Thanks to Julio Marchi for this space in MSX All
 

Compac (.VDC) and (.ATC)

  This file saves the Screen 2 in two files: the first contains the character table compressed using the Layout format and has the “.VDC” extension; the second file contains the color table compressed using the Run-Length algorithm and has the “.ATC” extension.

  The Run-Length method used on the ".ATC" file is described next.

  Let p as a file pointer and val(p) the returned value from p. For each byte, we have:

  • val(p) indicates the number of times that a color pattern will be repeated in sequence.
  • val(p+1) indicates the color pattern.


  The 8x1 line pattern is described here.

  Example:

 p
 08 F0

  Draw 8 lines in sequence, where the front color is 15 (white) and the background color is 0 (black).


Marcelo Silveira
Systems and Computing Engineer
Expert in Image Processing and Artificial Intelligence
© MarMSX 1999-2021