HP PCL/PJL reference (PCL 5 Color) - Technical Reference Manual

EN The PCL Print Model 5-9
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. The
Logical Operations (
?*l#O) command specifies which logical
operation is to be performed on the source, texture, and destination to
produce a new destination. Transparency modes should be specified
before the logical operation is performed or printable data is sent.
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 the Select Current
Pattern command (
?*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.
The Print Model allows logical operations, such as AND, OR, XOR,
NOT, to be performed on source, texture, and destination images.
Transparency modes and Logical Operation must be specified before
printable data is sent.