Main Workspace Integration

This commit does the main integration of workspaces, which is a design we agreed on during the 2.8 UI workshop (see https://wiki.blender.org/index.php/Dev:2.8/UI/Workshop_Writeup)

Workspaces should generally be stable, I'm not aware of any remaining bugs (or I've forgotten them :) ). If you find any, let me know!
(Exception: mode switching button might get out of sync with actual mode in some cases, would consider that a limitation/ToDo. Needs to be resolved at some point.)

== Main Changes/Features
* Introduces the new Workspaces as data-blocks.
* Allow storing a number of custom workspaces as part of the user configuration. Needs further work to allow adding and deleting individual workspaces.
* Bundle a default workspace configuration with Blender (current screen-layouts converted to workspaces).
* Pressing button to add a workspace spawns a menu to select between "Duplicate Current" and the workspaces from the user configuration. If no workspaces are stored in the user configuration, the default workspaces are listed instead.
* Store screen-layouts (`bScreen`) per workspace.
* Store an active screen-layout per workspace. Changing the workspace will enable this layout.
* Store active mode in workspace. Changing the workspace will also enter the mode of the new workspace. (Note that we still store the active mode in the object, moving this completely to workspaces is a separate project.)
* Store an active render layer per workspace.
* Moved mode switch from 3D View header to Info Editor header.
* Store active scene in window (not directly workspace related, but overlaps quite a bit).
* Removed 'Use Global Scene' User Preference option.
* Compatibility with old files - a new workspace is created for every screen-layout of old files. Old Blender versions should be able to read files saved with workspace support as well.
* Default .blend only contains one workspace ("General").
* Support appending workspaces.

Opening files without UI and commandline rendering should work fine.

Note that the UI is temporary! We plan to introduce a new global topbar
that contains the workspace options and tabs for switching workspaces.

== Technical Notes
* Workspaces are data-blocks.
* Adding and removing `bScreen`s should be done through `ED_workspace_layout` API now.
* A workspace can be active in multiple windows at the same time.
* The mode menu (which is now in the Info Editor header) doesn't display "Grease Pencil Edit" mode anymore since its availability depends on the active editor. Will be fixed by making Grease Pencil an own object type (as planned).
* The button to change the active workspace object mode may get out of sync with the mode of the active object. Will either be resolved by moving mode out of object data, or we'll disable workspace modes again (there's a `#define USE_WORKSPACE_MODE` for that).
* Screen-layouts (`bScreen`) are IDs and thus stored in a main list-base. Had to add a wrapper `WorkSpaceLayout` so we can store them in a list-base within workspaces, too. On the long run we could completely replace `bScreen` by workspace structs.
* `WorkSpace` types use some special compiler trickery to allow marking structs and struct members as private. BKE_workspace API should be used for accessing those.
* Added scene operators `SCENE_OT_`. Was previously done through screen operators.

== BPY API Changes
* Removed `Screen.scene`, added `Window.scene`
* Removed `UserPreferencesView.use_global_scene`
* Added `Context.workspace`, `Window.workspace` and `BlendData.workspaces`
* Added `bpy.types.WorkSpace` containing `screens`, `object_mode` and `render_layer`
* Added Screen.layout_name for the layout name that'll be displayed in the UI (may differ from internal name)

== What's left?
* There are a few open design questions (T50521). We should find the needed answers and implement them.
* Allow adding and removing individual workspaces from workspace configuration (needs UI design).
* Get the override system ready and support overrides per workspace.
* Support custom UI setups as part of workspaces (hidden panels, hidden buttons, customizable toolbars, etc).
* Allow enabling add-ons per workspace.
* Support custom workspace keymaps.
* Remove special exception for workspaces in linking code (so they're always appended, never linked). Depends on a few things, so best to solve later.
* Get the topbar done.
* Workspaces need a proper icon, current one is just a placeholder :)

Reviewed By: campbellbarton, mont29

Tags: #user_interface, #bf_blender_2.8

Maniphest Tasks: T50521

Differential Revision: https://developer.blender.org/D2451

1 files changed, 40 insertions, 7 deletions

diff --git a/source/blender/editors/include/ED_screen.h b/source/blender/editors/include/ED_screen.h
index 1208b1f31b6..dec8bf7d615 100644
--- a/source/blender/editors/include/ED_screen.h
+++ b/source/blender/editors/include/ED_screen.h
@@ -43,6 +43,8 @@ struct wmWindow;
 struct wmNotifier;
 struct wmEvent;
 struct wmKeyConfig;
+struct WorkSpace;
+struct WorkSpaceInstanceHook;
 struct bContext;
 struct Scene;
 struct bScreen;
@@ -107,12 +109,8 @@ void    ED_screens_initialize(struct wmWindowManager *wm);
 void    ED_screen_draw(struct wmWindow *win);
 void    ED_screen_refresh(struct wmWindowManager *wm, struct wmWindow *win);
 void    ED_screen_do_listen(struct bContext *C, struct wmNotifier *note);
-bScreen *ED_screen_duplicate(struct wmWindow *win, struct bScreen *sc);
-bScreen *ED_screen_add(struct wmWindow *win, struct Scene *scene, const char *name);
-bool    ED_screen_set(struct bContext *C, struct bScreen *sc);
-bool    ED_screen_delete(struct bContext *C, struct bScreen *sc);
-void    ED_screen_set_scene(struct bContext *C, struct bScreen *screen, struct Scene *scene);
-bool    ED_screen_delete_scene(struct bContext *C, struct Scene *scene);
+bool    ED_screen_change(struct bContext *C, struct bScreen *sc);
+void    ED_screen_update_after_scene_change(const struct bScreen *screen, struct Scene *scene_new);
 void    ED_screen_set_subwinactive(struct bContext *C, struct wmEvent *event);
 void    ED_screen_exit(struct bContext *C, struct wmWindow *window, struct bScreen *screen);
 void    ED_screen_animation_timer(struct bContext *C, int redraws, int refresh, int sync, int enable);
@@ -123,9 +121,42 @@ void    ED_screen_full_prevspace(struct bContext *C, ScrArea *sa);
 void    ED_screen_full_restore(struct bContext *C, ScrArea *sa);
 struct ScrArea *ED_screen_state_toggle(struct bContext *C, struct wmWindow *win, struct ScrArea *sa, const short state);
 void    ED_screens_header_tools_menu_create(struct bContext *C, struct uiLayout *layout, void *arg);
-bool    ED_screen_stereo3d_required(struct bScreen *screen);
+bool    ED_screen_stereo3d_required(const struct bScreen *screen, const struct Scene *scene);
+Scene   *ED_screen_scene_find(const struct bScreen *screen, const struct wmWindowManager *wm);
 void    ED_screen_preview_render(const struct bScreen *screen, int size_x, int size_y, unsigned int *r_rect) ATTR_NONNULL();
 
+/* workspaces */
+struct WorkSpace *ED_workspace_add(
+        struct Main *bmain,
+        const char *name,
+        SceneLayer *act_render_layer) ATTR_NONNULL();
+bool ED_workspace_change(
+        struct WorkSpace *workspace_new,
+        struct bContext *C,
+        struct wmWindowManager *wm, struct wmWindow *win) ATTR_NONNULL();
+struct WorkSpace *ED_workspace_duplicate(
+        struct WorkSpace *workspace_old,
+        struct Main *bmain, struct wmWindow *win);
+bool ED_workspace_delete(
+        struct WorkSpace *workspace,
+        struct Main *bmain, struct bContext *C,
+        struct wmWindowManager *wm, struct wmWindow *win) ATTR_NONNULL();
+void ED_workspace_scene_data_sync(
+        struct WorkSpaceInstanceHook *hook, Scene *scene) ATTR_NONNULL();
+struct WorkSpaceLayout *ED_workspace_layout_add(
+        struct WorkSpace *workspace,
+        struct wmWindow *win,
+        const char *name) ATTR_NONNULL();
+struct WorkSpaceLayout *ED_workspace_layout_duplicate(
+        struct WorkSpace *workspace, const struct WorkSpaceLayout *layout_old,
+        struct wmWindow *win) ATTR_NONNULL();
+bool ED_workspace_layout_delete(
+        struct WorkSpace *workspace, struct WorkSpaceLayout *layout_old,
+        struct bContext *C) ATTR_NONNULL();
+bool ED_workspace_layout_cycle(
+        struct WorkSpace *workspace, const short direction,
+        struct bContext *C) ATTR_NONNULL();
+
 /* anim */
 void    ED_update_for_newframe(struct Main *bmain, struct Scene *scene, int mute);
 
@@ -137,6 +168,8 @@ bScreen *ED_screen_animation_no_scrub(const struct wmWindowManager *wm);
 /* screen keymaps */
 void    ED_operatortypes_screen(void);
 void    ED_keymap_screen(struct wmKeyConfig *keyconf);
+/* workspace keymaps */
+void    ED_operatortypes_workspace(void);
 
 /* operators; context poll callbacks */
 int     ED_operator_screenactive(struct bContext *C);