UI: New Global Top-Bar (WIP)

== Main Features/Changes for Users

* Add horizontal bar at top of all non-temp windows, consisting out of two horizontal sub-bars.
* Upper sub-bar contains global menus (File, Render, etc.), tabs for workspaces and scene selector.
* Lower sub-bar contains object mode selector, screen-layout and render-layer selector. Later operator and/or tool settings will be placed here.
* Individual sections of the topbar are individually scrollable.
* Workspace tabs can be double- or ctrl-clicked for renaming and contain 'x' icon for deleting.
* Top-bar should scale nicely with DPI.
* The lower half of the top-bar can be hided by dragging the lower top-bar edge up. Better hiding options are planned (e.g. hide in fullscreen modes).
* Info editors at the top of the window and using the full window width with be replaced by the top-bar.
* In fullscreen modes, no more info editor is added on top, the top-bar replaces it.

== Technical Features/Changes

* Adds initial support for global areas

  A global area is part of the window, not part of the regular screen-layout.
  I've added a macro iterator to iterate over both, global and screen-layout level areas. When iterating over areas, from now on developers should always consider if they have to include global areas.
* Adds a TOPBAR editor type

  The editor type is hidden in the UI editor type menu.
* Adds a variation of the ID template to display IDs as tab buttons (template_ID_tabs in BPY)
* Does various changes to RNA button creation code to improve their appearance in the horizontal top-bar.
* Adds support for dynamically sized regions. That is, regions that scale automatically to the layout bounds.

  The code for this is currently a big hack (it's based on drawing the UI multiple times). This should definitely be improved.
* Adds a template for displaying operator properties optimized for the top-bar. This will probably change a lot still and is in fact disabled in code.

Since the final top-bar design depends a lot on other 2.8 designs (mainly tool-system and workspaces), we decided to not show the operator or tool settings in the top-bar for now. That means most of the lower sub-bar is empty for the time being.

NOTE: Top-bar or global area data is not written to files or SDNA. They are simply added to the window when opening Blender or reading a file. This allows us doing changes to the top-bar without having to care for compatibility.

== ToDo's

It's a bit hard to predict all the ToDo's here are the known main ones:
* Add options for the new active-tool system and for operator redo to the topbar.
* Automatically hide the top-bar in fullscreen modes.
* General visual polish.
* Top-bar drag & drop support (WIP in temp-tab_drag_drop).
* Improve dynamic regions (should also fix some layout glitches).
* Make internal terminology consistent.
* Enable topbar file writing once design is more advanced.
* Address TODO's and XXX's in code :)

Thanks @brecht for the review! And @sergey for the complaining ;)

Differential Revision: D2758

5 files changed, 102 insertions, 4 deletions

diff --git a/source/blender/makesrna/intern/rna_screen.c b/source/blender/makesrna/intern/rna_screen.c
index 97b89937081..61ec6339ce8 100644
--- a/source/blender/makesrna/intern/rna_screen.c
+++ b/source/blender/makesrna/intern/rna_screen.c
@@ -83,6 +83,12 @@ static int rna_Screen_is_animation_playing_get(PointerRNA *UNUSED(ptr))
 	return wm ? (ED_screen_animation_playing(wm) != NULL) : 0;
 }
 
+static int rna_region_alignment_get(PointerRNA *ptr)
+{
+	ARegion *region = ptr->data;
+	return (region->alignment & ~RGN_SPLIT_PREV);
+}
+
 static void rna_Screen_layout_name_get(PointerRNA *ptr, char *value)
 {
 	const bScreen *screen = ptr->data;
@@ -130,10 +136,22 @@ static int rna_Screen_fullscreen_get(PointerRNA *ptr)
 /* UI compatible list: should not be needed, but for now we need to keep EMPTY
  * at least in the static version of this enum for python scripts. */
 static const EnumPropertyItem *rna_Area_type_itemf(bContext *UNUSED(C), PointerRNA *UNUSED(ptr),
-                                             PropertyRNA *UNUSED(prop), bool *UNUSED(r_free))
+                                             PropertyRNA *UNUSED(prop), bool *r_free)
 {
+	EnumPropertyItem *item = NULL;
+	int totitem = 0;
+
 	/* +1 to skip SPACE_EMPTY */
-	return rna_enum_space_type_items + 1;
+	for (const EnumPropertyItem *item_from = rna_enum_space_type_items + 1; item_from->identifier; item_from++) {
+		if (ELEM(item_from->value, SPACE_TOPBAR)) {
+			continue;
+		}
+		RNA_enum_item_add(&item, &totitem, item_from);
+	}
+	RNA_enum_item_end(&item, &totitem);
+	*r_free = true;
+
+	return item;
 }
 
 static int rna_Area_type_get(PointerRNA *ptr)
@@ -145,6 +163,13 @@ static int rna_Area_type_get(PointerRNA *ptr)
 
 static void rna_Area_type_set(PointerRNA *ptr, int value)
 {
+	if (ELEM(value, SPACE_TOPBAR)) {
+		/* Special case: An area can not be set to show the top-bar editor (or
+		 * other global areas). However it should still be possible to identify
+		 * its type from Python. */
+		return;
+	}
+
 	ScrArea *sa = (ScrArea *)ptr->data;
 	sa->butspacetype = value;
 }
@@ -329,6 +354,19 @@ static void rna_def_region(BlenderRNA *brna)
 	StructRNA *srna;
 	PropertyRNA *prop;
 
+	static const EnumPropertyItem alignment_types[] = {
+		{RGN_ALIGN_NONE, "NONE", 0, "None", "Don't use any fixed alignment, fill available space"},
+		{RGN_ALIGN_TOP, "TOP", 0, "Top", ""},
+		{RGN_ALIGN_BOTTOM, "BOTTOM", 0, "Bottom", ""},
+		{RGN_ALIGN_LEFT, "LEFT", 0, "Left", ""},
+		{RGN_ALIGN_RIGHT, "RIGHT", 0, "Right", ""},
+		{RGN_ALIGN_HSPLIT, "HORIZONTAL_SPLIT", 0, "Horizontal Split", ""},
+		{RGN_ALIGN_VSPLIT, "VERTICAL_SPLIT", 0, "Vertical Split", ""},
+		{RGN_ALIGN_FLOAT, "FLOAT", 0, "Float", "Region floats on screen, doesn't use any fixed alignment"},
+		{RGN_ALIGN_QSPLIT, "QUAD_SPLIT", 0, "Quad Split", "Region is split horizontally and vertically"},
+		{0, NULL, 0, NULL, NULL}
+	};
+
 	srna = RNA_def_struct(brna, "Region", NULL);
 	RNA_def_struct_ui_text(srna, "Region", "Region in a subdivided screen area");
 	RNA_def_struct_sdna(srna, "ARegion");
@@ -365,6 +403,12 @@ static void rna_def_region(BlenderRNA *brna)
 	RNA_def_property_flag(prop, PROP_NEVER_NULL);
 	RNA_def_property_ui_text(prop, "View2D", "2D view of the region");
 
+	prop = RNA_def_property(srna, "alignment", PROP_ENUM, PROP_NONE);
+	RNA_def_property_clear_flag(prop, PROP_EDITABLE);
+	RNA_def_property_enum_items(prop, alignment_types);
+	RNA_def_property_enum_funcs(prop, "rna_region_alignment_get", NULL, NULL);
+	RNA_def_property_ui_text(prop, "Alignment", "Alignment of the region within the area");
+
 	RNA_def_function(srna, "tag_redraw", "ED_region_tag_redraw");
 }
 
diff --git a/source/blender/makesrna/intern/rna_space.c b/source/blender/makesrna/intern/rna_space.c
index 35e5cde17ef..92352a27e22 100644
--- a/source/blender/makesrna/intern/rna_space.c
+++ b/source/blender/makesrna/intern/rna_space.c
@@ -87,6 +87,8 @@ const EnumPropertyItem rna_enum_space_type_items[] = {
 	                "advanced editing and script development"},
 	{SPACE_INFO, "INFO", ICON_INFO, "Info", "Main menu bar and list of error messages "
 	             "(drag down to expand and display)"},
+	/* Special case: Top-bar isn't supposed to be a regular editor for the user. */
+	{SPACE_TOPBAR, "TOPBAR", ICON_NONE, "Top Bar", "Global bar at the top of the screen for global per-window settings"},
 
 	/* Data */
 	{0, "", ICON_NONE, "Data", ""},
@@ -1806,6 +1808,7 @@ static void rna_def_space(BlenderRNA *brna)
 	prop = RNA_def_property(srna, "type", PROP_ENUM, PROP_NONE);
 	RNA_def_property_enum_sdna(prop, NULL, "spacetype");
 	RNA_def_property_enum_items(prop, rna_enum_space_type_items);
+	/* When making this editable, take care for the special case of global areas (see rna_Area_type_set). */
 	RNA_def_property_clear_flag(prop, PROP_EDITABLE);
 	RNA_def_property_ui_text(prop, "Type", "Space data type");
 
diff --git a/source/blender/makesrna/intern/rna_ui.c b/source/blender/makesrna/intern/rna_ui.c
index 40657b3a225..bb4f6719fbc 100644
--- a/source/blender/makesrna/intern/rna_ui.c
+++ b/source/blender/makesrna/intern/rna_ui.c
@@ -568,7 +568,7 @@ static void rna_Header_unregister(Main *UNUSED(bmain), StructRNA *type)
 
 	if (!ht)
 		return;
-	if (!(art = region_type_find(NULL, ht->space_type, RGN_TYPE_HEADER)))
+	if (!(art = region_type_find(NULL, ht->space_type, ht->region_type)))
 		return;
 	
 	RNA_struct_free_extension(type, &ht->ext);
@@ -592,6 +592,7 @@ static StructRNA *rna_Header_register(
 
 	/* setup dummy header & header type to store static properties in */
 	dummyheader.type = &dummyht;
+	dummyht.region_type = RGN_TYPE_HEADER; /* RGN_TYPE_HEADER by default, may be overridden */
 	RNA_pointer_create(NULL, &RNA_Header, &dummyheader, &dummyhtr);
 
 	/* validate the python class */
@@ -604,7 +605,7 @@ static StructRNA *rna_Header_register(
 		return NULL;
 	}
 
-	if (!(art = region_type_find(reports, dummyht.space_type, RGN_TYPE_HEADER)))
+	if (!(art = region_type_find(reports, dummyht.space_type, dummyht.region_type)))
 		return NULL;
 
 	/* check if we have registered this header type before, and remove it */
@@ -1240,6 +1241,14 @@ static void rna_def_header(BlenderRNA *brna)
 	RNA_def_property_flag(prop, PROP_REGISTER);
 	RNA_def_property_ui_text(prop, "Space type", "The space where the header is going to be used in");
 
+	prop = RNA_def_property(srna, "bl_region_type", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_sdna(prop, NULL, "type->region_type");
+	RNA_def_property_enum_default(prop, RGN_TYPE_HEADER);
+	RNA_def_property_enum_items(prop, rna_enum_region_type_items);
+	RNA_def_property_flag(prop, PROP_REGISTER_OPTIONAL);
+	RNA_def_property_ui_text(prop, "Region Type", "The region where the header is going to be used in "
+	                         "(defaults to header region)");
+
 	RNA_define_verify_sdna(1);
 }
 
diff --git a/source/blender/makesrna/intern/rna_ui_api.c b/source/blender/makesrna/intern/rna_ui_api.c
index 5fc263ae171..367efd71519 100644
--- a/source/blender/makesrna/intern/rna_ui_api.c
+++ b/source/blender/makesrna/intern/rna_ui_api.c
@@ -715,6 +715,15 @@ void RNA_api_ui_layout(StructRNA *srna)
 	RNA_def_parameter_flags(parm, 0, PARM_REQUIRED);
 	api_ui_item_common_text(func);
 
+	func = RNA_def_function(srna, "template_ID_tabs", "uiTemplateIDTabs");
+	RNA_def_function_flag(func, FUNC_USE_CONTEXT);
+	api_ui_item_rna_common(func);
+	RNA_def_string(func, "new", NULL, 0, "", "Operator identifier to create a new ID block");
+	RNA_def_string(func, "open", NULL, 0, "", "Operator identifier to open a file for creating a new ID block");
+	RNA_def_string(func, "unlink", NULL, 0, "", "Operator identifier to unlink the ID block");
+	RNA_def_enum(func, "filter", id_template_filter_items, UI_TEMPLATE_ID_FILTER_ALL,
+	             "", "Optionally limit the items which can be selected");
+
 	func = RNA_def_function(srna, "template_search", "uiTemplateSearch");
 	RNA_def_function_flag(func, FUNC_USE_CONTEXT);
 	api_ui_item_rna_common(func);
@@ -756,6 +765,12 @@ void RNA_api_ui_layout(StructRNA *srna)
 	parm = RNA_def_pointer(func, "layout", "UILayout", "", "Sub-layout to put items in");
 	RNA_def_function_return(func, parm);
 
+#ifdef WITH_REDO_REGION_REMOVAL
+	func = RNA_def_function(srna, "template_operator_redo_props", "uiTemplateOperatorRedoProperties");
+	RNA_def_function_flag(func, FUNC_USE_CONTEXT);
+	RNA_def_function_ui_description(func, "Adds properties of the last executed operator using redo");
+#endif
+
 	func = RNA_def_function(srna, "template_constraint", "uiTemplateConstraint");
 	RNA_def_function_ui_description(func, "Generates the UI layout for constraints");
 	parm = RNA_def_pointer(func, "data", "Constraint", "", "Constraint data");
diff --git a/source/blender/makesrna/intern/rna_userdef.c b/source/blender/makesrna/intern/rna_userdef.c
index 2645dc081c8..8ef40f0dc66 100644
--- a/source/blender/makesrna/intern/rna_userdef.c
+++ b/source/blender/makesrna/intern/rna_userdef.c
@@ -1030,6 +1030,11 @@ static void rna_def_userdef_theme_ui(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "State Colors", "");
 	RNA_def_property_update(prop, 0, "rna_userdef_update");
 
+	prop = RNA_def_property(srna, "wcol_tab", PROP_POINTER, PROP_NONE);
+	RNA_def_property_flag(prop, PROP_NEVER_NULL);
+	RNA_def_property_ui_text(prop, "Tab Colors", "");
+	RNA_def_property_update(prop, 0, "rna_userdef_update");
+
 	prop = RNA_def_property(srna, "menu_shadow_fac", PROP_FLOAT, PROP_FACTOR);
 	RNA_def_property_ui_text(prop, "Menu Shadow Strength", "Blending factor for menu shadows");
 	RNA_def_property_range(prop, 0.01f, 1.0f);
@@ -2960,6 +2965,20 @@ static void rna_def_userdef_theme_space_clip(BlenderRNA *brna)
 	rna_def_userdef_theme_spaces_curves(srna, false, false, false, true);
 }
 
+static void rna_def_userdef_theme_space_topbar(BlenderRNA *brna)
+{
+	StructRNA *srna;
+
+	/* space_topbar */
+
+	srna = RNA_def_struct(brna, "ThemeTopBar", NULL);
+	RNA_def_struct_sdna(srna, "ThemeSpace");
+	RNA_def_struct_clear_flag(srna, STRUCT_UNDO);
+	RNA_def_struct_ui_text(srna, "Theme Top Bar", "Theme settings for the Top Bar");
+
+	rna_def_userdef_theme_spaces_main(srna);
+}
+
 static void rna_def_userdef_themes(BlenderRNA *brna)
 {
 	StructRNA *srna;
@@ -2985,6 +3004,7 @@ static void rna_def_userdef_themes(BlenderRNA *brna)
 		{16, "FILE_BROWSER", ICON_FILESEL, "File Browser", ""},
 		{17, "CONSOLE", ICON_CONSOLE, "Python Console", ""},
 		{20, "CLIP_EDITOR", ICON_CLIP, "Movie Clip Editor", ""},
+		{21, "TOPBAR", ICON_NONE, "Top Bar", ""},
 		{0, NULL, 0, NULL, NULL}
 	};
 
@@ -3112,6 +3132,12 @@ static void rna_def_userdef_themes(BlenderRNA *brna)
 	RNA_def_property_pointer_sdna(prop, NULL, "tclip");
 	RNA_def_property_struct_type(prop, "ThemeClipEditor");
 	RNA_def_property_ui_text(prop, "Clip Editor", "");
+
+	prop = RNA_def_property(srna, "topbar", PROP_POINTER, PROP_NONE);
+	RNA_def_property_flag(prop, PROP_NEVER_NULL);
+	RNA_def_property_pointer_sdna(prop, NULL, "ttopbar");
+	RNA_def_property_struct_type(prop, "ThemeTopBar");
+	RNA_def_property_ui_text(prop, "Top Bar", "");
 }
 
 static void rna_def_userdef_addon(BlenderRNA *brna)
@@ -3202,6 +3228,7 @@ static void rna_def_userdef_dothemes(BlenderRNA *brna)
 	rna_def_userdef_theme_space_userpref(brna);
 	rna_def_userdef_theme_space_console(brna);
 	rna_def_userdef_theme_space_clip(brna);
+	rna_def_userdef_theme_space_topbar(brna);
 	rna_def_userdef_theme_colorset(brna);
 	rna_def_userdef_themes(brna);
 }