HP PCL/PJL reference (PCL 5 Printer Language) - Technical Reference Manual Part II

19-4 The Configuration and Status Group EN
The Scaling Points P1 and P2
When you scale a drawing, you define your own units of measure-
ment, which the printer then converts to plotter units. Scaling relies
on the relationship between two points: P1 and P2. These two points
are called the scaling points because they take on the user-unit
values that you specify with the Scale (SC) command. You can
change the locations of P1 and P2 using either the Input P1 and P2
(IP), or Input Relative P1 and P2 (IR) command.
P1 and P2 always represent an absolute location in relation to the
PCL Picture Frame, defined in plotter-units. They designate opposite
corners of a rectangular printing area within the picture frame. You
can change the size of the rectangular printing area and move it
anywhere within the picture frame, or even outside the picture frame,
depending on the plotter-unit coordinates you specify using the IP or
IR commands.
Using the Scale Command
Scaling allows you to establish units of measure with which you
are familiar, or which are more logical to your drawing. The Scale
command (SC) determines the number of user-units along the X-
and Y-axes between P1 and P2. The actual size of the units depends
on the locations of P1 and P2 and the range of user-units set up by
the SC command.
There are three types of scaling:
z Anisotropic
z Isotropic
z Point-factor
Anisotropic scaling indicates that the size of the units along the
X-axis may be different than the size of the units on the Y-axis.
Isotropic scaling, then, indicates that the units are the same size
on both axes. Point-factor scaling sets up a ratio of plotter units to
user-units.
The Scale command does not change the locations of P1 and P2,
only their coordinate values. Also, scaling is not limited to the
rectangular area defined by P1 and P2, but extends across the
entire printing area within the PCL Picture Frame.