Dymo Costar 400 User Manual download pdf (Page 38)

4-34

ETB EL Mode Compressed Graphics

DESCRIPTION

Provided for LabelWriter EL compatibility.

The ETB command is a synchronization character used to encode

compressed EL bitmap print data. Print data is encoded in strings

of 8-bit bytes preceded by a singe ETB (Hex 17) character. The

control electronics in the printer do not check the validity of the

bitmap data.

Data compression is done via a form of run-length encoding. Bit

seven (the sign bit) of a compressed character represents the

value to be printed:

0 = white space, 1 = a printed pixel. Bits 6 through 0 represent the

number of consecutive bits of the selected value plus 1.

Examples: 00 = 1 white pixel

80 = 1 printed pixel

0F = 16 white pixels

FF = 128 printed pixels

The data sent to the LabelWriter is handled on a line-by-line

basis, so compressed lines may be intermixed with normal lines.

In addition, the compressed mode also uses the set bytes per line

command (ESC D) to determine how much data from the host to

expect for each line. However, the sum of the pixels must be

equal to the bytes per line variable (ESC D, default on the SE300

is 56) multiplied by 8. No error checking is done on the incoming

data and unexpected results will occur if the above caution is not

observed. Below is a sample compressed line for a ESC D 24

setting:

17 OF 8F 20 A0 20 A0 0F 8F

which would translate to:

16 white pixels

16 printed pixels

32 white pixels

32 printed pixels

32 white pixels

32 printed pixels

16 white pixels

16 printed pixels

Total 192 pixels = 24 bytes x 8

Use of the ETB command, along with the ESC D and ESC B

commands, can drastically reduce the number of data bytes

1 2 ... 33 34 35 36 37 38 39 40 41 42 43 ... 131 132

No comments

Dymo Costar 400 User Manual Page 38