Help for ADL

ADL adds a constant value to pixels that are on lines (oriented
in any direction) that have been specified by their end points.
Several different lines may be drawn simultaneously, using differing
constants. The lines drawn by ADL are one pixel wide. If the DN value
of a pixel on a line is to be adjusted to a value less than 0, it is set
to 0; if a pixel is to be adjusted to a value greater than 255, it is
set to 255.
RESTRICTIONS;
1. Maximum image size is 10000 lines and 10000 samples.
2. Maximum number of lines to be drawn is 25.
3. Maximum number of pixels to be changed is 12000.
4. Byte data only.
HISTORY
Made portable for UNIX ... J. Turner (CRI).............. 31 Oct. 1994
Enabled for 3D images  ... N. Toole .................... 16 Sep. 2003
16-Feb-06 -lwk- corrected treatment of SIZE field in processing of ADD