start_end: Add randomized XY print position on bed

README.md

@@ -261,6 +261,17 @@ _PRINT_START_PHASE_PURGE
 ; to generate the purge).
 ```
 
+#### Additional SuperSlicer Start G-code
+
+If you're using SuperSlicer you can add the following immediately before the
+`PRINT_START` line from above. This will perform some added bounds checking and
+will allow you to use the random print relocation feature without requiring
+`exclude_object` entries in the print file.
+
+```
+PRINT_START_SET MODEL_MIN={bounding_box[0]},{bounding_box[1]} MODEL_MAX={bounding_box[3]},{bounding_box[4]}
+```
+
 #### End G-code
 
 ```
@@ -922,22 +933,37 @@ These are the customization options you can add to your
   adjustments after the print completes or is cancelled (e.g. feedrate,
   flow percentage).
 
-* `variable_start_purge_clearance` *(default: 5.0)* Distance (in millimeters)
+* `variable_start_purge_clearance` *(default: 5.0)* - Distance (in millimeters)
   between the purge lines and the print area (if a `start_purge_length` is
   provided).
 
 * `variable_start_purge_length` *(default: 0.0)* - Length of filament (in
   millimeters) to purge after the extruder finishes heating and prior to
   starting the print. For most setups `30` is a good starting point.
 
-* `variable_start_purge_prime_length` *(default: 10.0)* Length of filament (in
+* `variable_start_purge_prime_length` *(default: 10.0)* - Length of filament (in
   millimeters) to prime the extruder before drawing the purge lines.
 
 * `variable_start_quad_gantry_level_at_temp` *(default: True if
   `quad_gantry_level` configured)* - If true the `PRINT_START` macro will run
   `QUAD_GANTRY_LEVEL` after the bed has stabilized at its target temperature.
 
-* `variable_start_try_saved_surface_mesh` *(default: False)* If enabled and
+* `variable_start_random_placement_max` *(default: 0)* - A positive value
+  specifies the +/- distance in the XY axes that the print can be randomly
+  relocated (assuming the bed has sufficient space). This can help reduce bed
+  wear from repeatedly printing in the same spot. Note that this feature
+  requires additional information to determine the proper bounds of the
+  relocated print. As such, `START_PRINT` must have valid `MESH_MIN`/`MESH_MAX`
+  parameters, and either `MODEL_MIN`/`MODEL_MAX` must be set or the print file
+  must include `EXCLUDE_OBJECT_DEFINE` statements with `POLYGON` lists that
+  define the bounds of the objects ([see `exclude_object` for more information](
+  https://www.klipper3d.org/Exclude_Object.html)).
+
+* `variable_start_random_placement_padding` *(default: 10.0)* - The minimum
+  distance the relocated print will be placed from the printable edge of the
+  bed.
+
+* `variable_start_try_saved_surface_mesh` *(default: False)* - If enabled and
   `bed_mesh.profiles` contains a matching mesh for the currently select bed
   surface, then the mesh will be loaded from the saved profile (and
   [`BED_MESH_CALIBRATE_FAST`](#bed-mesh-improvements) will be skipped if

globals.cfg

@@ -79,6 +79,10 @@ variable_start_purge_length: 0.0 # 30 is a good starting point.
 variable_start_purge_prime_length: 12.0
 # Level gantry in PRINT_START after bed temp stabilizes; False to disable.
 variable_start_quad_gantry_level_at_temp: True
+# Maximum distance to relocate print in random XY location to reduce bed wear.
+variable_start_random_placement_max: 0
+# The relocation will be at least this far from the printable edge of the bed.
+variable_start_random_placement_padding: 10.0
 # Skip level and load saved mesh for current sheet (if found); False to disable.
 variable_start_try_saved_surface_mesh: False
 # Adjust Z tilt in PRINT_START after bed temp stabilizes; False to disable.

pause_resume_cancel.cfg

@@ -132,6 +132,7 @@ gcode:
     RESTORE_GCODE_STATE NAME=_KM_PAUSE_OVERRIDE_STATE MOVE=0
   {% endif %}
   CLEAR_PAUSE
+  _KM_APPLY_PRINT_OFFSET RESET=1
   {% if 'virtual_sdcard' in printer and not printer.virtual_sdcard.is_active %}
     SDCARD_RESET_FILE
   {% endif %}

start_end.cfg

@@ -29,6 +29,7 @@ description: Inserted by slicer at start of print. Initializes PRINT_START
 gcode:
   CHECK_KM_CONFIG # Need this in case startup errors were missed.
   SET_GCODE_VARIABLE MACRO=_print_end_inner VARIABLE=cancelled VALUE="{False}"
+  _KM_APPLY_PRINT_OFFSET RESET=1
   {% set settings = printer["gcode_macro print_start_set"].settings %}
   {% if 'PRINT_START_PHASE' in settings %}
     { action_raise_error("Error in PRINT_START_PHASE: init") }
@@ -134,12 +135,46 @@ description: Inserted by slicer at start of print. Performs probing (including
   Usage: See PRINT_START.
 gcode:
   {% set settings = printer["gcode_macro print_start_set"].settings %}
+  {% set km = printer["gcode_macro _km_globals"] %}
   {% if settings.PRINT_START_PHASE != "probing" %}
     { action_raise_error("Error in PRINT_START_PHASE: %s" %
                            (settings.PRINT_START_PHASE,)) }
   {% endif %}
+
   {% set MESH_MIN = settings.MESH_MIN|default(None) %}
   {% set MESH_MAX = settings.MESH_MAX|default(None) %}
+  # Randomize the placement of the print on the bed.
+  {% if km.start_random_placement_max > 0 and settings.PRINT_MIN and MESH_MIN %}
+    {% set PRINT_MIN = settings.PRINT_MIN.split(",")|map('float')|list %}
+    {% set PRINT_MAX = settings.PRINT_MAX.split(",")|map('float')|list %}
+    {% set x_offset = (((km.print_max[0] - km.print_min[0] - PRINT_MAX[0] +
+         PRINT_MIN[0] - 2 * km.start_random_placement_padding)|int,
+         km.start_random_placement_max * 2)|min, 0)|max %}
+    {% set y_offset = (((km.print_max[1] - km.print_min[1] - PRINT_MAX[1] +
+         PRINT_MIN[1] - 2 * km.start_random_placement_padding)|int,
+         km.start_random_placement_max * 2)|min, 0)|max %}
+    {% if x_offset > 0 %}
+      {% set x_offset = range(x_offset)|random + km.print_min[0] -
+                          PRINT_MIN[0] + km.start_random_placement_padding %}
+    {% endif %}
+    {% if y_offset > 0 %}
+      {% set y_offset = range(y_offset)|random + km.print_min[1] -
+                          PRINT_MIN[1] + km.start_random_placement_padding %}
+    {% endif %}
+    # This MESH_MIN/MESH_MAX gets passed to BED_MESH_CALIBRATE below, but the
+    # rest of the macros rely on SET_GCODE_OFFSET performing the adjustment.
+    {% set MESH_MIN = MESH_MIN.split(",")|map('float')|list %}
+    {% set MESH_MAX = MESH_MAX.split(",")|map('float')|list %}
+    {% set MESH_MIN_NEW = (MESH_MIN[0] + x_offset, MESH_MIN[1] + y_offset) %}
+    {% set MESH_MAX_NEW = (MESH_MAX[0] + x_offset, MESH_MAX[1] + y_offset) %}
+    {action_respond_info(
+       "Relocating print origin from (%.3f,%.3f) "|format(*MESH_MIN) +
+       "to (%.3f,%.3f)"|format(*MESH_MIN_NEW))}
+    {% set MESH_MIN = (MESH_MIN_NEW[0], MESH_MIN_NEW[1])|join(',') %}
+    {% set MESH_MAX = (MESH_MAX_NEW[0], MESH_MAX_NEW[1])|join(',') %}
+    PRINT_START_SET PRINT_OFFSET={"%d,%d" % (x_offset,y_offset)}
+  {% endif %}
+
   {% set EXTRUDER = settings.EXTRUDER|int %}
   {% set km = printer["gcode_macro _km_globals"] %}
   {% set start_level_bed_at_temp = km.start_level_bed_at_temp and
@@ -188,6 +223,8 @@ gcode:
   # Wait for extruder to reach temperature
   _KM_PARK_IF_NEEDED HEATER={printer.toolhead.extruder} RANGE=ABOVE
   M109 S{EXTRUDER}
+  # Apply the offset for bed placement randomization.
+  _KM_APPLY_PRINT_OFFSET
   # apply Z offset for bed surface (just in case it was reset).
   _APPLY_BED_SURFACE_OFFSET
   PRINT_START_SET PRINT_START_PHASE="purge"
@@ -239,6 +276,24 @@ gcode:
     {% endif %}
   {% endif %}
 
+[gcode_macro _km_apply_print_offset]
+variable_offset: []
+gcode:
+  {% set settings = printer["gcode_macro print_start_set"].settings %}
+  {% if params.RESET|default(0)|int and offset and
+        not printer["gcode_macro _km_save_state"].is_ephemeral%}
+    {% set PRINT_OFFSET = [offset.pop(0) * -1, offset.pop() * -1] %}
+  {% elif settings.PRINT_OFFSET and not offset and
+          not printer["gcode_macro _km_save_state"].is_ephemeral %}
+    {% set PRINT_OFFSET = settings.PRINT_OFFSET.split(",")|map('float')|list %}
+    {% set dummy = offset.extend(PRINT_OFFSET) %}
+  {% endif %}
+
+  {% if PRINT_OFFSET %}
+    _KM_SET_GCODE_OFFSET_BASE {"X_ADJUST=%.2f Y_ADJUST=%.2f"|
+                                  format(*PRINT_OFFSET)}
+  {% endif %}
+
 [gcode_macro _km_mesh_if_needed]
 gcode:
   # TODO: Instead of blindly using the loaded mesh we could probe a few key
@@ -274,7 +329,6 @@ gcode:
     M220 S100
     M221 S100
   {% endif %}
-  _KM_APPLY_PRINT_OFFSET INVERT=1
   _RESET_LAYER_GCODE
   _RESET_VELOCITY_LIMITS
   TURN_OFF_HEATERS
@@ -308,6 +362,8 @@ gcode:
       G91
       G0 Z{z_safe} E-1.0 F{km.travel_speed_z * 2} ; move nozzle up
       G0 X{x_safe} Y{y_safe} E-1.0 F{km.travel_speed_xy} ; remove stringing
+      # Remove the offset now that we're done.
+      _KM_APPLY_PRINT_OFFSET RESET=1
     {% endif %}
 
     # Small retract to prevent ooze

state.cfg

@@ -32,3 +32,11 @@ gcode:
   _KM_RESTORE_GCODE_STATE {rawparams}
   {% set NAME = params.NAME|default("default") %}
   _km_save_state NAME={NAME} SAVE=0
+
+[gcode_macro _abort_on_gcode_state]
+gcode:
+  {% set save_state = printer["gcode_macro _km_save_state"] %}
+  {% if save_state.is_ephemeral %}
+    {action_raise_error("Encountered unexpected save state " +
+                          save_state.state_set|list|sort|string)}
+  {% endif %}