| | This file defines a standard character set by elementary
"draw" & "move" commands. The format is a very compact one from
the old days where every byte was still appreciated.
A font or character set is an array of strings. Each character is
addressed by its ASCII code.
A character is a (NULL-terminated) string of bytes. Each byte
codes for a draw or move action according to the code below:
Bit: 7 6 5 4 3 2 1 0
p x x x y y y y
p: Plot flag. If set, "draw to" new point, else "move to" it.
xxx: 3-bit unsigned integer (0...7). X coordinate of new point.
yyyy: 4-bit unsigned integer (0..15). Y coordinate of new point.
The baseline is y = 4 instead of y = 0, so characters with parts
below it can be drawn properly. Function "code_to_ucoord" transforms
these coordinates into actual user coordinates.
Example: code for character 'L': "\032\224\324" translates to:
moveto(1,10); drawto(1,4); drawto(5,4);
From the example you can conclude that the font below essentially is
defined on a 5x7 grid:
0 1 2 3 4 5 6 7
15 - - - - - - - - - : unused
14 - - - - - - - - # : always used
13 - - - - - - - - o : sometimes used
12 - - - - - - - -
11 - - - - - - - -
10 o # # # # # - -
9 o # # # # # - -
8 o # # # # # - -
7 o # # # # # - -
6 o # # # # # - -
5 o # # # # # - -
4 o # # # # # - -
3 o o o o o o - -
2 o o o o o o - -
1 o o o o o o - -
0 o o o o o o - -
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