pngtopnm
convert a Portable Network Graphics file into portable anymap
see also :
pnmtopng - pnmgamma
Synopsis
pngtopnm
[-verbose] [-alpha | -mix] [-background color]
[-gamma value] [-text file] [-time] [pngfile]
add an example, a script, a trick and tips
examples
source
t=/tmp/png2winicon.$$
pngtopnm "$1" > $t.pnm
#pngtopnm -alpha "$1" | pgmtopbm
-threshold | convert -negate pbm:- pbm:$t.pbm
#pngtopnm -alpha "$1" | pgmtopbm -threshold |
convert -negate pbm:- pbm:$t.pbm
pngtopnm -alpha "$1" | pgmtopbm
-threshold > $t.pbm
ppmtowinicon -andppms $t.pnm $t.pbm > "$2"
source
name=`echo $file | sed 's/\.png$//'`
pngtopnm $file >$name.pnm && pnmtops
-nocenter -nosetpage $name.pnm
>$name.eps && rm $name.pnm
source
t=/tmp/png2winicon.$$
pngtopnm "$1" > $t.pnm
#pngtopnm -alpha "$1" | pgmtopbm
-threshold | convert -negate pbm:- pbm:$t.pbm
#pngtopnm -alpha "$1" | pgmtopbm -threshold |
convert -negate pbm:- pbm:$t.pbm
pngtopnm -alpha "$1" | pgmtopbm
-threshold > $t.pbm
pnmcomp -alpha=$t.pbm $t.pnm $t.pbm $t.2.pnm
source
exit 1
fi
pngtopnm img/"$1" |
pnmtoplainpnm > "$1".txt
source
INPUT_FILE=$1;
pngtopnm "$INPUT_FILE" |
cpaldjvu - "$INPUT_FILE".djvu
ls -l "$INPUT_FILE" "$INPUT_FILE".djvu
source
usage
fi
pngtopnm $1 | ppmtolss16
\#cdcfd5=7 \#ffffff=1 \#000000=0 \#c90000=15 > $2
description
Reads a
Portable Network Graphics as input. Produces a portable
anymap as output. The type of the output file depends on the
input file - if it’s black & white, a pbm
file is written, else if it’s grayscale a pgm
file, else a ppm file.
options
-verbose
Display the format of the input
file and the type of the output file. If the chunks are part
of the png-file, the alpha, transparency and
gamma-values will be indicated.
-alpha
Output the alpha channel or transparency mask of the
image. The result is either a pbm file or pgm
file, depending on whether different levels of transparency
appear.
-mix
Compose the image with the transparency or alpha mask
against a the background. When a background chunk is
available that color is taken, else black will do.
-background color
If no background color chunck
is present in the png-file, or when another color is
required this parameter can be used to set the background
color of images. This is especially useful for alpha-channel
images or those with transparency chunks. The format, to
specify the color in, is either (in the case of orange)
"1.0,0.5,0.0", where the values are floats between
zero and one, or with the syntax "#RGB",
"#RRGGBB" or "#RRRRGGGGBBBB" where R, G
and B are hexa-decimal numbers.
-gamma value
Converts the image to a new
display-gamma value. When a gAMA chunk is present in the
png-file, the image-gamma value will be used. When
not, the image-gamma is considered to be 1.0. Based on the
image-gamma and the display-gamma given with this option the
colors written to the pnm-file will be adjusted.
Because the gamma’s of uncompensated monitors are
around 2.6, which results in an image-gamma of 0.45, some
typical situations are: when the image-gamma is 0.45 (use
-verbose to check) and the picture is too light, your system
is gamma-corrected, so convert with "-gamma 1.0".
When no gAMA chunk is present or the image-gamma is 1.0, use
2.2 to make the picture lighter and 0.45 to make the picture
darker.
-text file
Writes the tEXt and zTXt chunks
to a file, in a format as described in the pnmtopng
man-page. These chunks contain text comments or
annotations.
-time
Prints the tIME chunk to stderr.
All flags can
be abbreviated to their shortest unique prefix.
note
Instead of pngtopnm|pnmtoxxx, a specific converter should be
used, if available. E.g. ptot (PNG to TIFF conversion),
etc.
bugs
There could be
an option to read the comment text from pnm comments instead
of a separate file.
The program
could be much faster, with a bit of code optimizing.
see also
pnmtopng ,
ptot, pnmgamma , pnm
authors
Copyright (C)
1995-1997 by Alexander Lehmann
and Willem van Schaik.