Set Compression Method Command; Unencoded (Method 0); Run-Length Encoding (Method 1) - HP PCL 5 Reference Manual

Set Compression Method Command

The Set Compression Method command allows you to code raster
data in one of four compressed formats: Run-length encoding,
tagged imaged file format (TIFF) rev. 4.0, delta row compression,
and adaptive compression. The choice of compression methods
affects both the amount of code needed to generate a raster
graphic image and the efficiency with which the image is printed.
Default
Range

Unencoded (Method 0)

This is a simple binary transfer of data: no compression. Each bit
describes a single dot. Bit 7 of the first byte corresponds to the first
dot within the raster row, bit 0 corresponds to the eighth dot, and
so on.
Note
Compressed data formats allow for efficient transfer of data from
the host system to the printer. However, compressed data formats
do NOT reduce the amount of printer memory required to produce
an image.

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)] . [ . ] [ ]
15-16 Raster Graphics
E
& * b # M
C
# =0- Unencoded
1 - Run-length encoding
2 - Tagged Imaged File Format (TIFF) rev. 4.0
3 - Delta row compression
4 - Reserved
5 - Adaptive compression
= 0
= 0 - 5 (values outside the range are ignored)
EN