HP PCL/PJL reference - PCL 5 Comparison Guide

ENWW Printer-Specific Differences 2-13
Logical Operations
With the introduction of the HP LaserJet 4ML printer the print model
was expanded to include logical operations.
The basic print model defines how a pattern, source image, and
destination image are applied to each other using the print model’s
transparent and opaque modes to produce a resulting image (refer to
the PCL 5 Printer Language Technical Reference Manual for detailed
information about the basic print model operation). The Logical
Operations (
?*l#O) command can apply logical functions (e.g.,
AND, OR, XOR, NOT) to any of these operands except transparency,
which must be specified first.
The print model process consists of the following steps:
1 Specify source and/or pattern transparency modes, if desired.
2 Specify the logical operation (or use the default).
3 Define the desired operands (source, destination, pattern).
Definitions
Source: The source image may be one of the following:
• HP-GL/2 primitives
• Rules
• Characters
• Raster images (single plane mask or multiplane color)
Destination: The destination image contains whatever is currently
defined on the page. It includes any images placed through previous
operations.
Pattern or Texture: The pattern is defined by Current Pattern
(
?*v#T). The terms pattern and texture are used interchangeably in
this section.
Transparency Modes: The white pixels of the source and/or pattern
may be made transparent (source transparency 0, pattern
transparency 0). The destination shows through these areas.
Transparency modes are set by the Source Transparency (
?*v#N)
and Pattern Transparency (
?*v#O) commands (refer to the PCL 5
Printer Language Technical Reference Manual).