UI: Initial persistent floating redo panel

This is the first step to moving redo out of the top-bar, see: T55039

- Support for floating panels in the ScrArea has been added.
- A new region type RGN_TYPE_HUD is used for floating settings input.
- Only one HUD should be visible at a time.
- Currently HUD regions are only visible
  for 3D view and image space types.
- There are currently some remaining glitches with hide/show
  that need further investigation.

8 files changed, 367 insertions, 11 deletions

diff --git a/source/blender/editors/include/ED_screen.h b/source/blender/editors/include/ED_screen.h
index 2291e70fa4d..97653286f28 100644
--- a/source/blender/editors/include/ED_screen.h
+++ b/source/blender/editors/include/ED_screen.h
@@ -318,6 +318,10 @@ void ED_region_cache_draw_background(const struct ARegion *ar);
 void ED_region_cache_draw_curfra_label(const int framenr, const float x, const float y);
 void ED_region_cache_draw_cached_segments(const struct ARegion *ar, const int num_segments, const int *points, const int sfra, const int efra);
 
+/* interface_region_hud.c */
+struct ARegionType *ED_area_type_hud(int space_type);
+void ED_area_type_hud_ensure(struct bContext *C, struct ScrArea *sa);
+
 /* default keymaps, bitflags */
 #define ED_KEYMAP_UI        1
 #define ED_KEYMAP_VIEW2D    2
diff --git a/source/blender/editors/include/UI_interface.h b/source/blender/editors/include/UI_interface.h
index c82a320268f..547cfc65c09 100644
--- a/source/blender/editors/include/UI_interface.h
+++ b/source/blender/editors/include/UI_interface.h
@@ -830,6 +830,7 @@ struct Panel *UI_panel_begin(struct ScrArea *sa, struct ARegion *ar, struct List
 void UI_panel_end(uiBlock *block, int width, int height);
 void UI_panels_scale(struct ARegion *ar, float new_width);
 void UI_panel_label_offset(struct uiBlock *block, int *x, int *y);
+int UI_panel_size_y(const struct Panel *pa);
 
 bool                       UI_panel_category_is_visible(struct ARegion *ar);
 void                       UI_panel_category_add(struct ARegion *ar, const char *name);
diff --git a/source/blender/editors/interface/CMakeLists.txt b/source/blender/editors/interface/CMakeLists.txt
index 49fe6bfb2dc..07ba3b90e11 100644
--- a/source/blender/editors/interface/CMakeLists.txt
+++ b/source/blender/editors/interface/CMakeLists.txt
@@ -58,6 +58,7 @@ set(SRC
 	interface_panel.c
 	interface_regions.c
 	interface_region_color_picker.c
+	interface_region_hud.c
 	interface_region_menu_pie.c
 	interface_region_menu_popup.c
 	interface_region_popover.c
diff --git a/source/blender/editors/interface/interface_panel.c b/source/blender/editors/interface/interface_panel.c
index dbdf2a0863c..e383ae42f8c 100644
--- a/source/blender/editors/interface/interface_panel.c
+++ b/source/blender/editors/interface/interface_panel.c
@@ -110,7 +110,7 @@ typedef struct uiHandlePanelData {
 	int startsizex, startsizey;
 } uiHandlePanelData;
 
-static int get_panel_real_size_y(Panel *pa);
+static int get_panel_real_size_y(const Panel *pa);
 static void panel_activate_state(const bContext *C, Panel *pa, uiHandlePanelState state);
 
 /*********************** space specific code ************************/
@@ -855,7 +855,7 @@ void ui_draw_aligned_panel(uiStyle *style, uiBlock *block, const rcti *rect, con
 
 /************************** panel alignment *************************/
 
-static int get_panel_header(Panel *pa)
+static int get_panel_header(const Panel *pa)
 {
 	if (pa->type && (pa->type->flag & PNL_NO_HEADER))
 		return 0;
@@ -863,7 +863,7 @@ static int get_panel_header(Panel *pa)
 	return PNL_HEADER;
 }
 
-static int get_panel_size_y(Panel *pa)
+static int get_panel_size_y(const Panel *pa)
 {
 	if (pa->type && (pa->type->flag & PNL_NO_HEADER))
 		return pa->sizey;
@@ -871,7 +871,7 @@ static int get_panel_size_y(Panel *pa)
 	return PNL_HEADER + pa->sizey;
 }
 
-static int get_panel_real_size_y(Panel *pa)
+static int get_panel_real_size_y(const Panel *pa)
 {
 	int sizey = (pa->flag & PNL_CLOSED) ? 0 : pa->sizey;
 
@@ -881,6 +881,11 @@ static int get_panel_real_size_y(Panel *pa)
 	return PNL_HEADER + sizey;
 }
 
+int UI_panel_size_y(const Panel *pa)
+{
+	return get_panel_real_size_y(pa);
+}
+
 /* this function is needed because uiBlock and Panel itself don't
  * change sizey or location when closed */
 static int get_panel_real_ofsy(Panel *pa)
@@ -1596,6 +1601,10 @@ static void ui_handle_panel_header(const bContext *C, uiBlock *block, int mx, in
 			ED_region_tag_redraw(ar);
 	}
 	else if (show_drag && BLI_rctf_isect_x(&rect_drag, mx)) {
+		/* XXX, for now don't allow dragging in floating windows yet. */
+		if (ar->alignment == RGN_ALIGN_FLOAT) {
+			return;
+		}
 		panel_activate_state(C, block->panel, PANEL_STATE_DRAG);
 	}
 	else if (show_pin && BLI_rctf_isect_x(&rect_pin, mx)) {
diff --git a/source/blender/editors/interface/interface_region_hud.c b/source/blender/editors/interface/interface_region_hud.c
new file mode 100644
index 00000000000..ad779d2580f
--- /dev/null
+++ b/source/blender/editors/interface/interface_region_hud.c
@@ -0,0 +1,276 @@
+/*
+ * ***** 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) 2008 Blender Foundation.
+ * All rights reserved.
+ *
+ * Contributor(s): Blender Foundation
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/editors/interface/interface_region_hud.c
+ *  \ingroup edinterface
+ *
+ * Floating Persistent Region
+ */
+
+#include <string.h>
+
+#include "MEM_guardedalloc.h"
+
+#include "DNA_userdef_types.h"
+
+#include "BLI_string.h"
+#include "BLI_rect.h"
+#include "BLI_listbase.h"
+#include "BLI_utildefines.h"
+
+#include "BKE_context.h"
+#include "BKE_screen.h"
+#include "BKE_main.h"
+
+#include "WM_api.h"
+#include "WM_types.h"
+
+#include "RNA_access.h"
+
+#include "BIF_gl.h"
+
+#include "UI_interface.h"
+#include "UI_view2d.h"
+
+#include "BLT_translation.h"
+
+#include "ED_screen.h"
+#include "ED_undo.h"
+
+#include "interface_intern.h"
+
+
+/* -------------------------------------------------------------------- */
+/** \name Utilities
+ * \{ */
+
+static bool last_redo_poll(const bContext *C)
+{
+	wmOperator *op = WM_operator_last_redo(C);
+	if (op == NULL) {
+		return false;
+	}
+	bool success = false;
+	if (!WM_operator_check_ui_empty(op->type)) {
+		success = WM_operator_poll((bContext *)C, op->type);
+	}
+	return success;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Redo Panel
+ * \{ */
+
+static int hud_panel_operator_redo_poll(const bContext *C, PanelType *UNUSED(pt))
+{
+	return last_redo_poll(C);
+}
+
+static void hud_panel_operator_redo_draw_header(const bContext *C, Panel *pa)
+{
+	wmOperator *op = WM_operator_last_redo(C);
+	BLI_strncpy(pa->drawname, RNA_struct_ui_name(op->type->srna), sizeof(pa->drawname));
+}
+
+static void hud_panel_operator_redo_draw(const bContext *C, Panel *pa)
+{
+	wmOperator *op = WM_operator_last_redo(C);
+	if (op == NULL) {
+		return;
+	}
+	if (!WM_operator_check_ui_enabled(C, op->type->name)) {
+		uiLayoutSetEnabled(pa->layout, false);
+	}
+	uiLayout *col = uiLayoutColumn(pa->layout, false);
+	uiTemplateOperatorRedoProperties(col, C);
+}
+
+static void hud_panels_register(ARegionType *art, int space_type, int region_type)
+{
+	PanelType *pt;
+
+	pt = MEM_callocN(sizeof(PanelType), __func__);
+	strcpy(pt->idname, "OPERATOR_PT_redo");
+	strcpy(pt->label, N_("Redo"));
+	strcpy(pt->translation_context, BLT_I18NCONTEXT_DEFAULT_BPYRNA);
+	pt->draw_header = hud_panel_operator_redo_draw_header;
+	pt->draw = hud_panel_operator_redo_draw;
+	pt->poll = hud_panel_operator_redo_poll;
+	pt->space_type = space_type;
+	pt->region_type = region_type;
+	BLI_addtail(&art->paneltypes, pt);
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Callbacks for Floating Region
+ * \{ */
+
+static void hud_region_init(wmWindowManager *wm, ARegion *ar)
+{
+	ED_region_panels_init(wm, ar);
+	UI_region_handlers_add(&ar->handlers);
+}
+
+static void hud_region_layout(const bContext *C, ARegion *ar)
+{
+	if (!last_redo_poll(C)) {
+		ED_region_tag_redraw(ar);
+		ar->flag |= RGN_FLAG_HIDDEN;
+		return;
+	}
+
+	int size_y = ar->sizey;
+
+	ED_region_panels_layout_ex(C, ar, NULL, -1, true);
+
+	if (ar->panels.first && (ar->sizey != size_y)) {
+		View2D *v2d = &ar->v2d;
+		ar->winx = ar->sizex;
+		ar->winy = ar->sizey;
+
+		ar->winrct.xmax = (ar->winrct.xmin + ar->winx) - 1;
+		ar->winrct.ymax = (ar->winrct.ymin + ar->winy) - 1;
+
+		UI_view2d_region_reinit(v2d, V2D_COMMONVIEW_PANELS_UI, ar->winx, ar->winy);
+	}
+
+	/* restore view matrix */
+	UI_view2d_view_restore(C);
+}
+
+static void hud_region_draw(const bContext *C, ARegion *ar)
+{
+	UI_view2d_view_ortho(&ar->v2d);
+	wmOrtho2_region_pixelspace(ar);
+	glClearColor(0, 0, 0, 0.0f);
+	glClear(GL_COLOR_BUFFER_BIT);
+
+	if ((ar->flag & RGN_FLAG_HIDDEN) == 0) {
+		ui_draw_widget_back(UI_WTYPE_BOX, false, &(rcti){.xmax = ar->winx, .ymax = ar->winy});
+		ED_region_panels_draw(C, ar);
+	}
+}
+
+ARegionType *ED_area_type_hud(int space_type)
+{
+	ARegionType *art = MEM_callocN(sizeof(ARegionType), __func__);
+	art->regionid = RGN_TYPE_HUD;
+	art->keymapflag = ED_KEYMAP_UI | ED_KEYMAP_VIEW2D;
+	art->layout = hud_region_layout;
+	art->draw = hud_region_draw;
+	art->init = hud_region_init;
+
+	hud_panels_register(art, space_type, art->regionid);
+
+	art->lock = 1;   /* can become flag, see BKE_spacedata_draw_locks */
+	return art;
+}
+
+static ARegion *hud_region_add(ScrArea *sa)
+{
+	ARegion *ar = MEM_callocN(sizeof(ARegion), "area region");
+	ARegion *ar_win = BKE_area_find_region_type(sa, RGN_TYPE_WINDOW);
+	if (ar_win) {
+		BLI_insertlinkbefore(&sa->regionbase, ar_win, ar);
+	}
+	else {
+		BLI_addtail(&sa->regionbase, ar);
+	}
+	ar->regiontype = RGN_TYPE_HUD;
+	ar->alignment = RGN_ALIGN_FLOAT;
+	ar->overlap = true;
+	ar->flag |= RGN_FLAG_DYNAMIC_SIZE;
+
+	return ar;
+}
+
+void ED_area_type_hud_ensure(bContext *C, ScrArea *sa)
+{
+	/* We only want one at a time. */
+	Main *bmain = CTX_data_main(C);
+	for (wmWindowManager *wm = bmain->wm.first; wm; wm = wm->id.next) {
+		for (wmWindow *win = wm->windows.first; win; win = win->next) {
+			bScreen *screen = WM_window_get_active_screen(win);
+			for (ScrArea *sa_iter = screen->areabase.first; sa_iter; sa_iter = sa_iter->next) {
+				if (sa != sa_iter) {
+					for (ARegion *ar = sa_iter->regionbase.first; ar; ar = ar->next) {
+						if (ar->regiontype == RGN_TYPE_HUD) {
+							if ((ar->flag & RGN_FLAG_HIDDEN) == 0) {
+								ar->flag |= RGN_FLAG_HIDDEN;
+								ED_region_tag_redraw(ar);
+							}
+						}
+					}
+				}
+			}
+		}
+	}
+
+	ARegionType *art = BKE_regiontype_from_id(sa->type, RGN_TYPE_HUD);
+	if (art == NULL) {
+		return;
+	}
+
+	bool init = false;
+	ARegion *ar = BKE_area_find_region_type(sa, RGN_TYPE_HUD);
+	if (!last_redo_poll(C)) {
+		if (ar) {
+			ar->flag |= RGN_FLAG_HIDDEN;
+		}
+		return;
+	}
+
+	if (ar == NULL) {
+		init = true;
+		ar = hud_region_add(sa);
+		ar->type = art;
+	}
+
+	ED_region_init(ar);
+	ED_region_tag_redraw(ar);
+
+	/* Let 'ED_area_update_region_sizes' do the work of placing the region.
+	 * Otherwise we could set the 'ar->winrct' & 'ar->winx/winy' here. */
+	if (init) {
+		sa->flag |= AREA_FLAG_REGION_SIZE_UPDATE;
+	}
+	else {
+		if (ar->flag & RGN_FLAG_HIDDEN) {
+			sa->flag |= AREA_FLAG_REGION_SIZE_UPDATE;
+		}
+		ar->flag &= ~RGN_FLAG_HIDDEN;
+
+	}
+
+	/* We shouldn't need to do this every time :S */
+	/* XXX, this is evil! - it also makes the menu show on first draw. :( */
+	hud_region_layout(C, ar);
+}
+
+/** \} */
diff --git a/source/blender/editors/screen/area.c b/source/blender/editors/screen/area.c
index 4eef386dd04..316b8cbe55f 100644
--- a/source/blender/editors/screen/area.c
+++ b/source/blender/editors/screen/area.c
@@ -953,6 +953,9 @@ static void region_overlap_fix(ScrArea *sa, ARegion *ar)
 		}
 
 		if (ar1->overlap && ((ar1->alignment & RGN_SPLIT_PREV) == 0)) {
+			if (ELEM(ar1->alignment, RGN_ALIGN_FLOAT)) {
+				continue;
+			}
 			align1 = ar1->alignment;
 			if (BLI_rcti_isect(&ar1->winrct, &ar->winrct, NULL)) {
 				if (align1 != align) {
@@ -994,6 +997,9 @@ static void region_overlap_fix(ScrArea *sa, ARegion *ar)
 		if (ar1->flag & (RGN_FLAG_HIDDEN)) {
 			continue;
 		}
+		if (ELEM(ar1->alignment, RGN_ALIGN_FLOAT)) {
+			continue;
+		}
 
 		if (ar1->overlap && (ar1->alignment & RGN_SPLIT_PREV) == 0) {
 			if ((ar1->alignment != align) && BLI_rcti_isect(&ar1->winrct, &ar->winrct, NULL)) {
@@ -1009,6 +1015,9 @@ static void region_overlap_fix(ScrArea *sa, ARegion *ar)
 bool ED_region_is_overlap(int spacetype, int regiontype)
 {
 	if (U.uiflag2 & USER_REGION_OVERLAP) {
+		if (regiontype == RGN_TYPE_HUD) {
+			return 1;
+		}
 		if (ELEM(spacetype, SPACE_VIEW3D, SPACE_SEQ, SPACE_IMAGE)) {
 			if (ELEM(regiontype, RGN_TYPE_TOOLS, RGN_TYPE_UI, RGN_TYPE_TOOL_PROPS))
 				return 1;
@@ -1052,8 +1061,9 @@ static void region_rect_recursive(wmWindow *win, ScrArea *sa, ARegion *ar, rcti
 	/* clear state flags first */
 	ar->flag &= ~RGN_FLAG_TOO_SMALL;
 	/* user errors */
-	if (ar->next == NULL && alignment != RGN_ALIGN_QSPLIT)
+	if ((ar->next == NULL) && !ELEM(alignment, RGN_ALIGN_QSPLIT, RGN_ALIGN_FLOAT)) {
 		alignment = RGN_ALIGN_NONE;
+	}
 
 	/* prefsize, taking into account DPI */
 	prefsizex = UI_DPI_FAC * ((ar->sizex > 1) ? ar->sizex + 0.5f : ar->type->prefsizex);
@@ -1076,7 +1086,28 @@ static void region_rect_recursive(wmWindow *win, ScrArea *sa, ARegion *ar, rcti
 		/* hidden is user flag */
 	}
 	else if (alignment == RGN_ALIGN_FLOAT) {
-		/* XXX floating area region, not handled yet here */
+		/**
+		 * \note Currently this window type is only used for #RGN_TYPE_HUD,
+		 * We expect the panel to resize it's self to be larger.
+		 *
+		 * This aligns to the lower left of the area.
+		 */
+		rcti overlap_remainder_margin = *overlap_remainder;
+		BLI_rcti_resize(
+		        &overlap_remainder_margin,
+		        max_ii(0, BLI_rcti_size_x(overlap_remainder) - UI_UNIT_X / 2),
+		        max_ii(0, BLI_rcti_size_y(overlap_remainder) - UI_UNIT_Y / 2));
+		ar->winrct.xmin = overlap_remainder_margin.xmin;
+		ar->winrct.ymin = overlap_remainder_margin.ymin;
+		ar->winrct.xmax = ar->winrct.xmin + ar->sizex;
+		ar->winrct.ymax = ar->winrct.ymin + ar->sizey;
+
+		BLI_rcti_isect(&ar->winrct, &overlap_remainder_margin, &ar->winrct);
+		if (BLI_rcti_size_x(&ar->winrct) < UI_UNIT_X ||
+		    BLI_rcti_size_y(&ar->winrct) < UI_UNIT_Y)
+		{
+			ar->flag |= RGN_FLAG_TOO_SMALL;
+		}
 	}
 	else if (rct_fits(remainder, 'v', 1) < 0 || rct_fits(remainder, 'h', 1) < 0) {
 		/* remainder is too small for any usage */
@@ -1215,7 +1246,7 @@ static void region_rect_recursive(wmWindow *win, ScrArea *sa, ARegion *ar, rcti
 	if (ar->winy > 1) ar->sizey = (ar->winy + 0.5f) /  UI_DPI_FAC;
 
 	/* exception for multiple overlapping regions on same spot */
-	if (ar->overlap) {
+	if (ar->overlap & (alignment != RGN_ALIGN_FLOAT)) {
 		region_overlap_fix(sa, ar);
 	}
 
@@ -1781,7 +1812,10 @@ static ThemeColorID region_background_color_id(const bContext *C, const ARegion
 
 static void region_clear_color(const bContext *C, const ARegion *ar, ThemeColorID colorid)
 {
-	if (ar->overlap) {
+	if (ar->alignment == RGN_ALIGN_FLOAT) {
+		/* handle our own drawing. */
+	}
+	else if (ar->overlap) {
 		/* view should be in pixelspace */
 		UI_view2d_view_restore(C);
 
@@ -1911,6 +1945,7 @@ void ED_region_panels_layout_ex(
 	const char *category = NULL;
 	const int category_tabs_width = UI_PANEL_CATEGORY_MARGIN_WIDTH;
 	int margin_x = 0;
+	const bool region_layout_based = ar->flag & RGN_FLAG_DYNAMIC_SIZE;
 
 	BLI_SMALLSTACK_DECLARE(pt_stack, PanelType *);
 
@@ -2021,7 +2056,25 @@ void ED_region_panels_layout_ex(
 	UI_panels_end(C, ar, &x, &y);
 
 	/* before setting the view */
-	if (vertical) {
+	if (region_layout_based) {
+		/* XXX, only single panel support atm.
+		 * Can't use x/y values calculated above because they're not using the real height of panels,
+		 * instead they calculate offsets for the next panel to start drawing. */
+		Panel *panel = ar->panels.last;
+		int size_dyn[2] = {
+			UI_UNIT_X * 12,
+			UI_panel_size_y(panel),
+		};
+		/* region size is layout based and needs to be updated */
+		if ((ar->sizex != size_dyn[0]) ||
+		    (ar->sizey != size_dyn[1]))
+		{
+			ar->sizex = size_dyn[0];
+			ar->sizey = size_dyn[1];
+			sa->flag |= AREA_FLAG_REGION_SIZE_UPDATE;
+		}
+	}
+	else if (vertical) {
 		/* we always keep the scroll offset - so the total view gets increased with the scrolled away part */
 		if (v2d->cur.ymax < -FLT_EPSILON) {
 			/* Clamp to lower view boundary */
@@ -2071,7 +2124,9 @@ void ED_region_panels_draw(const bContext *C, ARegion *ar)
 {
 	View2D *v2d = &ar->v2d;
 
-	region_clear_color(C, ar, (ar->type->regionid == RGN_TYPE_PREVIEW) ? TH_PREVIEW_BACK : TH_BACK);
+	if (ar->alignment != RGN_ALIGN_FLOAT) {
+		region_clear_color(C, ar, (ar->type->regionid == RGN_TYPE_PREVIEW) ? TH_PREVIEW_BACK : TH_BACK);
+	}
 
 	/* reset line width for drawing tabs */
 	glLineWidth(1.0f);
@@ -2717,6 +2772,9 @@ void ED_region_visible_rect(ARegion *ar, rcti *rect)
 						rect->ymax = arn->winrct.ymin;
 					}
 				}
+				else if (arn->alignment == RGN_ALIGN_FLOAT) {
+					/* Skip floating. */
+				}
 				else {
 					BLI_assert(!"Region overlap with unknown alignment");
 				}
diff --git a/source/blender/editors/space_image/space_image.c b/source/blender/editors/space_image/space_image.c
index a99788dcb23..a73ed09a632 100644
--- a/source/blender/editors/space_image/space_image.c
+++ b/source/blender/editors/space_image/space_image.c
@@ -1096,7 +1096,6 @@ void ED_spacetype_image(void)
 	art->init = image_main_region_init;
 	art->draw = image_main_region_draw;
 	art->listener = image_main_region_listener;
-
 	BLI_addhead(&st->regiontypes, art);
 
 	/* regions: listview/buttons */
@@ -1134,5 +1133,9 @@ void ED_spacetype_image(void)
 
 	BLI_addhead(&st->regiontypes, art);
 
+	/* regions: hud */
+	art = ED_area_type_hud(st->spaceid);
+	BLI_addhead(&st->regiontypes, art);
+
 	BKE_spacetype_register(st);
 }
diff --git a/source/blender/editors/space_view3d/space_view3d.c b/source/blender/editors/space_view3d/space_view3d.c
index d3f24edc38e..964f6f8ea4e 100644
--- a/source/blender/editors/space_view3d/space_view3d.c
+++ b/source/blender/editors/space_view3d/space_view3d.c
@@ -1565,5 +1565,9 @@ void ED_spacetype_view3d(void)
 	art->message_subscribe = view3d_header_region_message_subscribe;
 	BLI_addhead(&st->regiontypes, art);
 
+	/* regions: hud */
+	art = ED_area_type_hud(st->spaceid);
+	BLI_addhead(&st->regiontypes, art);
+
 	BKE_spacetype_register(st);
 }