Revert "remove zero flickering lie"

This reverts commit b1c101515a.

Fixed by d3fa329.

README.md

@@ -153,6 +153,7 @@ given the base on which it is built. Implemented default features are:
 - Support screen lockers via ext-session-lock-v1 protocol
 - Various Wayland protocols
 - XWayland support as provided by wlroots (can be enabled in `config.mk`)
+- Zero flickering - Wayland users naturally expect that "every frame is perfect"
 - Layer shell popups (used by Waybar)
 - Damage tracking provided by scenegraph API
 

client.h

@@ -189,6 +189,7 @@ client_get_geometry(Client *c, struct wlr_box *geom)
 	}
 #endif
 	*geom = c->surface.xdg->geometry;
+	geom->x = geom->y = 0;
 }
 
 static inline Client *
@@ -257,48 +258,6 @@ client_is_float_type(Client *c)
 			(min.width == max.width || min.height == max.height));
 }
 
-static inline int
-client_is_rendered_on_mon(Client *c, Monitor *m)
-{
-	/* This is needed for when you don't want to check formal assignment,
-	 * but rather actual displaying of the pixels.
-	 * Usually VISIBLEON suffices and is also faster. */
-	struct wlr_surface_output *s;
-	int unused_lx, unused_ly;
-	if (!wlr_scene_node_coords(&c->scene->node, &unused_lx, &unused_ly))
-		return 0;
-	wl_list_for_each(s, &client_surface(c)->current_outputs, link)
-		if (s->output == m->wlr_output)
-			return 1;
-	return 0;
-}
-
-static inline int
-client_is_stopped(Client *c)
-{
-	int pid;
-	siginfo_t in = {0};
-#ifdef XWAYLAND
-	if (client_is_x11(c))
-		return 0;
-#endif
-
-	wl_client_get_credentials(c->surface.xdg->client->client, &pid, NULL, NULL);
-	if (waitid(P_PID, pid, &in, WNOHANG|WCONTINUED|WSTOPPED|WNOWAIT) < 0) {
-		/* This process is not our child process, while is very unlikely that
-		 * it is stopped, in order to do not skip frames, assume that it is. */
-		if (errno == ECHILD)
-			return 1;
-	} else if (in.si_pid) {
-		if (in.si_code == CLD_STOPPED || in.si_code == CLD_TRAPPED)
-			return 1;
-		if (in.si_code == CLD_CONTINUED)
-			return 0;
-	}
-
-	return 0;
-}
-
 static inline int
 client_is_unmanaged(Client *c)
 {
@@ -365,19 +324,36 @@ client_set_scale(struct wlr_surface *s, float scale)
 	wlr_surface_set_preferred_buffer_scale(s, (int32_t)ceilf(scale));
 }
 
-static inline void
+/* Returns nonzero if the client has to commit a buffer with the new size */
+static inline uint32_t
 client_set_size(Client *c, uint32_t width, uint32_t height)
 {
 #ifdef XWAYLAND
 	if (client_is_x11(c)) {
 		wlr_xwayland_surface_configure(c->surface.xwayland,
 				c->geom.x + c->bw, c->geom.y + c->bw, width, height);
-		return;
+		return (int)width != client_surface(c)->current.width
+				|| (int)height != client_surface(c)->current.height;
 	}
 #endif
-	if ((int32_t)width != c->surface.xdg->toplevel->current.width
-			|| (int32_t)height != c->surface.xdg->toplevel->current.height)
-		wlr_xdg_toplevel_set_size(c->surface.xdg->toplevel, (int32_t)width, (int32_t)height);
+	if ((int32_t)width == c->surface.xdg->toplevel->scheduled.width
+			&& (int32_t)height == c->surface.xdg->toplevel->scheduled.height)
+		return 0;
+	return wlr_xdg_toplevel_set_size(c->surface.xdg->toplevel, (int32_t)width, (int32_t)height);
+}
+
+static inline void
+client_send_frame_done_iterator(struct wlr_surface *s, int sx, int sy, void *data)
+{
+	wlr_surface_send_frame_done(s, data);
+}
+
+static inline void
+client_send_frame_done(Client *c)
+{
+	struct timespec now;
+	clock_gettime(CLOCK_MONOTONIC, &now);
+	wlr_surface_for_each_surface(client_surface(c), client_send_frame_done_iterator, &now);
 }
 
 static inline void

config.def.h

@@ -172,6 +172,9 @@ static const Button buttons[] = {
 };
 
 static const Axis axes[] = {
+	/* example of volume control:
 	{ MODKEY, AxisUp,   spawn, SHCMD("volume-up_EXAMPLE") },
-	{ MODKEY, AxisDown, spawn, SHCMD("volume-down_EXAMPLE") },
+	{ MODKEY, AxisDown, spawn, SHCMD("volume-down_EXAMPLE") }, */
+	{ 0, 0, NULL, {0} },
+	/* does nothing, but the array cannot be empty */
 };

config.mk

@@ -1,4 +1,4 @@
-_VERSION = 0.9-dev
+_VERSION = 0.10-dev
 VERSION  = `git describe --tags --dirty 2>/dev/null || echo $(_VERSION)`
 
 PKG_CONFIG = pkg-config

dwl.c

@@ -126,6 +126,9 @@ typedef struct {
 	struct wl_list flink;
 	struct wlr_box geom; /* layout-relative, includes border */
 	struct wlr_box prev; /* layout-relative, includes border */
+	struct wlr_box current; /* geom currently shown in the scene graph */
+	struct wlr_scene_node *snapshot; /* content shown while resizing */
+	uint32_t resize_serial; /* nonzero while waiting for a resized buffer */
 	struct wlr_box bounds; /* only width and height are used */
 	union {
 		struct wlr_xdg_surface *xdg;
@@ -211,6 +214,7 @@ struct Monitor {
 	struct wl_listener frame;
 	struct wl_listener destroy;
 	struct wl_listener request_state;
+	struct wl_listener commit_lock_surface;
 	struct wl_listener destroy_lock_surface;
 	struct wlr_session_lock_surface_v1 *lock_surface;
 	struct wlr_box m; /* monitor area, layout-relative */
@@ -261,6 +265,7 @@ typedef struct {
 
 /* function declarations */
 static void applybounds(Client *c, struct wlr_box *bbox);
+static void applygeom(Client *c);
 static void applyrules(Client *c);
 static void arrange(Monitor *m);
 static void arrangelayer(Monitor *m, struct wl_list *list,
@@ -276,6 +281,7 @@ static void cleanupmon(struct wl_listener *listener, void *data);
 static void cleanuplisteners(void);
 static void closemon(Monitor *m);
 static void commitlayersurfacenotify(struct wl_listener *listener, void *data);
+static void commitlocksurface(struct wl_listener *listener, void *data);
 static void commitnotify(struct wl_listener *listener, void *data);
 static void commitpopup(struct wl_listener *listener, void *data);
 static void createdecoration(struct wl_listener *listener, void *data);
@@ -303,7 +309,7 @@ static void destroypointerconstraint(struct wl_listener *listener, void *data);
 static void destroysessionlock(struct wl_listener *listener, void *data);
 static void destroykeyboardgroup(struct wl_listener *listener, void *data);
 static Monitor *dirtomon(enum wlr_direction dir);
-static void focusclient(Client *c, int lift);
+static void focusclient(Client *c, LayerSurface *l, int lift);
 static void focusmon(const Arg *arg);
 static void focusstack(const Arg *arg);
 static Client *focustop(Monitor *m);
@@ -350,6 +356,8 @@ static void setmon(Client *c, Monitor *m, uint32_t newtags);
 static void setpsel(struct wl_listener *listener, void *data);
 static void setsel(struct wl_listener *listener, void *data);
 static void setup(void);
+static struct wlr_scene_node *snapshot(struct wlr_scene_node *node,
+		struct wlr_scene_tree *parent, void *data);
 static void spawn(const Arg *arg);
 static void startdrag(struct wl_listener *listener, void *data);
 static void tag(const Arg *arg);
@@ -359,6 +367,11 @@ static void togglefloating(const Arg *arg);
 static void togglefullscreen(const Arg *arg);
 static void toggletag(const Arg *arg);
 static void toggleview(const Arg *arg);
+static void transactionapply(void);
+static void transactioncheck(void *data);
+static void transactioncommit(Client *c, int ready);
+static void transactionschedule(void);
+static int transactiontimeout(void *data);
 static void unlocksession(struct wl_listener *listener, void *data);
 static void unmaplayersurfacenotify(struct wl_listener *listener, void *data);
 static void unmapnotify(struct wl_listener *listener, void *data);
@@ -376,7 +389,6 @@ static void zoom(const Arg *arg);
 /* variables */
 static pid_t child_pid = -1;
 static int locked;
-static void *exclusive_focus;
 static Client *focused_client;
 static struct wl_display *dpy;
 static struct wl_event_loop *event_loop;
@@ -431,6 +443,14 @@ static struct wl_list mons;
 static Monitor *selmon;
 static int consumed[KEY_MAX + 1];
 
+/* Transactions: the scene graph is updated only once all visible clients have
+ * committed buffers with their new size, or after TRANSACTION_TIMEOUT ms */
+#define TRANSACTION_TIMEOUT 100
+static struct wl_event_source *transaction_idle;
+static struct wl_event_source *transaction_timer;
+static int transaction_waiting;
+static struct wl_array ghosts; /* struct wlr_scene_node *, unmapped clients */
+
 /* global event handlers */
 static struct wl_listener cursor_axis = {.notify = axisnotify};
 static struct wl_listener cursor_button = {.notify = buttonpress};
@@ -465,6 +485,7 @@ static struct wl_listener new_foreign_toplevel_capture_request = {.notify = capt
 #ifdef XWAYLAND
 static void activatex11(struct wl_listener *listener, void *data);
 static void associatex11(struct wl_listener *listener, void *data);
+static void commitx11(struct wl_listener *listener, void *data);
 static void configurex11(struct wl_listener *listener, void *data);
 static void createnotifyx11(struct wl_listener *listener, void *data);
 static void dissociatex11(struct wl_listener *listener, void *data);
@@ -515,6 +536,41 @@ applybounds(Client *c, struct wlr_box *bbox)
 		c->geom.y = bbox->y;
 }
 
+void
+applygeom(Client *c)
+{
+	struct wlr_box clip;
+	Client *p = client_get_parent(c);
+
+	/* We move all floating clients to LyrTile while in floating layout
+	 * to avoid "real" floating clients be always on top */
+	wlr_scene_node_reparent(&c->scene->node, layers[c->isfullscreen
+			|| (p && p->isfullscreen) ? LyrFS
+			: c->isfloating && c->mon->lt[c->mon->sellt]->arrange ? LyrFloat
+			: LyrTile]);
+
+	c->current = c->geom;
+	if (c->snapshot) {
+		wlr_scene_node_destroy(c->snapshot);
+		c->snapshot = NULL;
+		wlr_scene_node_set_enabled(&c->scene_surface->node, 1);
+	}
+
+	/* Update scene-graph, including borders */
+	wlr_scene_node_set_position(&c->scene->node, c->geom.x, c->geom.y);
+	wlr_scene_node_set_position(&c->scene_surface->node, c->bw, c->bw);
+	wlr_scene_rect_set_size(c->border[0], c->geom.width, c->bw);
+	wlr_scene_rect_set_size(c->border[1], c->geom.width, c->bw);
+	wlr_scene_rect_set_size(c->border[2], c->bw, c->geom.height - 2 * c->bw);
+	wlr_scene_rect_set_size(c->border[3], c->bw, c->geom.height - 2 * c->bw);
+	wlr_scene_node_set_position(&c->border[1]->node, 0, c->geom.height - c->bw);
+	wlr_scene_node_set_position(&c->border[2]->node, 0, c->bw);
+	wlr_scene_node_set_position(&c->border[3]->node, c->geom.width - c->bw, c->bw);
+
+	client_get_clip(c, &clip);
+	wlr_scene_subsurface_tree_set_clip(&c->scene_surface->node, &clip);
+}
+
 void
 applyrules(Client *c)
 {
@@ -554,37 +610,18 @@ arrange(Monitor *m)
 		return;
 
 	wl_list_for_each(c, &clients, link) {
-		if (c->mon == m) {
-			wlr_scene_node_set_enabled(&c->scene->node, VISIBLEON(c, m));
+		if (c->mon == m)
 			client_set_suspended(c, !VISIBLEON(c, m)
 					&& (!c->image_capture_source
 					|| wl_list_empty(&c->image_capture_source->resources)));
-		}
 	}
 
-	wlr_scene_node_set_enabled(&m->fullscreen_bg->node,
-			(c = focustop(m)) && c->isfullscreen);
-
 	strncpy(m->ltsymbol, m->lt[m->sellt]->symbol, LENGTH(m->ltsymbol));
 
-	/* We move all clients (except fullscreen and unmanaged) to LyrTile while
-	 * in floating layout to avoid "real" floating clients be always on top */
-	wl_list_for_each(c, &clients, link) {
-		if (c->mon != m || c->scene->node.parent == layers[LyrFS])
-			continue;
-
-		wlr_scene_node_reparent(&c->scene->node,
-				(!m->lt[m->sellt]->arrange && c->isfloating)
-						? layers[LyrTile]
-						: (m->lt[m->sellt]->arrange && c->isfloating)
-								? layers[LyrFloat]
-								: c->scene->node.parent);
-	}
-
 	if (m->lt[m->sellt]->arrange)
 		m->lt[m->sellt]->arrange(m);
-	motionnotify(0, NULL, 0, 0, 0, 0);
-	checkidleinhibitor(NULL);
+
+	transactionschedule();
 }
 
 void
@@ -641,10 +678,7 @@ arrangelayers(Monitor *m)
 					l->layer_surface->current.keyboard_interactive != ZWLR_LAYER_SURFACE_V1_KEYBOARD_INTERACTIVITY_EXCLUSIVE ||
 					!l->mapped)
 				continue;
-			/* Deactivate the focused client. */
-			focusclient(NULL, 0);
-			exclusive_focus = l;
-			client_notify_enter(l->layer_surface->surface, wlr_seat_get_keyboard(seat));
+			focusclient(NULL, l, 0);
 			return;
 		}
 	}
@@ -663,16 +697,18 @@ axisnotify(struct wl_listener *listener, void *data)
 
 	wlr_idle_notifier_v1_notify_activity(idle_notifier, seat);
 
-	if (event->orientation == WL_POINTER_AXIS_VERTICAL_SCROLL)
-		adir = event->delta > 0 ? AxisDown : AxisUp;
-	else
-		adir = event->delta > 0 ? AxisRight : AxisLeft;
-	keyboard = wlr_seat_get_keyboard(seat);
-	mods = keyboard ? wlr_keyboard_get_modifiers(keyboard) : 0;
-	for (a = axes; a < END(axes); a++) {
-		if (CLEANMASK(mods) == CLEANMASK(a->mod) && adir == a->dir && a->func) {
-			a->func(&a->arg);
-			return;
+	if (!locked) {
+		if (event->orientation == WL_POINTER_AXIS_VERTICAL_SCROLL)
+			adir = event->delta > 0 ? AxisDown : AxisUp;
+		else
+			adir = event->delta > 0 ? AxisRight : AxisLeft;
+		keyboard = wlr_seat_get_keyboard(seat);
+		mods = keyboard ? wlr_keyboard_get_modifiers(keyboard) : 0;
+		for (a = axes; a < END(axes); a++) {
+			if (CLEANMASK(mods) == CLEANMASK(a->mod) && adir == a->dir && a->func) {
+				a->func(&a->arg);
+				return;
+			}
 		}
 	}
 
@@ -705,10 +741,9 @@ buttonpress(struct wl_listener *listener, void *data)
 		   or a layer surface with on-demand keyboard interactivity */
 		xytonode(cursor->x, cursor->y, NULL, &c, &l, NULL, NULL);
 		if (c && (!client_is_unmanaged(c) || client_wants_focus(c))) {
-			focusclient(c, 1);
+			focusclient(c, NULL, 1);
 		} else if (l && l->layer_surface->current.keyboard_interactive) {
-			focusclient(NULL, 0);
-			client_notify_enter(l->layer_surface->surface, wlr_seat_get_keyboard(seat));
+			focusclient(NULL, l, 0);
 		}
 
 		keyboard = wlr_seat_get_keyboard(seat);
@@ -810,6 +845,11 @@ cleanup(void)
 	 * Destroy it until it's fixed on the wlroots side */
 	wlr_backend_destroy(backend);
 
+	if (transaction_idle)
+		wl_event_source_remove(transaction_idle);
+	wl_event_source_remove(transaction_timer);
+	wl_array_release(&ghosts);
+
 	wl_display_destroy(dpy);
 	/* Destroy after the wayland display (when the monitors are already destroyed)
 	   to avoid destroying them with an invalid scene output. */
@@ -877,8 +917,10 @@ cleanuplisteners(void)
 	wl_list_remove(&new_session_lock.link);
 	wl_list_remove(&new_foreign_toplevel_capture_request.link);
 #ifdef XWAYLAND
-	wl_list_remove(&new_xwayland_surface.link);
-	wl_list_remove(&xwayland_ready.link);
+	if (xwayland) {
+		wl_list_remove(&new_xwayland_surface.link);
+		wl_list_remove(&xwayland_ready.link);
+	}
 #endif
 }
 
@@ -907,7 +949,7 @@ closemon(Monitor *m)
 		if (c->mon == m)
 			setmon(c, selmon, c->tags);
 	}
-	focusclient(focustop(selmon), 1);
+	focusclient(focustop(selmon), NULL, 1);
 	printstatus();
 }
 
@@ -931,11 +973,6 @@ commitlayersurfacenotify(struct wl_listener *listener, void *data)
 		return;
 	}
 
-	if (layer_surface == exclusive_focus
-			&& layer_surface->current.keyboard_interactive !=
-				ZWLR_LAYER_SURFACE_V1_KEYBOARD_INTERACTIVITY_EXCLUSIVE)
-		exclusive_focus = NULL;
-
 	if (layer_surface->current.committed == 0 && l->mapped == layer_surface->surface->mapped)
 		return;
 	l->mapped = layer_surface->surface->mapped;
@@ -951,6 +988,20 @@ commitlayersurfacenotify(struct wl_listener *listener, void *data)
 	arrangelayers(l->mon);
 }
 
+void
+commitlocksurface(struct wl_listener *listener, void *data)
+{
+	Monitor *m = wl_container_of(listener, m, commit_lock_surface);
+
+	if (!m->lock_surface->surface->mapped)
+		return;
+
+	wl_list_remove(&m->commit_lock_surface.link);
+	wl_list_init(&m->commit_lock_surface.link);
+
+	motionnotify(0, NULL, 0, 0, 0, 0);
+}
+
 void
 commitnotify(struct wl_listener *listener, void *data)
 {
@@ -980,6 +1031,8 @@ commitnotify(struct wl_listener *listener, void *data)
 		return;
 	}
 
+	transactioncommit(c, c->resize_serial && c->surface.xdg->current.configure_serial
+			>= c->resize_serial);
 	resize(c, c->geom, (c->isfloating && !c->isfullscreen));
 }
 
@@ -1006,8 +1059,8 @@ commitpopup(struct wl_listener *listener, void *data)
 		return;
 	}
 	box = type == LayerShell ? l->mon->m : c->mon->w;
-	box.x -= (type == LayerShell ? l->scene->node.x : c->geom.x);
-	box.y -= (type == LayerShell ? l->scene->node.y : c->geom.y);
+	box.x -= (type == LayerShell ? l->scene->node.x : c->geom.x - c->surface.xdg->geometry.x);
+	box.y -= (type == LayerShell ? l->scene->node.y : c->geom.y - c->surface.xdg->geometry.y);
 	wlr_xdg_popup_unconstrain_from_box(popup, &box);
 	wl_list_remove(&listener->link);
 	free(listener);
@@ -1128,6 +1181,7 @@ createlocksurface(struct wl_listener *listener, void *data)
 	wlr_session_lock_surface_v1_configure(lock_surface, m->m.width, m->m.height);
 
 	LISTEN(&lock_surface->events.destroy, &m->destroy_lock_surface, destroylocksurface);
+	LISTEN(&lock_surface->surface->events.commit, &m->commit_lock_surface, commitlocksurface);
 
 	if (m == selmon)
 		client_notify_enter(lock_surface->surface, wlr_seat_get_keyboard(seat));
@@ -1349,7 +1403,7 @@ void
 destroydragicon(struct wl_listener *listener, void *data)
 {
 	/* Focus enter isn't sent during drag, so refocus the focused node. */
-	focusclient(focustop(selmon), 1);
+	focusclient(focustop(selmon), NULL, 1);
 	motionnotify(0, NULL, 0, 0, 0, 0);
 	wl_list_remove(&listener->link);
 	free(listener);
@@ -1388,7 +1442,7 @@ destroylock(SessionLock *lock, int unlock)
 
 	wlr_scene_node_set_enabled(&locked_bg->node, 0);
 
-	focusclient(focustop(selmon), 0);
+	focusclient(focustop(selmon), NULL, 0);
 	motionnotify(0, NULL, 0, 0, 0, 0);
 
 destroy:
@@ -1409,6 +1463,7 @@ destroylocksurface(struct wl_listener *listener, void *data)
 
 	m->lock_surface = NULL;
 	wl_list_remove(&m->destroy_lock_surface.link);
+	wl_list_remove(&m->commit_lock_surface.link);
 
 	if (lock_surface->surface != seat->keyboard_state.focused_surface)
 		return;
@@ -1417,7 +1472,7 @@ destroylocksurface(struct wl_listener *listener, void *data)
 		surface = wl_container_of(cur_lock->surfaces.next, surface, link);
 		client_notify_enter(surface->surface, wlr_seat_get_keyboard(seat));
 	} else if (!locked) {
-		focusclient(focustop(selmon), 1);
+		focusclient(focustop(selmon), NULL, 1);
 	} else {
 		wlr_seat_keyboard_clear_focus(seat);
 	}
@@ -1505,9 +1560,9 @@ dirtomon(enum wlr_direction dir)
 }
 
 void
-focusclient(Client *c, int lift)
+focusclient(Client *c, LayerSurface *l, int lift)
 {
-	struct wlr_surface *old = seat->keyboard_state.focused_surface;
+	struct wlr_surface *surface, *old = seat->keyboard_state.focused_surface;
 	int unused_lx, unused_ly, old_client_type;
 	Client *old_c = NULL;
 	LayerSurface *old_l = NULL;
@@ -1528,9 +1583,6 @@ focusclient(Client *c, int lift)
 			wlr_xdg_popup_destroy(popup);
 	}
 
-	if (old_c && old_c == exclusive_focus && client_wants_focus(old_c))
-		exclusive_focus = NULL;
-
 	/* Put the new client atop the focus stack and select its monitor */
 	if (c && !client_is_unmanaged(c)) {
 		wl_list_remove(&c->flink);
@@ -1540,14 +1592,16 @@ focusclient(Client *c, int lift)
 
 		/* Don't change border color if there is an exclusive focus or we are
 		 * handling a drag operation */
-		if (!exclusive_focus && !seat->drag)
+		if (!(old_l && old_l->layer_surface->current.keyboard_interactive == ZWLR_LAYER_SURFACE_V1_KEYBOARD_INTERACTIVITY_EXCLUSIVE)
+				&& !(old_c && client_wants_focus(old_c))
+				&& !seat->drag)
 			client_set_border_color(c, focuscolor);
 	}
 
 	/* If an overlay is focused, don't focus or activate the client,
 	 * but only update its position in fstack to render its border with focuscolor
 	 * and focus it after the overlay is closed. */
-	if (old && (!c || client_surface(c) != old)
+	if (!l && old && (!c || client_surface(c) != old)
 			&& old_client_type == LayerShell && wlr_scene_node_coords(
 				&old_l->scene->node, &unused_lx, &unused_ly)
 			&& old_l->layer_surface->current.layer >= ZWLR_LAYER_SHELL_V1_LAYER_TOP
@@ -1564,24 +1618,23 @@ focusclient(Client *c, int lift)
 	}
 	printstatus();
 
-	if (!c) {
+	if (!c && !l) {
 		/* With no client, all we have left is to clear focus */
 		input_method_relay_set_focus(input_method_relay, NULL);
 		wlr_seat_keyboard_notify_clear_focus(seat);
 		return;
 	}
 
-	/* Change cursor surface */
+	surface = c ? client_surface(c) : l->layer_surface->surface;
+	input_method_relay_set_focus(input_method_relay, surface);
+	client_notify_enter(surface, wlr_seat_get_keyboard(seat));
+
+	if (l)
+		return;
+
+	client_activate_surface(surface, 1);
 	motionnotify(0, NULL, 0, 0, 0, 0);
 
-	input_method_relay_set_focus(input_method_relay, client_surface(c));
-
-	/* Have a client, so focus its top-level wlr_surface */
-	client_notify_enter(client_surface(c), wlr_seat_get_keyboard(seat));
-
-	/* Activate the new client */
-	client_activate_surface(client_surface(c), 1);
-
 	if (!client_is_unmanaged(c))
 		focused_client = c;
 }
@@ -1595,7 +1648,7 @@ focusmon(const Arg *arg)
 			selmon = dirtomon(arg->i);
 		while (!selmon->wlr_output->enabled && i++ < nmons);
 	}
-	focusclient(focustop(selmon), 1);
+	focusclient(focustop(selmon), NULL, 1);
 }
 
 void
@@ -1621,7 +1674,7 @@ focusstack(const Arg *arg)
 		}
 	}
 	/* If only one client is visible on selmon, then c == sel */
-	focusclient(c, 1);
+	focusclient(c, NULL, 1);
 }
 
 /* We probably should change the name of this: it sounds like it
@@ -1810,7 +1863,7 @@ int
 keyrepeat(void *data)
 {
 	KeyboardGroup *group = data;
-	if (group->wlr_group->keyboard.repeat_info.rate <= 0)
+	if (locked || group->wlr_group->keyboard.repeat_info.rate <= 0)
 		return 0;
 
 	wl_event_source_timer_update(group->key_repeat_source,
@@ -1846,12 +1899,18 @@ locksession(struct wl_listener *listener, void *data)
 		return;
 	}
 	lock = session_lock->data = ecalloc(1, sizeof(*lock));
-	focusclient(NULL, 0);
+	focusclient(NULL, NULL, 0);
 
 	lock->scene = wlr_scene_tree_create(layers[LyrBlock]);
 	cur_lock = lock->lock = session_lock;
 	locked = 1;
 
+	/* Cancel any interactive move/resize and take the pointer focus away
+	 * from the clients below the lock screen */
+	cursor_mode = CurNormal;
+	grabc = NULL;
+	motionnotify(0, NULL, 0, 0, 0, 0);
+
 	LISTEN(&session_lock->events.new_surface, &lock->new_surface, createlocksurface);
 	LISTEN(&session_lock->events.destroy, &lock->destroy, destroysessionlock);
 	LISTEN(&session_lock->events.unlock, &lock->unlock, unlocksession);
@@ -1889,10 +1948,8 @@ mapnotify(struct wl_listener *listener, void *data)
 		/* Unmanaged clients always are floating */
 		wlr_scene_node_reparent(&c->scene->node, layers[LyrUnmanaged]);
 		wlr_scene_node_set_position(&c->scene->node, c->geom.x, c->geom.y);
-		if (client_wants_focus(c)) {
-			focusclient(c, 1);
-			exclusive_focus = c;
-		}
+		if (client_wants_focus(c))
+			focusclient(c, NULL, 1);
 		goto unset_fullscreen;
 	}
 
@@ -1903,8 +1960,15 @@ mapnotify(struct wl_listener *listener, void *data)
 	}
 
 	/* Initialize client geometry with room for border */
+	client_set_tiled(c, WLR_EDGE_TOP | WLR_EDGE_BOTTOM | WLR_EDGE_LEFT |
+			WLR_EDGE_RIGHT);
 	c->geom.width += 2 * c->bw;
 	c->geom.height += 2 * c->bw;
+	if (client_is_x11(c)) {
+		int x = c->geom.x - (int)c->bw, y = c->geom.y - (int)c->bw;
+		c->geom.x = c->geom.x < sgeom.x ? x : MAX(x, sgeom.x);
+		c->geom.y = c->geom.y < sgeom.y ? y : MAX(y, sgeom.y);
+	}
 
 	/* Insert this client into client lists. */
 	wl_list_insert(&clients, &c->link);
@@ -2228,10 +2292,9 @@ pointerfocus(Client *c, LayerSurface *l, struct wlr_surface *surface, double sx,
 
 	if (surface != seat->pointer_state.focused_surface && sloppyfocus && time) {
 		if (c && (!client_is_unmanaged(c) || client_wants_focus(c))) {
-			focusclient(c, 0);
+			focusclient(c, NULL, 0);
 		} else if (l && l->layer_surface->current.keyboard_interactive) {
-			focusclient(NULL, 0);
-			client_notify_enter(l->layer_surface->surface, wlr_seat_get_keyboard(seat));
+			focusclient(NULL, l, 0);
 		}
 	}
 
@@ -2365,7 +2428,7 @@ void
 resize(Client *c, struct wlr_box geo, int interact)
 {
 	struct wlr_box *bbox;
-	struct wlr_box clip;
+	uint32_t serial;
 
 	if (!c->mon || !client_surface(c)->mapped)
 		return;
@@ -2376,20 +2439,27 @@ resize(Client *c, struct wlr_box geo, int interact)
 	c->geom = geo;
 	applybounds(c, bbox);
 
-	/* Update scene-graph, including borders */
-	wlr_scene_node_set_position(&c->scene->node, c->geom.x, c->geom.y);
-	wlr_scene_node_set_position(&c->scene_surface->node, c->bw, c->bw);
-	wlr_scene_rect_set_size(c->border[0], c->geom.width, c->bw);
-	wlr_scene_rect_set_size(c->border[1], c->geom.width, c->bw);
-	wlr_scene_rect_set_size(c->border[2], c->bw, c->geom.height - 2 * c->bw);
-	wlr_scene_rect_set_size(c->border[3], c->bw, c->geom.height - 2 * c->bw);
-	wlr_scene_node_set_position(&c->border[1]->node, 0, c->geom.height - c->bw);
-	wlr_scene_node_set_position(&c->border[2]->node, 0, c->bw);
-	wlr_scene_node_set_position(&c->border[3]->node, c->geom.width - c->bw, c->bw);
+	if ((serial = client_set_size(c, c->geom.width - 2 * c->bw,
+			c->geom.height - 2 * c->bw)))
+		c->resize_serial = serial;
 
-	client_set_size(c, c->geom.width - 2 * c->bw, c->geom.height - 2 * c->bw);
-	client_get_clip(c, &clip);
-	wlr_scene_subsurface_tree_set_clip(&c->scene_surface->node, &clip);
+	if (interact || (!c->resize_serial && wlr_box_equal(&c->geom, &c->current))) {
+		c->resize_serial = 0;
+		applygeom(c);
+		return;
+	}
+
+	/* Until the transaction is applied, keep showing the current content
+	 * instead of buffers with the new size at the old position. */
+	if (c->resize_serial) {
+		if (!c->snapshot && c->scene->node.enabled
+				&& (c->snapshot = snapshot(&c->scene_surface->node, c->scene, c)))
+			wlr_scene_node_set_enabled(&c->scene_surface->node, 0);
+		/* The scene graph doesn't send frame done events to hidden
+		 * surfaces, but the client may be waiting for one to redraw */
+		client_send_frame_done(c);
+	}
+	transactionschedule();
 }
 
 void
@@ -2490,14 +2560,10 @@ setcursorshape(struct wl_listener *listener, void *data)
 void
 setfloating(Client *c, int floating)
 {
-	Client *p = client_get_parent(c);
 	c->isfloating = floating;
 	/* If in floating layout do not change the client's layer */
 	if (!c->mon || !client_surface(c)->mapped || !c->mon->lt[c->mon->sellt]->arrange)
 		return;
-	wlr_scene_node_reparent(&c->scene->node, layers[c->isfullscreen ||
-			(p && p->isfullscreen) ? LyrFS
-			: c->isfloating ? LyrFloat : LyrTile]);
 	arrange(c->mon);
 	printstatus();
 }
@@ -2510,8 +2576,6 @@ setfullscreen(Client *c, int fullscreen)
 		return;
 	c->bw = fullscreen ? 0 : borderpx;
 	client_set_fullscreen(c, fullscreen);
-	wlr_scene_node_reparent(&c->scene->node, layers[c->isfullscreen
-			? LyrFS : c->isfloating ? LyrFloat : LyrTile]);
 
 	if (fullscreen) {
 		c->prev = c->geom;
@@ -2574,7 +2638,7 @@ setmon(Client *c, Monitor *m, uint32_t newtags)
 		setfullscreen(c, c->isfullscreen); /* This will call arrange(c->mon) */
 		setfloating(c, c->isfloating);
 	}
-	focusclient(focustop(selmon), 1);
+	focusclient(focustop(selmon), NULL, 1);
 }
 
 void
@@ -2715,6 +2779,9 @@ setup(void)
 	wl_list_init(&clients);
 	wl_list_init(&fstack);
 
+	transaction_timer = wl_event_loop_add_timer(event_loop, transactiontimeout, NULL);
+	wl_array_init(&ghosts);
+
 	xdg_shell = wlr_xdg_shell_create(dpy, 6);
 	wl_signal_add(&xdg_shell->events.new_toplevel, &new_xdg_toplevel);
 	wl_signal_add(&xdg_shell->events.new_popup, &new_xdg_popup);
@@ -2836,6 +2903,57 @@ setup(void)
 #endif
 }
 
+struct wlr_scene_node *
+snapshot(struct wlr_scene_node *node, struct wlr_scene_tree *parent, void *data)
+{
+	/* Copy the visible part of a scene graph subtree, keeping references to
+	 * the buffers so that they can be shown after the client changes them */
+	struct wlr_scene_node *child, *copy;
+	struct wlr_scene_tree *tree;
+	struct wlr_scene_rect *rect;
+	struct wlr_scene_buffer *src, *buffer;
+
+	if (!node->enabled)
+		return NULL;
+
+	switch (node->type) {
+	case WLR_SCENE_NODE_TREE:
+		tree = wlr_scene_tree_create(parent);
+		wl_list_for_each(child, &wlr_scene_tree_from_node(node)->children, link)
+			snapshot(child, tree, data);
+		copy = &tree->node;
+		break;
+	case WLR_SCENE_NODE_RECT:
+		rect = wlr_scene_rect_from_node(node);
+		copy = &wlr_scene_rect_create(parent, rect->width, rect->height, rect->color)->node;
+		break;
+	case WLR_SCENE_NODE_BUFFER:
+		src = wlr_scene_buffer_from_node(node);
+		buffer = wlr_scene_buffer_create(parent, NULL);
+		wlr_scene_buffer_set_dest_size(buffer, src->dst_width, src->dst_height);
+		wlr_scene_buffer_set_opaque_region(buffer, &src->opaque_region);
+		wlr_scene_buffer_set_opacity(buffer, src->opacity);
+		wlr_scene_buffer_set_filter_mode(buffer, src->filter_mode);
+		wlr_scene_buffer_set_transfer_function(buffer, src->transfer_function);
+		wlr_scene_buffer_set_primaries(buffer, src->primaries);
+		wlr_scene_buffer_set_color_encoding(buffer, src->color_encoding);
+		wlr_scene_buffer_set_color_range(buffer, src->color_range);
+		wlr_scene_buffer_set_source_box(buffer, &src->src_box);
+		wlr_scene_buffer_set_transform(buffer, src->transform);
+		wlr_scene_buffer_set_buffer(buffer, src->buffer);
+		copy = &buffer->node;
+		break;
+	default:
+		return NULL;
+	}
+
+	copy->data = data;
+	wlr_scene_node_set_position(copy, node->x, node->y);
+	if (node->parent == parent)
+		wlr_scene_node_place_above(copy, node);
+	return copy;
+}
+
 void
 spawn(const Arg *arg)
 {
@@ -2866,7 +2984,7 @@ tag(const Arg *arg)
 		return;
 
 	sel->tags = arg->ui & TAGMASK;
-	focusclient(focustop(selmon), 1);
+	focusclient(focustop(selmon), NULL, 1);
 	arrange(selmon);
 	printstatus();
 }
@@ -2939,7 +3057,7 @@ toggletag(const Arg *arg)
 		return;
 
 	sel->tags = newtags;
-	focusclient(focustop(selmon), 1);
+	focusclient(focustop(selmon), NULL, 1);
 	arrange(selmon);
 	printstatus();
 }
@@ -2952,11 +3070,93 @@ toggleview(const Arg *arg)
 		return;
 
 	selmon->tagset[selmon->seltags] = newtagset;
-	focusclient(focustop(selmon), 1);
+	focusclient(focustop(selmon), NULL, 1);
 	arrange(selmon);
 	printstatus();
 }
 
+void
+transactionapply(void)
+{
+	struct wlr_scene_node **ghost;
+	Client *c;
+	Monitor *m;
+
+	wl_event_source_timer_update(transaction_timer, 0);
+	transaction_waiting = 0;
+
+	wl_array_for_each(ghost, &ghosts)
+		wlr_scene_node_destroy(*ghost);
+	ghosts.size = 0;
+
+	wl_list_for_each(c, &clients, link) {
+		c->resize_serial = 0;
+		if (!c->mon)
+			continue;
+		if (c->mon->wlr_output->enabled)
+			wlr_scene_node_set_enabled(&c->scene->node, VISIBLEON(c, c->mon));
+		applygeom(c);
+	}
+
+	wl_list_for_each(m, &mons, link) {
+		if (m->wlr_output->enabled)
+			wlr_scene_node_set_enabled(&m->fullscreen_bg->node,
+					(c = focustop(m)) && c->isfullscreen);
+	}
+
+	motionnotify(0, NULL, 0, 0, 0, 0);
+	checkidleinhibitor(NULL);
+}
+
+void
+transactioncheck(void *data)
+{
+	Client *c;
+
+	transaction_idle = NULL;
+
+	/* Hidden clients don't have to redraw before the layout is shown */
+	wl_list_for_each(c, &clients, link) {
+		if (c->resize_serial && VISIBLEON(c, c->mon) && c->mon->wlr_output->enabled) {
+			if (!transaction_waiting) {
+				/* Don't restart the timer on updates of the pending
+				 * layout, so the delay is bounded */
+				wl_event_source_timer_update(transaction_timer, TRANSACTION_TIMEOUT);
+				transaction_waiting = 1;
+			}
+			return;
+		}
+	}
+
+	transactionapply();
+}
+
+void
+transactioncommit(Client *c, int ready)
+{
+	if (c->resize_serial && ready) {
+		c->resize_serial = 0;
+		transactionschedule();
+	} else if (c->snapshot) {
+		/* This buffer is not shown, let the client draw again */
+		client_send_frame_done(c);
+	}
+}
+
+void
+transactionschedule(void)
+{
+	if (!transaction_idle)
+		transaction_idle = wl_event_loop_add_idle(event_loop, transactioncheck, NULL);
+}
+
+int
+transactiontimeout(void *data)
+{
+	transactionapply();
+	return 0;
+}
+
 void
 unlocksession(struct wl_listener *listener, void *data)
 {
@@ -2971,12 +3171,10 @@ unmaplayersurfacenotify(struct wl_listener *listener, void *data)
 
 	l->mapped = 0;
 	wlr_scene_node_set_enabled(&l->scene->node, 0);
-	if (l == exclusive_focus)
-		exclusive_focus = NULL;
 	if (l->layer_surface->output && (l->mon = l->layer_surface->output->data))
 		arrangelayers(l->mon);
 	if (l->layer_surface->surface == seat->keyboard_state.focused_surface)
-		focusclient(focustop(selmon), 1);
+		focusclient(focustop(selmon), NULL, 1);
 	motionnotify(0, NULL, 0, 0, 0, 0);
 }
 
@@ -2985,6 +3183,7 @@ unmapnotify(struct wl_listener *listener, void *data)
 {
 	/* Called when the surface is unmapped, and should no longer be shown. */
 	Client *c = wl_container_of(listener, c, unmap);
+	struct wlr_scene_node *ghost, **slot;
 	if (c == grabc) {
 		cursor_mode = CurNormal;
 		grabc = NULL;
@@ -2992,15 +3191,21 @@ unmapnotify(struct wl_listener *listener, void *data)
 	if (c == focused_client)
 		focused_client = NULL;
 
-	if (client_is_unmanaged(c)) {
-		if (c == exclusive_focus) {
-			exclusive_focus = NULL;
-			focusclient(focustop(selmon), 1);
+	if (!client_is_unmanaged(c)) {
+		/* Keep showing the client until the transaction rearranging the
+		 * remaining ones is applied, to not show a gap */
+		if ((ghost = snapshot(&c->scene->node, c->scene->node.parent, NULL))) {
+			if ((slot = wl_array_add(&ghosts, sizeof(ghost))))
+				*slot = ghost;
+			else
+				wlr_scene_node_destroy(ghost);
+			transactionschedule();
 		}
-	} else {
 		wl_list_remove(&c->link);
 		setmon(c, NULL, 0);
 		wl_list_remove(&c->flink);
+	} else if (client_wants_focus(c)) {
+		focusclient(focustop(selmon), NULL, 1);
 	}
 
 	if (c->foreign_toplevel_handle) {
@@ -3019,6 +3224,9 @@ unmapnotify(struct wl_listener *listener, void *data)
 	c->image_capture_source = NULL;
 	wlr_scene_node_destroy(&c->scene->node);
 	client_surface(c)->data = NULL;
+	c->snapshot = NULL;
+	c->resize_serial = 0;
+	c->current = (struct wlr_box){0};
 	printstatus();
 	motionnotify(0, NULL, 0, 0, 0, 0);
 }
@@ -3114,7 +3322,7 @@ updatemons(struct wl_listener *listener, void *data)
 			if (!c->mon && client_surface(c)->mapped)
 				setmon(c, selmon, c->tags);
 		}
-		focusclient(focustop(selmon), 1);
+		focusclient(focustop(selmon), NULL, 1);
 		if (selmon->lock_surface) {
 			client_notify_enter(selmon->lock_surface->surface,
 					wlr_seat_get_keyboard(seat));
@@ -3173,7 +3381,7 @@ view(const Arg *arg)
 	selmon->seltags ^= 1; /* toggle sel tagset */
 	if (arg->ui & TAGMASK)
 		selmon->tagset[selmon->seltags] = arg->ui & TAGMASK;
-	focusclient(focustop(selmon), 1);
+	focusclient(focustop(selmon), NULL, 1);
 	arrange(selmon);
 	printstatus();
 }
@@ -3218,20 +3426,26 @@ xytonode(double x, double y, struct wlr_surface **psurface,
 		Client **pc, LayerSurface **pl, double *nx, double *ny)
 {
 	struct wlr_scene_node *node;
+	struct wlr_scene_surface *scene_surface;
 	struct wlr_surface *surface = NULL;
+	Client *c = NULL;
 	int layer;
 
-	for (layer = NUM_LAYERS - 1; !surface && layer >= 0; layer--) {
+	for (layer = NUM_LAYERS - 1; !surface && !c && layer >= (locked ? LyrBlock : 0); layer--) {
 		if (layer == LyrIMPopup ||
-				!(node = wlr_scene_node_at(&layers[layer]->node, x, y, nx, ny)))
+				!(node = wlr_scene_node_at(&layers[layer]->node, x, y, nx, ny))
+				|| node->type != WLR_SCENE_NODE_BUFFER)
 			continue;
 
-		if (node->type == WLR_SCENE_NODE_BUFFER)
-			surface = wlr_scene_surface_try_from_buffer(
-					wlr_scene_buffer_from_node(node))->surface;
+		if ((scene_surface = wlr_scene_surface_try_from_buffer(
+				wlr_scene_buffer_from_node(node))))
+			surface = scene_surface->surface;
+		else /* snapshot of a client during a transaction */
+			c = node->data;
 	}
 
 	if (psurface) *psurface = surface;
+	if (pc) *pc = c;
 	toplevel_from_wlr_surface(surface, pc, pl);
 }
 
@@ -3264,7 +3478,7 @@ zoom(const Arg *arg)
 	wl_list_remove(&sel->link);
 	wl_list_insert(&clients, &sel->link);
 
-	focusclient(sel, 1);
+	focusclient(sel, NULL, 1);
 	arrange(selmon);
 }
 
@@ -3284,10 +3498,21 @@ associatex11(struct wl_listener *listener, void *data)
 {
 	Client *c = wl_container_of(listener, c, associate);
 
+	LISTEN(&client_surface(c)->events.commit, &c->commit, commitx11);
 	LISTEN(&client_surface(c)->events.map, &c->map, mapnotify);
 	LISTEN(&client_surface(c)->events.unmap, &c->unmap, unmapnotify);
 }
 
+void
+commitx11(struct wl_listener *listener, void *data)
+{
+	Client *c = wl_container_of(listener, c, commit);
+	struct wlr_surface *surface = client_surface(c);
+
+	transactioncommit(c, surface->current.width == c->geom.width - 2 * (int)c->bw
+			&& surface->current.height == c->geom.height - 2 * (int)c->bw);
+}
+
 void
 configurex11(struct wl_listener *listener, void *data)
 {
@@ -3336,6 +3561,7 @@ void
 dissociatex11(struct wl_listener *listener, void *data)
 {
 	Client *c = wl_container_of(listener, c, dissociate);
+	wl_list_remove(&c->commit.link);
 	wl_list_remove(&c->map.link);
 	wl_list_remove(&c->unmap.link);
 }

ime.h

@@ -594,7 +594,7 @@ handle_focused_surface_destroy(struct wl_listener *listener,
 }
 
 struct input_method_relay *
-input_method_relay_create()
+input_method_relay_create(void)
 {
 	struct input_method_relay *relay = ecalloc(1, sizeof(*relay));
 	wl_list_init(&relay->text_inputs);