add popup menu to allow python scripts to show popups without having to define a menu class first.

doc/python_api/examples/bpy.types.WindowManager.popup_menu.py

@@ -0,0 +1,14 @@
+"""
+Popup Menus
++++++++++++
+Popup menus can be useful for creating menus without having to register menu classes.
+
+Note that they will not block the scripts execution, so the caller can't wait for user input.
+"""
+
+import bpy
+
+def draw(self, context):
+    self.layout.label("Hello World")
+
+bpy.context.window_manager.popup_menu(draw, title="Greeting", icon='INFO')

release/scripts/modules/bpy_types.py

@@ -128,6 +128,19 @@ class Object(bpy_types.ID):
                      if self in scene.objects[:])
 
 
+class WindowManager(bpy_types.ID):
+    __slots__ = ()
+
+    def popup_menu(self, draw_func, title="", icon='NONE'):
+        import bpy
+        popup = self.pupmenu_begin__internal(title, icon)
+
+        try:
+            draw_func(popup, bpy.context)
+        finally:
+            self.pupmenu_end__internal(popup)
+
+
 class _GenericBone:
     """
     functions for bones, common between Armature/Pose/Edit bones.

source/blender/editors/interface/interface_regions.c

@@ -2368,7 +2368,6 @@ struct uiPopupMenu {
 
 	int mx, my;
 	bool popup, slideout;
-	int startx, starty, maxrow;
 
 	uiMenuCreateFunc menu_func;
 	void *menu_arg;

source/blender/makesrna/RNA_access.h

@@ -626,6 +626,7 @@ extern StructRNA RNA_TransformConstraint;
 extern StructRNA RNA_TransformSequence;
 extern StructRNA RNA_UILayout;
 extern StructRNA RNA_UIList;
+extern StructRNA RNA_UIPopupMenu;
 extern StructRNA RNA_UVWarpModifier;
 extern StructRNA RNA_UVProjectModifier;
 extern StructRNA RNA_UVProjector;

source/blender/makesrna/intern/rna_define.c

@@ -3015,6 +3015,7 @@ void RNA_def_function_return(FunctionRNA *func, PropertyRNA *ret)
 		return;
 	}
 
+	BLI_assert(func->c_ret == NULL);
 	func->c_ret = ret;
 
 	RNA_def_function_output(func, ret);

source/blender/makesrna/intern/rna_wm.c

@@ -450,6 +450,8 @@ EnumPropertyItem wm_report_items[] = {
 
 #include "WM_api.h"
 
+#include "UI_interface.h"
+
 #include "BKE_idprop.h"
 
 #include "MEM_guardedalloc.h"
@@ -561,6 +563,17 @@ static int rna_Event_unicode_length(PointerRNA *ptr)
 	}
 }
 
+static PointerRNA rna_PopupMenu_layout_get(PointerRNA *ptr)
+{
+	struct uiPopupMenu *pup = ptr->data;
+	uiLayout *layout = uiPupMenuLayout(pup);
+
+	PointerRNA rptr;
+	RNA_pointer_create(ptr->id.data, &RNA_UILayout, layout, &rptr);
+
+	return rptr;
+}
+
 static void rna_Window_screen_set(PointerRNA *ptr, PointerRNA value)
 {
 	wmWindow *win = (wmWindow *)ptr->data;
@@ -1659,6 +1672,26 @@ static void rna_def_timer(BlenderRNA *brna)
 	RNA_define_verify_sdna(1); /* not in sdna */
 }
 
+static void rna_def_popupmenu(BlenderRNA *brna)
+{
+	StructRNA *srna;
+	PropertyRNA *prop;
+
+	srna = RNA_def_struct(brna, "UIPopupMenu", NULL);
+	RNA_def_struct_ui_text(srna, "PopupMenu", "");
+	RNA_def_struct_sdna(srna, "uiPopupMenu");
+
+	RNA_define_verify_sdna(0); /* not in sdna */
+
+	/* could wrap more, for now this is enough */
+	prop = RNA_def_property(srna, "layout", PROP_POINTER, PROP_NONE);
+	RNA_def_property_struct_type(prop, "UILayout");
+	RNA_def_property_pointer_funcs(prop, "rna_PopupMenu_layout_get",
+	                               NULL, NULL, NULL);
+
+	RNA_define_verify_sdna(1); /* not in sdna */
+}
+
 static void rna_def_window(BlenderRNA *brna)
 {
 	StructRNA *srna;
@@ -2018,6 +2051,7 @@ void RNA_def_wm(BlenderRNA *brna)
 	rna_def_operator_type_macro(brna);
 	rna_def_event(brna);
 	rna_def_timer(brna);
+	rna_def_popupmenu(brna);
 	rna_def_window(brna);
 	rna_def_windowmanager(brna);
 	rna_def_keyconfig(brna);

source/blender/makesrna/intern/rna_wm_api.c

@@ -45,6 +45,7 @@
 
 #ifdef RNA_RUNTIME
 
+#include "UI_interface.h"
 #include "BKE_context.h"
 
 static wmKeyMap *rna_keymap_active(wmKeyMap *km, bContext *C)
@@ -250,6 +251,24 @@ static void rna_KeyConfig_remove(wmWindowManager *wm, ReportList *reports, Point
 	RNA_POINTER_INVALIDATE(keyconf_ptr);
 }
 
+/* popup menu wrapper */
+static PointerRNA rna_PupMenuBegin(bContext *C, const char *title, int icon)
+{
+	PointerRNA r_ptr;
+	void *data;
+
+	data = (void *)uiPupMenuBegin(C, title, icon);
+
+	RNA_pointer_create(NULL, &RNA_UIPopupMenu, data, &r_ptr);
+
+	return r_ptr;
+}
+
+static void rna_PupMenuEnd(bContext *C, PointerRNA *handle)
+{
+	uiPupMenuEnd(C, handle->data);
+}
+
 #else
 
 #define WM_GEN_INVOKE_EVENT (1 << 0)
@@ -348,7 +367,25 @@ void RNA_api_wm(StructRNA *srna)
 	func = RNA_def_function(srna, "invoke_confirm", "rna_Operator_confirm");
 	RNA_def_function_ui_description(func, "Operator confirmation");
 	rna_generic_op_invoke(func, WM_GEN_INVOKE_EVENT | WM_GEN_INVOKE_RETURN);
-	
+
+
+	/* wrap uiPupMenuBegin */
+	func = RNA_def_function(srna, "pupmenu_begin__internal", "rna_PupMenuBegin");
+	RNA_def_function_flag(func, FUNC_NO_SELF | FUNC_USE_CONTEXT);
+	parm = RNA_def_string(func, "title", "", 0, "", "");
+	RNA_def_property_flag(parm, PROP_REQUIRED);
+	parm = RNA_def_property(func, "icon", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_items(parm, icon_items);
+	/* return */
+	parm = RNA_def_pointer(func, "menu", "UIPopupMenu", "", "");
+	RNA_def_property_flag(parm, PROP_RNAPTR | PROP_NEVER_NULL);
+	RNA_def_function_return(func, parm);
+
+	/* wrap uiPupMenuEnd */
+	func = RNA_def_function(srna, "pupmenu_end__internal", "rna_PupMenuEnd");
+	RNA_def_function_flag(func, FUNC_NO_SELF | FUNC_USE_CONTEXT);
+	parm = RNA_def_pointer(func, "menu", "UIPopupMenu", "", "");
+	RNA_def_property_flag(parm, PROP_RNAPTR | PROP_NEVER_NULL);
 }
 
 void RNA_api_operator(StructRNA *srna)