/*
 * 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) 2008 Blender Foundation.
 * All rights reserved.
 */

/** \file
 * \ingroup edscr
 */


#include <string.h>
#include <math.h>


#include "MEM_guardedalloc.h"

#include "DNA_object_types.h"
#include "DNA_scene_types.h"
#include "DNA_workspace_types.h"
#include "DNA_userdef_types.h"

#include "BLI_blenlib.h"
#include "BLI_utildefines.h"

#include "BKE_context.h"
#include "BKE_global.h"
#include "BKE_icons.h"
#include "BKE_image.h"
#include "BKE_layer.h"
#include "BKE_library.h"
#include "BKE_main.h"
#include "BKE_node.h"
#include "BKE_screen.h"
#include "BKE_scene.h"
#include "BKE_workspace.h"

#include "WM_api.h"
#include "WM_types.h"

#include "ED_object.h"
#include "ED_screen.h"
#include "ED_screen_types.h"
#include "ED_clip.h"
#include "ED_node.h"
#include "ED_render.h"

#include "UI_interface.h"

#include "WM_message.h"

#include "DEG_depsgraph_query.h"

#include "screen_intern.h"  /* own module include */


/* adds no space data */
static ScrArea *screen_addarea_ex(
        ScrAreaMap *area_map,
        ScrVert *bottom_left, ScrVert *top_left, ScrVert *top_right, ScrVert *bottom_right,
        short spacetype)
{
	ScrArea *sa = MEM_callocN(sizeof(ScrArea), "addscrarea");

	sa->v1 = bottom_left;
	sa->v2 = top_left;
	sa->v3 = top_right;
	sa->v4 = bottom_right;
	sa->spacetype = spacetype;

	BLI_addtail(&area_map->areabase, sa);

	return sa;
}
static ScrArea *screen_addarea(
        bScreen *sc,
        ScrVert *left_bottom, ScrVert *left_top, ScrVert *right_top, ScrVert *right_bottom,
        short spacetype)
{
	return screen_addarea_ex(AREAMAP_FROM_SCREEN(sc), left_bottom, left_top, right_top, right_bottom,
	                         spacetype);
}

static void screen_delarea(bContext *C, bScreen *sc, ScrArea *sa)
{

	ED_area_exit(C, sa);

	BKE_screen_area_free(sa);

	BLI_remlink(&sc->areabase, sa);
	MEM_freeN(sa);
}

ScrArea *area_split(const wmWindow *win, bScreen *sc, ScrArea *sa, char dir, float fac, int merge)
{
	ScrArea *newa = NULL;
	ScrVert *sv1, *sv2;
	short split;
	rcti window_rect;

	if (sa == NULL) return NULL;

	WM_window_rect_calc(win, &window_rect);

	split = screen_geom_find_area_split_point(sa, &window_rect, dir, fac);
	if (split == 0) return NULL;

	/* note regarding (fac > 0.5f) checks below.
	 * normally it shouldn't matter which is used since the copy should match the original
	 * however with viewport rendering and python console this isn't the case. - campbell */

	if (dir == 'h') {
		/* new vertices */
		sv1 = screen_geom_vertex_add(sc, sa->v1->vec.x, split);
		sv2 = screen_geom_vertex_add(sc, sa->v4->vec.x, split);

		/* new edges */
		screen_geom_edge_add(sc, sa->v1, sv1);
		screen_geom_edge_add(sc, sv1, sa->v2);
		screen_geom_edge_add(sc, sa->v3, sv2);
		screen_geom_edge_add(sc, sv2, sa->v4);
		screen_geom_edge_add(sc, sv1, sv2);

		if (fac > 0.5f) {
			/* new areas: top */
			newa = screen_addarea(sc, sv1, sa->v2, sa->v3, sv2, sa->spacetype);

			/* area below */
			sa->v2 = sv1;
			sa->v3 = sv2;
		}
		else {
			/* new areas: bottom */
			newa = screen_addarea(sc, sa->v1, sv1, sv2, sa->v4, sa->spacetype);

			/* area above */
			sa->v1 = sv1;
			sa->v4 = sv2;
		}

		ED_area_data_copy(newa, sa, true);

	}
	else {
		/* new vertices */
		sv1 = screen_geom_vertex_add(sc, split, sa->v1->vec.y);
		sv2 = screen_geom_vertex_add(sc, split, sa->v2->vec.y);

		/* new edges */
		screen_geom_edge_add(sc, sa->v1, sv1);
		screen_geom_edge_add(sc, sv1, sa->v4);
		screen_geom_edge_add(sc, sa->v2, sv2);
		screen_geom_edge_add(sc, sv2, sa->v3);
		screen_geom_edge_add(sc, sv1, sv2);

		if (fac > 0.5f) {
			/* new areas: right */
			newa = screen_addarea(sc, sv1, sv2, sa->v3, sa->v4, sa->spacetype);

			/* area left */
			sa->v3 = sv2;
			sa->v4 = sv1;
		}
		else {
			/* new areas: left */
			newa = screen_addarea(sc, sa->v1, sa->v2, sv2, sv1, sa->spacetype);

			/* area right */
			sa->v1 = sv1;
			sa->v2 = sv2;
		}

		ED_area_data_copy(newa, sa, true);
	}

	/* remove double vertices en edges */
	if (merge)
		BKE_screen_remove_double_scrverts(sc);
	BKE_screen_remove_double_scredges(sc);
	BKE_screen_remove_unused_scredges(sc);

	return newa;
}

/**
 * Empty screen, with 1 dummy area without spacedata. Uses window size.
 */
bScreen *screen_add(Main *bmain, const char *name, const rcti *rect)
{
	bScreen *sc;
	ScrVert *sv1, *sv2, *sv3, *sv4;

	sc = BKE_libblock_alloc(bmain, ID_SCR, name, 0);
	sc->do_refresh = true;
	sc->redraws_flag = TIME_ALL_3D_WIN | TIME_ALL_ANIM_WIN;

	sv1 = screen_geom_vertex_add(sc, rect->xmin,     rect->ymin);
	sv2 = screen_geom_vertex_add(sc, rect->xmin,     rect->ymax - 1);
	sv3 = screen_geom_vertex_add(sc, rect->xmax - 1, rect->ymax - 1);
	sv4 = screen_geom_vertex_add(sc, rect->xmax - 1, rect->ymin);

	screen_geom_edge_add(sc, sv1, sv2);
	screen_geom_edge_add(sc, sv2, sv3);
	screen_geom_edge_add(sc, sv3, sv4);
	screen_geom_edge_add(sc, sv4, sv1);

	/* dummy type, no spacedata */
	screen_addarea(sc, sv1, sv2, sv3, sv4, SPACE_EMPTY);

	return sc;
}

void screen_data_copy(bScreen *to, bScreen *from)
{
	ScrVert *s1, *s2;
	ScrEdge *se;
	ScrArea *sa, *saf;

	/* free contents of 'to', is from blenkernel screen.c */
	BKE_screen_free(to);

	to->flag = from->flag;

	BLI_duplicatelist(&to->vertbase, &from->vertbase);
	BLI_duplicatelist(&to->edgebase, &from->edgebase);
	BLI_duplicatelist(&to->areabase, &from->areabase);
	BLI_listbase_clear(&to->regionbase);

	s2 = to->vertbase.first;
	for (s1 = from->vertbase.first; s1; s1 = s1->next, s2 = s2->next) {
		s1->newv = s2;
	}

	for (se = to->edgebase.first; se; se = se->next) {
		se->v1 = se->v1->newv;
		se->v2 = se->v2->newv;
		BKE_screen_sort_scrvert(&(se->v1), &(se->v2));
	}

	saf = from->areabase.first;
	for (sa = to->areabase.first; sa; sa = sa->next, saf = saf->next) {
		sa->v1 = sa->v1->newv;
		sa->v2 = sa->v2->newv;
		sa->v3 = sa->v3->newv;
		sa->v4 = sa->v4->newv;

		BLI_listbase_clear(&sa->spacedata);
		BLI_listbase_clear(&sa->regionbase);
		BLI_listbase_clear(&sa->actionzones);
		BLI_listbase_clear(&sa->handlers);

		ED_area_data_copy(sa, saf, true);
	}

	/* put at zero (needed?) */
	for (s1 = from->vertbase.first; s1; s1 = s1->next)
		s1->newv = NULL;
}

/**
 * Prepare a newly created screen for initializing it as active screen.
 */
void screen_new_activate_prepare(const wmWindow *win, bScreen *screen_new)
{
	screen_new->winid = win->winid;
	screen_new->do_refresh = true;
	screen_new->do_draw = true;
}


/* with sa as center, sb is located at: 0=W, 1=N, 2=E, 3=S */
/* -1 = not valid check */
/* used with join operator */
int area_getorientation(ScrArea *sa, ScrArea *sb)
{
	ScrVert *sav1, *sav2, *sav3, *sav4;
	ScrVert *sbv1, *sbv2, *sbv3, *sbv4;

	if (sa == NULL || sb == NULL) return -1;

	sav1 = sa->v1;
	sav2 = sa->v2;
	sav3 = sa->v3;
	sav4 = sa->v4;
	sbv1 = sb->v1;
	sbv2 = sb->v2;
	sbv3 = sb->v3;
	sbv4 = sb->v4;

	if (sav1 == sbv4 && sav2 == sbv3) { /* sa to right of sb = W */
		return 0;
	}
	else if (sav2 == sbv1 && sav3 == sbv4) { /* sa to bottom of sb = N */
		return 1;
	}
	else if (sav3 == sbv2 && sav4 == sbv1) { /* sa to left of sb = E */
		return 2;
	}
	else if (sav1 == sbv2 && sav4 == sbv3) { /* sa on top of sb = S*/
		return 3;
	}

	return -1;
}

/* Helper function to join 2 areas, it has a return value, 0=failed 1=success
 * used by the split, join operators
 */
int screen_area_join(bContext *C, bScreen *scr, ScrArea *sa1, ScrArea *sa2)
{
	int dir;

	dir = area_getorientation(sa1, sa2);
	/*printf("dir is : %i\n", dir);*/

	if (dir == -1) {
		return 0;
	}

	if (dir == 0) {
		sa1->v1 = sa2->v1;
		sa1->v2 = sa2->v2;
		screen_geom_edge_add(scr, sa1->v2, sa1->v3);
		screen_geom_edge_add(scr, sa1->v1, sa1->v4);
	}
	else if (dir == 1) {
		sa1->v2 = sa2->v2;
		sa1->v3 = sa2->v3;
		screen_geom_edge_add(scr, sa1->v1, sa1->v2);
		screen_geom_edge_add(scr, sa1->v3, sa1->v4);
	}
	else if (dir == 2) {
		sa1->v3 = sa2->v3;
		sa1->v4 = sa2->v4;
		screen_geom_edge_add(scr, sa1->v2, sa1->v3);
		screen_geom_edge_add(scr, sa1->v1, sa1->v4);
	}
	else if (dir == 3) {
		sa1->v1 = sa2->v1;
		sa1->v4 = sa2->v4;
		screen_geom_edge_add(scr, sa1->v1, sa1->v2);
		screen_geom_edge_add(scr, sa1->v3, sa1->v4);
	}

	screen_delarea(C, scr, sa2);
	BKE_screen_remove_double_scrverts(scr);
	/* Update preview thumbnail */
	BKE_icon_changed(scr->id.icon_id);

	return 1;
}


/* ****************** EXPORTED API TO OTHER MODULES *************************** */

/* screen sets cursor based on active region */
static void region_cursor_set(wmWindow *win, bool swin_changed)
{
	bScreen *screen = WM_window_get_active_screen(win);

	ED_screen_areas_iter(win, screen, sa) {
		for (ARegion *ar = sa->regionbase.first; ar; ar = ar->next) {
			if (ar == screen->active_region) {
				if (swin_changed || (ar->type && ar->type->event_cursor)) {
					if (ar->gizmo_map != NULL) {
						if (WM_gizmomap_cursor_set(ar->gizmo_map, win)) {
							return;
						}
					}
					ED_region_cursor_set(win, sa, ar);
				}
				return;
			}
		}
	}
}

void ED_screen_do_listen(bContext *C, wmNotifier *note)
{
	wmWindow *win = CTX_wm_window(C);
	bScreen *screen = CTX_wm_screen(C);

	/* generic notes */
	switch (note->category) {
		case NC_WM:
			if (note->data == ND_FILEREAD)
				screen->do_draw = true;
			break;
		case NC_WINDOW:
			screen->do_draw = true;
			break;
		case NC_SCREEN:
			if (note->action == NA_EDITED)
				screen->do_draw = screen->do_refresh = true;
			break;
		case NC_SCENE:
			if (note->data == ND_MODE)
				region_cursor_set(win, true);
			break;
	}
}

/* helper call for below, dpi changes headers */
static void screen_refresh_headersizes(void)
{
	const ListBase *lb = BKE_spacetypes_list();
	SpaceType *st;

	for (st = lb->first; st; st = st->next) {
		ARegionType *art;
		art = BKE_regiontype_from_id(st, RGN_TYPE_HEADER);
		if (art) art->prefsizey = ED_area_headersize();

		art = BKE_regiontype_from_id(st, RGN_TYPE_FOOTER);
		if (art) art->prefsizey = ED_area_headersize();
	}
}

/* make this screen usable */
/* for file read and first use, for scaling window, area moves */
void ED_screen_refresh(wmWindowManager *wm, wmWindow *win)
{
	bScreen *screen = WM_window_get_active_screen(win);

	/* exception for bg mode, we only need the screen context */
	if (!G.background) {
		/* header size depends on DPI, let's verify */
		WM_window_set_dpi(win);

		ED_screen_global_areas_refresh(win);
		screen_refresh_headersizes();

		screen_geom_vertices_scale(win, screen);

		ED_screen_areas_iter(win, screen, area) {
			/* set spacetype and region callbacks, calls init() */
			/* sets subwindows for regions, adds handlers */
			ED_area_initialize(wm, win, area);
		}

		/* wake up animtimer */
		if (screen->animtimer)
			WM_event_timer_sleep(wm, win, screen->animtimer, false);
	}

	if (G.debug & G_DEBUG_EVENTS) {
		printf("%s: set screen\n", __func__);
	}
	screen->do_refresh = false;
	/* prevent multiwin errors */
	screen->winid = win->winid;

	screen->context = ed_screen_context;
}

/* file read, set all screens, ... */
void ED_screens_initialize(Main *bmain, wmWindowManager *wm)
{
	wmWindow *win;

	for (win = wm->windows.first; win; win = win->next) {
		if (BKE_workspace_active_get(win->workspace_hook) == NULL) {
			BKE_workspace_active_set(win->workspace_hook, bmain->workspaces.first);
		}

		ED_screen_refresh(wm, win);
		if (win->eventstate) {
			ED_screen_set_active_region(NULL, win, &win->eventstate->x);
		}
	}

	if (U.uiflag & USER_HEADER_FROM_PREF) {
		for (bScreen *screen = bmain->screens.first; screen; screen = screen->id.next) {
			BKE_screen_header_alignment_reset(screen);
		}
	}
}

void ED_screen_ensure_updated(wmWindowManager *wm, wmWindow *win, bScreen *screen)
{
	if (screen->do_refresh) {
		ED_screen_refresh(wm, win);
	}
}


/* *********** exit calls are for closing running stuff ******** */

void ED_region_exit(bContext *C, ARegion *ar)
{
	wmWindowManager *wm = CTX_wm_manager(C);
	wmWindow *win = CTX_wm_window(C);
	ARegion *prevar = CTX_wm_region(C);

	if (ar->type && ar->type->exit)
		ar->type->exit(wm, ar);

	CTX_wm_region_set(C, ar);

	WM_event_remove_handlers(C, &ar->handlers);
	WM_event_modal_handler_region_replace(win, ar, NULL);
	WM_draw_region_free(ar);

	if (ar->headerstr) {
		MEM_freeN(ar->headerstr);
		ar->headerstr = NULL;
	}

	if (ar->regiontimer) {
		WM_event_remove_timer(wm, win, ar->regiontimer);
		ar->regiontimer = NULL;
	}

	WM_msgbus_clear_by_owner(wm->message_bus, ar);

	CTX_wm_region_set(C, prevar);
}

void ED_area_exit(bContext *C, ScrArea *sa)
{
	wmWindowManager *wm = CTX_wm_manager(C);
	wmWindow *win = CTX_wm_window(C);
	ScrArea *prevsa = CTX_wm_area(C);
	ARegion *ar;

	if (sa->type && sa->type->exit)
		sa->type->exit(wm, sa);

	CTX_wm_area_set(C, sa);

	for (ar = sa->regionbase.first; ar; ar = ar->next)
		ED_region_exit(C, ar);

	WM_event_remove_handlers(C, &sa->handlers);
	WM_event_modal_handler_area_replace(win, sa, NULL);

	CTX_wm_area_set(C, prevsa);
}

void ED_screen_exit(bContext *C, wmWindow *window, bScreen *screen)
{
	wmWindowManager *wm = CTX_wm_manager(C);
	wmWindow *prevwin = CTX_wm_window(C);

	CTX_wm_window_set(C, window);

	if (screen->animtimer)
		WM_event_remove_timer(wm, window, screen->animtimer);
	screen->animtimer = NULL;
	screen->scrubbing = false;

	screen->active_region = NULL;

	for (ARegion *ar = screen->regionbase.first; ar; ar = ar->next) {
		ED_region_exit(C, ar);
	}
	for (ScrArea *sa = screen->areabase.first; sa; sa = sa->next) {
		ED_area_exit(C, sa);
	}
	/* Don't use ED_screen_areas_iter here, it skips hidden areas. */
	for (ScrArea *sa = window->global_areas.areabase.first; sa; sa = sa->next) {
		ED_area_exit(C, sa);
	}

	/* mark it available for use for other windows */
	screen->winid = 0;

	if (!WM_window_is_temp_screen(prevwin)) {
		/* use previous window if possible */
		CTX_wm_window_set(C, prevwin);
	}
	else {
		/* none otherwise */
		CTX_wm_window_set(C, NULL);
	}

}

/* *********************************** */

/* case when on area-edge or in azones, or outside window */
static void screen_cursor_set(wmWindow *win, const int xy[2])
{
	const bScreen *screen = WM_window_get_active_screen(win);
	AZone *az = NULL;
	ScrArea *sa;

	for (sa = screen->areabase.first; sa; sa = sa->next)
		if ((az = ED_area_actionzone_find_xy(sa, xy)))
			break;

	if (sa) {
		if (az->type == AZONE_AREA)
			WM_cursor_set(win, CURSOR_EDIT);
		else if (az->type == AZONE_REGION) {
			if (az->edge == AE_LEFT_TO_TOPRIGHT || az->edge == AE_RIGHT_TO_TOPLEFT)
				WM_cursor_set(win, CURSOR_X_MOVE);
			else
				WM_cursor_set(win, CURSOR_Y_MOVE);
		}
	}
	else {
		ScrEdge *actedge = screen_geom_find_active_scredge(win, screen, xy[0], xy[1]);

		if (actedge) {
			if (screen_geom_edge_is_horizontal(actedge))
				WM_cursor_set(win, CURSOR_Y_MOVE);
			else
				WM_cursor_set(win, CURSOR_X_MOVE);
		}
		else
			WM_cursor_set(win, CURSOR_STD);
	}
}


/* called in wm_event_system.c. sets state vars in screen, cursors */
/* event type is mouse move */
void ED_screen_set_active_region(bContext *C, wmWindow *win, const int xy[2])
{
	bScreen *scr = WM_window_get_active_screen(win);

	if (scr) {
		ScrArea *sa = NULL;
		ARegion *ar;
		ARegion *old_ar = scr->active_region;

		ED_screen_areas_iter(win, scr, area_iter) {
			if (xy[0] > area_iter->totrct.xmin && xy[0] < area_iter->totrct.xmax) {
				if (xy[1] > area_iter->totrct.ymin && xy[1] < area_iter->totrct.ymax) {
					if (ED_area_azones_update(area_iter, xy) == NULL) {
						sa = area_iter;
						break;
					}
				}
			}
		}
		if (sa) {
			/* make overlap active when mouse over */
			for (ar = sa->regionbase.first; ar; ar = ar->next) {
				if (BLI_rcti_isect_pt_v(&ar->winrct, xy)) {
					scr->active_region = ar;
					break;
				}
			}
		}
		else
			scr->active_region = NULL;

		/* check for redraw headers */
		if (old_ar != scr->active_region) {

			ED_screen_areas_iter(win, scr, area_iter) {
				bool do_draw = false;

				for (ar = area_iter->regionbase.first; ar; ar = ar->next) {
					if (ar == old_ar || ar == scr->active_region) {
						do_draw = true;
					}
				}

				if (do_draw) {
					for (ar = area_iter->regionbase.first; ar; ar = ar->next) {
						if (ar->regiontype == RGN_TYPE_HEADER) {
							ED_region_tag_redraw_no_rebuild(ar);
						}
					}
				}
			}
		}

		/* cursors, for time being set always on edges, otherwise aregion doesn't switch */
		if (scr->active_region == NULL) {
			screen_cursor_set(win, xy);
		}
		else {
			/* notifier invokes freeing the buttons... causing a bit too much redraws */
			if (old_ar != scr->active_region) {
				region_cursor_set(win, true);

				/* this used to be a notifier, but needs to be done immediate
				 * because it can undo setting the right button as active due
				 * to delayed notifier handling */
				if (C) {
					UI_screen_free_active_but(C, scr);
				}
			}
			else
				region_cursor_set(win, false);
		}
	}
}

int ED_screen_area_active(const bContext *C)
{
	wmWindow *win = CTX_wm_window(C);
	bScreen *sc = CTX_wm_screen(C);
	ScrArea *sa = CTX_wm_area(C);

	if (win && sc && sa) {
		AZone *az = ED_area_actionzone_find_xy(sa, &win->eventstate->x);
		ARegion *ar;

		if (az && az->type == AZONE_REGION)
			return 1;

		for (ar = sa->regionbase.first; ar; ar = ar->next)
			if (ar == sc->active_region)
				return 1;
	}
	return 0;
}

/**
 * Add an area and geometry (screen-edges and -vertices) for it to \a area_map,
 * with coordinates/dimensions matching \a rect.
 */
static ScrArea *screen_area_create_with_geometry(
        ScrAreaMap *area_map, const rcti *rect,
        short spacetype)
{
	ScrVert *bottom_left  = screen_geom_vertex_add_ex(area_map, rect->xmin, rect->ymin);
	ScrVert *top_left     = screen_geom_vertex_add_ex(area_map, rect->xmin, rect->ymax);
	ScrVert *top_right    = screen_geom_vertex_add_ex(area_map, rect->xmax, rect->ymax);
	ScrVert *bottom_right = screen_geom_vertex_add_ex(area_map, rect->xmax, rect->ymin);

	screen_geom_edge_add_ex(area_map, bottom_left, top_left);
	screen_geom_edge_add_ex(area_map, top_left, top_right);
	screen_geom_edge_add_ex(area_map, top_right, bottom_right);
	screen_geom_edge_add_ex(area_map, bottom_right, bottom_left);

	return screen_addarea_ex(area_map, bottom_left, top_left, top_right, bottom_right, spacetype);
}

static void screen_area_set_geometry_rect(ScrArea *sa, const rcti *rect)
{
	sa->v1->vec.x = rect->xmin;
	sa->v1->vec.y = rect->ymin;
	sa->v2->vec.x = rect->xmin;
	sa->v2->vec.y = rect->ymax;
	sa->v3->vec.x = rect->xmax;
	sa->v3->vec.y = rect->ymax;
	sa->v4->vec.x = rect->xmax;
	sa->v4->vec.y = rect->ymin;
}

static void screen_global_area_refresh(
        wmWindow *win, bScreen *screen,
        eSpace_Type space_type, GlobalAreaAlign align, const rcti *rect,
        const short height_cur, const short height_min, const short height_max)
{
	ScrArea *area;

	for (area = win->global_areas.areabase.first; area; area = area->next) {
		if (area->spacetype == space_type) {
			break;
		}
	}

	if (area) {
		screen_area_set_geometry_rect(area, rect);
	}
	else {
		area = screen_area_create_with_geometry(&win->global_areas, rect, space_type);
		SpaceType *stype = BKE_spacetype_from_id(space_type);
		SpaceLink *slink = stype->new(area, WM_window_get_active_scene(win));

		area->regionbase = slink->regionbase;

		BLI_addhead(&area->spacedata, slink);
		BLI_listbase_clear(&slink->regionbase);

		/* Data specific to global areas. */
		area->global = MEM_callocN(sizeof(*area->global), __func__);
		area->global->size_max = height_max;
		area->global->size_min = height_min;
		area->global->align = align;
	}

	if (area->global->cur_fixed_height != height_cur) {
		/* Refresh layout if size changes. */
		area->global->cur_fixed_height = height_cur;
		screen->do_refresh = true;
	}
}

static int screen_global_header_size(void)
{
	return (int)ceilf(ED_area_headersize() / UI_DPI_FAC);
}

static void screen_global_topbar_area_refresh(wmWindow *win, bScreen *screen)
{
	const short size_min = screen_global_header_size();
	const short size_max = 2.25 * screen_global_header_size();
	const short size = (screen->flag & SCREEN_COLLAPSE_TOPBAR) ? size_min : size_max;
	rcti rect;

	BLI_rcti_init(&rect, 0, WM_window_pixels_x(win) - 1, 0, WM_window_pixels_y(win) - 1);
	rect.ymin = rect.ymax - size_max;

	screen_global_area_refresh(win, screen, SPACE_TOPBAR, GLOBAL_AREA_ALIGN_TOP, &rect, size, size_min, size_max);
}

static void screen_global_statusbar_area_refresh(wmWindow *win, bScreen *screen)
{
	const short size_min = 1;
	const short size_max = 0.8f * screen_global_header_size();
	const short size = (screen->flag & SCREEN_COLLAPSE_STATUSBAR) ? size_min : size_max;
	rcti rect;

	BLI_rcti_init(&rect, 0, WM_window_pixels_x(win) - 1, 0, WM_window_pixels_y(win) - 1);
	rect.ymax = rect.ymin + size_max;

	screen_global_area_refresh(win, screen, SPACE_STATUSBAR, GLOBAL_AREA_ALIGN_BOTTOM, &rect, size, size_min, size_max);
}

void ED_screen_global_areas_sync(wmWindow *win)
{
	/* Update screen flags from height in window, this is weak and perhaps
	 * global areas should just become part of the screen instead. */
	bScreen *screen = BKE_workspace_active_screen_get(win->workspace_hook);

	screen->flag &= ~(SCREEN_COLLAPSE_STATUSBAR | SCREEN_COLLAPSE_TOPBAR);

	for (ScrArea *area = win->global_areas.areabase.first; area; area = area->next) {
		if (area->global->cur_fixed_height == area->global->size_min) {
			if (area->spacetype == SPACE_TOPBAR) {
				screen->flag |= SCREEN_COLLAPSE_TOPBAR;
			}
			else if (area->spacetype == SPACE_STATUSBAR) {
				screen->flag |= SCREEN_COLLAPSE_STATUSBAR;
			}
		}
	}
}

void ED_screen_global_areas_refresh(wmWindow *win)
{
	/* Don't create global area for child and temporary windows. */
	bScreen *screen = BKE_workspace_active_screen_get(win->workspace_hook);
	if ((win->parent != NULL) || screen->temp) {
		if (win->global_areas.areabase.first) {
			screen->do_refresh = true;
			BKE_screen_area_map_free(&win->global_areas);
		}
		return;
	}

	screen_global_topbar_area_refresh(win, screen);
	screen_global_statusbar_area_refresh(win, screen);
}


/* -------------------------------------------------------------------- */
/* Screen changing */

static bScreen *screen_fullscreen_find_associated_normal_screen(const Main *bmain, bScreen *screen)
{
	for (bScreen *screen_iter = bmain->screens.first; screen_iter; screen_iter = screen_iter->id.next) {
		ScrArea *sa = screen_iter->areabase.first;
		if (sa && sa->full == screen) {
			return screen_iter;
		}
	}

	return screen;
}

/**
 * \return the screen to activate.
 * \warning The returned screen may not always equal \a screen_new!
 */
bScreen *screen_change_prepare(bScreen *screen_old, bScreen *screen_new, Main *bmain, bContext *C, wmWindow *win)
{
	/* validate screen, it's called with notifier reference */
	if (BLI_findindex(&bmain->screens, screen_new) == -1) {
		return NULL;
	}

	if (ELEM(screen_new->state, SCREENMAXIMIZED, SCREENFULL)) {
		screen_new = screen_fullscreen_find_associated_normal_screen(bmain, screen_new);
	}

	/* check for valid winid */
	if (!(screen_new->winid == 0 || screen_new->winid == win->winid)) {
		return NULL;
	}

	if (screen_old != screen_new) {
		wmTimer *wt = screen_old->animtimer;

		/* remove handlers referencing areas in old screen */
		for (ScrArea *sa = screen_old->areabase.first; sa; sa = sa->next) {
			WM_event_remove_area_handler(&win->modalhandlers, sa);
		}

		/* we put timer to sleep, so screen_exit has to think there's no timer */
		screen_old->animtimer = NULL;
		if (wt) {
			WM_event_timer_sleep(CTX_wm_manager(C), win, wt, true);
		}
		ED_screen_exit(C, win, screen_old);

		/* Same scene, "transfer" playback to new screen. */
		if (wt) {
			screen_new->animtimer = wt;
		}

		return screen_new;
	}

	return NULL;
}

void screen_change_update(bContext *C, wmWindow *win, bScreen *sc)
{
	Scene *scene = WM_window_get_active_scene(win);
	WorkSpace *workspace = BKE_workspace_active_get(win->workspace_hook);
	WorkSpaceLayout *layout = BKE_workspace_layout_find(workspace, sc);

	CTX_wm_window_set(C, win);  /* stores C->wm.screen... hrmf */

	ED_screen_refresh(CTX_wm_manager(C), win);

	BKE_screen_view3d_scene_sync(sc, scene); /* sync new screen with scene data */
	WM_event_add_notifier(C, NC_WINDOW, NULL);
	WM_event_add_notifier(C, NC_SCREEN | ND_LAYOUTSET, layout);

	/* makes button hilites work */
	WM_event_add_mousemove(C);
}


/**
 * \brief Change the active screen.
 *
 * Operator call, WM + Window + screen already existed before
 *
 * \warning Do NOT call in area/region queues!
 * \returns if screen changing was successful.
 */
bool ED_screen_change(bContext *C, bScreen *sc)
{
	Main *bmain = CTX_data_main(C);
	wmWindow *win = CTX_wm_window(C);
	bScreen *screen_old = CTX_wm_screen(C);
	bScreen *screen_new = screen_change_prepare(screen_old, sc, bmain, C, win);

	if (screen_new) {
		WorkSpace *workspace = BKE_workspace_active_get(win->workspace_hook);
		WM_window_set_active_screen(win, workspace, sc);
		screen_change_update(C, win, screen_new);

		return true;
	}

	return false;
}

static void screen_set_3dview_camera(Scene *scene, ViewLayer *view_layer, ScrArea *sa, View3D *v3d)
{
	/* fix any cameras that are used in the 3d view but not in the scene */
	BKE_screen_view3d_sync(v3d, scene);

	if (!v3d->camera || !BKE_view_layer_base_find(view_layer, v3d->camera)) {
		v3d->camera = BKE_view_layer_camera_find(view_layer);
		// XXX if (sc == curscreen) handle_view3d_lock();
		if (!v3d->camera) {
			ARegion *ar;
			ListBase *regionbase;

			/* regionbase is in different place depending if space is active */
			if (v3d == sa->spacedata.first)
				regionbase = &sa->regionbase;
			else
				regionbase = &v3d->regionbase;

			for (ar = regionbase->first; ar; ar = ar->next) {
				if (ar->regiontype == RGN_TYPE_WINDOW) {
					RegionView3D *rv3d = ar->regiondata;
					if (rv3d->persp == RV3D_CAMOB) {
						rv3d->persp = RV3D_PERSP;
					}
				}
			}
		}
	}
}

void ED_screen_scene_change(bContext *C, wmWindow *win, Scene *scene)
{
#if 0
	ViewLayer *view_layer_old = WM_window_get_active_view_layer(win);
#endif

	/* Switch scene. */
	win->scene = scene;
	if (CTX_wm_window(C) == win) {
		CTX_data_scene_set(C, scene);
	}

	/* Ensure the view layer name is updated. */
	WM_window_ensure_active_view_layer(win);
	ViewLayer *view_layer = WM_window_get_active_view_layer(win);

#if 0
	/* Mode Syncing. */
	if (view_layer_old) {
		WorkSpace *workspace = CTX_wm_workspace(C);
		Object *obact_new = OBACT(view_layer);
		UNUSED_VARS(obact_new);
		eObjectMode object_mode_old = workspace->object_mode;
		Object *obact_old = OBACT(view_layer_old);
		UNUSED_VARS(obact_old, object_mode_old);
	}
#endif

	/* Update 3D view cameras. */
	const bScreen *screen = WM_window_get_active_screen(win);
	for (ScrArea *sa = screen->areabase.first; sa; sa = sa->next) {
		for (SpaceLink *sl = sa->spacedata.first; sl; sl = sl->next) {
			if (sl->spacetype == SPACE_VIEW3D) {
				View3D *v3d = (View3D *)sl;
				screen_set_3dview_camera(scene, view_layer, sa, v3d);
			}
		}
	}
}

ScrArea *ED_screen_full_newspace(bContext *C, ScrArea *sa, int type)
{
	wmWindow *win = CTX_wm_window(C);
	ScrArea *newsa = NULL;

	if (!sa || sa->full == NULL) {
		newsa = ED_screen_state_toggle(C, win, sa, SCREENMAXIMIZED);
	}

	if (!newsa) {
		newsa = sa;
	}

	BLI_assert(newsa);

	if (sa && (sa->spacetype != type)) {
		newsa->flag |= AREA_FLAG_TEMP_TYPE;
	}
	else {
		newsa->flag &= ~AREA_FLAG_TEMP_TYPE;
	}

	ED_area_newspace(C, newsa, type, (newsa->flag & AREA_FLAG_TEMP_TYPE));

	return newsa;
}

/**
 * \a was_prev_temp for the case previous space was a temporary fullscreen as well
 */
void ED_screen_full_prevspace(bContext *C, ScrArea *sa)
{
	BLI_assert(sa->full);

	if (sa->flag & AREA_FLAG_STACKED_FULLSCREEN) {
		/* stacked fullscreen -> only go back to previous screen and don't toggle out of fullscreen */
		ED_area_prevspace(C, sa);
	}
	else {
		ED_screen_restore_temp_type(C, sa);
	}
}

void ED_screen_restore_temp_type(bContext *C, ScrArea *sa)
{
	/* incase nether functions below run */
	ED_area_tag_redraw(sa);

	if (sa->flag & AREA_FLAG_TEMP_TYPE) {
		ED_area_prevspace(C, sa);
		/* Flag should be cleared now. */
		BLI_assert((sa->flag & AREA_FLAG_TEMP_TYPE) == 0);
	}

	if (sa->full) {
		ED_screen_state_toggle(C, CTX_wm_window(C), sa, SCREENMAXIMIZED);
	}
}

/* restore a screen / area back to default operation, after temp fullscreen modes */
void ED_screen_full_restore(bContext *C, ScrArea *sa)
{
	wmWindow *win = CTX_wm_window(C);
	SpaceLink *sl = sa->spacedata.first;
	bScreen *screen = CTX_wm_screen(C);
	short state = (screen ? screen->state : SCREENMAXIMIZED);

	/* if fullscreen area has a temporary space (such as a file browser or fullscreen render
	 * overlaid on top of an existing setup) then return to the previous space */

	if (sl->next) {
		if (sa->flag & AREA_FLAG_TEMP_TYPE) {
			ED_screen_full_prevspace(C, sa);
		}
		else {
			ED_screen_state_toggle(C, win, sa, state);
		}
		/* warning: 'sa' may be freed */
	}
	/* otherwise just tile the area again */
	else {
		ED_screen_state_toggle(C, win, sa, state);
	}
}

/**
 * this function toggles: if area is maximized/full then the parent will be restored
 *
 * \warning \a sa may be freed.
 */
ScrArea *ED_screen_state_toggle(bContext *C, wmWindow *win, ScrArea *sa, const short state)
{
	Main *bmain = CTX_data_main(C);
	wmWindowManager *wm = CTX_wm_manager(C);
	WorkSpace *workspace = WM_window_get_active_workspace(win);
	bScreen *sc, *oldscreen;
	ARegion *ar;

	if (sa) {
		/* ensure we don't have a button active anymore, can crash when
		 * switching screens with tooltip open because region and tooltip
		 * are no longer in the same screen */
		for (ar = sa->regionbase.first; ar; ar = ar->next) {
			UI_blocklist_free(C, &ar->uiblocks);

			if (ar->regiontimer) {
				WM_event_remove_timer(wm, NULL, ar->regiontimer);
				ar->regiontimer = NULL;
			}
		}

		/* prevent hanging status prints */
		ED_area_status_text(sa, NULL);
		ED_workspace_status_text(C, NULL);
	}

	if (sa && sa->full) {
		WorkSpaceLayout *layout_old = WM_window_get_active_layout(win);
		/* restoring back to SCREENNORMAL */
		sc = sa->full;       /* the old screen to restore */
		oldscreen = WM_window_get_active_screen(win); /* the one disappearing */

		BLI_assert(BKE_workspace_layout_screen_get(layout_old) != sc);
		BLI_assert(BKE_workspace_layout_screen_get(layout_old)->state != SCREENNORMAL);

		sc->state = SCREENNORMAL;
		sc->flag = oldscreen->flag;

		/* find old area to restore from */
		ScrArea *fullsa = NULL;
		for (ScrArea *old = sc->areabase.first; old; old = old->next) {
			/* area to restore from is always first */
			if (old->full && !fullsa) {
				fullsa = old;
			}

			/* clear full screen state */
			old->full = NULL;
		}

		sa->full = NULL;

		if (fullsa == NULL) {
			if (G.debug & G_DEBUG)
				printf("%s: something wrong in areafullscreen\n", __func__);
			return NULL;
		}

		if (state == SCREENFULL) {
			/* unhide global areas */
			for (ScrArea *glob_area = win->global_areas.areabase.first; glob_area; glob_area = glob_area->next) {
				glob_area->global->flag &= ~GLOBAL_AREA_IS_HIDDEN;
			}
			/* restore the old side panels/header visibility */
			for (ar = sa->regionbase.first; ar; ar = ar->next) {
				ar->flag = ar->flagfullscreen;
			}
		}

		ED_area_data_swap(fullsa, sa);

		/* animtimer back */
		sc->animtimer = oldscreen->animtimer;
		oldscreen->animtimer = NULL;

		ED_screen_change(C, sc);

		BKE_workspace_layout_remove(CTX_data_main(C), workspace, layout_old);

		/* After we've restored back to SCREENNORMAL, we have to wait with
		 * screen handling as it uses the area coords which aren't updated yet.
		 * Without doing so, the screen handling gets wrong area coords,
		 * which in worst case can lead to crashes (see T43139) */
		sc->skip_handling = true;
	}
	else {
		/* change from SCREENNORMAL to new state */
		WorkSpaceLayout *layout_new;
		ScrArea *newa;
		char newname[MAX_ID_NAME - 2];

		BLI_assert(ELEM(state, SCREENMAXIMIZED, SCREENFULL));

		oldscreen = WM_window_get_active_screen(win);

		oldscreen->state = state;
		BLI_snprintf(newname, sizeof(newname), "%s-%s", oldscreen->id.name + 2, "nonnormal");

		layout_new = ED_workspace_layout_add(bmain, workspace, win, newname);

		sc = BKE_workspace_layout_screen_get(layout_new);
		sc->state = state;
		sc->redraws_flag = oldscreen->redraws_flag;
		sc->temp = oldscreen->temp;
		sc->flag = oldscreen->flag;

		/* timer */
		sc->animtimer = oldscreen->animtimer;
		oldscreen->animtimer = NULL;

		/* use random area when we have no active one, e.g. when the
		 * mouse is outside of the window and we open a file browser */
		if (!sa || sa->global) {
			sa = oldscreen->areabase.first;
		}

		newa = (ScrArea *)sc->areabase.first;

		/* copy area */
		ED_area_data_swap(newa, sa);
		newa->flag = sa->flag; /* mostly for AREA_FLAG_WASFULLSCREEN */

		if (state == SCREENFULL) {
			/* temporarily hide global areas */
			for (ScrArea *glob_area = win->global_areas.areabase.first; glob_area; glob_area = glob_area->next) {
				glob_area->global->flag |= GLOBAL_AREA_IS_HIDDEN;
			}
			/* temporarily hide the side panels/header */
			for (ar = newa->regionbase.first; ar; ar = ar->next) {
				ar->flagfullscreen = ar->flag;

				if (ELEM(ar->regiontype,
				         RGN_TYPE_UI, RGN_TYPE_HEADER, RGN_TYPE_FOOTER,
				         RGN_TYPE_TOOLS, RGN_TYPE_NAV_BAR, RGN_TYPE_EXECUTE))
				{
					ar->flag |= RGN_FLAG_HIDDEN;
				}
			}
		}

		sa->full = oldscreen;
		newa->full = oldscreen;

		ED_screen_change(C, sc);
	}

	/* XXX bad code: setscreen() ends with first area active. fullscreen render assumes this too */
	CTX_wm_area_set(C, sc->areabase.first);

	return sc->areabase.first;
}

/* update frame rate info for viewport drawing */
void ED_refresh_viewport_fps(bContext *C)
{
	wmTimer *animtimer = CTX_wm_screen(C)->animtimer;
	Scene *scene = CTX_data_scene(C);

	/* is anim playback running? */
	if (animtimer && (U.uiflag & USER_SHOW_FPS)) {
		ScreenFrameRateInfo *fpsi = scene->fps_info;

		/* if there isn't any info, init it first */
		if (fpsi == NULL)
			fpsi = scene->fps_info = MEM_callocN(sizeof(ScreenFrameRateInfo), "refresh_viewport_fps fps_info");

		/* update the values */
		fpsi->redrawtime = fpsi->lredrawtime;
		fpsi->lredrawtime = animtimer->ltime;
	}
	else {
		/* playback stopped or shouldn't be running */
		if (scene->fps_info)
			MEM_freeN(scene->fps_info);
		scene->fps_info = NULL;
	}
}

/* redraws: uses defines from stime->redraws
 * enable: 1 - forward on, -1 - backwards on, 0 - off
 */
void ED_screen_animation_timer(bContext *C, int redraws, int refresh, int sync, int enable)
{
	bScreen *screen = CTX_wm_screen(C);
	wmWindowManager *wm = CTX_wm_manager(C);
	wmWindow *win = CTX_wm_window(C);
	Scene *scene = CTX_data_scene(C);
	bScreen *stopscreen = ED_screen_animation_playing(wm);

	if (stopscreen) {
		WM_event_remove_timer(wm, win, stopscreen->animtimer);
		stopscreen->animtimer = NULL;
	}

	if (enable) {
		ScreenAnimData *sad = MEM_callocN(sizeof(ScreenAnimData), "ScreenAnimData");

		screen->animtimer = WM_event_add_timer(wm, win, TIMER0, (1.0 / FPS));

		sad->ar = CTX_wm_region(C);
		/* if startframe is larger than current frame, we put currentframe on startframe.
		 * note: first frame then is not drawn! (ton) */
		if (PRVRANGEON) {
			if (scene->r.psfra > scene->r.cfra) {
				sad->sfra = scene->r.cfra;
				scene->r.cfra = scene->r.psfra;
			}
			else
				sad->sfra = scene->r.cfra;
		}
		else {
			if (scene->r.sfra > scene->r.cfra) {
				sad->sfra = scene->r.cfra;
				scene->r.cfra = scene->r.sfra;
			}
			else
				sad->sfra = scene->r.cfra;
		}
		sad->redraws = redraws;
		sad->refresh = refresh;
		sad->flag |= (enable < 0) ? ANIMPLAY_FLAG_REVERSE : 0;
		sad->flag |= (sync == 0) ? ANIMPLAY_FLAG_NO_SYNC : (sync == 1) ? ANIMPLAY_FLAG_SYNC : 0;

		ScrArea *sa = CTX_wm_area(C);

		char spacetype = -1;

		if (sa)
			spacetype = sa->spacetype;

		sad->from_anim_edit = (ELEM(spacetype, SPACE_GRAPH, SPACE_ACTION, SPACE_NLA));

		screen->animtimer->customdata = sad;

	}

	/* notifier catched by top header, for button */
	WM_event_add_notifier(C, NC_SCREEN | ND_ANIMPLAY, NULL);
}

/* helper for screen_animation_play() - only to be used for TimeLine */
static ARegion *time_top_left_3dwindow(bScreen *screen)
{
	ARegion *aret = NULL;
	ScrArea *sa;
	int min = 10000;

	for (sa = screen->areabase.first; sa; sa = sa->next) {
		if (sa->spacetype == SPACE_VIEW3D) {
			ARegion *ar;
			for (ar = sa->regionbase.first; ar; ar = ar->next) {
				if (ar->regiontype == RGN_TYPE_WINDOW) {
					if (ar->winrct.xmin - ar->winrct.ymin < min) {
						aret = ar;
						min = ar->winrct.xmin - ar->winrct.ymin;
					}
				}
			}
		}
	}

	return aret;
}

void ED_screen_animation_timer_update(bScreen *screen, int redraws, int refresh)
{
	if (screen && screen->animtimer) {
		wmTimer *wt = screen->animtimer;
		ScreenAnimData *sad = wt->customdata;

		sad->redraws = redraws;
		sad->refresh = refresh;
		sad->ar = NULL;
		if (redraws & TIME_REGION)
			sad->ar = time_top_left_3dwindow(screen);
	}
}

/* results in fully updated anim system */
void ED_update_for_newframe(Main *bmain, Depsgraph *depsgraph)
{
	Scene *scene = DEG_get_input_scene(depsgraph);

#ifdef DURIAN_CAMERA_SWITCH
	void *camera = BKE_scene_camera_switch_find(scene);
	if (camera && scene->camera != camera) {
		bScreen *sc;
		scene->camera = camera;
		/* are there cameras in the views that are not in the scene? */
		for (sc = bmain->screens.first; sc; sc = sc->id.next) {
			BKE_screen_view3d_scene_sync(sc, scene);
		}
		DEG_id_tag_update(&scene->id, ID_RECALC_COPY_ON_WRITE);
	}
#endif

	ED_clip_update_frame(bmain, scene->r.cfra);

	/* this function applies the changes too */
	BKE_scene_graph_update_for_newframe(depsgraph, bmain);

	/* composite */
	if (scene->use_nodes && scene->nodetree)
		ntreeCompositTagAnimated(scene->nodetree);

	/* update animated texture nodes */
	{
		Tex *tex;
		for (tex = bmain->textures.first; tex; tex = tex->id.next) {
			if (tex->use_nodes && tex->nodetree) {
				ntreeTexTagAnimated(tex->nodetree);
			}
		}
	}

}

/*
 * return true if any active area requires to see in 3D
 */
bool ED_screen_stereo3d_required(const bScreen *screen, const Scene *scene)
{
	ScrArea *sa;
	const bool is_multiview = (scene->r.scemode & R_MULTIVIEW) != 0;

	for (sa = screen->areabase.first; sa; sa = sa->next) {
		switch (sa->spacetype) {
			case SPACE_VIEW3D:
			{
				View3D *v3d;

				if (!is_multiview)
					continue;

				v3d = sa->spacedata.first;
				if (v3d->camera && v3d->stereo3d_camera == STEREO_3D_ID) {
					ARegion *ar;
					for (ar = sa->regionbase.first; ar; ar = ar->next) {
						if (ar->regiondata && ar->regiontype == RGN_TYPE_WINDOW) {
							RegionView3D *rv3d = ar->regiondata;
							if (rv3d->persp == RV3D_CAMOB) {
								return true;
							}
						}
					}
				}
				break;
			}
			case SPACE_IMAGE:
			{
				SpaceImage *sima;

				/* images should always show in stereo, even if
				 * the file doesn't have views enabled */
				sima = sa->spacedata.first;
				if (sima->image && BKE_image_is_stereo(sima->image) &&
				    (sima->iuser.flag & IMA_SHOW_STEREO))
				{
					return true;
				}
				break;
			}
			case SPACE_NODE:
			{
				SpaceNode *snode;

				if (!is_multiview)
					continue;

				snode = sa->spacedata.first;
				if ((snode->flag & SNODE_BACKDRAW) && ED_node_is_compositor(snode)) {
					return true;
				}
				break;
			}
			case SPACE_SEQ:
			{
				SpaceSeq *sseq;

				if (!is_multiview)
					continue;

				sseq = sa->spacedata.first;
				if (ELEM(sseq->view, SEQ_VIEW_PREVIEW, SEQ_VIEW_SEQUENCE_PREVIEW)) {
					return true;
				}

				if (sseq->draw_flag & SEQ_DRAW_BACKDROP) {
					return true;
				}

				break;
			}
		}
	}

	return false;
}

/**
 * Find the scene displayed in \a screen.
 * \note Assumes \a screen to be visible/active!
 */

Scene *ED_screen_scene_find_with_window(const bScreen *screen, const wmWindowManager *wm, struct wmWindow **r_window)
{
	for (wmWindow *win = wm->windows.first; win; win = win->next) {
		if (WM_window_get_active_screen(win) == screen) {
			if (r_window) {
				*r_window = win;
			}
			return WM_window_get_active_scene(win);
		}
	}

	BLI_assert(0);
	return NULL;
}

ScrArea *ED_screen_area_find_with_spacedata(const bScreen *screen, const SpaceLink *sl, const bool only_visible)
{
	if (only_visible) {
		for (ScrArea *sa = screen->areabase.first; sa; sa = sa->next) {
			if (sa->spacedata.first == sl) {
				return sa;
			}
		}
	}
	else {
		for (ScrArea *sa = screen->areabase.first; sa; sa = sa->next) {
			if (BLI_findindex(&sa->spacedata, sl) != -1) {
				return sa;
			}
		}
	}
	return NULL;
}

Scene *ED_screen_scene_find(const bScreen *screen, const wmWindowManager *wm)
{
	return ED_screen_scene_find_with_window(screen, wm, NULL);
}


wmWindow *ED_screen_window_find(const bScreen *screen, const wmWindowManager *wm)
{
	for (wmWindow *win = wm->windows.first; win; win = win->next) {
		if (WM_window_get_active_screen(win) == screen) {
			return win;
		}
	}
	return NULL;
}