tiffdither¶
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 - Compressiontag 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, and- fillto 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- g3option; e.g.- -c g3:2d:fillto 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 the- lzwoption; e.g.- -c lzw:2for 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 - FillOrdertag set to- LSB2MSB, while -f msb2lsb will force data to be written with the- FillOrdertag 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 (3tiff)