Contents, cont'd. - Intermec

Chapter 3 Image Transfer
Image Format The following image format is valid for Intelhex, UBI00, UBI01, UBI02 and
UBI03 image transfer protocols, but not for the UBI10 protocol, which is a
combined image transfer protocol and format.
A bitmap picture can be encoded in one of two ways, as a plain bit
representation or encoded with a Run Lenght Limited (RLL) algoritm.
Pictures can be magnified, by the printer, up to four times independently in
both x and y directions.
The pictures can be rotated 180 degres by the printer (i.e. printed upsidedown).
To print a bitmap in all four directions you have to define two bitmaps, one
straight and one rotated 90 degrees. To comply with the Intermec Fingerprint
convention, use the extension .1 for the straight bitmap and extension .2 for
the rotated one.
Bitmap pictures, in both encoding schemes, are printed with the lowest
address first, i.e. first row of defined data is the first thing out. (This may be
somewhat confusing. The only result, if you missinterpretate this, is that your
picture will come out upside down.)
Bitmap pattern, bit representation
The bitmap picture is encoded word oriented (i.e. 16 bits), low byte first. The
bits in each byte is read from lsb first (i.e. bit 0).
Bitmap pattern, Run Lenght Limited (RLL)
RLL encoding is a very efficient way of compressing big bitmaps with
relatively big black and/or white areas.
The RLL encoded picture is encoded byte oriented (i.e. 8 bits). Each byte
represents the number of consecutive black or white dots. The sum of bytes
for each row must equal the width of the pattern. The first byte represent white
dots, the second black and so on. The last byte must alter the color back to
white. If the first dot is black just enter a zero first. Valid values for dot fields
is 0...127 (0..7f hex). To get a row longer then 127, concatenate two rows with
zero, e.g. to get a row of 240 dots, enter 128,0,112.
The next step in our RLL encoding algoritm is to compress identicals rows,
two identical rows are compressed by adding a byte in both ends of the dot
row, the valid range for these bytes are -1...-128 (ff..80 hex).
Intermec Fingerprint 7.2 – Reference Manual Ed. 3 246