MAN page from Fedora 11 libtiff-3.8.2-15.fc11.x86_64.rpm
TIFFDITHER
Section: User Commands (1)
Updated: September 20, 2005
Index NAME
tiffdither - convert a greyscale image to bilevel using dithering
SYNOPSIS
tiffdither[
options]
input.tifoutput.tif DESCRIPTION
tiffditherconverts a single channel 8-bit greyscale image to a bilevel imageusing Floyd-Steinberg error propagation with thresholding.
OPTIONS
- -c
- Specify the compression to use for data written to the output file:none for no compression,packbitsfor PackBits compression,lzwfor Lempel-Ziv & Welch compression,zipfor Deflate compression,g3for CCITT Group 3 (T.4) compression,andg4for CCITT Group 4 (T.6) compression.By defaulttiffditherwill compress data according to the value of theCompressiontag found in the source file.
- TheCCITTGroup 3 and Group 4 compression algorithms can onlybe used with bilevel data.
- Group 3 compression can be specified together with severalT.4-specific options:1dfor 1-dimensional encoding,2dfor 2-dimensional encoding,andfillto force each encoded scanline to be zero-filled so that theterminating EOL code lies on a byte boundary.Group 3-specific options are specified by appending a ``:''-separatedlist to the ``g3'' option; e.g.-c g3:2d:fillto get 2D-encoded data with byte-aligned EOL codes.
- LZWcompression can be specified together with a predictorvalue.A predictor value of 2 causeseach scanline of the output image to undergo horizontaldifferencing before it is encoded; a valueof 1 forces each scanline to be encoded without differencing.LZW-specific options are specified by appending a ``:''-separatedlist to the ``lzw'' option; e.g.-c lzw:2forLZWcompression with horizontal differencing.
- -f
- Specify the bit fill order to use in writing output data.By default,tiffditherwill create a new file with the same fill order as the original.Specifying-f lsb2msbwill force data to be written with the FillOrder tag set toLSB2MSB ,while-f msb2lsbwill force data to be written with the FillOrder tag set toMSB2LSB .
- -t
- Set the threshold value for dithering.By default the threshold value is 128.
NOTES
The dither algorithm is taken from the
tiffmedian(1)program (written by Paul Heckbert).
SEE ALSO
pal2rgb(1),
fax2tiff(1),
tiffinfo(1),
tiffcp(1),
tiff2bw(1),
libtiff(3TIFF)
Libtiff library home page:http://www.remotesensing.org/libtiff/
Index
- NAME
- SYNOPSIS
- DESCRIPTION
- OPTIONS
- NOTES
- SEE ALSO
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