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#===========================================================================#
# caTools - R library #
# Copyright (C) 2005 Jarek Tuszynski #
# Distributed under GNU General Public License version 3 #
#===========================================================================#
write.gif = function(image, filename, col="gray",
scale=c("smart", "never", "always"), transparent=NULL,
comment=NULL, delay=0, flip=FALSE, interlace=FALSE)
{
if (!is.character(filename)) stop("write.gif: 'filename' has to be a string")
if (length(filename)>1) filename = paste(filename, collapse = "") # combine characters into a string
#======================================
# cast 'image' into a proper dimentions
#======================================
dm = dim(image)
if (is.null(dm)) stop("write.gif: input 'x' has to be an matrix or 3D array")
if (length(dm)<=2) { # this is a 2D matrix or smaller
image = as.matrix(image) # cast to 2D matrix
if (flip) x = image[,dm[2]:1]
else x = t(image)
} else { # 3D data cube or bigger
dim(image) = c(dm[1], dm[2], prod(dm)/(dm[1]*dm[2])) # cast to 3D
if (flip) x = image[,dm[2]:1,]
else x = aperm(image, c(2,1,3))
}
image = 0 # release memory
dm = dim(x) # save dimentions and ...
x = as.vector(x) # convert to 1D vector
#=================================
# scale x into a proper range
#=================================
scale = match.arg(scale)
if (!is.null(transparent))
if ((transparent<0) || (transparent>255))
stop("write.gif:'transparent' has to be an integer between 0 and 255")
mask = !is.finite(x)
xx = 0
mColor = 255
if (any(mask)) { # some non-finite numbers were found
if (is.null(transparent)) mColor = 254
xx = x # save original x
x = x[!mask] # remove non-finite numbers
}
minx = min(x)
maxx = max(x)
d = mColor/(maxx-minx)
if (scale=="never") {
if ((minx<0) || (maxx>mColor))
warning("write.gif: 'x' is not in proper range and 'scale' is set to 'never',",
" clipping 'x' to proper range ")
if (minx<0 ) x[x<0 ] = 0
if (maxx>mColor) x[x>mColor] = mColor
} else
if (scale=="always") {
if ((minx>=0) && (maxx<=1))
x = mColor*x # doubles between [0 and 1] -> scale them
else
x = (x-minx)*d # numbers outside allowed range -> scale them
} else
if (scale=="smart") {
if ((minx<0) || (maxx>mColor)) {
x = (x-minx)*d # numbers outside allowed range -> scale them
} else if ((minx>=0) && (maxx<=1)) {
if (any(x!=as.integer(x))) x = mColor*x # doubles between [0 and 1] -> scale them
}
}
maxx = max(x)
if (length(xx)>1) { # some non-finite numbers were found
if (is.null(transparent)) transparent = maxx+1
xx[ mask] = transparent
xx[!mask] = x
x = xx
}
if (is.null(transparent)) transparent = -1
x = as.integer(round(x))
#=================================
# format color palette
#=================================
n = maxx+1
if (is.character(col) && length(col)==1) {
if (col %in% c("grey", "gray")) col = gray(0:n/n)
if (col=="jet")
col = colorRampPalette(c("#00007F", "blue", "#007FFF", "cyan", "#7FFF7F",
"yellow", "#FF7F00", "red", "#7F0000")) # define "jet" palette
}
if (length(col)==1) { # if not a vector than maybe it is a palette function
FUN = match.fun(col) # make sure it is a function not a string with function name
col = FUN(n)
}
crgb = col2rgb(col)
Palette = as.integer(c(256^(2:0) %*% crgb)) # convert to internal int format
nColor = length(Palette)
if (nColor<maxx)
stop("write.gif: not enough colors in color palette 'col'. Has ",nColor,
" need at least ", maxx)
if (nColor<256) Palette = c(Palette, rep(0,256-nColor)) # pad it
# format and cast other input variables into proper format
param = as.integer(c( dm[2], dm[1], prod(dm)/(dm[1]*dm[2]), nColor, transparent, delay, interlace, 0 ))
if (is.null(comment)) comment = as.character("")
else comment = as.character(comment)
# call C++ function
.C("imwritegif", filename, x, Palette, param, comment,
NAOK=FALSE, PACKAGE="caTools")
if (param[7]<0) stop("write.gif: cannot open the output file (connection)")
invisible(NULL)
}
#==============================================================================
read.gif = function(filename, frame=0, flip=FALSE, verbose=FALSE)
{
if (!is.character(filename)) stop("write.gif: 'filename' has to be a string")
if (length(filename)>1) filename = paste(filename, collapse = "") # combine characters into a string
isURL = length(grep("^http://", filename)) |
length(grep("^ftp://", filename)) |
length(grep("^file://", filename))
if(isURL) {
tf <- tempfile()
download.file(filename, tf, mode='wb', quiet=TRUE)
filename = tf
}
x = .Call("imreadgif", filename, as.integer(frame), as.integer(verbose),
PACKAGE="caTools")
comt = as.character(attr(x, 'comm'))
if (isURL) file.remove(filename)
nRow = x[1]
nCol = x[2]
nBand = x[3]
tran = x[4]
success = x[5]
nPixel = nRow*nCol*nBand
stats = -success
if (stats>=6) {
warning("write.gif: file '", filename,
"' contains multiple color-maps. Use 'frame' > 0.")
stats = stats-6
}
if (nPixel==0) {
switch (stats,
stop("write.gif: cannot open the input file: ", filename, call.=FALSE),
stop("write.gif: input file '", filename, "' is not a GIF file", call.=FALSE),
stop("write.gif: unexpected end of file: ", filename, call.=FALSE),
stop("write.gif: syntax error in file: ", filename, call.=FALSE) )
} else {
switch (stats, , ,
warning("write.gif: unexpected end of file: ", filename, call.=FALSE),
warning("write.gif: syntax error in file: ", filename, call.=FALSE),
warning("write.gif: file '", filename,
"' contains multiple images (frames) of uneven length. Use 'frame' > 0." , call.=FALSE))
}
Palette = x[ 10:265 ]
x = x[-(1:265)] # delete non image data
if (nBand>1) { # 3D data cubes
dim(x) = c(nCol, nRow, nBand)
if (flip) x = x[,ncol(x):1,]
else x = aperm(x, c(2,1,3))
} else { # this is a matrix
dim(x) = c(nCol, nRow)
if (flip) x = x[,ncol(x):1]
else x = t(x)
}
Palette = Palette[Palette>=0]
red = bitAnd(bitShiftR(Palette,16), 255)
green = bitAnd(bitShiftR(Palette, 8), 255)
blue = bitAnd( Palette , 255)
Palette = rgb (red, green, blue, 255, maxColorValue = 255)
if (tran==-1) tran = NULL
return (list(image=x, col=Palette, transparent=tran, comment=comt))
}
# source("c:/programs/R/rw2011/src/library/caTools/R/GIF.R")
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