tiffdither(1) LibTIFF tiffdither(1)
NAME
tiffdither - convert a greyscale TIFF image to bilevel using dithering
SYNOPSIS
tiffdither [ options ] input.tif output.tif
DESCRIPTION
tiffdither converts a single channel 8-bit greyscale image to a bilevel
image using Floyd-Steinberg error propagation with thresholding.
OPTIONS
-c compress
Specify the compression to use for data written to the output
file:
+------------+-------------------------+
|Compression | Description |
+------------+-------------------------+
|none | no compression |
+------------+-------------------------+
|packbits | PackBits compression |
+------------+-------------------------+
|lzw | Lempel-Ziv & Welch |
| | compression |
+------------+-------------------------+
|zip | Deflate compression |
+------------+-------------------------+
|g3 | CCITT Group 3 (T.4) |
| | compression |
+------------+-------------------------+
|g4 | for CCITT Group 4 (T.6) |
| | compression |
+------------+-------------------------+
By default tiffdither will compress data according to the value of
the Compression tag found in the source file.
The CCITT 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 for 1-dimensional encoding, 2d for
2-dimensional encoding, and fill to force each encoded scanline to
be zero-filled so that the terminating EOL code lies on a byte
boundary. Group 3-specific options are specified by appending a
:-separated list to the g3 option; e.g. -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 it is encoded; a value of 1
forces each scanline to be encoded without differencing.
LZW-specific options are specified by appending a :-separated list
to the lzw option; e.g. -c lzw:2 for LZW compression with
horizontal differencing.
-f Specify the bit fill order to use in writing output data. By
default, tiffdither will create a new file with the same fill
order as the original. Specifying -f lsb2msb will force data to
be written with the FillOrder tag set to LSB2MSB, while -f msb2lsb
will force data to be written with the FillOrder tag set to
MSB2LSB.
-r Make each strip have no more than the given number of rows.
-t Set the threshold value for dithering. By default the threshold
value is 128.
NOTES
The dither algorithm is taken from the tiffmedian program (written by
Paul Heckbert).
SEE ALSO
pal2rgb(1), fax2tiff(1), tiffinfo(1), tiffcp(1), tiff2bw(3)
AUTHOR
LibTIFF contributors
COPYRIGHT
1988-2022, LibTIFF contributors
4.5 December 23, 2022 tiffdither(1)
tiff 4.5.0 - Generated Sat Dec 24 13:05:01 CST 2022