ProbePointsHelper: Optionally add xy offsets to probe points

Signed-off-by:  Eric Callahan <arksine.code@gmail.com>

klippy/extras/probe.py

@@ -283,6 +283,7 @@ class ProbePointsHelper:
                     self.name))
         self.horizontal_move_z = config.getfloat('horizontal_move_z', 5.)
         self.speed = config.getfloat('speed', 50., above=0.)
+        self.use_offsets = False
         # Internal probing state
         self.lift_speed = self.speed
         self.probe_offsets = (0., 0., 0.)
@@ -291,6 +292,8 @@ class ProbePointsHelper:
         if len(self.probe_points) < n:
             raise self.printer.config_error(
                 "Need at least %d probe points for %s" % (n, self.name))
+    def use_xy_offsets(self, use_offsets):
+        self.use_offsets = use_offsets
     def get_lift_speed(self):
         return self.lift_speed
     def _move_next(self):
@@ -313,6 +316,9 @@ class ProbePointsHelper:
             self.results = []
         # Move to next XY probe point
         curpos[:2] = self.probe_points[len(self.results)]
+        if self.use_offsets:
+            curpos[0] -= self.probe_offsets[0]
+            curpos[1] -= self.probe_offsets[1]
         toolhead.move(curpos, self.speed)
         self.gcode.reset_last_position()
         return False