GPv3: "Set Active Layer" operator and menu

Resolves #113915 .

Ports the `layer_active` operator to set the active layer from an index.
Adds the menu to set the active layer from a list.

Pull Request: https://projects.blender.org/blender/blender/pulls/115606

scripts/presets/keyconfig/keymap_data/blender_default.py

@@ -4575,6 +4575,9 @@ def km_grease_pencil_paint(_params):
          {"properties": [("mode", 'INVERT')]}),
         ("grease_pencil.brush_stroke", {"type": 'LEFTMOUSE', "value": 'PRESS', "shift": True},
          {"properties": [("mode", 'SMOOTH')]}),
+
+        # Active layer
+        op_menu("GREASE_PENCIL_MT_layer_active", {"type": 'Y', "value": 'PRESS'}),
     ])
 
     return keymap
@@ -4623,6 +4626,9 @@ def km_grease_pencil_edit(params):
         ("grease_pencil.cyclical_set", {"type": 'C', "value": 'PRESS',
          "alt": True}, {"properties": [("type", "TOGGLE")]}),
 
+        # Active layer
+        op_menu("GREASE_PENCIL_MT_layer_active", {"type": 'Y', "value": 'PRESS'}),
+
         # Context menu
         *_template_items_context_menu("VIEW3D_MT_greasepencil_edit_context_menu", params.context_menu_event),
     ])

scripts/startup/bl_ui/properties_grease_pencil_common.py

@@ -273,6 +273,28 @@ class GPENCIL_MT_layer_active(Menu):
                 layout.operator("gpencil.layer_active", text=gpl.info, icon=icon).layer = i
                 i -= 1
 
+class GREASE_PENCIL_MT_layer_active(Menu):
+    bl_label = "Change Active Layer"
+
+    def draw(self, context):
+        layout = self.layout
+        layout.operator_context = 'INVOKE_REGION_WIN'
+        obd = context.active_object.data
+        if not obd.layers:
+            return
+
+        nlop = layout.operator("grease_pencil.layer_add", text="New Layer", icon='ADD')
+        nlop.new_layer_name = "Layer"
+
+        layout.separator()
+
+        for i in range(len(obd.layers) - 1,  -1,  -1):
+            layer = obd.layers[i]
+            if layer == obd.layers.active:
+                icon = 'GREASEPENCIL'
+            else:
+                icon = 'NONE'
+            layout.operator("grease_pencil.layer_active", text=layer.name, icon=icon).layer = i
 
 class GPENCIL_MT_material_active(Menu):
     bl_label = "Change Active Material"
@@ -917,6 +939,8 @@ classes = (
     GPENCIL_UL_layer,
     GPENCIL_UL_masks,
 
+    GREASE_PENCIL_MT_layer_active,
+
     GreasePencilFlipTintColors,
 )
 

scripts/startup/bl_ui/space_view3d.py

@@ -2166,7 +2166,9 @@ class VIEW3D_MT_paint_grease_pencil(Menu):
     bl_label = "Paint"
 
     def draw(self, _context):
-        pass
+        layout = self.layout
+
+        layout.menu("GREASE_PENCIL_MT_layer_active", text="Active Layer")
 
 
 class VIEW3D_MT_paint_gpencil(Menu):
@@ -5811,6 +5813,10 @@ class VIEW3D_MT_edit_greasepencil(Menu):
 
         layout.separator()
 
+        layout.menu("GREASE_PENCIL_MT_layer_active", text="Active Layer")
+
+        layout.separator()
+
         layout.menu("VIEW3D_MT_edit_greasepencil_delete")
 
 

source/blender/editors/grease_pencil/intern/grease_pencil_layers.cc

@@ -197,6 +197,43 @@ static void GREASE_PENCIL_OT_layer_reorder(wmOperatorType *ot)
       ot->srna, "location", prop_layer_reorder_location, LAYER_REORDER_ABOVE, "Location", "");
 }
 
+static int grease_pencil_layer_active_exec(bContext *C, wmOperator *op)
+{
+  using namespace blender::bke::greasepencil;
+  Object *object = CTX_data_active_object(C);
+  GreasePencil &grease_pencil = *static_cast<GreasePencil *>(object->data);
+  int layer_index = RNA_int_get(op->ptr, "layer");
+
+  const Layer &layer = *grease_pencil.layers()[layer_index];
+
+  if (grease_pencil.is_layer_active(&layer)) {
+    return OPERATOR_CANCELLED;
+  }
+  grease_pencil.set_active_layer(&layer);
+
+  WM_event_add_notifier(C, NC_GPENCIL | ND_DATA | NA_SELECTED, &grease_pencil);
+
+  return OPERATOR_FINISHED;
+}
+
+static void GREASE_PENCIL_OT_layer_active(wmOperatorType *ot)
+{
+  /* identifiers */
+  ot->name = "Set Active Layer";
+  ot->idname = "GREASE_PENCIL_OT_layer_active";
+  ot->description = "Set the active Grease Pencil layer";
+
+  /* callbacks */
+  ot->exec = grease_pencil_layer_active_exec;
+  ot->poll = active_grease_pencil_poll;
+
+  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+
+  PropertyRNA *prop = RNA_def_int(
+      ot->srna, "layer", 0, 0, INT_MAX, "Grease Pencil Layer", "", 0, INT_MAX);
+  RNA_def_property_flag(prop, PROP_HIDDEN | PROP_SKIP_SAVE);
+}
+
 static int grease_pencil_layer_group_add_exec(bContext *C, wmOperator *op)
 {
   using namespace blender::bke::greasepencil;
@@ -252,6 +289,7 @@ void ED_operatortypes_grease_pencil_layers()
   WM_operatortype_append(GREASE_PENCIL_OT_layer_add);
   WM_operatortype_append(GREASE_PENCIL_OT_layer_remove);
   WM_operatortype_append(GREASE_PENCIL_OT_layer_reorder);
+  WM_operatortype_append(GREASE_PENCIL_OT_layer_active);
 
   WM_operatortype_append(GREASE_PENCIL_OT_layer_group_add);
 }