pnmcat
TLDR
Concatenate horizontally
$ pnmcat -lr [image1.pnm] [image2.pnm] > [result.pnm]
Concatenate vertically$ pnmcat -tb [image1.pnm] [image2.pnm] > [result.pnm]
With background color$ pnmcat -lr -white [image1.pnm] [image2.pnm] > [result.pnm]
Center alignment$ pnmcat -tb -jcenter [image1.pnm] [image2.pnm] > [result.pnm]
SYNOPSIS
pnmcat [options] pnmfiles...
DESCRIPTION
pnmcat concatenates multiple PNM images either horizontally or vertically. It's the image equivalent of cat for files.
Handles images of different sizes with alignment and background options.
PARAMETERS
-lr
Left to right (horizontal).-tb
Top to bottom (vertical).-jleft, -jcenter, -jright
Horizontal justification.-jtop, -jcenter, -jbottom
Vertical justification.-white
White background.-black
Black background.
EXAMPLES
$ # Side by side
pnmcat -lr left.ppm right.ppm > combined.ppm
# Stack vertically
pnmcat -tb top.ppm bottom.ppm > stacked.ppm
# Multiple images
pnmcat -lr img1.ppm img2.ppm img3.ppm > row.ppm
# Centered with white background
pnmcat -tb -jcenter -white small.ppm large.ppm > out.ppm
pnmcat -lr left.ppm right.ppm > combined.ppm
# Stack vertically
pnmcat -tb top.ppm bottom.ppm > stacked.ppm
# Multiple images
pnmcat -lr img1.ppm img2.ppm img3.ppm > row.ppm
# Centered with white background
pnmcat -tb -jcenter -white small.ppm large.ppm > out.ppm
CAVEATS
All images must be same type (PBM, PGM, or PPM). Different depths are handled. Part of Netpbm.
HISTORY
pnmcat is part of Netpbm by Jef Poskanzer, providing image concatenation since early Pbmplus.
