HP 4 FAMILY - Manual (Page 76)

exist, some glyph data will be output. For double-byte
characters, the glyph of the default character defined for
the given TrueType font is used. For single-byte characters,
the glyph at 0xA5 (small dot, U+FF65) is used.”
The following table shows a Galley Character Segment
which follows the Japanese Windows specification.
Byte 15 (MSB) 8 7 (LSB) 0 Byte
0 GC (18243) 1
2
4 Data Segment Size (12) * 3
5
6 Format = 0 7
8 Default Galley Character = 0xFFFF 9
10 Number of Regions (n) = 1 11
12 Region #1 Upper Left
Character Code = 0x0000 13
14 Region #1 Lower Right
Character Code = 0x00FF 15
16 Region #1 Galley Character = 0x00A5 17
* This segment is for Font Format 16. The Data Segment Size field for Font Format 16
fonts is 4 bytes; the segment for Font Format 15 fonts is identical except the Data
Segment Size field is 2 bytes instead.
In this example segment, there is one galley character
region. This region is applied to all one-byte characters
(character codes 0x0000-0x00FF); any missing character in
this region is replaced with the character at character code
location 0x00A5. Any missing characters falling into this
region (e.g. character codes 0x0100 - 0xFFFF) are replaced
with the default galley character. Since in this example the
Default Galley Character field = 0xFFFF, the missing
character glyph is printed if it is present in the font.
2-40 Printer-Specific Differences