tiffdither1
Convert a greyscale tiff image to bilevel using dithering
Usage
tiffdither [options]
input.tif
output.tif
Overview
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
tiffditherwill compress data according to the value of theCompressiontag 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:
1dfor 1-dimensional encoding,2dfor 2-dimensional encoding, andfillto 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 theg3option; e.g. -c g3:2d:fill to get 2D-encoded data with byte-aligned EOL codes.LZW compression can be specified together with a
predictorvalue. 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 thelzwoption; 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,
tiffditherwill create a new file with the same fill order as the original. Specifying -f lsb2msb will force data to be written with theFillOrdertag set toLSB2MSB, while -f msb2lsb will force data to be written with theFillOrdertag set toMSB2LSB.
-
-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).
Releases
17 releases since Debian 1.2 (Rex); the text changed 10 times.
-r since Debian 9 (Stretch).