C:/usr/src/avr/plotter/font173.c File Reference

#include <avr/pgmspace.h>

Go to the source code of this file.

Variables

PGM_P charset173 [256]


Variable Documentation

PGM_P charset173[256]

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 corresponds to one of these strings, which 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 without a need for sign bits. 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 . . The following array of strings contains the ps math font (173), which differs from ventura math (205) only in the sequence of characters in the upper half of the font

Definition at line 83 of file font173.c.


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