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

1 files changed, 41 insertions, 4 deletions

diff --git a/source/blender/editors/interface/interface_align.c b/source/blender/editors/interface/interface_align.c
index 9aeb685a907..1fc38a27303 100644
--- a/source/blender/editors/interface/interface_align.c
+++ b/source/blender/editors/interface/interface_align.c
@@ -320,13 +320,43 @@ static int ui_block_align_butal_cmp(const void *a, const void *b)
 	return 0;
 }
 
+static void ui_block_align_but_to_region(uiBut *but, const ARegion *region)
+{
+	rctf *rect = &but->rect;
+	const float but_width = BLI_rctf_size_x(rect);
+	const float but_height = BLI_rctf_size_y(rect);
+	const float px = U.pixelsize;
+
+	switch (but->drawflag & UI_BUT_ALIGN) {
+		case UI_BUT_ALIGN_TOP:
+			rect->ymax = region->winy + px;
+			rect->ymin = but->rect.ymax - but_height;
+			break;
+		case UI_BUT_ALIGN_DOWN:
+			rect->ymin = -px;
+			rect->ymax = rect->ymin + but_height;
+			break;
+		case UI_BUT_ALIGN_LEFT:
+			rect->xmin = -px;
+			rect->xmax = rect->xmin + but_width;
+			break;
+		case UI_BUT_ALIGN_RIGHT:
+			rect->xmax = region->winx + px;
+			rect->xmin = rect->xmax - but_width;
+			break;
+		default:
+			BLI_assert(0);
+			break;
+	}
+}
+
 /**
  * Compute the alignment of all 'align groups' of buttons in given block.
  *
  * This is using an order-independent algorithm, i.e. alignment of buttons should be OK regardless of order in which
  * they are added to the block.
  */
-void ui_block_align_calc(uiBlock *block)
+void ui_block_align_calc(uiBlock *block, const ARegion *region)
 {
 	uiBut *but;
 	int num_buttons = 0;
@@ -338,10 +368,17 @@ void ui_block_align_calc(uiBlock *block)
 	int side;
 	int i, j;
 
-	/* First loop: we count number of buttons belonging to an align group, and clear their align flag. */
+	/* First loop: we count number of buttons belonging to an align group, and clear their align flag.
+	 * Tabs get some special treatment here, they get aligned to region border. */
 	for (but = block->buttons.first; but; but = but->next) {
-		/* Clear old align flags. */
-		but->drawflag &= ~UI_BUT_ALIGN_ALL;
+		/* special case: tabs need to be aligned to a region border, drawflag tells which one */
+		if (but->type == UI_BTYPE_TAB) {
+			ui_block_align_but_to_region(but, region);
+		}
+		else {
+			/* Clear old align flags. */
+			but->drawflag &= ~UI_BUT_ALIGN_ALL;
+		}
 
 		if (but->alignnr != 0) {
 			num_buttons++;