1 files changed, 87 insertions, 0 deletions
diff --git a/rigify/utils/components.py b/rigify/utils/components.py
new file mode 100644
index 00000000..5c1ebcb6
--- /dev/null
+++ b/rigify/utils/components.py
@@ -0,0 +1,87 @@
+import bpy
+
+from .naming import make_derived_name
+from .bones import put_bone, copy_bone_position, align_bone_orientation
+from .widgets_basic import create_pivot_widget
+from .misc import force_lazy
+
+from ..base_rig import RigComponent, stage
+
+
+class CustomPivotControl(RigComponent):
+    """
+    A utility that generates a pivot control with a custom position.
+
+    Generates a control bone, and a MCH output bone.
+    """
+
+    def __init__(
+        self, rig, id_name, org_bone, *,
+        name=None, parent=None, position=None, matrix=None,
+        scale=1.0, scale_mch=None,
+        move_to=None, align_to=None, snap_to=None,
+        widget_axis=1.5, widget_cap=1.0, widget_square=True,
+    ):
+        super().__init__(rig)
+
+        assert rig.generator.stage == 'generate_bones'
+
+        self.bones = rig.bones
+        self.id_name = id_name
+
+        self.parent = parent
+        self.scale = scale or 1
+        self.scale_mch = scale_mch or (self.scale * 0.7)
+        self.move_to = move_to
+        self.align_to = align_to
+        self.snap_to = snap_to
+        self.widget_axis = widget_axis
+        self.widget_cap = widget_cap
+        self.widget_square = widget_square
+
+        name = name or make_derived_name(org_bone, 'ctrl', '_pivot')
+
+        self.do_make_bones(org_bone, name, position, matrix)
+
+    @property
+    def control(self):
+        return self.ctrl
+
+    @property
+    def output(self):
+        return self.mch
+
+    def do_make_bones(self, org, name, position, matrix):
+        self.bones.ctrl[self.id_name] = self.ctrl = self.copy_bone(org, name, parent=not self.parent, scale=self.scale)
+        self.bones.mch[self.id_name] = self.mch = self.copy_bone(org, make_derived_name(name, 'mch'), scale=self.scale_mch)
+
+        if position or matrix:
+            put_bone(self.obj, self.ctrl, position, matrix=matrix)
+            put_bone(self.obj, self.mch, position, matrix=matrix)
+
+    def parent_bones(self):
+        if self.snap_to:
+            bone = force_lazy(self.snap_to)
+            copy_bone_position(self.obj, bone, self.ctrl, scale=self.scale)
+            copy_bone_position(self.obj, bone, self.mch, scale=self.scale_mch)
+
+        if self.move_to:
+            pos = self.get_bone(force_lazy(self.move_to)).head
+            put_bone(self.obj, self.ctrl, pos)
+            put_bone(self.obj, self.mch, pos)
+
+        if self.align_to:
+            self.align_to = force_lazy(self.align_to)
+            align_bone_orientation(self.obj, self.ctrl, self.align_to)
+            align_bone_orientation(self.obj, self.mch, self.align_to)
+
+        if self.parent:
+            self.set_bone_parent(self.ctrl, force_lazy(self.parent))
+
+        self.set_bone_parent(self.mch, self.ctrl)
+
+    def rig_bones(self):
+        self.make_constraint(self.mch, 'COPY_LOCATION', self.ctrl, space='LOCAL', invert_xyz=(True,)*3)
+
+    def generate_widgets(self):
+        create_pivot_widget(self.obj, self.ctrl, axis_size=self.widget_axis, cap_size=self.widget_cap, square=self.widget_square)