Microcom 412 - Manual (Page 66)

Downloadable Graphic Images Chapter 6
412 Operators Manual 58
Label start: ;the beginning of the file
Word, Word, lookup_table_offset ;distance in bytes from start to beginning
;of lookup_table (4 bytes)
Word tallest_char ;height of graphic image in dots
Word widest_char ;width of graphic image in dots
Byte default_spacing ;default spacing, usually 0
Byte byte_width ;width of graphic image in bytes
Byte first_char ;(20h)
Byte last_char ;(20h)
Byte default_char ;(20h)
Label lookup_table ;beginning of lookup table
Word char_offset[last_char-first_char] ;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
;of
fset to the first character’s data, the last word is
;the offset to the last character's data.
Label first_char_data ;the beginning of the graphic image data
Word char_height ;height of this char's bitmap in dots
Word char_width ;width of graphic image in dots
Byte bitmap_data[char_height][byte_width] ;bitmap of char, 2d array
;The most significant bit of the first byte in each
;row prints as the right most dot of the character,
;and the first row is the bottom row when printed.
The above method allows graphic images to span 64KB memory segments. When using
graphics over 64KB, the printer will determine the number of 64KB slots required to store the
entire graphic, and will split the large file into the correct number of smaller files internally. It will
store these smaller files sequentially in the slots following the one specified in the command.
Therefore, before sending a graphic file that is 64K or more bytes long (uncompressed size),
make sure that the specified font slot and enough following slots to store the file are
unoccupied.
Graphics that are stored in multiple slots in this way may still be printed as if they are one large
graphic. In the label format, refer to the first slot (the one specified in the download command).
The printer will automatically append the additional graphic files seamlessly without additional
user intervention.