Brother HL-Series Technical Reference Manual page 77

Revision C 16/01/96
[Bitmapped font ]
Byte Data
0 - 1 Format
2 - 3 Descriptor size
4 - 5 Orientation
6 - 7 Left offset
8 - 9 Top offset
10 - 11 Character width
12 - 13 Character height
14 - 15 Delta X
16 - Raster Character Data
< Bitmapped continuation data >
Byte
0-1
• The bytes which follow the header are the raster data that make up the character.
• Attributes are in one of four numerical formats.
• Format (UB) - 4 for bitmap fonts.
• Continuation (B) - signifies whether the character data represents a new character (0) or is a continuation of
the character described by the previous character descriptor block and its data (non-zero). If the continuation
byte is non-zero the bytes following it are interpreted as character data.
• Descriptor size (UB) - 14 for bitmap fonts.
• Class (UB) - 1 for bitmap fonts, 2 for compressed bitmap fonts. Bitmap fonts are described using uncompressed
raster data. Compressed bitmap fonts character data is encoded as follows. The first byte of a line of data
contains the number of times that the line is successively repeated. The second byte indicates the number of
successive white pixels that start the line and the third byte indicates the number of successive black pixels
that follow the white pixels. Subsequent even and odd numbered bytes indicate the number of successive white
and black pixels respectively that make up the line. If there are more than 255 successive pixels of a single
color this is indicated by a byte set to 255 followed by a byte set to 0 followed by a byte indicating the
remaining number of pixels of that colour. The width of each line is determined by the character width
attribute. All rows must contain the same number of pixels. The total number of pixels on each row must equal
the character width attribute.
• Orientation (UB) - the orientation of the character. 0 = portrait, 1 = landscape, 2 = reverse portrait or 3 =
reverse landscape. This attribute setting must match the orientation specified in the font descriptor block.
• Left offset (SI) - the distance between the character reference point and the leftmost dot of the character on the
grid. The offset can be from -16384 to 16383.
• Top offset (SI) - the distance between the character reference point and the topmost dot of the character on the
grid. The offset can be from -16384 to 16383.
• Character width (UI) - the width of the download character in grid dots. This can be in the range 1 to 16384.
Format
2 Raster Character Data
Unsigned integer (UI) 0 to 65535
Signed integer (SI) –32768 to 32767
Unsigned byte (UB) 0 to 255
Boolean - 0 or 1
Chapter 2 "PCL" - 62
Continuation
Class
Reserved
Data
Continuation