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

4 files changed, 155 insertions, 69 deletions

diff --git a/source/blender/blenloader/intern/readblenentry.c b/source/blender/blenloader/intern/readblenentry.c
index 73109413271..8d90a11f5d9 100644
--- a/source/blender/blenloader/intern/readblenentry.c
+++ b/source/blender/blenloader/intern/readblenentry.c
@@ -282,7 +282,7 @@ LinkNode *BLO_blendhandle_get_linkable_groups(BlendHandle *bh)
 		else if (BKE_idcode_is_valid(bhead->code)) {
 			if (BKE_idcode_is_linkable(bhead->code)) {
 				const char *str = BKE_idcode_to_name(bhead->code);
-				
+
 				if (BLI_gset_add(gathered, (void *)str)) {
 					BLI_linklist_prepend(&names, strdup(str));
 				}
diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index 5dc98964fbd..b9f9fc638cc 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -6396,6 +6396,8 @@ static void direct_link_area(FileData *fd, ScrArea *area)
 	area->type = NULL;	/* spacetype callbacks */
 	area->region_active_win = -1;
 
+	area->global = newdataadr(fd, area->global);
+
 	/* if we do not have the spacetype registered we cannot
 	 * free it, so don't allocate any new memory for such spacetypes. */
 	if (!BKE_spacetype_exists(area->spacetype)) {
@@ -6630,9 +6632,9 @@ static void direct_link_area(FileData *fd, ScrArea *area)
 	area->v4 = newdataadr(fd, area->v4);
 }
 
-static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
+static void lib_link_area(FileData *fd, ID *parent_id, ScrArea *area)
 {
-	area->full = newlibadr(fd, sc->id.lib, area->full);
+	area->full = newlibadr(fd, parent_id->lib, area->full);
 
 	for (SpaceLink *sl = area->spacedata.first; sl; sl= sl->next) {
 		switch (sl->spacetype) {
@@ -6640,11 +6642,11 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 			{
 				View3D *v3d = (View3D*) sl;
 
-				v3d->camera= newlibadr(fd, sc->id.lib, v3d->camera);
-				v3d->ob_centre= newlibadr(fd, sc->id.lib, v3d->ob_centre);
+				v3d->camera= newlibadr(fd, parent_id->lib, v3d->camera);
+				v3d->ob_centre= newlibadr(fd, parent_id->lib, v3d->ob_centre);
 
 				if (v3d->localvd) {
-					v3d->localvd->camera = newlibadr(fd, sc->id.lib, v3d->localvd->camera);
+					v3d->localvd->camera = newlibadr(fd, parent_id->lib, v3d->localvd->camera);
 				}
 				break;
 			}
@@ -6654,15 +6656,15 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 				bDopeSheet *ads = sipo->ads;
 
 				if (ads) {
-					ads->source = newlibadr(fd, sc->id.lib, ads->source);
-					ads->filter_grp = newlibadr(fd, sc->id.lib, ads->filter_grp);
+					ads->source = newlibadr(fd, parent_id->lib, ads->source);
+					ads->filter_grp = newlibadr(fd, parent_id->lib, ads->filter_grp);
 				}
 				break;
 			}
 			case SPACE_BUTS:
 			{
 				SpaceButs *sbuts = (SpaceButs *)sl;
-				sbuts->pinid = newlibadr(fd, sc->id.lib, sbuts->pinid);
+				sbuts->pinid = newlibadr(fd, parent_id->lib, sbuts->pinid);
 				if (sbuts->pinid == NULL) {
 					sbuts->flag &= ~SB_PIN_CONTEXT;
 				}
@@ -6676,24 +6678,24 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 				bDopeSheet *ads = &saction->ads;
 
 				if (ads) {
-					ads->source = newlibadr(fd, sc->id.lib, ads->source);
-					ads->filter_grp = newlibadr(fd, sc->id.lib, ads->filter_grp);
+					ads->source = newlibadr(fd, parent_id->lib, ads->source);
+					ads->filter_grp = newlibadr(fd, parent_id->lib, ads->filter_grp);
 				}
 
-				saction->action = newlibadr(fd, sc->id.lib, saction->action);
+				saction->action = newlibadr(fd, parent_id->lib, saction->action);
 				break;
 			}
 			case SPACE_IMAGE:
 			{
 				SpaceImage *sima = (SpaceImage *)sl;
 
-				sima->image = newlibadr_real_us(fd, sc->id.lib, sima->image);
-				sima->mask_info.mask = newlibadr_real_us(fd, sc->id.lib, sima->mask_info.mask);
+				sima->image = newlibadr_real_us(fd, parent_id->lib, sima->image);
+				sima->mask_info.mask = newlibadr_real_us(fd, parent_id->lib, sima->mask_info.mask);
 
 				/* NOTE: pre-2.5, this was local data not lib data, but now we need this as lib data
 				 * so fingers crossed this works fine!
 				 */
-				sima->gpd = newlibadr_us(fd, sc->id.lib, sima->gpd);
+				sima->gpd = newlibadr_us(fd, parent_id->lib, sima->gpd);
 				break;
 			}
 			case SPACE_SEQ:
@@ -6703,7 +6705,7 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 				/* NOTE: pre-2.5, this was local data not lib data, but now we need this as lib data
 				 * so fingers crossed this works fine!
 				 */
-				sseq->gpd = newlibadr_us(fd, sc->id.lib, sseq->gpd);
+				sseq->gpd = newlibadr_us(fd, parent_id->lib, sseq->gpd);
 				break;
 			}
 			case SPACE_NLA:
@@ -6712,8 +6714,8 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 				bDopeSheet *ads= snla->ads;
 
 				if (ads) {
-					ads->source = newlibadr(fd, sc->id.lib, ads->source);
-					ads->filter_grp = newlibadr(fd, sc->id.lib, ads->filter_grp);
+					ads->source = newlibadr(fd, parent_id->lib, ads->source);
+					ads->filter_grp = newlibadr(fd, parent_id->lib, ads->filter_grp);
 				}
 				break;
 			}
@@ -6721,7 +6723,7 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 			{
 				SpaceText *st= (SpaceText *)sl;
 
-				st->text= newlibadr(fd, sc->id.lib, st->text);
+				st->text= newlibadr(fd, parent_id->lib, st->text);
 				break;
 			}
 			case SPACE_SCRIPT:
@@ -6729,7 +6731,7 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 				SpaceScript *scpt = (SpaceScript *)sl;
 				/*scpt->script = NULL; - 2.45 set to null, better re-run the script */
 				if (scpt->script) {
-					scpt->script = newlibadr(fd, sc->id.lib, scpt->script);
+					scpt->script = newlibadr(fd, parent_id->lib, scpt->script);
 					if (scpt->script) {
 						SCRIPT_SET_NULL(scpt->script);
 					}
@@ -6763,11 +6765,11 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 				bNodeTree *ntree;
 
 				/* node tree can be stored locally in id too, link this first */
-				snode->id = newlibadr(fd, sc->id.lib, snode->id);
-				snode->from = newlibadr(fd, sc->id.lib, snode->from);
+				snode->id = newlibadr(fd, parent_id->lib, snode->id);
+				snode->from = newlibadr(fd, parent_id->lib, snode->from);
 
 				ntree = snode->id ? ntreeFromID(snode->id) : NULL;
-				snode->nodetree = ntree ? ntree : newlibadr_us(fd, sc->id.lib, snode->nodetree);
+				snode->nodetree = ntree ? ntree : newlibadr_us(fd, parent_id->lib, snode->nodetree);
 
 				for (path = snode->treepath.first; path; path = path->next) {
 					if (path == snode->treepath.first) {
@@ -6775,7 +6777,7 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 						path->nodetree = snode->nodetree;
 					}
 					else
-						path->nodetree = newlibadr_us(fd, sc->id.lib, path->nodetree);
+						path->nodetree = newlibadr_us(fd, parent_id->lib, path->nodetree);
 
 					if (!path->nodetree)
 						break;
@@ -6803,9 +6805,8 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 			case SPACE_CLIP:
 			{
 				SpaceClip *sclip = (SpaceClip *)sl;
-
-				sclip->clip = newlibadr_real_us(fd, sc->id.lib, sclip->clip);
-				sclip->mask_info.mask = newlibadr_real_us(fd, sc->id.lib, sclip->mask_info.mask);
+				sclip->clip = newlibadr_real_us(fd, parent_id->lib, sclip->clip);
+				sclip->mask_info.mask = newlibadr_real_us(fd, parent_id->lib, sclip->mask_info.mask);
 				break;
 			}
 			default:
@@ -6814,6 +6815,34 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 	}
 }
 
+/**
+ * \return false on error.
+ */
+static bool direct_link_area_map(FileData *fd, ScrAreaMap *area_map)
+{
+	link_list(fd, &area_map->vertbase);
+	link_list(fd, &area_map->edgebase);
+	link_list(fd, &area_map->areabase);
+	for (ScrArea *area = area_map->areabase.first; area; area = area->next) {
+		direct_link_area(fd, area);
+	}
+
+	/* edges */
+	for (ScrEdge *se = area_map->edgebase.first; se; se = se->next) {
+		se->v1 = newdataadr(fd, se->v1);
+		se->v2 = newdataadr(fd, se->v2);
+		BKE_screen_sort_scrvert(&se->v1, &se->v2);
+
+		if (se->v1 == NULL) {
+			BLI_remlink(&area_map->edgebase, se);
+
+			return false;
+		}
+	}
+
+	return true;
+}
+
 /* ************ READ WM ***************** */
 
 static void direct_link_windowmanager(FileData *fd, wmWindowManager *wm)
@@ -6830,6 +6859,8 @@ static void direct_link_windowmanager(FileData *fd, wmWindowManager *wm)
 		/* we need to restore a pointer to this later when reading workspaces, so store in global oldnew-map */
 		oldnewmap_insert(fd->globmap, hook, win->workspace_hook, 0);
 
+		direct_link_area_map(fd, &win->global_areas);
+
 		win->ghostwin = NULL;
 		win->gwnctx = NULL;
 		win->eventstate = NULL;
@@ -6901,6 +6932,10 @@ static void lib_link_windowmanager(FileData *fd, Main *main)
 				win->scene = newlibadr(fd, wm->id.lib, win->scene);
 				/* deprecated, but needed for versioning (will be NULL'ed then) */
 				win->screen = newlibadr(fd, NULL, win->screen);
+	
+				for (ScrArea *area = win->global_areas.areabase.first; area; area = area->next) {
+					lib_link_area(fd, &wm->id, area);
+				}
 			}
 
 			wm->id.tag &= ~LIB_TAG_NEED_LINK;
@@ -6927,7 +6962,7 @@ static void lib_link_screen(FileData *fd, Main *main)
 			sc->scrubbing = false;
 			
 			for (ScrArea *area = sc->areabase.first; area; area = area->next) {
-				lib_link_area(fd, sc, area);
+				lib_link_area(fd, &sc->id, area);
 			}
 			sc->id.tag &= ~LIB_TAG_NEED_LINK;
 		}
@@ -7353,14 +7388,8 @@ void blo_do_versions_view3d_split_250(View3D *v3d, ListBase *regions)
 
 static bool direct_link_screen(FileData *fd, bScreen *sc)
 {
-	ScrArea *sa;
-	ScrVert *sv;
-	ScrEdge *se;
 	bool wrong_id = false;
 	
-	link_list(fd, &(sc->vertbase));
-	link_list(fd, &(sc->edgebase));
-	link_list(fd, &(sc->areabase));
 	sc->regionbase.first = sc->regionbase.last= NULL;
 	sc->context = NULL;
 	sc->active_region = NULL;
@@ -7368,28 +7397,11 @@ static bool direct_link_screen(FileData *fd, bScreen *sc)
 
 	sc->preview = direct_link_preview_image(fd, sc->preview);
 
-	/* edges */
-	for (se = sc->edgebase.first; se; se = se->next) {
-		se->v1 = newdataadr(fd, se->v1);
-		se->v2 = newdataadr(fd, se->v2);
-		if ((intptr_t)se->v1 > (intptr_t)se->v2) {
-			sv = se->v1;
-			se->v1 = se->v2;
-			se->v2 = sv;
-		}
-		
-		if (se->v1 == NULL) {
-			printf("Error reading Screen %s... removing it.\n", sc->id.name+2);
-			BLI_remlink(&sc->edgebase, se);
-			wrong_id = true;
-		}
+	if (!direct_link_area_map(fd, AREAMAP_FROM_SCREEN(sc))) {
+		printf("Error reading Screen %s... removing it.\n", sc->id.name + 2);
+		wrong_id = true;
 	}
-	
-	/* areas */
-	for (sa = sc->areabase.first; sa; sa = sa->next) {
-		direct_link_area(fd, sa);
-	}
-	
+
 	return wrong_id;
 }
 
diff --git a/source/blender/blenloader/intern/versioning_280.c b/source/blender/blenloader/intern/versioning_280.c
index 493bf17a552..18eff782d99 100644
--- a/source/blender/blenloader/intern/versioning_280.c
+++ b/source/blender/blenloader/intern/versioning_280.c
@@ -65,6 +65,7 @@
 #include "BKE_node.h"
 #include "BKE_report.h"
 #include "BKE_scene.h"
+#include "BKE_screen.h"
 #include "BKE_workspace.h"
 
 #include "BLO_readfile.h"
@@ -945,4 +946,60 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *main)
 			}
 		}
 	}
+
+	if (!DNA_struct_find(fd->filesdna, "SpaceTopBar")) {
+		/* Remove info editor, but only if at the top of the window. */
+		for (bScreen *screen = main->screen.first; screen; screen = screen->id.next) {
+			/* Calculate window width/height from screen vertices */
+			int win_width = 0, win_height = 0;
+			for (ScrVert *vert = screen->vertbase.first; vert; vert = vert->next) {
+				win_width  = MAX2(win_width, vert->vec.x);
+				win_height = MAX2(win_height, vert->vec.y);
+			}
+
+			for (ScrArea *area = screen->areabase.first, *area_next; area; area = area_next) {
+				area_next = area->next;
+
+				if (area->spacetype == SPACE_INFO) {
+					if ((area->v2->vec.y == win_height) && (area->v1->vec.x == 0) && (area->v4->vec.x == win_width)) {
+						BKE_screen_area_free(area);
+
+						BLI_remlink(&screen->areabase, area);
+
+						BKE_screen_remove_double_scredges(screen);
+						BKE_screen_remove_unused_scredges(screen);
+						BKE_screen_remove_unused_scrverts(screen);
+
+						MEM_freeN(area);
+					}
+				}
+				/* AREA_TEMP_INFO is deprecated from now on, it should only be set for info areas
+				 * which are deleted above, so don't need to unset it. Its slot/bit can be reused */
+			}
+		}
+	}
+
+#ifdef WITH_REDO_REGION_REMOVAL
+	if (!MAIN_VERSION_ATLEAST(main, 280, TO_BE_DETERMINED)) {
+		/* Remove tool property regions. */
+		for (bScreen *screen = main->screen.first; screen; screen = screen->id.next) {
+			for (ScrArea *sa = screen->areabase.first; sa; sa = sa->next) {
+				for (SpaceLink *sl = sa->spacedata.first; sl; sl = sl->next) {
+					if (ELEM(sl->spacetype, SPACE_VIEW3D, SPACE_CLIP)) {
+						ListBase *regionbase = (sl == sa->spacedata.first) ? &sa->regionbase : &sl->regionbase;
+
+						for (ARegion *region = regionbase->first, *region_next; region; region = region_next) {
+							region_next = region->next;
+
+							if (region->regiontype == RGN_TYPE_TOOL_PROPS) {
+								BKE_area_region_free(NULL, region);
+								BLI_freelinkN(regionbase, region);
+							}
+						}
+					}
+				}
+			}
+		}
+	}
+#endif
 }
diff --git a/source/blender/blenloader/intern/writefile.c b/source/blender/blenloader/intern/writefile.c
index d137510b510..ea6a18b2b48 100644
--- a/source/blender/blenloader/intern/writefile.c
+++ b/source/blender/blenloader/intern/writefile.c
@@ -2878,8 +2878,12 @@ static void write_area_regions(WriteData *wd, ScrArea *area)
 				writedata(wd, DATA, cl->len + 1, cl->line);
 			}
 			writestruct(wd, DATA, SpaceConsole, 1, sl);
-
 		}
+#ifdef WITH_TOPBAR_WRITING
+		else if (sl->spacetype == SPACE_TOPBAR) {
+			writestruct(wd, DATA, SpaceTopBar, 1, sl);
+		}
+#endif
 		else if (sl->spacetype == SPACE_USERPREF) {
 			writestruct(wd, DATA, SpaceUserPref, 1, sl);
 		}
@@ -2890,7 +2894,21 @@ static void write_area_regions(WriteData *wd, ScrArea *area)
 			writestruct(wd, DATA, SpaceInfo, 1, sl);
 		}
 	}
+}
+
+static void write_area_map(WriteData *wd, ScrAreaMap *area_map)
+{
+	writelist(wd, DATA, ScrVert, &area_map->vertbase);
+	writelist(wd, DATA, ScrEdge, &area_map->edgebase);
+	for (ScrArea *area = area_map->areabase.first; area; area = area->next) {
+		writestruct(wd, DATA, ScrArea, 1, area);
+
+#ifdef WITH_TOPBAR_WRITING
+		writestruct(wd, DATA, ScrGlobalAreaData, 1, area->global);
+#endif
 
+		write_area_regions(wd, area);
+	}
 }
 
 static void write_windowmanager(WriteData *wd, wmWindowManager *wm)
@@ -2899,6 +2917,11 @@ static void write_windowmanager(WriteData *wd, wmWindowManager *wm)
 	write_iddata(wd, &wm->id);
 
 	for (wmWindow *win = wm->windows.first; win; win = win->next) {
+#ifndef WITH_TOPBAR_WRITING
+		/* Don't write global areas yet, while we make changes to them. */
+		ScrAreaMap global_areas = win->global_areas;
+		memset(&win->global_areas, 0, sizeof(win->global_areas));
+#endif
 
 		/* update deprecated screen member (for so loading in 2.7x uses the correct screen) */
 		win->screen = BKE_workspace_active_screen_get(win->workspace_hook);
@@ -2907,6 +2930,12 @@ static void write_windowmanager(WriteData *wd, wmWindowManager *wm)
 		writestruct(wd, DATA, WorkSpaceInstanceHook, 1, win->workspace_hook);
 		writestruct(wd, DATA, Stereo3dFormat, 1, win->stereo3d_format);
 
+#ifdef WITH_TOPBAR_WRITING
+		write_area_map(wd, &win->global_areas);
+#else
+		win->global_areas = global_areas;
+#endif
+
 		/* data is written, clear deprecated data again */
 		win->screen = NULL;
 	}
@@ -2922,19 +2951,7 @@ static void write_screen(WriteData *wd, bScreen *sc)
 	write_previews(wd, sc->preview);
 
 	/* direct data */
-	for (ScrVert *sv = sc->vertbase.first; sv; sv = sv->next) {
-		writestruct(wd, DATA, ScrVert, 1, sv);
-	}
-
-	for (ScrEdge *se = sc->edgebase.first; se; se = se->next) {
-		writestruct(wd, DATA, ScrEdge, 1, se);
-	}
-
-	for (ScrArea *sa = sc->areabase.first; sa; sa = sa->next) {
-		writestruct(wd, DATA, ScrArea, 1, sa);
-
-		write_area_regions(wd, sa);
-	}
+	write_area_map(wd, AREAMAP_FROM_SCREEN(sc));
 }
 
 static void write_bone(WriteData *wd, Bone *bone)