Provided by: netpbm_11.10.02-1build1_amd64 
NAME
pamdice - slice a Netpbm image into many horizontally and/or vertically
EXAMPLE
$ pamdice myimage.ppm -outstem=myimage_part -width=10 -height=8
$ pamundice myimage_part_%1d_%1a.ppm -across=10 -down=8 >myimage.ppm
$ pamdice myimage.ppm -outstem=myimage_part -height=12 -voverlap=9
$ pamdice myimage.ppm -width=10 -height=8 -listfile=tiles.txt myimage.ppm
$ pamundice -across=10 -down=4 -listfile=tiles.txt >myimage.ppm
$ pamdice myimage.ppm -width=10 -height=8 -outstem=myimage_part \
-indexfile=tiles.pam myimage.ppm
$ pamundice myimage_part_%1d_%1a.ppm -across=10 -down=8 \
-indexfile=tiles.pam >myimage.ppm
SYNOPSIS
pamdice
-outstem=filenamestem
[-width=width]
[-height=height]
[-hoverlap=hoverlap]
[-voverlap=voverlap]
[-numberwidth=N]
[-listfile=textfilename]
[-indexfile=pamfilename
[-dry-run]
[-verbose]
[filename]
You can use the minimum unique abbreviation of the options. You can use two hyphens instead of one. You
can separate an option name from its value with white space instead of an equals sign.
DESCRIPTION
This program is part of Netpbm(1).
pamdice reads a PAM, PBM, PGM, or PPM image as input and splits it horizontally and/or vertically into
equal size pieces and writes them into separate files as the same kind of image. You can optionally make
the pieces overlap.
See the -outstem option for information on naming of the output files.
The -width and -height options determine the size of the output pieces.
pamundice can rejoin the images. For finer control, you can also use pamcat.
One use for this is to make pieces that take less computer resources than the whole image to process.
For example, you might have an image so large that an image editor can't read it all into memory or
processes it very slowly. With pamdice, you can split it into smaller pieces, edit one at a time, and
then reassemble them.
Another use for this is to print a large image in small printer-sized pieces that you can glue together.
ppmglobe does a similar thing; it lets you glue the pieces together into a sphere.
If you want to cut pieces from an image individually, not in a regular grid, use pamcut.
OPTIONS
In addition to the options common to all programs based on libnetpbm (most notably -quiet, see Common
Options ), pamdice recognizes the following command line options:
-outstem=filenamestem
This option determines the names of the output files. Each output file is named
filenamestem_y_x.type, where filenamestem is the value of the -outstem option, x and y are the
horizontal and vertical locations, respectively, in the input image of the output image, zero
being the leftmost and top, and type is .pbm, .pgm, .ppm, or .pam, depending on the type of image.
x and y are filled with leading zeroes so are the same width in every file. Use -numberwidth to
specify that width; otherwise, it defaults to the minimum width that works for all the files. For
example, if you have 25 slices across and no -numberwidth, x is 2 digits for all the output files.
The leftmost slice is numbered '00'; the next one is '01', etc. With -numberwidth=3, x is '000',
'001', etc.
-numberwidth=N
This option determines the width of the numbers in the output file names. See the -outstem option
for details.
It is not valid to specify a width less than is necessary to represent all the slices.
This option was new in Netpbm 11.10 (March 2025).
-width=width
This gives the width in pixels of the output images. The rightmost pieces are smaller than this
if the input image is not a multiple of width pixels wide.
-height=height
This gives the height in pixels of the output images. The bottom pieces are smaller than this if
the input image is not a multiple of height pixels high.
-hoverlap=hoverlap
This gives the horizontal overlap in pixels between output images. Each image in a row will
overlap the previous one by hoverlap pixels. By default, there is no overlap.
This option was new in Netpbm 10.23 (July 2004).
-voverlap=voverlap
This gives the vertical overlap in pixels between output images. Each row of images will overlap
the previous row by voverlap pixels. By default, there is no overlap.
This option was new in Netpbm 10.23 (July 2004).
-listfile=textfilename
This causes the program to generate a file listing the names of all the tile files it creates. It
is in row-major order. For example,
$ pamdice -width=100 -height=100 -outstem=myimage_part -listfile=mylist.txt \
-numberwidth=3 myimage.ppm
on a 200x200 image generates the file mylist.txt containing this:
myimage_part_000_000.ppm
myimage_part_000_001.ppm
myimage_part_001_000.ppm
myimage_part_001_001.ppm
You can use this list file with pamundice -listfile in lieu of an input file name pattern
argument, which may save you the trouble of coordinating the patterns used in your invocations of
pamdice and pamundice.
This option was new in Netpbm 11.10 (March 2025).
-indexfile=pamfilename
This causes the program to generate a file containing a PAM image that contains rank and file
numbers for the tiles. It is simply an image whose width and height are the number of horizontal
and vertical slices, respectively, in which each tuple is just the row and column number of that
tuple. For example, if pamdice produces 3 slices across and 2 down, the image looks like this:
(0,0) (0,1) (0,2)
(1,0) (1,1) (1,2)
The depth of the image is 2, the tuple type is 'grid_coord' (a tuple type invented for use with
pamdice and pamundice), and the maxval is 255 unless the height or width is greater than 256, in
which case it is 65535.
This image can be useful as input to pamundice, particularly after doing transformations on it.
The prime example of such usage is in flipping a large image. You can dice the image with
pamdice, then flip each of the tiles produced (with pamflip), then flip the index image (again
with pamflip), then use pamundice with the flipped tiles and the flipped index image to generate a
flipped version of the original large image.
This option was new in Netpbm 11.10 (March 2025).
-dry-run
This makes pamdice skip creating the output tile images. It still creates the list file (with
-listfile) and the index file (with -indexfile) and checks for most errors.
This option was new in Netpbm 11.10 (March 2025).
-verbose
Print information about the processing to Standard Error.
HISTORY
pamdice was new in Netpbm 9.25 (March 2002).
Before Netpbm 10.29 (August 2005), there was a limit of 100 slices in each direction.
SEE ALSO
pamundice(1), pamcut(1), pamcat(1), pgmslice(1), ppmglobe(1) pamflip(1) pnm(1) pam(1)
DOCUMENT SOURCE
This manual page was generated by the Netpbm tool 'makeman' from HTML source. The master documentation
is at
http://netpbm.sourceforge.net/doc/pamdice.html
netpbm documentation 07 February 2025 Pamdice User Manual(1)