User Commands tiffdither(1)
NAME
tiffdither - convert a grayscale image to bilevel using
dithering
SYNOPSIS
tiffdither [options] input.tif output.tif
DESCRIPTION
tiffdither converts a single-channel 8-bit grayscale image
to a bilevel image using Floyd-Steinberg error propagation
with thresholding.
OPTIONS
The following options are supported:
-c Specify a compression scheme to use when
writing image data:
-c g3 CIT Group 3
compression algo-
rithm.
-c g4 CIT Group 4
compression algo-
rithm.
-c lzw Lempel-Ziv and Welch
algorithm.
-c none No compression.
-c packbits PackBits compression
algorithm.
-c zip Deflate compression
algorithm.
By default, tiffdither compresses data
according to the value of the Compression
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User Commands tiffdither(1)
tag found in the source file.
-f Specify the bit fill order to use to write
output data. By default, tiffdither creates
a new file with the same fill order as the
original. Specify -f lsb2msb to force data
to be written with the FillOrder tag set to
LSB2MSB. Specify -f msb2lsb to force data to
be written with the FillOrder tag set to
MSB2LSB.
-t Set the threshold value for dithering. By
default, the threshold value is 128.
OPERANDS
The following operands are supported:
input.tif The name of the input file.
output.tif The name of the output file.
EXTENDED DESCRIPTION
The CIT Group 3 and Group 4 compression algorithms can
only be used with bilevel data.
Group 3 compression can be specified together with several
T.4-specific options:
1d 1-dimensional encoding
2d 2-dimensional encoding
fill Force each encoded scanline to be
zero-filled so that the terminating
EOL code lies on a byte boundary.
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User Commands tiffdither(1)
Group 3-specific options are specified by appending a
colon-separated list to the g3 option. For example, specify
-c g3:2d:fill to get 2D-encoded data with byte-aligned EOL
codes.
LZW compression can be specified together with a predictor
value. A predictor value of 2 causes each scanline of the
output image to undergo horizontal differencing before being
encoded. A predictor value of 1 forces each scanline to be
encoded without differencing.
LZW-specific options are specified by appending a colon-
separated list to the lzw option. For example, specify -c
lzw:2 for LZW compression with horizontal differencing.
ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
ATRIBUTE TYPE ATRIBUTE VALUE
Availability SUNWTiff
Interface stability Uncommitted
SEE ALSO
pal2rgb(1), fax2tiff(1), tiffinfo(1), tiffcp(1), tiff2bw(1),
libtiff(3)
NOTES
Updated by Breda McColgan, Sun Microsystems Inc., 2004.
SunOS 5.11 Last change: 26 Mar 2004 3
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