gcode_arcs: support XY, XZ and YZ planes

add G17, G18 and G19 commands to select arc planes
enhance G2/G3 to support arc moves in XY, XZ and YZ planes

Signed-off-by: Andrew Mirsky <andrew@mirsky.net>

3 files changed, 98 insertions, 31 deletions

diff --git a/docs/G-Codes.md b/docs/G-Codes.md
index d9cefd80..137d14ba 100644
--- a/docs/G-Codes.md
+++ b/docs/G-Codes.md
@@ -549,8 +549,9 @@ clears any error state from the micro-controller.
 The following standard G-Code commands are available if a
 [gcode_arcs config section](Config_Reference.md#gcode_arcs) is
 enabled:
-- Controlled Arc Move (G2 or G3): `G2 [X<pos>] [Y<pos>] [Z<pos>]
-  [E<pos>] [F<speed>] I<value> J<value>`
+- Arc Move Clockwise (G2), Arc Move Counter-clockwise (G3): `G2|G3 [X<pos>] [Y<pos>] [Z<pos>]
+  [E<pos>] [F<speed>] I<value> J<value>|I<value> K<value>|J<value> K<value>`
+- Arc Plane Select: G17 (XY plane), G18 (XZ plane), G19 (YZ plane)
 
 ### [gcode_macro]
 
diff --git a/klippy/extras/gcode_arcs.py b/klippy/extras/gcode_arcs.py
index 61fa7234..eac89050 100644
--- a/klippy/extras/gcode_arcs.py
+++ b/klippy/extras/gcode_arcs.py
@@ -7,12 +7,25 @@
 #
 # This file may be distributed under the terms of the GNU GPLv3 license.
 import math
-
+from gcode import Coord
 # Coordinates created by this are converted into G1 commands.
 #
-# note: only IJ version available
+# supports XY, XZ & YZ planes with remaining axis as helical
+
+# Enum
+ARC_PLANE_X_Y = 0
+ARC_PLANE_X_Z = 1
+ARC_PLANE_Y_Z = 2
+
+# Enum
+X_AXIS = 0
+Y_AXIS = 1
+Z_AXIS = 2
+E_AXIS = 3
+
 
 class ArcSupport:
+
     def __init__(self, config):
         self.printer = config.get_printer()
         self.mm_per_arc_segment = config.getfloat('resolution', 1., above=0.0)
@@ -22,12 +35,28 @@ class ArcSupport:
         self.gcode.register_command("G2", self.cmd_G2)
         self.gcode.register_command("G3", self.cmd_G3)
 
+        self.gcode.register_command("G17", self.cmd_G17)
+        self.gcode.register_command("G18", self.cmd_G18)
+        self.gcode.register_command("G19", self.cmd_G19)
+
+        # backwards compatibility, prior implementation only supported XY
+        self.plane = ARC_PLANE_X_Y
+
     def cmd_G2(self, gcmd):
         self._cmd_inner(gcmd, True)
 
     def cmd_G3(self, gcmd):
         self._cmd_inner(gcmd, False)
 
+    def cmd_G17(self, gcmd):
+        self.plane = ARC_PLANE_X_Y
+
+    def cmd_G18(self, gcmd):
+        self.plane = ARC_PLANE_X_Z
+
+    def cmd_G19(self, gcmd):
+        self.plane = ARC_PLANE_Y_Z
+
     def _cmd_inner(self, gcmd, clockwise):
         gcodestatus = self.gcode_move.get_status()
         if not gcodestatus['absolute_coordinates']:
@@ -35,21 +64,33 @@ class ArcSupport:
         currentPos = gcodestatus['gcode_position']
 
         # Parse parameters
-        asX = gcmd.get_float("X", currentPos[0])
-        asY = gcmd.get_float("Y", currentPos[1])
-        asZ = gcmd.get_float("Z", currentPos[2])
+        asTarget = Coord(x=gcmd.get_float("X", currentPos[0]),
+                         y=gcmd.get_float("Y", currentPos[1]),
+                         z=gcmd.get_float("Z", currentPos[2]),
+                         e=None)
+
         if gcmd.get_float("R", None) is not None:
             raise gcmd.error("G2/G3 does not support R moves")
-        asI = gcmd.get_float("I", 0.)
-        asJ = gcmd.get_float("J", 0.)
-        if not asI and not asJ:
-            raise gcmd.error("G2/G3 neither I nor J given")
+
+        # determine the plane coordinates and the helical axis
+        asPlanar = [ gcmd.get_float(a, 0.) for i,a in enumerate('IJ') ]
+        axes = (X_AXIS, Y_AXIS, Z_AXIS)
+        if self.plane == ARC_PLANE_X_Z:
+            asPlanar = [ gcmd.get_float(a, 0.) for i,a in enumerate('IK') ]
+            axes = (X_AXIS, Z_AXIS, Y_AXIS)
+        elif self.plane == ARC_PLANE_Y_Z:
+            asPlanar = [ gcmd.get_float(a, 0.) for i,a in enumerate('JK') ]
+            axes = (Y_AXIS, Z_AXIS, X_AXIS)
+
+        if not asPlanar[0] or not asPlanar[1]:
+            raise gcmd.error("G2/G3 requires IJ, IK or JK parameters")
+
         asE = gcmd.get_float("E", None)
         asF = gcmd.get_float("F", None)
 
-        # Build list of linear coordinates to move to
-        coords = self.planArc(currentPos, [asX, asY, asZ], [asI, asJ],
-                              clockwise)
+        # Build list of linear coordinates to move
+        coords = self.planArc(currentPos, asTarget, asPlanar,
+                              clockwise, *axes)
         e_per_move = e_base = 0.
         if asE is not None:
             if gcodestatus['absolute_extrude']:
@@ -74,37 +115,37 @@ class ArcSupport:
     # The arc is approximated by generating many small linear segments.
     # The length of each segment is configured in MM_PER_ARC_SEGMENT
     # Arcs smaller then this value, will be a Line only
-    def planArc(self, currentPos, targetPos, offset, clockwise):
+    #
+    # alpha and beta axes are the current plane, helical axis is linear travel
+    def planArc(self, currentPos, targetPos, offset, clockwise,
+                alpha_axis, beta_axis, helical_axis):
         # todo: sometimes produces full circles
-        X_AXIS = 0
-        Y_AXIS = 1
-        Z_AXIS = 2
 
         # Radius vector from center to current location
         r_P = -offset[0]
         r_Q = -offset[1]
 
         # Determine angular travel
-        center_P = currentPos[X_AXIS] - r_P
-        center_Q = currentPos[Y_AXIS] - r_Q
-        rt_X = targetPos[X_AXIS] - center_P
-        rt_Y = targetPos[Y_AXIS] - center_Q
-        angular_travel = math.atan2(r_P * rt_Y - r_Q * rt_X,
-                                    r_P * rt_X + r_Q * rt_Y)
+        center_P = currentPos[alpha_axis] - r_P
+        center_Q = currentPos[beta_axis] - r_Q
+        rt_Alpha = targetPos[alpha_axis] - center_P
+        rt_Beta = targetPos[beta_axis] - center_Q
+        angular_travel = math.atan2(r_P * rt_Beta - r_Q * rt_Alpha,
+                                    r_P * rt_Alpha + r_Q * rt_Beta)
         if angular_travel < 0.:
             angular_travel += 2. * math.pi
         if clockwise:
             angular_travel -= 2. * math.pi
 
         if (angular_travel == 0.
-            and currentPos[X_AXIS] == targetPos[X_AXIS]
-            and currentPos[Y_AXIS] == targetPos[Y_AXIS]):
+            and currentPos[alpha_axis] == targetPos[alpha_axis]
+            and currentPos[beta_axis] == targetPos[beta_axis]):
             # Make a circle if the angular rotation is 0 and the
             # target is current position
             angular_travel = 2. * math.pi
 
         # Determine number of segments
-        linear_travel = targetPos[Z_AXIS] - currentPos[Z_AXIS]
+        linear_travel = targetPos[helical_axis] - currentPos[helical_axis]
         radius = math.hypot(r_P, r_Q)
         flat_mm = radius * angular_travel
         if linear_travel:
@@ -118,14 +159,18 @@ class ArcSupport:
         linear_per_segment = linear_travel / segments
         coords = []
         for i in range(1, int(segments)):
-            dist_Z = i * linear_per_segment
+            dist_Helical = i * linear_per_segment
             cos_Ti = math.cos(i * theta_per_segment)
             sin_Ti = math.sin(i * theta_per_segment)
             r_P = -offset[0] * cos_Ti + offset[1] * sin_Ti
             r_Q = -offset[0] * sin_Ti - offset[1] * cos_Ti
 
-            c = [center_P + r_P, center_Q + r_Q, currentPos[Z_AXIS] + dist_Z]
-            coords.append(c)
+            # Coord doesn't support index assignment, create list
+            c = [None, None, None, None]
+            c[alpha_axis] = center_P + r_P
+            c[beta_axis] = center_Q + r_Q
+            c[helical_axis] = currentPos[helical_axis] + dist_Helical
+            coords.append(Coord(*c))
 
         coords.append(targetPos)
         return coords
diff --git a/test/klippy/gcode_arcs.test b/test/klippy/gcode_arcs.test
index 2be4efc9..6f9a7e3a 100644
--- a/test/klippy/gcode_arcs.test
+++ b/test/klippy/gcode_arcs.test
@@ -2,10 +2,31 @@
 DICTIONARY atmega2560.dict
 CONFIG gcode_arcs.cfg
 
-# Home and move in arcs
+# Home and move in XY arc
 G28
+G90
 G1 X20 Y20 Z20
 G2 X125 Y32 Z20 E1 I10.5 J10.5
 
 # XY+Z arc move
 G2 X20 Y20 Z10 E1 I10.5 J10.5
+
+# Home and move in XZ arc
+G28
+G90
+G1 X20 Y20 Z20
+G18
+G2 X125 Y20 Z32 E1 I10.5 K10.5
+
+# XZ+Y arc move
+G2 X20 Y10 Z20 E1 I10.5 K10.5
+
+# Home and move in YZ arc
+G28
+G90
+G1 X20 Y20 Z20
+G19
+G2 X20 Y125 Z32 E1 J10.5 K10.5
+
+# YZ+X arc move
+G2 X10 Y20 Z20 E1 J10.5 K10.5