gcode: Add support for SAVE_GCODE_STATE and RESTORE_GCODE_STATE commands

Add commands to save and restore the current g-code state.

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

3 files changed, 71 insertions, 2 deletions

diff --git a/docs/G-Codes.md b/docs/G-Codes.md
index 486be0da..6f895e52 100644
--- a/docs/G-Codes.md
+++ b/docs/G-Codes.md
@@ -105,6 +105,22 @@ The following standard commands are supported:
   axis). If "MOVE_SPEED" is specified then the toolhead move will be
   performed with the given speed (in mm/s); otherwise the toolhead
   move will use the last specified G-Code speed.
+- `SAVE_GCODE_STATE [NAME=<state_name>]`: Save the current
+  g-code coordinate parsing state. Saving and restoring the g-code
+  state is useful in scripts and macros. This command saves the
+  current g-code absolute coordinate mode (G90/G91), absolute extrude
+  mode (M82/M83), origin (G92), offset (SET_GCODE_OFFSET), speed
+  override (M220), extruder override (M221), move speed, current XYZ
+  position, and relative extruder "E" position. If NAME is provided it
+  allows one to name the saved state to the given string. If NAME is
+  not provided it defaults to "default".
+- `RESTORE_GCODE_STATE [NAME=<state_name>]
+  [MOVE=1 [MOVE_SPEED=<speed>]]`: Restore a state previously saved via
+  SAVE_GCODE_STATE. If "MOVE=1" is specified then a toolhead move will
+  be issued to move back to the previous XYZ position. If "MOVE_SPEED"
+  is specified then the toolhead move will be performed with the given
+  speed (in mm/s); otherwise the toolhead move will use the restored
+  g-code speed.
 - `PID_CALIBRATE HEATER=<config_name> TARGET=<temperature>
   [WRITE_FILE=1]`: Perform a PID calibration test. The specified
   heater will be enabled until the specified target temperature is
diff --git a/klippy/gcode.py b/klippy/gcode.py
index 5328ae4e..975bfcfe 100644
--- a/klippy/gcode.py
+++ b/klippy/gcode.py
@@ -53,9 +53,10 @@ class GCodeParser:
         self.speed = 25.
         self.speed_factor = 1. / 60.
         self.extrude_factor = 1.
+        # G-Code state
+        self.saved_states = {}
         self.move_transform = self.move_with_transform = None
         self.position_with_transform = (lambda: [0., 0., 0., 0.])
-        # G-Code state
         self.need_ack = False
         self.toolhead = self.fan = self.extruder = None
         self.heaters = None
@@ -485,7 +486,7 @@ class GCodeParser:
     all_handlers = [
         'G1', 'G4', 'G28', 'M18', 'M400',
         'G20', 'M82', 'M83', 'G90', 'G91', 'G92', 'M114', 'M220', 'M221',
-        'SET_GCODE_OFFSET', 'M206',
+        'SET_GCODE_OFFSET', 'M206', 'SAVE_GCODE_STATE', 'RESTORE_GCODE_STATE',
         'M105', 'M104', 'M109', 'M140', 'M190', 'M106', 'M107',
         'M112', 'M115', 'IGNORE', 'GET_POSITION',
         'RESTART', 'FIRMWARE_RESTART', 'ECHO', 'STATUS', 'HELP']
@@ -631,6 +632,43 @@ class GCodeParser:
             delta = offset - self.homing_position[pos]
             self.base_position[pos] += delta
             self.homing_position[pos] = offset
+    cmd_SAVE_GCODE_STATE_help = "Save G-Code coordinate state"
+    def cmd_SAVE_GCODE_STATE(self, params):
+        state_name = self.get_str('NAME', params, 'default')
+        self.saved_states[state_name] = {
+            'absolute_coord': self.absolute_coord,
+            'absolute_extrude': self.absolute_extrude,
+            'base_position': list(self.base_position),
+            'last_position': list(self.last_position),
+            'homing_position': list(self.homing_position),
+            'speed': self.speed, 'speed_factor': self.speed_factor,
+            'extrude_factor': self.extrude_factor,
+        }
+    cmd_RESTORE_GCODE_STATE_help = "Restore a previously saved G-Code state"
+    def cmd_RESTORE_GCODE_STATE(self, params):
+        state_name = self.get_str('NAME', params, 'default')
+        state = self.saved_states.get(state_name)
+        if state is None:
+            raise error("Unknown g-code state: %s" % (state_name,))
+        # Restore state
+        self.absolute_coord = state['absolute_coord']
+        self.absolute_extrude = state['absolute_extrude']
+        self.base_position = list(state['base_position'])
+        self.homing_position = list(state['homing_position'])
+        self.speed = state['speed']
+        self.speed_factor = state['speed_factor']
+        self.extrude_factor = state['extrude_factor']
+        # Restore the relative E position
+        e_diff = self.last_position[3] - state['last_position'][3]
+        self.base_position[3] += e_diff
+        # Move the toolhead back if requested
+        if self.get_int('MOVE', params, 0):
+            speed = self.get_float('MOVE_SPEED', params, self.speed, above=0.)
+            self.last_position[:3] = state['last_position'][:3]
+            try:
+                self.move_with_transform(self.last_position, speed)
+            except homing.EndstopError as e:
+                raise error(str(e))
     # G-Code temperature and fan commands
     cmd_M105_when_not_ready = True
     def cmd_M105(self, params):
diff --git a/test/klippy/commands.test b/test/klippy/commands.test
index a32b26e2..3327696e 100644
--- a/test/klippy/commands.test
+++ b/test/klippy/commands.test
@@ -19,6 +19,21 @@ RESTART
 
 M18
 
+# G-code state commands
+G28
+SAVE_GCODE_STATE
+G92 Z-5
+G92 E5
+SAVE_GCODE_STATE NAME=test
+G1 Z-5
+G91
+G1 Z0
+RESTORE_GCODE_STATE NAME=test
+G1 Z-5
+RESTORE_GCODE_STATE
+G1 Z0 E0
+RESTORE_GCODE_STATE MOVE=1
+
 # Update commands
 SET_GCODE_OFFSET Z=.1
 M206 Z-.2