This commit frees list ui items from their dependencies to Panel, and hence from all the limitations this implied (mostly, the "only one list per panel" one).

It introduces a new (py-extendable and registrable) RNA type, UIList (roughly similar to Panel one), which currently contains only "standard" list's scroll pos and size (but may be expended to include e.g. some filtering data, etc.). This now makes lists completely independent from Panels!

This UIList has a draw_item callback which allows to customize items' drawing from python, that all addons can now use. Incidentally, this also greatly simplifies the C code of this widget, as we do not code any "special case" here anymore!

To make all this work, other changes were also necessary:

* Now all buttons (uiBut struct) have a 'custom_data' void pointer, used currently to store the uiList struct associated with a given uiLayoutListBox.

* DynamicPaintSurface now exposes a new bool, use_color_preview (readonly), saying whether that surface has some 3D view preview data or not.

* UILayout class has now four new (static) functions, to get the actual icon of any RNA object (important e.g. with materials or textures), and to get an enum item's UI name, description and icon.

* UILayout's label() func now takes an optional 'icon_value' integer parameter, which if not zero will override the 'icon' one (mandatory to use "custom" icons as generated for material/texture/... previews).
  Note: not sure whether we should add that one to all UILayout's prop funcs?

Note: will update addons using template list asap.

1 files changed, 164 insertions, 0 deletions

diff --git a/source/blender/makesrna/intern/rna_ui.c b/source/blender/makesrna/intern/rna_ui.c
index de359fd6413..e6e953c412b 100644
--- a/source/blender/makesrna/intern/rna_ui.c
+++ b/source/blender/makesrna/intern/rna_ui.c
@@ -55,6 +55,16 @@ EnumPropertyItem operator_context_items[] = {
 	{0, NULL, 0, NULL, NULL}
 };
 
+EnumPropertyItem uilist_layout_type_items[] = {
+	{UILST_LAYOUT_DEFAULT, "DEFAULT", 0, "Default Layout",
+	                       "Use the default, multi-rows layout"},
+	{UILST_LAYOUT_COMPACT, "COMPACT", 0, "Compact Layout",
+	                       "Use the compact, single-row layout"},
+	{UILST_LAYOUT_GRID, "GRID", 0, "Grid Layout",
+	                    "Use the grid-based layout"},
+	{0, NULL, 0, NULL, NULL}
+};
+
 #ifdef RNA_RUNTIME
 
 #include <assert.h>
@@ -252,6 +262,105 @@ static StructRNA *rna_Panel_refine(PointerRNA *ptr)
 	return (hdr->type && hdr->type->ext.srna) ? hdr->type->ext.srna : &RNA_Panel;
 }
 
+/* UIList */
+static void uilist_draw_item(uiList *uilst, bContext *C, uiLayout *layout, PointerRNA *dataptr, PointerRNA *itemptr,
+                             int icon, PointerRNA *active_dataptr, const char *active_propname, int index)
+{
+	extern FunctionRNA rna_UIList_draw_item_func;
+
+	PointerRNA ultr;
+	ParameterList list;
+	FunctionRNA *func;
+
+	RNA_pointer_create(&CTX_wm_screen(C)->id, uilst->type->ext.srna, uilst, &ultr);
+	func = &rna_UIList_draw_item_func; /* RNA_struct_find_function(&ultr, "draw_item"); */
+
+	RNA_parameter_list_create(&list, &ultr, func);
+	RNA_parameter_set_lookup(&list, "context", &C);
+	RNA_parameter_set_lookup(&list, "layout", &layout);
+	RNA_parameter_set_lookup(&list, "data", dataptr);
+	RNA_parameter_set_lookup(&list, "item", itemptr);
+	RNA_parameter_set_lookup(&list, "icon", &icon);
+	RNA_parameter_set_lookup(&list, "active_data", active_dataptr);
+	RNA_parameter_set_lookup(&list, "active_property", &active_propname);
+	RNA_parameter_set_lookup(&list, "index", &index);
+	uilst->type->ext.call((bContext *)C, &ultr, func, &list);
+
+	RNA_parameter_list_free(&list);
+}
+
+static void rna_UIList_unregister(Main *UNUSED(bmain), StructRNA *type)
+{
+	uiListType *ult = RNA_struct_blender_type_get(type);
+
+	if (!ult)
+		return;
+
+	RNA_struct_free_extension(type, &ult->ext);
+
+	WM_uilisttype_freelink(ult);
+
+	RNA_struct_free(&BLENDER_RNA, type);
+
+	/* update while blender is running */
+	WM_main_add_notifier(NC_SCREEN | NA_EDITED, NULL);
+}
+
+static StructRNA *rna_UIList_register(Main *bmain, ReportList *reports, void *data, const char *identifier,
+                                      StructValidateFunc validate, StructCallbackFunc call, StructFreeFunc free)
+{
+	uiListType *ult, dummyult = {NULL};
+	uiList dummyuilist = {NULL};
+	PointerRNA dummyultr;
+	int have_function[1];
+	size_t over_alloc = 0; /* warning, if this becomes a bess, we better do another alloc */
+
+	/* setup dummy menu & menu type to store static properties in */
+	dummyuilist.type = &dummyult;
+	RNA_pointer_create(NULL, &RNA_UIList, &dummyuilist, &dummyultr);
+
+	/* validate the python class */
+	if (validate(&dummyultr, data, have_function) != 0)
+		return NULL;
+
+	if (strlen(identifier) >= sizeof(dummyult.idname)) {
+		BKE_reportf(reports, RPT_ERROR, "Registering uilist class: '%s' is too long, maximum length is %d",
+		            identifier, (int)sizeof(dummyult.idname));
+		return NULL;
+	}
+
+	/* check if we have registered this uilist type before, and remove it */
+	ult = WM_uilisttype_find(dummyult.idname, TRUE);
+	if (ult && ult->ext.srna)
+		rna_UIList_unregister(bmain, ult->ext.srna);
+
+	/* create a new menu type */
+	ult = MEM_callocN(sizeof(uiListType) + over_alloc, "python uilist");
+	memcpy(ult, &dummyult, sizeof(dummyult));
+
+	ult->ext.srna = RNA_def_struct(&BLENDER_RNA, ult->idname, "UIList");
+	ult->ext.data = data;
+	ult->ext.call = call;
+	ult->ext.free = free;
+	RNA_struct_blender_type_set(ult->ext.srna, ult);
+	RNA_def_struct_flag(ult->ext.srna, STRUCT_NO_IDPROPERTIES);
+
+	ult->draw_item = (have_function[0]) ? uilist_draw_item : NULL;
+
+	WM_uilisttype_add(ult);
+
+	/* update while blender is running */
+	WM_main_add_notifier(NC_SCREEN | NA_EDITED, NULL);
+
+	return ult->ext.srna;
+}
+
+static StructRNA *rna_UIList_refine(PointerRNA *ptr)
+{
+	uiList *uilst = (uiList *)ptr->data;
+	return (uilst->type && uilst->type->ext.srna) ? uilst->type->ext.srna : &RNA_UIList;
+}
+
 /* Header */
 
 static void header_draw(const bContext *C, Header *hdr)
@@ -495,6 +604,8 @@ static void rna_Menu_bl_description_set(PointerRNA *ptr, const char *value)
 	else assert(!"setting the bl_description on a non-builtin menu");
 }
 
+/* UILayout */
+
 static int rna_UILayout_active_get(PointerRNA *ptr)
 {
 	return uiLayoutGetActive(ptr->data);
@@ -738,6 +849,58 @@ static void rna_def_panel(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "Options",  "Options for this panel type");
 }
 
+static void rna_def_uilist(BlenderRNA *brna)
+{
+	StructRNA *srna;
+	PropertyRNA *prop;
+	PropertyRNA *parm;
+	FunctionRNA *func;
+
+	srna = RNA_def_struct(brna, "UIList", NULL);
+	RNA_def_struct_ui_text(srna, "UIList", "UI list containing the elements of a collection");
+	RNA_def_struct_sdna(srna, "uiList");
+	RNA_def_struct_refine_func(srna, "rna_UIList_refine");
+	RNA_def_struct_register_funcs(srna, "rna_UIList_register", "rna_UIList_unregister", NULL);
+
+	/* draw */
+	func = RNA_def_function(srna, "draw_item", NULL);
+	RNA_def_function_ui_description(func, "Draw an item in the list (NOTE: when you define your own draw_item "
+	                                      "function, you may want to check given 'item' is of the right type...)");
+	RNA_def_function_flag(func, FUNC_REGISTER);
+	parm = RNA_def_pointer(func, "context", "Context", "", "");
+	RNA_def_property_flag(parm, PROP_REQUIRED);
+	parm = RNA_def_pointer(func, "layout", "UILayout", "", "Layout to draw the item");
+	RNA_def_property_flag(parm, PROP_REQUIRED | PROP_NEVER_NULL);
+	parm = RNA_def_pointer(func, "data", "AnyType", "", "Data from which to take Collection property");
+	RNA_def_property_flag(parm, PROP_REQUIRED | PROP_RNAPTR);
+	parm = RNA_def_pointer(func, "item", "AnyType", "", "Item of the collection property");
+	RNA_def_property_flag(parm, PROP_REQUIRED | PROP_RNAPTR);
+	parm = RNA_def_int(func, "icon", 0, 0, INT_MAX, "", "Icon of the item in the collection", 0, INT_MAX);
+	RNA_def_property_flag(parm, PROP_REQUIRED);
+	parm = RNA_def_pointer(func, "active_data", "AnyType", "",
+	                       "Data from which to take property for the active element");
+	RNA_def_property_flag(parm, PROP_REQUIRED | PROP_RNAPTR | PROP_NEVER_NULL);
+	parm = RNA_def_string(func, "active_property", "", 0, "",
+	                      "Identifier of property in active_data, for the active element");
+	RNA_def_property_flag(parm, PROP_REQUIRED);
+	RNA_def_int(func, "index", 0, 0, INT_MAX, "", "Index of the item in the collection", 0, INT_MAX);
+	RNA_def_property_flag(parm, PROP_REQUIRED);
+
+	prop = RNA_def_property(srna, "layout_type", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_items(prop, uilist_layout_type_items);
+	RNA_def_property_clear_flag(prop, PROP_EDITABLE);
+
+	/* registration */
+	prop = RNA_def_property(srna, "bl_idname", PROP_STRING, PROP_NONE);
+	RNA_def_property_string_sdna(prop, NULL, "type->idname");
+	RNA_def_property_flag(prop, PROP_REGISTER | PROP_NEVER_CLAMP);
+	RNA_def_property_ui_text(prop, "ID Name",
+	                         "If this is set, the uilist gets a custom ID, otherwise it takes the "
+	                         "name of the class used to define the uilist (for example, if the "
+	                         "class name is \"OBJECT_UL_vgroups\", and bl_idname is not set by the "
+	                         "script, then bl_idname = \"OBJECT_UL_vgroups\")");
+}
+
 static void rna_def_header(BlenderRNA *brna)
 {
 	StructRNA *srna;
@@ -852,6 +1015,7 @@ void RNA_def_ui(BlenderRNA *brna)
 {
 	rna_def_ui_layout(brna);
 	rna_def_panel(brna);
+	rna_def_uilist(brna);
 	rna_def_header(brna);
 	rna_def_menu(brna);
 }