Curves: Move type conversion to the geometry module

This helps to separate concerns, and makes the functionality
available for edit mode.

1 files changed, 40 insertions, 0 deletions

diff --git a/source/blender/geometry/GEO_set_curve_type.hh b/source/blender/geometry/GEO_set_curve_type.hh
new file mode 100644
index 00000000000..f7ac8be5889
--- /dev/null
+++ b/source/blender/geometry/GEO_set_curve_type.hh
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#pragma once
+
+#include "DNA_curves_types.h"
+
+#include "BLI_function_ref.hh"
+#include "BLI_index_mask.hh"
+
+struct Curves;
+struct CurveComponent;
+
+namespace blender::bke {
+class CurvesGeometry;
+}
+
+namespace blender::geometry {
+
+/**
+ * Try the conversion to the #dst_type-- avoiding the majority of the work done in
+ * #convert_curves by modifying an existing object in place rather than creating a new one.
+ *
+ * \note This function is necessary because attributes do not have proper support for CoW.
+ *
+ * \param get_writable_curves_fn: Should return the write-able curves to change directly if
+ * possible. This is a function in order to avoid the cost of retrieval when unnecessary.
+ */
+bool try_curves_conversion_in_place(IndexMask selection,
+                                    CurveType dst_type,
+                                    FunctionRef<Curves &()> get_writable_curves_fn);
+
+/**
+ * Change the types of the selected curves, potentially changing the total point count.
+ */
+Curves *convert_curves(const CurveComponent &src_component,
+                       const bke::CurvesGeometry &src_curves,
+                       IndexMask selection,
+                       CurveType dst_type);
+
+}  // namespace blender::geometry