View Source: pnminterp(1) - Waikato Linux Users Group

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pnminterp
!!!pnminterp
NAME
SYNOPSIS
DESCRIPTION
OPTIONS
BUGS
SEE ALSO
AUTHOR
----
!!NAME


pnminterp - scale up portable anymap by interpolating between pixels.
!!SYNOPSIS


__pnminterp__ [[__-blackedge__] [[__-dropedge__]
''N'' [[''pnmfile'']


You can use the minimum unique abbreviation of the
options.
!!DESCRIPTION


Pnminterp scales up pictures, producing output with one
''N''x''N'' pixel for each pixel in the original
image. Where pnminterp improves over using
pnmscale/pnmenlarge for this is that it interpolates between
pixels, producing better-looking output.


To scale up to non-integer pixel sizes, e.g. 2.5, try
pnminterp-gen(1) instead.
!!OPTIONS


The options let you select alternative methods of dealing
with the right/bottom edges of the picture. Since the
interpolation is done between the top-left corners of the
scaled-up pixels, it's not obvious what to do with the
right/bottom edges. The default behaviour is to scale those
up without interpolation (more precisely, the right edge is
only interpolated vertically, and the bottom edge is only
interpolated horizontally), but there are two other
possibilities, listed below.


__-blackedge__


interpolate to black at right/bottom edges.


__-dropedge__


drop one (source) pixel at right/bottom edges. This is
arguably more logical than the default behaviour, but it
means producing output which is a slightly odd
size.
!!BUGS


Usually produces fairly ugly output for PBMs. For most PBM
input you'll probably want to reduce the `noise' first using
something like pnmnlfilt(1).


Always produces images with a maxval of 255, which may lose
sample resolution if the input is (say) a 16-bit
PGM.
!!SEE ALSO


pnmenlarge(1), pnmscale(1),
pnmnlfilt(1)
!!AUTHOR


Russell Marks (russell.marks@ntlworld.com).
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Last edited on Tuesday, June 4, 2002 12:22:43 am by "perry"

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