HP L 5 Unencoded Method, Run-length Encoding Method, Tagged Image File Format Encoding Method

The Set Compression Mode command has the following form:

?* b # M

# = 0 - Unencoded

1- Run-length encoding

2- Tagged Imaged File Format (TIFF) rev. 4.0

3- Delta row compression

5 - Adaptive compression

Default = 0

Range = 0 - 3, 5 (other values are ignored)

Unencoded (Method 0)

This is a simple transfer of binary data without any compression.

Run-length Encoding (Method 1)

Run-length encoding interprets raster data in pairs of bytes. The first byte of each pair is the repetition count for the data in the second byte. The second byte is the raster data to be printed. A repetition count of 0 signifies the pattern in the data byte is not repeated (it occurs only once). A repetition count of 1 signifies the pattern occurs twice. The repetition count can range from 0 to 255 for a repetition of 1 to 256 times.

[(Repetition count byte 0-255)(pattern byte)] . [ . ] [ ]

Tagged Image File Format Encoding (Method 2)

Tagged Image File Format encoding interprets raster data as TIFF “Packbits.” This format combines features of methods 0 and 1. A control byte precedes the raster data (pattern bytes). The control byte identifies whether the pattern byte(s) represent a byte that is to be repeated some number of times (up to 127), or represent some number of bytes (up to 127) which are to be printed as is (literally).

EN Raster Graphics 6-21