Rigify: add utility and operator classes for the upcoming face rigs.

- LazyRef utility class that provides a hashable field reference.
- NodeMerger plugin for grouping abstract points by distance.
- pose.rigify_copy_single_parameter operator for copying a single
  property to all selected rigs that inherit from a specific class
  (intended to be used via property panel buttons).

2 files changed, 176 insertions, 0 deletions

diff --git a/rigify/operators/__init__.py b/rigify/operators/__init__.py
new file mode 100644
index 00000000..4263c8dd
--- /dev/null
+++ b/rigify/operators/__init__.py
@@ -0,0 +1,47 @@
+# ====================== BEGIN GPL LICENSE BLOCK ======================
+#
+#  This program is free software; you can redistribute it and/or
+#  modify it under the terms of the GNU General Public License
+#  as published by the Free Software Foundation; either version 2
+#  of the License, or (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with this program; if not, write to the Free Software Foundation,
+#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+# ======================= END GPL LICENSE BLOCK ========================
+
+# <pep8 compliant>
+
+import importlib
+
+
+# Submodules to load during register
+submodules = (
+    'copy_mirror_parameters',
+)
+
+loaded_submodules = []
+
+
+def register():
+    # Lazily load modules to make reloading easier. Loading this way
+    # hides the sub-modules and their dependencies from initial_load_order.
+    loaded_submodules[:] = [
+        importlib.import_module(__name__ + '.' + name) for name in submodules
+    ]
+
+    for mod in loaded_submodules:
+        mod.register()
+
+
+def unregister():
+    for mod in reversed(loaded_submodules):
+        mod.unregister()
+
+    loaded_submodules.clear()
diff --git a/rigify/operators/copy_mirror_parameters.py b/rigify/operators/copy_mirror_parameters.py
new file mode 100644
index 00000000..95818ba8
--- /dev/null
+++ b/rigify/operators/copy_mirror_parameters.py
@@ -0,0 +1,129 @@
+# ====================== BEGIN GPL LICENSE BLOCK ======================
+#
+#  This program is free software; you can redistribute it and/or
+#  modify it under the terms of the GNU General Public License
+#  as published by the Free Software Foundation; either version 2
+#  of the License, or (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with this program; if not, write to the Free Software Foundation,
+#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+# ======================= END GPL LICENSE BLOCK ========================
+
+# <pep8 compliant>
+
+import bpy
+import importlib
+
+from ..utils.naming import Side, get_name_base_and_sides, mirror_name
+
+from ..utils.rig import get_rigify_type
+from ..rig_lists import get_rig_class
+
+
+# =============================================
+# Single parameter copy button
+
+class POSE_OT_rigify_copy_single_parameter(bpy.types.Operator):
+    bl_idname = "pose.rigify_copy_single_parameter"
+    bl_label = "Copy Option To Selected Rigs"
+    bl_description = "Copy this property value to all selected rigs of the appropriate type"
+    bl_options = {'UNDO', 'INTERNAL'}
+
+    property_name: bpy.props.StringProperty(name='Property Name')
+    mirror_bone: bpy.props.BoolProperty(name='Mirror As Bone Name')
+
+    module_name: bpy.props.StringProperty(name='Module Name')
+    class_name: bpy.props.StringProperty(name='Class Name')
+
+    @classmethod
+    def poll(cls, context):
+        return (
+            context.active_object and context.active_object.type == 'ARMATURE'
+            and context.active_pose_bone
+            and context.active_object.data.get('rig_id') is None
+            and get_rigify_type(context.active_pose_bone)
+        )
+
+    def invoke(self, context, event):
+        return context.window_manager.invoke_confirm(self, event)
+
+    def execute(self, context):
+        try:
+            module = importlib.import_module(self.module_name)
+            filter_rig_class = getattr(module, self.class_name)
+        except (KeyError, AttributeError, ImportError):
+            self.report(
+                {'ERROR'}, f"Cannot find class {self.class_name} in {self.module_name}")
+            return {'CANCELLED'}
+
+        active_pbone = context.active_pose_bone
+        active_split = get_name_base_and_sides(active_pbone.name)
+
+        value = getattr(active_pbone.rigify_parameters, self.property_name)
+        num_copied = 0
+
+        # Copy to different bones of appropriate rig types
+        for sel_pbone in context.selected_pose_bones:
+            rig_type = get_rigify_type(sel_pbone)
+
+            if rig_type and sel_pbone != active_pbone:
+                rig_class = get_rig_class(rig_type)
+
+                if rig_class and issubclass(rig_class, filter_rig_class):
+                    new_value = value
+
+                    # If mirror requested and copying to a different side bone, mirror the value
+                    if self.mirror_bone and active_split.side != Side.MIDDLE and value:
+                        sel_split = get_name_base_and_sides(sel_pbone.name)
+
+                        if sel_split.side == -active_split.side:
+                            new_value = mirror_name(value)
+
+                    # Assign the final value
+                    setattr(sel_pbone.rigify_parameters,
+                            self.property_name, new_value)
+                    num_copied += 1
+
+        if num_copied:
+            self.report({'INFO'}, f"Copied the value to {num_copied} bones.")
+            return {'FINISHED'}
+        else:
+            self.report({'WARNING'}, "No suitable selected bones to copy to.")
+            return {'CANCELLED'}
+
+
+def make_copy_parameter_button(layout, property_name, *, base_class, mirror_bone=False):
+    """Displays a button that copies the property to selected rig of the specified base type."""
+    props = layout.operator(
+        POSE_OT_rigify_copy_single_parameter.bl_idname, icon='DUPLICATE', text='')
+    props.property_name = property_name
+    props.mirror_bone = mirror_bone
+    props.module_name = base_class.__module__
+    props.class_name = base_class.__name__
+
+
+# =============================================
+# Registration
+
+classes = (
+    POSE_OT_rigify_copy_single_parameter,
+)
+
+
+def register():
+    from bpy.utils import register_class
+    for cls in classes:
+        register_class(cls)
+
+
+def unregister():
+    from bpy.utils import unregister_class
+    for cls in classes:
+        unregister_class(cls)