gcode_arcs: Add back in support for E moves in absolute extrude mode

This reverts commit 43fa41c1af648ea626040e17f0eebda39dcdb2cb.

The above commit disabled absolute extrude moves because it was
unclear if the code would work properly when an M221 extrude factor or
G92 offset was in use.  However, since the calculation is done
relative to the raw E position and is sent as a raw E position to
gcode.cmd_G1() these modes should not matter.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

klippy/extras/gcode_arcs.py

@@ -38,20 +38,23 @@ class ArcSupport:
         if not asI and not asJ:
             raise gcmd.error("G2/G3 neither I nor J given")
         asE = gcmd.get_float("E", None)
-        if asE is not None and gcodestatus['absolute_extrude']:
-            raise gcmd.error("G2/G3 only supports relative extrude mode")
         asF = gcmd.get_float("F", None)
         clockwise = (gcmd.get_command() == 'G2')
 
         # Build list of linear coordinates to move to
         coords = self.planArc(currentPos, [asX, asY, asZ], [asI, asJ],
                               clockwise)
+        e_per_move = e_base = 0.
+        if asE is not None:
+            if gcodestatus['absolute_extrude']:
+                e_base = currentPos[3]
+            e_per_move = (asE - e_base) / len(coords)
 
         # Convert coords into G1 commands
         for coord in coords:
             g1_params = {'X': coord[0], 'Y': coord[1], 'Z': coord[2]}
-            if asE is not None:
-                g1_params['E'] = asE / len(coords)
+            if e_per_move:
+                g1_params['E'] = e_base + e_per_move
             if asF is not None:
                 g1_params['F'] = asF
             g1_gcmd = self.gcode.create_gcode_command("G1", "G1", g1_params)

test/klippy/gcode_arcs.test

@@ -3,7 +3,6 @@ DICTIONARY atmega2560.dict
 CONFIG gcode_arcs.cfg
 
 # Home and move in arcs
-M83
 G28
 G1 X20 Y20 Z20
 G2 X125 Y32 Z20 E1 I10.5 J10.5