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

2 files changed, 310 insertions, 0 deletions

diff --git a/source/blender/editors/space_topbar/CMakeLists.txt b/source/blender/editors/space_topbar/CMakeLists.txt
new file mode 100644
index 00000000000..9559c28de0a
--- /dev/null
+++ b/source/blender/editors/space_topbar/CMakeLists.txt
@@ -0,0 +1,45 @@
+# ***** BEGIN GPL LICENSE BLOCK *****
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+# Contributor(s): Jacques Beaurain.
+#
+# ***** END GPL LICENSE BLOCK *****
+
+set(INC
+	../include
+	../../blenkernel
+	../../blenlib
+	../../blenloader
+	../../blentranslation
+	../../gpu
+	../../makesdna
+	../../makesrna
+	../../windowmanager
+	../../../../intern/guardedalloc
+	../../../../intern/glew-mx
+)
+
+set(INC_SYS
+	${GLEW_INCLUDE_PATH}
+)
+
+set(SRC
+	space_topbar.c
+)
+
+add_definitions(${GL_DEFINITIONS})
+
+blender_add_lib(bf_editor_space_topbar "${SRC}" "${INC}" "${INC_SYS}")
diff --git a/source/blender/editors/space_topbar/space_topbar.c b/source/blender/editors/space_topbar/space_topbar.c
new file mode 100644
index 00000000000..35858a927fe
--- /dev/null
+++ b/source/blender/editors/space_topbar/space_topbar.c
@@ -0,0 +1,265 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2017 Blender Foundation.
+ * All rights reserved.
+ *
+ * Contributor(s): Blender Foundation
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/editors/space_topbar/space_topbar.c
+ *  \ingroup sptopbar
+ */
+
+
+#include <string.h>
+#include <stdio.h>
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_blenlib.h"
+#include "BLI_utildefines.h"
+
+#include "BLO_readfile.h"
+#include "BLT_translation.h"
+
+#include "BKE_context.h"
+#include "BKE_global.h"
+#include "BKE_screen.h"
+
+#include "ED_screen.h"
+#include "ED_space_api.h"
+
+#include "UI_interface.h"
+#include "UI_resources.h"
+#include "UI_view2d.h"
+
+#include "WM_api.h"
+#include "WM_types.h"
+
+
+/* ******************** default callbacks for topbar space ***************** */
+
+static SpaceLink *topbar_new(const bContext *UNUSED(C))
+{
+	ARegion *ar;
+	SpaceTopBar *stopbar;
+
+	stopbar = MEM_callocN(sizeof(*stopbar), "init topbar");
+	stopbar->spacetype = SPACE_TOPBAR;
+
+	/* header */
+	ar = MEM_callocN(sizeof(ARegion), "left aligned header for topbar");
+	BLI_addtail(&stopbar->regionbase, ar);
+	ar->regiontype = RGN_TYPE_HEADER;
+	ar->alignment = RGN_ALIGN_TOP;
+	ar = MEM_callocN(sizeof(ARegion), "right aligned header for topbar");
+	BLI_addtail(&stopbar->regionbase, ar);
+	ar->regiontype = RGN_TYPE_HEADER;
+	ar->alignment = RGN_ALIGN_RIGHT | RGN_SPLIT_PREV;
+
+	/* main regions */
+	ar = MEM_callocN(sizeof(ARegion), "left aligned main region for topbar");
+	BLI_addtail(&stopbar->regionbase, ar);
+	ar->regiontype = RGN_TYPE_WINDOW;
+	ar->alignment = RGN_ALIGN_LEFT;
+	ar = MEM_callocN(sizeof(ARegion), "right aligned main region for topbar");
+	BLI_addtail(&stopbar->regionbase, ar);
+	ar->regiontype = RGN_TYPE_WINDOW;
+	ar->alignment = RGN_ALIGN_RIGHT;
+	ar = MEM_callocN(sizeof(ARegion), "center main region for topbar");
+	BLI_addtail(&stopbar->regionbase, ar);
+	ar->regiontype = RGN_TYPE_WINDOW;
+
+	return (SpaceLink *)stopbar;
+}
+
+/* not spacelink itself */
+static void topbar_free(SpaceLink *UNUSED(sl))
+{
+	
+}
+
+
+/* spacetype; init callback */
+static void topbar_init(struct wmWindowManager *UNUSED(wm), ScrArea *UNUSED(sa))
+{
+	
+}
+
+static SpaceLink *topbar_duplicate(SpaceLink *sl)
+{
+	SpaceTopBar *stopbarn = MEM_dupallocN(sl);
+
+	/* clear or remove stuff from old */
+
+	return (SpaceLink *)stopbarn;
+}
+
+
+
+/* add handlers, stuff you only do once or on area/region changes */
+static void topbar_main_region_init(wmWindowManager *wm, ARegion *region)
+{
+	wmKeyMap *keymap;
+
+	/* force delayed UI_view2d_region_reinit call */
+	if (ELEM(region->alignment, RGN_ALIGN_LEFT, RGN_ALIGN_RIGHT)) {
+		region->flag |= RGN_FLAG_DYNAMIC_SIZE;
+	}
+	UI_view2d_region_reinit(&region->v2d, V2D_COMMONVIEW_HEADER, region->winx, region->winy);
+
+	keymap = WM_keymap_find(wm->defaultconf, "View2D Buttons List", 0, 0);
+	WM_event_add_keymap_handler(&region->handlers, keymap);
+}
+
+static void topbar_main_region_draw(const bContext *C, ARegion *region)
+{
+	ED_region_header(C, region);
+}
+
+static void topbar_operatortypes(void)
+{
+	
+}
+
+static void topbar_keymap(struct wmKeyConfig *UNUSED(keyconf))
+{
+	
+}
+
+/* add handlers, stuff you only do once or on area/region changes */
+static void topbar_header_region_init(wmWindowManager *UNUSED(wm), ARegion *ar)
+{
+	if ((ar->alignment & ~RGN_SPLIT_PREV) == RGN_ALIGN_RIGHT) {
+		ar->flag |= RGN_FLAG_DYNAMIC_SIZE;
+	}
+	ED_region_header_init(ar);
+}
+
+static void topbar_header_region_draw(const bContext *C, ARegion *ar)
+{
+	ED_region_header(C, ar);
+}
+
+static void topbar_main_region_listener(bScreen *UNUSED(sc), ScrArea *UNUSED(sa), ARegion *ar,
+                                        wmNotifier *wmn, const Scene *UNUSED(scene))
+{
+	/* context changes */
+	switch (wmn->category) {
+		case NC_WM:
+			if (wmn->data == ND_HISTORY)
+				ED_region_tag_redraw(ar);
+			break;
+		case NC_SCENE:
+			if (wmn->data == ND_MODE)
+				ED_region_tag_redraw(ar);
+			break;
+		case NC_SPACE:
+			if (wmn->data == ND_SPACE_VIEW3D)
+				ED_region_tag_redraw(ar);
+			break;
+	}
+}
+
+static void topbar_header_listener(bScreen *UNUSED(sc), ScrArea *UNUSED(sa), ARegion *UNUSED(ar),
+                                   wmNotifier *UNUSED(wmn), const Scene *UNUSED(scene))
+{
+	/* context changes */
+#if 0
+	switch (wmn->category) {
+		default:
+			break;
+	}
+#endif
+}
+
+static void recent_files_menu_draw(const bContext *UNUSED(C), Menu *menu)
+{
+	struct RecentFile *recent;
+	uiLayout *layout = menu->layout;
+	uiLayoutSetOperatorContext(layout, WM_OP_EXEC_REGION_WIN);
+	if (!BLI_listbase_is_empty(&G.recent_files)) {
+		for (recent = G.recent_files.first; (recent); recent = recent->next) {
+			const char *file = BLI_path_basename(recent->filepath);
+			const int icon = BLO_has_bfile_extension(file) ? ICON_FILE_BLEND : ICON_FILE_BACKUP;
+			uiItemStringO(layout, file, icon, "WM_OT_open_mainfile", "filepath", recent->filepath);
+		}
+	}
+	else {
+		uiItemL(layout, IFACE_("No Recent Files"), ICON_NONE);
+	}
+}
+
+static void recent_files_menu_register(void)
+{
+	MenuType *mt;
+
+	mt = MEM_callocN(sizeof(MenuType), "spacetype info menu recent files");
+	strcpy(mt->idname, "TOPBAR_MT_file_open_recent");
+	strcpy(mt->label, N_("Open Recent..."));
+	strcpy(mt->translation_context, BLT_I18NCONTEXT_DEFAULT_BPYRNA);
+	mt->draw = recent_files_menu_draw;
+	WM_menutype_add(mt);
+}
+
+
+/* only called once, from space/spacetypes.c */
+void ED_spacetype_topbar(void)
+{
+	SpaceType *st = MEM_callocN(sizeof(SpaceType), "spacetype topbar");
+	ARegionType *art;
+
+	st->spaceid = SPACE_TOPBAR;
+	strncpy(st->name, "Top Bar", BKE_ST_MAXNAME);
+
+	st->new = topbar_new;
+	st->free = topbar_free;
+	st->init = topbar_init;
+	st->duplicate = topbar_duplicate;
+	st->operatortypes = topbar_operatortypes;
+	st->keymap = topbar_keymap;
+
+	/* regions: main window */
+	art = MEM_callocN(sizeof(ARegionType), "spacetype topbar main region");
+	art->regionid = RGN_TYPE_WINDOW;
+	art->init = topbar_main_region_init;
+	art->draw = topbar_main_region_draw;
+	art->listener = topbar_main_region_listener;
+	art->prefsizex = UI_UNIT_X * 5; /* Mainly to avoid glitches */
+	art->keymapflag = ED_KEYMAP_UI | ED_KEYMAP_VIEW2D | ED_KEYMAP_HEADER;
+
+	BLI_addhead(&st->regiontypes, art);
+
+	/* regions: header */
+	art = MEM_callocN(sizeof(ARegionType), "spacetype topbar header region");
+	art->regionid = RGN_TYPE_HEADER;
+	art->prefsizey = HEADERY;
+	art->prefsizex = UI_UNIT_X * 5; /* Mainly to avoid glitches */
+	art->keymapflag = ED_KEYMAP_UI | ED_KEYMAP_VIEW2D | ED_KEYMAP_HEADER;
+	art->listener = topbar_header_listener;
+	art->init = topbar_header_region_init;
+	art->draw = topbar_header_region_draw;
+
+	BLI_addhead(&st->regiontypes, art);
+
+	recent_files_menu_register();
+
+	BKE_spacetype_register(st);
+}