The PIC2 image format

The PIC2 image format is used some Japanese personal computer users.
The PIC2 format is designed by A.Yanagisawa. It is very excellent format except for it's encode/decode speed ;-)


The outline of the Compression algorithm of PIC2 format

  1. In the first place, try to record pixel color, uses color caches which keep some recent colors, and formed accding to color's frequency. PIC2 has some color cache spaces that are switched by upper pixel value of current pixel. If cache is hit, record that.
  2. Unfortunately, in the case of color cache didn't hit, record the difference from the value estimated with the value of upper and left pixel of current pixel
  3. And extract image's color chain if exist, and record that (It results in image's outline).
  4. In all time of recording values, it is pressed with arithmetric compression method which produce the ideal compression ratio in theory(P2SS).

The PIC2 module for XV

Supported internal formats



XV japanese extension Bug report:
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Last modified: Wed Oct 23 21:07:38 JST 1996