1 files changed, 50 insertions, 0 deletions
diff --git a/source/blender/blenkernel/intern/spline_bezier.cc b/source/blender/blenkernel/intern/spline_bezier.cc
index b36d7a21669..f719a1cfda2 100644
--- a/source/blender/blenkernel/intern/spline_bezier.cc
+++ b/source/blender/blenkernel/intern/spline_bezier.cc
@@ -289,6 +289,56 @@ void BezierSpline::transform(const blender::float4x4 &matrix)
   this->mark_cache_invalid();
 }
 
+static void set_handle_position(const float3 &position,
+                                const BezierSpline::HandleType type,
+                                const BezierSpline::HandleType type_other,
+                                const float3 &new_value,
+                                float3 &handle,
+                                float3 &handle_other)
+{
+  /* Don't bother when the handle positions are calculated automatically anyway. */
+  if (ELEM(type, BezierSpline::HandleType::Auto, BezierSpline::HandleType::Vector)) {
+    return;
+  }
+
+  handle = new_value;
+  if (type_other == BezierSpline::HandleType::Align) {
+    /* Keep track of the old length of the opposite handle. */
+    const float length = float3::distance(handle_other, position);
+    /* Set the other handle to directly opposite from the current handle. */
+    const float3 dir = (handle - position).normalized();
+    handle_other = position - dir * length;
+  }
+}
+
+/**
+ * Set positions for the right handle of the control point, ensuring that
+ * aligned handles stay aligned. Has no effect for auto and vector type handles.
+ */
+void BezierSpline::set_handle_position_right(const int index, const blender::float3 &value)
+{
+  set_handle_position(positions_[index],
+                      handle_types_right_[index],
+                      handle_types_left_[index],
+                      value,
+                      handle_positions_right_[index],
+                      handle_positions_left_[index]);
+}
+
+/**
+ * Set positions for the left handle of the control point, ensuring that
+ * aligned handles stay aligned. Has no effect for auto and vector type handles.
+ */
+void BezierSpline::set_handle_position_left(const int index, const blender::float3 &value)
+{
+  set_handle_position(positions_[index],
+                      handle_types_left_[index],
+                      handle_types_right_[index],
+                      value,
+                      handle_positions_left_[index],
+                      handle_positions_right_[index]);
+}
+
 bool BezierSpline::point_is_sharp(const int index) const
 {
   return ELEM(handle_types_left_[index], HandleType::Vector, HandleType::Free) ||