Fix items in mode pie changing position by supporting more than 8 items in operator-enum pies

Now a 'More' item is added to the pie when there are too many items. It opens a sub-pie that contains the remaining items.
Note that this only touches operator-enum pies (like the object mode pie is), it is not a complete support for pies with more than 8 items. For this further design and code work would be needed, but this is too urgent to wait for that.

This is a better fix for T46973, should definitely be applied for 2.77 release.

Patch D1800 by myself with some edits by @campbellbarton, thanks!

4 files changed, 247 insertions, 83 deletions

diff --git a/source/blender/editors/include/UI_interface.h b/source/blender/editors/include/UI_interface.h
index 617b0d12684..574c6d93cbf 100644
--- a/source/blender/editors/include/UI_interface.h
+++ b/source/blender/editors/include/UI_interface.h
@@ -977,7 +977,13 @@ void uiItemEnumR(uiLayout *layout, const char *name, int icon, struct PointerRNA
 void uiItemEnumR_string(uiLayout *layout, struct PointerRNA *ptr, const char *propname, const char *value, const char *name, int icon);
 void uiItemsEnumR(uiLayout *layout, struct PointerRNA *ptr, const char *propname);
 void uiItemPointerR(uiLayout *layout, struct PointerRNA *ptr, const char *propname, struct PointerRNA *searchptr, const char *searchpropname, const char *name, int icon);
-void uiItemsFullEnumO(uiLayout *layout, const char *opname, const char *propname, struct IDProperty *properties, int context, int flag);
+void uiItemsFullEnumO(
+        uiLayout *layout, const char *opname, const char *propname,
+        struct IDProperty *properties, int context, int flag);
+void uiItemsFullEnumO_items(
+        uiLayout *layout, struct wmOperatorType *ot, PointerRNA ptr, PropertyRNA *prop,
+        IDProperty *properties, int context, int flag,
+        const EnumPropertyItem *item_array, int totitem);
 
 void uiItemL(uiLayout *layout, const char *name, int icon); /* label */
 void uiItemLDrag(uiLayout *layout, struct PointerRNA *ptr, const char *name, int icon); /* label icon for dragging */
diff --git a/source/blender/editors/interface/interface_intern.h b/source/blender/editors/interface/interface_intern.h
index 06de5f99769..66510fb470d 100644
--- a/source/blender/editors/interface/interface_intern.h
+++ b/source/blender/editors/interface/interface_intern.h
@@ -182,6 +182,9 @@ enum {
 
 #define PIE_CLICK_THRESHOLD_SQ 50.0f
 
+/* max amount of items a radial menu (pie menu) can contain */
+#define PIE_MAX_ITEMS 8
+
 typedef struct uiLinkLine {  /* only for draw/edit */
 	struct uiLinkLine *next, *prev;
 	struct uiBut *from, *to;
@@ -332,6 +335,10 @@ typedef struct ColorPickerData {
 } ColorPickerData;
 
 struct PieMenuData {
+	/* store title and icon to allow access when pie levels are created */
+	const char *title;
+	int icon;
+
 	float pie_dir[2];
 	float pie_center_init[2];
 	float pie_center_spawned[2];
@@ -603,6 +610,10 @@ uiPopupBlockHandle *ui_popup_menu_create(
         struct bContext *C, struct ARegion *butregion, uiBut *but,
         uiMenuCreateFunc create_func, void *arg);
 
+void ui_pie_menu_level_create(
+        uiBlock *block, struct wmOperatorType *ot, const char *propname, IDProperty *properties,
+        const EnumPropertyItem *items, int totitem, int context, int flag);
+
 void ui_popup_block_free(struct bContext *C, uiPopupBlockHandle *handle);
 
 int  ui_but_menu_step(uiBut *but, int step);
diff --git a/source/blender/editors/interface/interface_layout.c b/source/blender/editors/interface/interface_layout.c
index 0b53232c29b..4d9c1b387a1 100644
--- a/source/blender/editors/interface/interface_layout.c
+++ b/source/blender/editors/interface/interface_layout.c
@@ -720,7 +720,7 @@ void UI_context_active_but_prop_get_filebrowser(
 /**
  * Update a buttons tip with an enum's description if possible.
  */
-static void ui_but_tip_from_enum_item(uiBut *but, EnumPropertyItem *item)
+static void ui_but_tip_from_enum_item(uiBut *but, const EnumPropertyItem *item)
 {
 	if (but->tip == NULL || but->tip[0] == '\0') {
 		if (item->description && item->description[0]) {
@@ -883,6 +883,125 @@ void uiItemEnumO(uiLayout *layout, const char *opname, const char *name, int ico
 
 }
 
+BLI_INLINE bool ui_layout_is_radial(const uiLayout *layout)
+{
+	return (layout->item.type == ITEM_LAYOUT_RADIAL) ||
+	       ((layout->item.type == ITEM_LAYOUT_ROOT) && (layout->root->type == UI_LAYOUT_PIEMENU));
+}
+
+/**
+ * Create ui items for enum items in \a item_array.
+ *
+ * A version of #uiItemsFullEnumO that takes pre-calculated item array.
+ */
+void uiItemsFullEnumO_items(
+        uiLayout *layout, wmOperatorType *ot, PointerRNA ptr, PropertyRNA *prop, IDProperty *properties,
+        int context, int flag,
+        const EnumPropertyItem *item_array, int totitem)
+{
+	const char *propname = RNA_property_identifier(prop);
+	if (RNA_property_type(prop) != PROP_ENUM) {
+		RNA_warning("%s.%s, not an enum type", RNA_struct_identifier(ptr.type), propname);
+		return;
+	}
+
+	uiLayout *target, *split = NULL;
+	const EnumPropertyItem *item;
+	uiBlock *block = layout->root->block;
+	const bool radial = ui_layout_is_radial(layout);
+
+	if (radial) {
+		target = uiLayoutRadial(layout);
+	}
+	else {
+		split = uiLayoutSplit(layout, 0.0f, false);
+		target = uiLayoutColumn(split, layout->align);
+	}
+
+
+	int i;
+	bool last_iter = false;
+
+	for (i = 1, item = item_array; item->identifier && !last_iter; i++, item++) {
+		/* handle oversized pies */
+		if (radial && (totitem > PIE_MAX_ITEMS) && (i >= PIE_MAX_ITEMS)) {
+			if (item->name) { /* only visible items */
+				const EnumPropertyItem *tmp;
+
+				/* Check if there are more visible items for the next level. If not, we don't
+				 * add a new level and add the remaining item instead of the 'more' button. */
+				for (tmp = item + 1; tmp->identifier; tmp++)
+					if (tmp->name)
+						break;
+
+				if (tmp->identifier) { /* only true if loop above found item and did early-exit */
+					ui_pie_menu_level_create(block, ot, propname, properties, item_array, totitem, context, flag);
+					/* break since rest of items is handled in new pie level */
+					break;
+				}
+				else {
+					last_iter = true;
+				}
+			}
+			else {
+				continue;
+			}
+		}
+
+		if (item->identifier[0]) {
+			PointerRNA tptr;
+
+			WM_operator_properties_create_ptr(&tptr, ot);
+			if (properties) {
+				if (tptr.data) {
+					IDP_FreeProperty(tptr.data);
+					MEM_freeN(tptr.data);
+				}
+				tptr.data = IDP_CopyProperty(properties);
+			}
+			RNA_property_enum_set(&tptr, prop, item->value);
+
+			uiItemFullO_ptr(target, ot, item->name, item->icon, tptr.data, context, flag);
+
+			ui_but_tip_from_enum_item(block->buttons.last, item);
+		}
+		else {
+			if (item->name) {
+				uiBut *but;
+
+				if (item != item_array && !radial) {
+					target = uiLayoutColumn(split, layout->align);
+
+					/* inconsistent, but menus with labels do not look good flipped */
+					block->flag |= UI_BLOCK_NO_FLIP;
+				}
+
+				if (item->icon || radial) {
+					uiItemL(target, item->name, item->icon);
+
+					but = block->buttons.last;
+				}
+				else {
+					/* Do not use uiItemL here, as our root layout is a menu one, it will add a fake blank icon! */
+					but = uiDefBut(block, UI_BTYPE_LABEL, 0, item->name, 0, 0, UI_UNIT_X * 5, UI_UNIT_Y, NULL,
+					               0.0, 0.0, 0, 0, "");
+				}
+				ui_but_tip_from_enum_item(but, item);
+			}
+			else {
+				if (radial) {
+					/* invisible dummy button to ensure all items are always at the same position */
+					uiItemS(target);
+				}
+				else {
+					/* XXX bug here, colums draw bottom item badly */
+					uiItemS(target);
+				}
+			}
+		}
+	}
+}
+
 void uiItemsFullEnumO(
         uiLayout *layout, const char *opname, const char *propname, IDProperty *properties,
         int context, int flag)
@@ -892,8 +1011,6 @@ void uiItemsFullEnumO(
 	PointerRNA ptr;
 	PropertyRNA *prop;
 	uiBlock *block = layout->root->block;
-	const bool radial = (layout->item.type == ITEM_LAYOUT_RADIAL) ||
-	                     ((layout->item.type == ITEM_LAYOUT_ROOT) && (layout->root->type == UI_LAYOUT_PIEMENU));
 
 	if (!ot || !ot->srna) {
 		ui_item_disabled(layout, opname);
@@ -910,89 +1027,22 @@ void uiItemsFullEnumO(
 	BLI_assert((prop == NULL) || (RNA_property_type(prop) == PROP_ENUM));
 
 	if (prop && RNA_property_type(prop) == PROP_ENUM) {
-		EnumPropertyItem *item, *item_array = NULL;
+		EnumPropertyItem *item_array = NULL;
+		int totitem;
 		bool free;
-		uiLayout *split = NULL;
-		uiLayout *target;
 
-		if (radial) {
-			target = uiLayoutRadial(layout);
+		if (ui_layout_is_radial(layout)) {
+			RNA_property_enum_items_gettexted_all(block->evil_C, &ptr, prop, &item_array, &totitem, &free);
 		}
 		else {
-			split = uiLayoutSplit(layout, 0.0f, false);
-			target = uiLayoutColumn(split, layout->align);
-		}
-
-		if (0 && radial) {
-			/* XXX Disabled as temporary workaround!
-			 *
-			 * Normally, we always draw a button for all items even if they're unavailable (we draw invisible
-			 * dummy buttons then), so items are always at the same position. This causes issues with current
-			 * 'Object Mode' pie since more than 8 modes exist now (see T46973).
-			 * Disabling this until more than 8 items per pie are supported (or a better solution is found).
-			 * We should work on that ASAP though.
-			 *
-			 * - Julian (Dec 2015)
-			 */
-			RNA_property_enum_items_gettexted_all(block->evil_C, &ptr, prop, &item_array, NULL, &free);
-		}
-		else {
-			RNA_property_enum_items_gettexted(block->evil_C, &ptr, prop, &item_array, NULL, &free);
+			RNA_property_enum_items_gettexted(block->evil_C, &ptr, prop, &item_array, &totitem, &free);
 		}
 
-		for (item = item_array; item->identifier; item++) {
-			if (item->identifier[0]) {
-				PointerRNA tptr;
+		/* add items */
+		uiItemsFullEnumO_items(
+		        layout, ot, ptr, prop, properties, context, flag,
+		        item_array, totitem);
 
-				WM_operator_properties_create_ptr(&tptr, ot);
-				if (properties) {
-					if (tptr.data) {
-						IDP_FreeProperty(tptr.data);
-						MEM_freeN(tptr.data);
-					}
-					tptr.data = IDP_CopyProperty(properties);
-				}
-				RNA_property_enum_set(&tptr, prop, item->value);
-
-				uiItemFullO_ptr(target, ot, item->name, item->icon, tptr.data, context, flag);
-
-				ui_but_tip_from_enum_item(block->buttons.last, item);
-			}
-			else {
-				if (item->name) {
-					uiBut *but;
-
-					if (item != item_array && !radial) {
-						target = uiLayoutColumn(split, layout->align);
-
-						/* inconsistent, but menus with labels do not look good flipped */
-						block->flag |= UI_BLOCK_NO_FLIP;
-					}
-
-					if (item->icon || radial) {
-						uiItemL(target, item->name, item->icon);
-
-						but = block->buttons.last;
-					}
-					else {
-						/* Do not use uiItemL here, as our root layout is a menu one, it will add a fake blank icon! */
-						but = uiDefBut(block, UI_BTYPE_LABEL, 0, item->name, 0, 0, UI_UNIT_X * 5, UI_UNIT_Y, NULL,
-						               0.0, 0.0, 0, 0, "");
-					}
-					ui_but_tip_from_enum_item(but, item);
-				}
-				else {
-					if (radial) {
-						/* invisible dummy button to ensure all items are always at the same position */
-						uiItemS(target);
-					}
-					else {
-						/* XXX bug here, colums draw bottom item badly */
-						uiItemS(target);
-					}
-				}
-			}
-		}
 		if (free) {
 			MEM_freeN(item_array);
 		}
@@ -2178,9 +2228,9 @@ static RadialDirection ui_get_radialbut_vec(float vec[2], short itemnum)
 {
 	RadialDirection dir;
 
-	if (itemnum >= 8) {
-		itemnum %= 8;
-		printf("Warning: Pie menus with more than 8 items are currently unsupported\n");
+	if (itemnum >= PIE_MAX_ITEMS) {
+		itemnum %= PIE_MAX_ITEMS;
+		printf("Warning: Pie menus with more than %i items are currently unsupported\n", PIE_MAX_ITEMS);
 	}
 
 	dir = ui_radial_dir_order[itemnum];
diff --git a/source/blender/editors/interface/interface_regions.c b/source/blender/editors/interface/interface_regions.c
index 877aea9bb95..1f9be649c56 100644
--- a/source/blender/editors/interface/interface_regions.c
+++ b/source/blender/editors/interface/interface_regions.c
@@ -2840,6 +2840,8 @@ uiPieMenu *UI_pie_menu_begin(struct bContext *C, const char *title, int icon, co
 		}
 		/* do not align left */
 		but->drawflag &= ~UI_BUT_TEXT_LEFT;
+		pie->block_radial->pie_data.title = but->str;
+		pie->block_radial->pie_data.icon = icon;
 	}
 
 	return pie;
@@ -2951,6 +2953,101 @@ int UI_pie_menu_invoke_from_rna_enum(
 	return OPERATOR_INTERFACE;
 }
 
+/**
+ * \name Pie Menu Levels
+ *
+ * Pie menus can't contain more than 8 items (yet). When using #uiItemsFullEnumO, a "More" button is created that calls
+ * a new pie menu if the enum has too many items. We call this a new "level".
+ * Indirect recursion is used, so that a theoretically unlimited number of items is supported.
+ *
+ * This is a implementation specifically for operator enums, needed since the object mode pie now has more than 8
+ * items. Ideally we'd have some way of handling this for all kinds of pie items, but that's tricky.
+ *
+ * - Julian (Feb 2016)
+ *
+ * \{ */
+
+typedef struct PieMenuLevelData {
+	char title[UI_MAX_NAME_STR]; /* parent pie title, copied for level */
+	int icon; /* parent pie icon, copied for level */
+	int totitem; /* total count of *remaining* items */
+
+	/* needed for calling uiItemsFullEnumO_array again for new level */
+	wmOperatorType *ot;
+	const char *propname;
+	IDProperty *properties;
+	int context, flag;
+} PieMenuLevelData;
+
+/**
+ * Invokes a new pie menu for a new level.
+ */
+static void ui_pie_menu_level_invoke(bContext *C, void *argN, void *arg2)
+{
+	EnumPropertyItem *item_array = (EnumPropertyItem *)argN;
+	PieMenuLevelData *lvl = (PieMenuLevelData *)arg2;
+	wmWindow *win = CTX_wm_window(C);
+
+	uiPieMenu *pie = UI_pie_menu_begin(C, IFACE_(lvl->title), lvl->icon, win->eventstate);
+	uiLayout *layout = UI_pie_menu_layout(pie);
+
+	layout = uiLayoutRadial(layout);
+
+	PointerRNA ptr;
+
+	WM_operator_properties_create_ptr(&ptr, lvl->ot);
+	/* so the context is passed to itemf functions (some need it) */
+	WM_operator_properties_sanitize(&ptr, false);
+	PropertyRNA *prop = RNA_struct_find_property(&ptr, lvl->propname);
+
+	if (prop) {
+		uiItemsFullEnumO_items(
+		        layout, lvl->ot, ptr, prop, lvl->properties, lvl->context, lvl->flag,
+		        item_array, lvl->totitem);
+	}
+	else {
+		RNA_warning("%s.%s not found", RNA_struct_identifier(ptr.type), lvl->propname);
+	}
+
+	UI_pie_menu_end(C, pie);
+}
+
+/**
+ * Set up data for defining a new pie menu level and add button that invokes it.
+ */
+void ui_pie_menu_level_create(
+        uiBlock *block, wmOperatorType *ot, const char *propname, IDProperty *properties,
+        const EnumPropertyItem *items, int totitem, int context, int flag)
+{
+	const int totitem_parent = PIE_MAX_ITEMS - 1;
+	const int totitem_remain = totitem - totitem_parent;
+	size_t array_size = sizeof(EnumPropertyItem) * totitem_remain;
+
+	/* used as but->func_argN so freeing is handled elsewhere */
+	EnumPropertyItem *remaining = MEM_mallocN(array_size + sizeof(EnumPropertyItem), "pie_level_item_array");
+	memcpy(remaining, items + totitem_parent, array_size);
+	/* a NULL terminating sentinal element is required */
+	memset(&remaining[totitem_remain], 0, sizeof(EnumPropertyItem));
+
+
+	/* yuk, static... issue is we can't reliably free this without doing dangerous changes */
+	static PieMenuLevelData lvl;
+	BLI_strncpy(lvl.title, block->pie_data.title, UI_MAX_NAME_STR);
+	lvl.totitem    = totitem_remain;
+	lvl.ot         = ot;
+	lvl.propname   = propname;
+	lvl.properties = properties;
+	lvl.context    = context;
+	lvl.flag       = flag;
+
+	/* add a 'more' menu entry */
+	uiBut *but = uiDefIconTextBut(block, UI_BTYPE_BUT, 0, ICON_PLUS, "More", 0, 0, UI_UNIT_X * 3, UI_UNIT_Y, NULL,
+	                              0.0f, 0.0f, 0.0f, 0.0f, "Show more items of this menu");
+	UI_but_funcN_set(but, ui_pie_menu_level_invoke, remaining, &lvl);
+}
+
+/** \} */ /* Pie Menu Levels */
+
 
 /*************************** Standard Popup Menus ****************************/