Microcom 428LT Operator's Manual page 108

Chapter 6
required to store the entire graphic and will split the large file into the correct number of
smaller files internally. The printer stores these smaller files sequentially in the slots
following the one specified in the appropriate load or save graphic command. Therefore,
before sending a graphic file that is 64KB or more (uncompressed size), make sure that the
specified font slot has enough following empty slots to store the file properly.
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) regardless of how many slots that may be required for large graphics. The
printer will automatically append the additional graphic files seamlessly without additional
user intervention.
(Word is a 16-bit value, Byte is an 8-bit value, and Label is a location within the file)
Label start:
Word, 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]
428LT Operator's Manual - 880040-0200
Downloadable Graphics
the beginning of the file
distance in bytes from start to beginning of
lookup_table (4 bytes)
height of graphic image in dots
Width of graphic image in dots
Default spacing, usually 0
Width of graphic image in bytes
20 HEX
20 HEX
20 HEX
beginning of lookup table
an array of offsets, one for each character in
font. Each offset is the distance, in bytes, from
the 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 graphic image data
height of this character's bitmap in dots
width of the graphic image in dots
bitmap of character, 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.
6-7