Provided by: pngnq_1.1+ds-3build1_amd64 
NAME
pngnq - quantize png images
SYNOPSIS
pngnq [-vfhV][-s sample_factor ][-Q dither ][-g gamma ][-e extension ][-d dir ][-n colors ][ inputfiles ]
DESCRIPTION
pngnq quantizes a 32-bit RGBA PNG image to an 8 bit RGBA palette PNG using the neuquant algorithm. The
output file name is the input file name extended with "-nq8.png" or a specified extension.
The "input files" defaults to standard input if not specified. If standard input is being processed the
output is sent to standard output.
OPTIONS
-d dir Tells pngnq to put output files in a directory other than the one the input files are in.
-e extension
Specifies the new filename extension. Defaults to "-nq8.png". Pngnq drops .png from the original
filenames. If you set the argument of the -e option to .png and choose the -f option the input
file will be overwritten.
-f Force overwriting of files.
-g gamma
Set the image gamma correction. If not present, uses the png file's gamma or defaults to 1.0.
-h Print program help.
-n colors
Specifies the number of colors to quantize to. Defaults to 256 which is the maximum. The minimum
here is 2.
-Q dither
Choose a dithering method: n = no dither (default), f = Floyd Steinberg dithering.
-s sample factor
Sample factor. The neuquant algorithm samples pixels stepping by this value. The default value of
3 gives good results. Higher values sample less of the image pixels and thus are faster but less
accurate. A factor of 1 samples every image pixel.
-v Verbose mode. Prints status messages.
-V Print version number and library versions.
BUGS
Does not deal correctly with greyscale alpha images with low bit depths, but these wont benefit from
quantizing.
AUTHOR
Stuart Coyle <stuart.coyle@gmail.com>
SEE ALSO
png(5)
Linux MAY 2009 PNGNQ(1)