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.

1 files changed, 64 insertions, 6 deletions

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");
 				}