UI: toolbar single column size snapping

Once a region is set to it's snapped size, zooming keeps the size.

6 files changed, 93 insertions, 6 deletions

diff --git a/source/blender/blenkernel/BKE_screen.h b/source/blender/blenkernel/BKE_screen.h
index 2736833a5ca..69b5e7ea6fe 100644
--- a/source/blender/blenkernel/BKE_screen.h
+++ b/source/blender/blenkernel/BKE_screen.h
@@ -140,6 +140,8 @@ typedef struct ARegionType {
 	void (*exit)(struct wmWindowManager *, struct ARegion *);
 	/* draw entirely, view changes should be handled here */
 	void (*draw)(const struct bContext *, struct ARegion *);
+	/* snap the size of the region (can be NULL for no snapping). */
+	int (*snap_size)(const struct ARegion *ar, int size, int axis);
 	/* contextual changes should be handled here */
 	void (*listener)(struct bScreen *, struct ScrArea *, struct ARegion *,
 	                 struct wmNotifier *, const struct Scene *scene);
diff --git a/source/blender/editors/include/ED_screen.h b/source/blender/editors/include/ED_screen.h
index 6d9b4af7c01..b4857051c89 100644
--- a/source/blender/editors/include/ED_screen.h
+++ b/source/blender/editors/include/ED_screen.h
@@ -91,6 +91,9 @@ void    ED_region_grid_draw(struct ARegion *ar, float zoomx, float zoomy);
 float	ED_region_blend_factor(struct ARegion *ar);
 void	ED_region_visible_rect(struct ARegion *ar, struct rcti *rect);
 
+int     ED_region_snap_size_test(const struct ARegion *ar);
+bool    ED_region_snap_size_apply(struct ARegion *ar, int snap_flag);
+
 /* message_bus callbacks */
 void ED_region_do_msg_notify_tag_redraw(
         struct bContext *C, struct wmMsgSubscribeKey *msg_key, struct wmMsgSubscribeValue *msg_val);
diff --git a/source/blender/editors/interface/view2d_ops.c b/source/blender/editors/interface/view2d_ops.c
index dc68c8b58de..6150b7e254e 100644
--- a/source/blender/editors/interface/view2d_ops.c
+++ b/source/blender/editors/interface/view2d_ops.c
@@ -641,6 +641,7 @@ static void view_zoomstep_apply_ex(
 	View2D *v2d = &ar->v2d;
 	const rctf cur_old = v2d->cur;
 	float dx, dy;
+	const int snap_test = ED_region_snap_size_test(ar);
 
 	/* calculate amount to move view by, ensuring symmetry so the
 	 * old zoom level is restored after zooming back the same amount 
@@ -725,6 +726,12 @@ static void view_zoomstep_apply_ex(
 	/* validate that view is in valid configuration after this operation */
 	UI_view2d_curRect_validate(v2d);
 
+	if (ED_region_snap_size_apply(ar, snap_test)) {
+		ScrArea *sa = CTX_wm_area(C);
+		ED_area_tag_redraw(sa);
+		WM_event_add_notifier(C, NC_SCREEN | NA_EDITED, NULL);
+	}
+
 	/* request updates to be done... */
 	ED_region_tag_redraw(vzd->ar);
 	UI_view2d_sync(CTX_wm_screen(C), CTX_wm_area(C), v2d, V2D_LOCK_COPY);
@@ -898,7 +905,8 @@ static void view_zoomdrag_apply(bContext *C, wmOperator *op)
 	v2dViewZoomData *vzd = op->customdata;
 	View2D *v2d = vzd->v2d;
 	float dx, dy;
-	
+	const int snap_test = ED_region_snap_size_test(vzd->ar);
+
 	/* get amount to move view by */
 	dx = RNA_float_get(op->ptr, "deltax");
 	dy = RNA_float_get(op->ptr, "deltay");
@@ -961,7 +969,13 @@ static void view_zoomdrag_apply(bContext *C, wmOperator *op)
 	
 	/* validate that view is in valid configuration after this operation */
 	UI_view2d_curRect_validate(v2d);
-	
+
+	if (ED_region_snap_size_apply(vzd->ar, snap_test)) {
+		ScrArea *sa = CTX_wm_area(C);
+		ED_area_tag_redraw(sa);
+		WM_event_add_notifier(C, NC_SCREEN | NA_EDITED, NULL);
+	}
+
 	/* request updates to be done... */
 	ED_region_tag_redraw(vzd->ar);
 	UI_view2d_sync(CTX_wm_screen(C), CTX_wm_area(C), v2d, V2D_LOCK_COPY);
@@ -2000,6 +2014,7 @@ static int reset_exec(bContext *C, wmOperator *UNUSED(op))
 	ARegion *ar = CTX_wm_region(C);
 	View2D *v2d = &ar->v2d;
 	int winx, winy;
+	const int snap_test = ED_region_snap_size_test(ar);
 
 	/* zoom 1.0 */
 	winx = (float)(BLI_rcti_size_x(&v2d->mask) + 1);
@@ -2033,7 +2048,13 @@ static int reset_exec(bContext *C, wmOperator *UNUSED(op))
 
 	/* validate that view is in valid configuration after this operation */
 	UI_view2d_curRect_validate(v2d);
-	
+
+	if (ED_region_snap_size_apply(ar, snap_test)) {
+		ScrArea *sa = CTX_wm_area(C);
+		ED_area_tag_redraw(sa);
+		WM_event_add_notifier(C, NC_SCREEN | NA_EDITED, NULL);
+	}
+
 	/* request updates to be done... */
 	ED_region_tag_redraw(ar);
 	UI_view2d_sync(CTX_wm_screen(C), CTX_wm_area(C), v2d, V2D_LOCK_COPY);
diff --git a/source/blender/editors/screen/area.c b/source/blender/editors/screen/area.c
index 678c3281335..0f9378d0a41 100644
--- a/source/blender/editors/screen/area.c
+++ b/source/blender/editors/screen/area.c
@@ -2741,3 +2741,36 @@ void ED_region_message_subscribe(
 		ar->type->message_subscribe(C, workspace, scene, screen, sa, ar, mbus);
 	}
 }
+
+int ED_region_snap_size_test(const ARegion *ar)
+{
+	/* Use a larger value because toggling scrollbars can jump in size. */
+	const int snap_match_threshold = 16;
+	if (ar->type->snap_size != NULL) {
+		return ((((ar->sizex - ar->type->snap_size(ar, ar->sizex, 0)) <= snap_match_threshold) << 0) |
+		        (((ar->sizey - ar->type->snap_size(ar, ar->sizey, 1)) <= snap_match_threshold) << 1));
+	}
+	return 0;
+}
+
+bool ED_region_snap_size_apply(ARegion *ar, int snap_flag)
+{
+	bool changed = false;
+	if (ar->type->snap_size != NULL) {
+		if (snap_flag & (1 << 0)) {
+			short snap_size = ar->type->snap_size(ar, ar->sizex, 0);
+			if (snap_size != ar->sizex) {
+				ar->sizex = snap_size;
+				changed = true;
+			}
+		}
+		if (snap_flag & (1 << 1)) {
+			short snap_size = ar->type->snap_size(ar, ar->sizey, 1);
+			if (snap_size != ar->sizey) {
+				ar->sizey = snap_size;
+				changed = true;
+			}
+		}
+	}
+	return changed;
+}
diff --git a/source/blender/editors/screen/screen_ops.c b/source/blender/editors/screen/screen_ops.c
index 6ed56e91a0f..7dab2c7c3db 100644
--- a/source/blender/editors/screen/screen_ops.c
+++ b/source/blender/editors/screen/screen_ops.c
@@ -2156,7 +2156,8 @@ static int region_scale_modal(bContext *C, wmOperator *op, const wmEvent *event)
 	/* execute the events */
 	switch (event->type) {
 		case MOUSEMOVE:
-			
+		{
+			const int snap_size_threshold = U.widget_unit * 3;
 			if (rmd->edge == AE_LEFT_TO_TOPRIGHT || rmd->edge == AE_RIGHT_TO_TOPLEFT) {
 				delta = event->x - rmd->origx;
 				if (rmd->edge == AE_LEFT_TO_TOPRIGHT) delta = -delta;
@@ -2165,8 +2166,15 @@ static int region_scale_modal(bContext *C, wmOperator *op, const wmEvent *event)
 				delta /= UI_DPI_FAC;
 				
 				rmd->ar->sizex = rmd->origval + delta;
+
+				if (rmd->ar->type->snap_size) {
+					short sizex_test = rmd->ar->type->snap_size(rmd->ar, rmd->ar->sizex, 0);
+					if (ABS(rmd->ar->sizex - sizex_test) < snap_size_threshold) {
+						rmd->ar->sizex = sizex_test;
+					}
+				}
 				CLAMP(rmd->ar->sizex, 0, rmd->maxsize);
-				
+
 				if (rmd->ar->sizex < UI_UNIT_X) {
 					rmd->ar->sizex = rmd->origval;
 					if (!(rmd->ar->flag & RGN_FLAG_HIDDEN))
@@ -2184,6 +2192,13 @@ static int region_scale_modal(bContext *C, wmOperator *op, const wmEvent *event)
 				delta /= UI_DPI_FAC;
 
 				rmd->ar->sizey = rmd->origval + delta;
+
+				if (rmd->ar->type->snap_size) {
+					short sizey_test = rmd->ar->type->snap_size(rmd->ar, rmd->ar->sizey, 1);
+					if (ABS(rmd->ar->sizey - sizey_test) < snap_size_threshold) {
+						rmd->ar->sizey = sizey_test;
+					}
+				}
 				CLAMP(rmd->ar->sizey, 0, rmd->maxsize);
 
 				/* note, 'UI_UNIT_Y/4' means you need to drag the header almost
@@ -2203,7 +2218,7 @@ static int region_scale_modal(bContext *C, wmOperator *op, const wmEvent *event)
 			WM_event_add_notifier(C, NC_SCREEN | NA_EDITED, NULL);
 			
 			break;
-			
+		}
 		case LEFTMOUSE:
 			if (event->val == KM_RELEASE) {
 				
diff --git a/source/blender/editors/space_view3d/space_view3d.c b/source/blender/editors/space_view3d/space_view3d.c
index b4d6d554e4f..4fb4193517b 100644
--- a/source/blender/editors/space_view3d/space_view3d.c
+++ b/source/blender/editors/space_view3d/space_view3d.c
@@ -1277,6 +1277,18 @@ static void view3d_buttons_region_listener(
 	}
 }
 
+static int view3d_tools_region_snap_size(const ARegion *ar, int size, int axis)
+{
+	if (axis == 0) {
+		/* Note, this depends on the icon size: see #ICON_DEFAULT_HEIGHT_TOOLBAR. */
+		const float snap_units = 3.25f;
+		const float aspect = BLI_rctf_size_x(&ar->v2d.cur) / (BLI_rcti_size_x(&ar->v2d.mask) + 1);
+		const int snap_size = (snap_units * U.widget_unit) / aspect;
+		return snap_size;
+	}
+	return size;
+}
+
 /* add handlers, stuff you only do once or on area/region changes */
 static void view3d_tools_region_init(wmWindowManager *wm, ARegion *ar)
 {
@@ -1474,6 +1486,7 @@ void ED_spacetype_view3d(void)
 	art->prefsizey = 50; /* XXX */
 	art->keymapflag = ED_KEYMAP_UI | ED_KEYMAP_FRAMES;
 	art->listener = view3d_buttons_region_listener;
+	art->snap_size = view3d_tools_region_snap_size;
 	art->init = view3d_tools_region_init;
 	art->draw = view3d_tools_region_draw;
 	BLI_addhead(&st->regiontypes, art);