Unslice quickly assembles a number of horizontal image strips into a single
output image. A typical use for unslice is to put together
portions of an image ("slices") computed independently into a single
output picture. Because unslice uses the "raw" RLE library
calls to read and write the images, it runs much faster than doing the
equivalent operations with crop and comp.
unslice has two modes of operation. If given the
-f flag, unslice reads a control file telling it how to assemble
the images. This is a text file with two decimal numbers on each
line, one line for each slice to be assembled into the output image.
Each line gives the starting and stopping scanlines (inclusive) for
each slice. These must be in ascending order. This is useful if the
slices have excess image area that should be cropped away.
If no control file is given, the
-y flag is used. This tells unslice what the maximum Y value of
the output image is.
Unslice reads the files in order, using the RLE headers to
determine where to place the slices. If two slices overlap, the first
scanlines from the second slice are thrown away. In both cases, the slices
must be in ascending order, and are expected to be of uniform width.