Dr. Halo PIC

Dr. Halo (including Dr. Halo Plus and Dr. Genius) is a line of raster image editing software for DOS, developed by Media Cybernetics.

Its main native file format is .PIC. Sometimes, a PIC file has a companion .PAL file. This article is about PIC format, and the software in general. There are separate articles for some formats:
 * Dr. Halo CUT
 * Dr. Halo PAL

PIC format does not seem to be as well known as CUT. A reference to "Dr. Halo format" most likely means CUT, not PIC.

Discussion
PIC is highly "device dependent". A PIC file contains identifiers for the relevant graphics hardware and mode, and a compressed copy of raw video memory.

Some editions of Dr. Halo support several dozen video cards, each with a handful of graphics modes, so supporting the entire format would be quite difficult. But it is realistic to support files that use the standard CGA/EGA/VGA modes.

Format details
''[Some of this information is based on reverse engineering, and may be incorrect. Written for the fileformats.archiveteam.org wiki.]''

A PIC file consists of a header segment, followed by the compressed image data. Byte order is little-endian.

Header structure
For 4-color CGA-like modes:

Compression scheme
Compression is byte-oriented. The "next multiple of 512 bytes" instructions refer to the absolute file position.

To decompress, read a byte (N), follow the instructions below, repeat.

Identification
PIC files start with ASCII "", and the byte at offset 6 is.

Software

 * Dr. Halo
 * Dr Halo II (at WinWorld) - Includes v2.03, and a manual
 * Dr. Halo III (v3.00/1988-02-02)
 * Dr. Halo III (at WinWorld) - Includes Dr. Halo III (v3.00/1989-02-06) & Dr. Genius (v3.00)
 * Dr. Halo Plus (v3.00-German)
 * Dr. Genius (v3.00)
 * Various versions at old-dos.ru - Includes Dr. Halo III (v3.01) and Dr. Halo Plus (v3.00).
 * Possibly relevant:

Sample files

 * → screen*.pic (NSFW)
 * → screen*.pic (NSFW)

Links

 * Dr. Halo
 * Dr. Halo User's Guide (v1.23)