Programmer's Reference Manual Intermec Fingerprint® v8.70.0 ...

Chapter —Image Transfer
PRBUF Protocol
The PRBUF Protocol is designed for downloading bitmap print image data
directly from an application program, such as a Windows printer driver,
directly to the printer’s image buffer in connection with the PRBUF statement.
The protocol consist of a two-byte header and a number of data bytes:
Header
Byte No 1. is always the @-sign (Commercial at; Unicode 0x0040) and
indicates start of the protocol header.
Byte No 2 is:
0 Reserved (bitmap format)
1 Reserved (RLL image format)
2 RLL buffer format
3-255 Reserved
RLL Buffer format
The RLL buffer format is optimized for use by Windows drivers. In most
cases the performance of the host outruns the performance of the printer,
so it is preferred to to do most of the processing in the host before sending
the job down to the printer.
- Data byte 1 & 2 specifies the pixelwidth (unsigned) of data in BIG
Endian format for one line.
- Data byte 3 & 4 specifies the pixelheight (unsigned) of the buffer when
it is expanded BIG Endian.
- Data byte 5-nn specifies the bitmap in RLL format.
Example of RLL buffer protocol header, 515x212 pixels hexdump:
40 02 02 03 00 d4
RLL format
The RLL format is good for black and white pixel runs. It compresses data
in both dimensions. It works well with one-dimensional bar codes, but
grayscales grow in size instead of shrinking. The format is symmetric so
that all pixel runs start and end with a white pixel and with line repetitions
whenever applicable. This makes the format possible to turn upside down.
The RLL format is specified on the next page.
08 Intermec Fingerprint v8.70.0/v10.0.0 Programmer´s Reference Manual