Select: support 'diselect on nothing' for masks.

Also moved that operator option from 3d-view op to generic
WM_operator_properties_mouse_select() helper, and renamed its label
(since 'Deselect' is already in use).

Part of T57918.

1 files changed, 10 insertions, 0 deletions

diff --git a/source/blender/editors/mask/mask_select.c b/source/blender/editors/mask/mask_select.c
index 00699c8ffe0..a592f39d24b 100644
--- a/source/blender/editors/mask/mask_select.c
+++ b/source/blender/editors/mask/mask_select.c
@@ -262,6 +262,7 @@ static int select_exec(bContext *C, wmOperator *op)
   bool extend = RNA_boolean_get(op->ptr, "extend");
   bool deselect = RNA_boolean_get(op->ptr, "deselect");
   bool toggle = RNA_boolean_get(op->ptr, "toggle");
+  const bool deselect_all = RNA_boolean_get(op->ptr, "deselect_all");
   eMaskWhichHandle which_handle;
   const float threshold = 19;
 
@@ -368,6 +369,15 @@ static int select_exec(bContext *C, wmOperator *op)
 
       return OPERATOR_FINISHED;
     }
+    else if (deselect_all) {
+      ED_mask_select_toggle_all(mask, SEL_DESELECT);
+
+      ED_mask_select_flush_all(mask);
+
+      WM_event_add_notifier(C, NC_MASK | ND_SELECT, mask);
+
+      return OPERATOR_FINISHED;
+    }
   }
 
   return OPERATOR_PASS_THROUGH;