Gizmo: changes to internal drag logic

Minor changes to recent gizmo click/drag logic 08dff7b40bc6a

Changing the gizmos highlighted part in the invoke_prepare
callback is too error prone since it needs to run
before it's known which operator will execute.

Add back 'drag_part', since it simplifies click-drag use.
While this isn't essential with custom keymaps per gizmo
it avoids having to define a keymap in the case a drag
event needs a different action.

1 files changed, 6 insertions, 0 deletions

diff --git a/source/blender/windowmanager/gizmo/WM_gizmo_types.h b/source/blender/windowmanager/gizmo/WM_gizmo_types.h
index 5398c262c72..cd8bcc6696b 100644
--- a/source/blender/windowmanager/gizmo/WM_gizmo_types.h
+++ b/source/blender/windowmanager/gizmo/WM_gizmo_types.h
@@ -199,6 +199,12 @@ struct wmGizmo {
    * -1 when unset, otherwise a valid index. (Used as index to 'op_data'). */
   int highlight_part;
 
+  /**
+   * For gizmos that differentiate between click & drag,
+   * use a different part for any drag events, -1 when unused.
+   */
+  int drag_part;
+
   /** Distance to bias this gizmo above others when picking
    * (in worldspace, scaled by the gizmo scale - when used). */
   float select_bias;