Microcom 412 Operator's Manual page 72

Downloadable Fonts
The font structure consists of a set of data structures and location offsets to those structures.
All data are stored in binary form. Multi-byte values are stored least-significant-byte first. A.
Word is a 16-bit value, Byte is an 8-bit value, Label is a location within the file. The Model 412
can store a font of approximately 64KB or less in any one slot.
Label start:
Word lookup_table_offset
Word tallest_char
Word widest_char
Byte default_spacing
Byte byte_width
Byte first_char
Byte last_char
Byte default_char
Label lookup_table
Word char_offset[last_char-first_char]
Label first_char_data
Word char_height
Word char_width
Byte bitmap_data[char_height][byte_width] ;bitmap of char, 2d array
row
the
Label second_char_data
Word char_height
Word char_width
Byte bitmap_data[char_height][byte_width] ;(same definition as for first char)
...
(Repeat char_data structures as needed)
...
Label last_char_data
Word char_height
Word char_width
Byte bitmap_data[char_height][byte_width] ;(same definition as for first char)
64
;the beginning of the file
;distance in bytes from start to beginning
;of lookup_table
;height of tallest char in font, in dots
;width of widest char in font, in dots
;default character spacing, usually 0
;width of all char bitmaps, in bytes
;first char code in set - usually space (20h)
;last char in set
;what char to use if it isn't in the font
;beginning of lookup table
;array of offsets, one for each character in font.
;Each offset is the distance, in bytes, from start to
;the beginning of the corresponding character's
;data structure. The first word in this array is the
;offset to the first character's data, the last word is
;the offset to the last character's data.
;the beginning of the first char's data structure
;height of this char's bitmap in dots
;width of this char's bitmap in dots (may be
narrower
;than the width of the bitmap_data array)
;The most significant bit of the first byte in each
;prints as the rightmost dot of the character, and
;first row is the bottom row when printed.
;the beginning of the second char's data structure
;(same definition as for first char)
;(same definition as for first char)
;the beginning of the last char's data structure
;(same definition as for first char)
;(same definition as for first char)
Chapter 7
412 Operators Manual