pnmtopng
Section: User Commands (1)
Updated: 27 May 1995
Index
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NAME
pnmtopng - convert a portable anymap into a Portable Network Graphics file
SYNOPSIS
pnmtopng
[-verbose]
[-interlace]
[-downscale]
[pnmfile]
DESCRIPTION
Reads a portable pixmap as input.
Produces a Portable Network Graphics file as output.
Color values in PNG files are either eight or sixteen bits wide, so
pnmtopng
will automatically scale colors to have a maxval of 255 or 65535.
Grayscale files will be produced with bit depths 1, 2, 4, 8 or 16.
An extra
pnmdepth
step is not necessary.
OPTIONS
- -verbose
-
Display the format of the output file.
- -interlace
-
Creates an interlaced PNG file (Adam7).
- -downscale
-
Enables scaling of maxvalues of more then 65535 to 16 bit. Since this means
loss of image data, the step is not performed by default.
All flags can be abbreviated to their shortest unique prefix.
SEE ALSO
pngtopnm(1), gif2png(1), pnm(5)
BUGS
Due the fact that PNM files only include image data, it is not possible to
preserve extra data (e.g. comments) stored with an image file. Instead of
xxxtopnm|pnmtopng, a specific converter should be used, if available. E.g.
gif2png
(GIF conversion), etc. (This is not really a bug in
pnmtopng,
more a general problem with intermediate formats.)
Information about scaling is not preserved. No
sBIT
chunks are created.
AUTHOR
Copyright (C) 1995 by Alexander Lehmann, based on pnmtorast, (C) 1989,1990 by
Jef Poskanzer.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- OPTIONS
-
- SEE ALSO
-
- BUGS
-
- AUTHOR
-
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