UI: Ctrl+Tab and Ctrl+Shift+Tab to cycle through space context "tabs"

In User Preferences, Properties Editor and toolshelf, Ctrl+Tab and Ctrl+Shift+Tab now activates the next or previous space context (or category in case of toolshelf tabs), respectively.

For Properties Editor such functionality was completely missing, only toolshelf allowed cycling using ctrl+mousewheel (or only mousewheel while hovering tab region). Ctrl+Tab and Ctrl+Shift+Tab are common web browser shortcuts, so they're a reasonable choice to go with.
Reaching the first/last item doesn't cause the cycling to stop, we continue at the other end of the list then. (I didn't add this to Ctrl+Mousewheel toggling in toolshelf since I wanted to keep its behavior unchanged.)

We could get rid of (Ctrl+)Mousewheel cycling in toolshelf, but this may break user habits.

The cycling happens using a new operator, UI_OT_space_context_cycle, for toolshelf tabs it's hardcoded in panel handling code though.
Generalized rna_property_enum_step a bit and moved it to rna_access.c to allow external reuse.

Reviewed By: venomgfx
Differential Revision: https://developer.blender.org/D2189

1 files changed, 73 insertions, 0 deletions

diff --git a/source/blender/editors/interface/interface_ops.c b/source/blender/editors/interface/interface_ops.c
index 1af6d902b18..cb539bb1c5d 100644
--- a/source/blender/editors/interface/interface_ops.c
+++ b/source/blender/editors/interface/interface_ops.c
@@ -1082,6 +1082,78 @@ static void UI_OT_drop_color(wmOperatorType *ot)
 	RNA_def_boolean(ot->srna, "gamma", 0, "Gamma Corrected", "The source color is gamma corrected ");
 }
 
+/* ------------------------------------------------------------------------- */
+
+static EnumPropertyItem space_context_cycle_direction[] = {
+	{SPACE_CONTEXT_CYCLE_PREV, "PREV", 0, "Previous", ""},
+	{SPACE_CONTEXT_CYCLE_NEXT, "NEXT", 0, "Next", ""},
+	{0, NULL, 0, NULL, NULL}
+};
+
+static int space_context_cycle_poll(bContext *C)
+{
+	ScrArea *sa = CTX_wm_area(C);
+	return ELEM(sa->spacetype, SPACE_BUTS, SPACE_USERPREF);
+}
+
+/**
+ * Helper to get the correct RNA pointer/property pair for changing
+ * the display context of active space type in \sa.
+ */
+static void context_cycle_prop_get(
+        bScreen *screen, const ScrArea *sa,
+        PointerRNA *r_ptr, PropertyRNA **r_prop)
+{
+	const char *propname;
+
+	switch (sa->spacetype) {
+		case SPACE_BUTS:
+			RNA_pointer_create(&screen->id, &RNA_SpaceProperties, sa->spacedata.first, r_ptr);
+			propname = "context";
+			break;
+		case SPACE_USERPREF:
+			RNA_pointer_create(NULL, &RNA_UserPreferences, &U, r_ptr);
+			propname = "active_section";
+			break;
+	}
+
+	*r_prop = RNA_struct_find_property(r_ptr, propname);
+}
+
+static int space_context_cycle_invoke(bContext *C, wmOperator *op, const wmEvent *UNUSED(event))
+{
+	const int direction = RNA_enum_get(op->ptr, "direction");
+
+	PointerRNA ptr;
+	PropertyRNA *prop;
+	context_cycle_prop_get(CTX_wm_screen(C), CTX_wm_area(C), &ptr, &prop);
+
+	const int old_context = RNA_property_enum_get(&ptr, prop);
+	const int new_context = RNA_property_enum_step(
+	                  C, &ptr, prop, old_context,
+	                  direction == SPACE_CONTEXT_CYCLE_PREV ? -1 : 1);
+	RNA_property_enum_set(&ptr, prop, new_context);
+	RNA_property_update(C, &ptr, prop);
+
+	return OPERATOR_FINISHED;
+}
+
+static void UI_OT_space_context_cycle(wmOperatorType *ot)
+{
+	/* identifiers */
+	ot->name = "Cycle Space Context";
+	ot->description = "Cycle through the editor context by activating the next/previous one";
+	ot->idname = "UI_OT_space_context_cycle";
+
+	/* api callbacks */
+	ot->invoke = space_context_cycle_invoke;
+	ot->poll = space_context_cycle_poll;
+
+	ot->flag = 0;
+
+	RNA_def_enum(ot->srna, "direction", space_context_cycle_direction, SPACE_CONTEXT_CYCLE_NEXT, "Direction",
+	             "Direction to cycle through");
+}
 
 
 /* ********************************************************* */
@@ -1102,6 +1174,7 @@ void ED_operatortypes_ui(void)
 	WM_operatortype_append(UI_OT_edittranslation_init);
 #endif
 	WM_operatortype_append(UI_OT_reloadtranslation);
+	WM_operatortype_append(UI_OT_space_context_cycle);
 
 	/* external */
 	WM_operatortype_append(UI_OT_eyedropper_color);