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

EN DI, Absolute Direction 23-31
Figure 23-16Effect of Horizontal and Vertical Text Paths
Note If an SB1; command has been sent, the printer draws the label along
the nearest perpendicular. In the case of bisection, the angle is
rounded down (e.g., 45° would round to 0°). Refer to the following
illustration.
Figure 23-17Scalable Versus Bitmap Variable Text Path Printing
Suppose you want your label plotted in the direction shown in the
following illustration. You can do this in one of two ways: measure the
run and rise, or measure the angle.