HP Pcl 5 Manual

ENSet Compression Method Command 15-23
Repeating a Row
 E
C*b0W
When using the delta compression method, it is possible to repeat 
or copy the previous raster row using the Raster Data Transfer 
command. This is accomplished by setting the Raster Data Transfer 
command, value field, to zero.
Printing A Zeroed Row (Setting the Seed Row to Zero)  
E
C*b1Y
It is possible to print a row of all zeros using the Raster Y-Offset 
command. Sending a Raster Y Offset command, with a value field 
of 1, sets the seed...

15-24   Raster GraphicsEN
Example: Delta Row Compression
The following example demonstrates how to compress the following 
data using the delta row compression. (The bytes highlighted in italic 
type indicate those bytes needing replacement — those bytes that 
are different from the previous row, the seed row.)
E
C*r1A – The start raster graphics command initializes the seed row 
to all zeros.
Row 1 — 
E
C*b3m2W(00000001)(11111111)
The 3m selects the delta row compression method and the 2W 
indicates...

ENSet Compression Method Command 15-25
Adaptive Compression  (Method 5)
Adaptive compression enables the combined use of any of the four 
previous compression methods (0 through 3), and it includes the 
ability to print empty (all zeros) rows or to duplicate rows.
Adaptive compression interprets a raster image as a block of raster 
data rather than as individual rows. The result of this interpretation is 
that the Transfer Raster Data (
E
C*b#W) command is sent only once 
at the beginning of a raster...

15-26   Raster GraphicsEN
For command byte values 0 - 3, the two   bytes 
specify the number of bytes (row length) for the row. For command 
byte values 4 and 5, these bytes identify the number of empty or 
duplicate rows to print. The maximum value for these two bytes is 
65,535; however, the image is clipped to the logical page. Thus, the 
value of these bytes should not exceed the maximum number of 
bytes/rows that can be printed on the current logical page size.
If an out of range command byte is...

ENSet Compression Method Command 15-27
Adaptive Compression Operation Hints
NoteSome HP LaserJet printers perform internal compression techniques 
to support full-page graphics. Refer to Chapter 1 of the PCL 5 
Comparison Guide for specifics.
zThe compression methods cannot be mixed within one raster row. 
A raster row must be compressed using only one method.
zThe cursor position is updated with each row of the raster block. 
The cursor position is also incremented when a block count of 
less than 3 is...

15-28   Raster GraphicsEN z
For method 3 - Since delta row compression requires that the 
seed row be available whenever raster graphics mode is entered, 
the seed row is initialized to zeros upon raster graphics mode 
entry (
E
C*r#A). The seed row is also initialized upon receipt and 
completion of each raster block.
zFor method 3 - If the row length terminates the data before the 
control byte value is satisfied (literal byte count greater than row 
length), the data following the control byte (if...

ENTransfer Raster Data Command 15-29
Transfer Raster Data Command 
The Transfer Raster Data command is used to transfer a row of raster 
data to the printer.
E
C * b # W   [raster data]
Default =N/A
Range =0 - 32767
The value field (#) identifies the number of bytes in the raster row. 
These bytes are interpreted as one row of raster graphics data that 
is printed at the current Y position at the left raster graphics margin. 
Upon completion of this command, the cursor position is at the 
beginning of...

15-30   Raster GraphicsEN
NotesIf the last byte indicated by the value field in the Transfer Raster Data 
command is a control byte, that byte is ignored.
If a Transfer Raster Data command is received without an 
accompanying Start Raster Graphics command, any preceding start 
raster values are used (such as left graphics margin, raster height 
and width, etc.).
End Raster Graphics Command 
The End Raster Graphics command signifies the end of a raster 
graphic data transfer.
E
C * r C
zReceipt of this...

ENRaster Graphics Example 15-31
Raster Graphics Example 
To transfer an unencoded raster graphic image (see Figure 15-11) in 
the shape of an arrow, perform the following steps:
Table 15-10
1. Position the cursor:
E
C*p300x400
Y This moves the cursor to PCL Unit position 
(300, 400) within the PCL coordinate 
system.
2. Specify the raster graphics resolution:
E
C*t75R  This sets the raster graphics resolution to 
75 dots-per-inch.
3. Specify the raster graphics presentation method:
E
C*r0F  This...

15-32   Raster GraphicsEN
The brackets and commas are not part of the raster data command; 
they are used only to delineate the data. 6
00000000 00000000 11111100 00000000E
C*b4W[  0,   0,252,  0]
7
00000000 00000000 11111110 00000000E
C*b4W[  0,   0,254,  0]
8
00000000 00000000 11111111 00000000E
C*b4W[  0,   0,255,  0]
9
00000000 00000000 11111111 10000000E
C*b4W[  0,  0,255,128]
10
11111111 11111111 11111111 11000000E
C*b4W[255,255,255,192]
11
11111111 11111111 11111111 11100000E...