EN Absolute and Relative Pen Movement 17-25
Absolute and Relative Pen Movement
The Plot Absolute (PA) and Plot Relative (PR) commands allow you to
set whether you want to draw using absolute or relative “pen” moves.
Absolute pen movement uses X,Y coordinates to specify an exact,
fixed point relative to the origin (0,0). In Figure 17-9, the coordinates
(3,8), (5,4), and (8,1) are always in the same place with respect to the
origin, no matter where the pen is when the coordinates are issued.
Figure 17-9 Absolute Coordinates
Relative pen movement uses X,Y increments to specify the number
of units the pen moves from its current pen location. All commands
that use relative increments include “relative” in their name (except
the PE command). (An example is the Edge Rectangle Relative
(ER) command.
In Figure 17-10 for example, assume that the pen is currently at the
origin (0,0). To move to the absolute points shown in Figure 17-9
using relative coordinates, count 3 units to the right and 8 units up
from the current pen location; these are both positive directions with
respect to the origin. This is the relative location (3,8). Now move 5
positive X-units and 7 negative Y-units from this location to the lower
point; this is the relative location (5,-7). From this location, move to
the last point by moving 3 negative X-units and 3 positive Y-units
(-3,3).
To Next Page
Loading...