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

EN DR, Relative Direction 23-39
The following illustration shows the effects of using three different sets
of run/rise parameters. Notice how the text baseline varies as the run
percentage is greater than, equal to, and less than the value for rise.
Figure 23-22Effects of Different Rise/Run Parameters
If the P1/P2 rectangle is square, the DR and DI commands have
exactly the same effect. The advantage of using the DR command
is that, as the locations of P1 and P2 change, the slope of the
baseline changes to match the stretching or compressing of the
P1/P2 rectangle. For example, if the relative direction is set so that
rise = run, the slope of the baseline is 45° as long as the P1/P2
rectangle is square. If the P1/P2 rectangle stretches so that it is twice
as high as it is wide, the slope of the baseline remains parallel to an
imaginary line running from P1 to P2 (see illustration below).