HP 700, 800 Raster Compression, Value, Effect, Compression Method, Unencoded, Run-length encoding

HP PCL Commands

10.15Raster Compression

Since raster images take a large amount of memory and processing time, raster data should be reduced as much as possible. White-space data transfer can be reduced by sending empty rows and planes (Esc * b 0 W, Esc * b 0 V), or by offsetting the left graphic margin (Esc * r 1

A) or the vertical starting point (Esc * b # Y). The Compression Method (Esc * b # M) com- mand provides several other ways of compressing data.

10.15.1Compression Method

TABLE 55.						Compression Method - Esc * b # M
Value	DJ600	DJ610C	DJ660C	DJ670C	DJ680C	DJ690C	DJ695C	DJ810C	DJ830C	DJ850C	DJ870C	DJ880C	DJ890C	DJ895C	DJ970C	HP2000C	EFFECT
#
0	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	Unencoded
1	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	Run-length encoding
2	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	Tagged Image File Format
																	(TIFF) revision 4.0 “Packbits”
																	encoding
3	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	Delta row encoding
9	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	Compressed replacement delta
																	row encoding
Default	0
Range	0-3, 9 - Out of range values default to 0

Determines how raster data is interpreted in the Transfer Raster by Row or Transfer Raster by Plane commands. The compression method stays in effect until explicitly changed to another method or reset by Reset (Esc E) or End raster (Esc * r C).

Method 0- Unencoded

This is a simple binary transfer: no compression.

Method 1- Run-Length Encoding

Method 1 interprets raster data as byte pairs. The first byte tells how many times the second byte is repeated, i.e., a repetition count. The second byte is the data to be printed. The repeti- tion count can be 0 through 255. A count of 0 means the byte pattern occurs once and is not repeated; a count of 1 means the pattern occurs twice; and a count of 255 means the pattern occurs 256 times.

HP DeskJet 600, 700, 800, 900 & HP 2000 Series PCL Developer’s Guide 77