functions, including calls for reading and
# writing GIF files -- this package depends on
# package 'bitopts' (but contains no system
# requirements)
#
# note that image() needs 'flip' = TRUE and 'asp'
# sets the aspect ratio to unity
library(caTools)
gif <- read.gif("my.gif", verbose = TRUE, flip = TRUE)
image(gif$image, col = gif$col, main = gif$comment, asp = 1)
# TIFF
# ---------------------------------
# package 'rtiff' reads TIFF format images and
# return them as pixmaps
library(rtiff)
tif <- read.tiff("my.tif")
plot(tif)
# PPM (similarly for PGM and PPM)
# ---------------------------------
# package 'pixmap' provides functions for the
# import, export, plotting and manipulation of
# bitmapped images (the package has no R
# dependencies or system requirements)
library(pixmap)
p <- system.file("my.ppm", package="pixmap")
ppm <- read.pnm(p)
plot(ppm)
Additional material can be added to the plot frame,
thereby relegating the original graphic to that of a
backing image.
See also the following packages:
'GDD' - produce bitmaps without X11
Finally, the ImageMagick 'display' utility can be
called directly from R, thereby bypassing the need to
read and display the graphics file as data:
frameTitle <- "\"override default\""
graphic <- "my.png" # ImageMagick also supports PNG, GIF, JPEG,
TIFF, PPM
imagemagickCall <- paste("display", "-title", frameTitle, graphic, "&")
ret <- system(imagemagickCall)
if ( ret != 0 ) warning("display call returned fail: ", ret)
thanks in advance, Robbie
---
Robbie Morrison
PhD student -- policy-oriented energy system simulation
Technical University of Berlin (TU-Berlin), Germany
University email (redirected) : morri...@iet.tu-berlin.de
Webmail (preferred) : rob...@actrix.co.nz
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