Curves: new Grow/Shrink brush

This adds a new Grow/Shrink brush which is similar to the Length
brush in the old hair system.
* It's possible to switch between growing and shrinking by hold
  down ctrl and/or by changing the direction enum.
* 3d brush is supported.
* Different brush falloffs are supported.
* Supports scaling curves uniformly or shrinking/extrapolating
  them. Extrapolation is linear only in this patch.
* A minimum length settings helps to avoid creating zero-sized curves.

Differential Revision: https://developer.blender.org/D14474

1 files changed, 3 insertions, 0 deletions

diff --git a/source/blender/editors/sculpt_paint/curves_sculpt_intern.hh b/source/blender/editors/sculpt_paint/curves_sculpt_intern.hh
index d021627921f..03413221907 100644
--- a/source/blender/editors/sculpt_paint/curves_sculpt_intern.hh
+++ b/source/blender/editors/sculpt_paint/curves_sculpt_intern.hh
@@ -5,6 +5,7 @@
 #include <optional>
 
 #include "curves_sculpt_intern.h"
+#include "paint_intern.h"
 
 #include "BLI_math_vector.hh"
 
@@ -36,6 +37,8 @@ std::unique_ptr<CurvesSculptStrokeOperation> new_add_operation();
 std::unique_ptr<CurvesSculptStrokeOperation> new_comb_operation();
 std::unique_ptr<CurvesSculptStrokeOperation> new_delete_operation();
 std::unique_ptr<CurvesSculptStrokeOperation> new_snake_hook_operation();
+std::unique_ptr<CurvesSculptStrokeOperation> new_grow_shrink_operation(
+    const BrushStrokeMode brush_mode, bContext *C);
 
 struct CurvesBrush3D {
   float3 position_cu;