writeTIFF {tiff}R Documentation

Write one or more bitmap images in TIFF format

Description

Writes images into a TIFF file or a raw vector representing such.

Usage

writeTIFF(what, where, bits.per.sample = 8L,
          compression = c("LZW", "none", "PackBits", "RLE", "JPEG", "deflate"),
          reduce = TRUE)

Arguments

what

either an image or a list of images. An image is a real matrix or array of three dimensions, or an object of the class "nativeRaster".

where

file name or a raw vector

bits.per.sample

number of bits per sample (numeric scalar). Supported values in this version are 8, 16, and 32.

compression

desired compression algorithm (string). Optionally, it can be specified as a numeric value corresponding to the compression TIFF tag, but it needs to be also supported by the underlying TIFF library

reduce

if TRUE then writeTIFF will attempt to reduce the number of planes in native rasters by analyzing the image to choose one of RGBA, RGB, GA or G formats, whichever uses the least planes without any loss. Otherwise the image is always saved with four planes (RGBA).

Details

By default writeTIFF uses the same number of planes as there are planes in the input image. For native images it is always four unless reduce = TRUE is set (see above). Consequently, color maps are not used. The output always uses contiguous planar configuration (baseline TIFF). The output is tagged with a photometric tag of either RGB (3 or 4 planes) or zero-is-black (1 or 2 planes). If what is a list then the TIFF output will be a directory of the corresponding number of images (in TIFF speak - not to be confused with file directories).

Value

If where is a raw vector then the value is the raw vector containg the TIFF contents, otherwise a scalar integer specifying the number of images written in the file.

Author(s)

Simon Urbanek

See Also

readTIFF

Examples

img <- readTIFF(system.file("img", "Rlogo.tiff", package="tiff"))
# write without the alpha channel
tiff <- writeTIFF(img[,,-4], raw(0))
# read as native
i2 <- readTIFF(tiff, native=TRUE)
# write reduced - should be the same as tiff
t2 <- writeTIFF(i2, raw(0), reduce=TRUE)

[Package tiff version 0.1-5 Index]