Pamtopnm User Manual(0) Pamtopnm User Manual(0)NAMEpamtopnm - convert PAM image to PBM, PGM, or PPM
SYNOPSISpamtopnm
[-assume]
[pnmfile]
Minimum unique abbreviation of option is acceptable. You may use dou‐
ble hyphens instead of single hyphen to denote options. You may use
white space in place of the equals sign to separate an option name from
its value.
DESCRIPTION
This program is part of Netpbm(1)pamtopnm reads a PAM image as input and produces an equivalent PBM,
PGM, or PPM (i.e. PNM) image, whichever is most appropriate, as output.
pamtopnm assumes the PAM image represents the information required for
a PBM, PGM, or PPM image if its tuple type is 'BLACKANDWHITE',
'GRAYSCALE', or 'RGB' and its depth and maxval are appropriate. If
this is not the case, pamtopnm fails.
However, you can override the tuple type requirement with the -assume
option.
pamtopnm produces a PPM image if the input PAM has depth 3 or 4; it
produces PGM or PBM if the input PAM has depth 1 or 2. Whether it pro‐
duced PGM or PBM depends upon the maxval: PBM for 1, PGM for anything
higher. The tuple type does not play a role in determining the output
type. You can use Netpbm programs such as pgmtopgm to generate a dif‐
ferent PNM output, but remember that Netpbm program that expects PGM
input will take PBM and so on.
As with any Netpbm program that reads PAM images, pamtopnm also reads
PNM images as if they were PAM. In that case, pamtopnm's functions
reduces to simply copying the input to the output. But this can be
useful in a program that doesn't know whether its input is PAM or PNM
but needs to feed it to a program that only recognizes PNM.
OPTIONS-assume
When you specify -assume, you tell pamtopnm that you personally
vouch for the fact that the tuples contain the same data as
belongs in the channels of a PBM, PGM, or PPM file. The depth
must still conform, though, so to truly force a conversion, you
may have to run the input through pamchannel first. But be
careful with -assume. When you -assume, you make an -ass of u
and me.
SEE ALSOpbmtopgm(1) , pamditherbw(1) , pgmtoppm(1) , ppmtopgm(1) , pam(1) ,
pnm(1) , pbm(1) , pgm(1) , ppm(1)HISTORYpamtopnm was new, along with the PAM format, in Netpbm 9.7 (August
2000).
netpbm documentation 10 May 2010 Pamtopnm User Manual(0)
