win: track number of in progress animations with transition callbacks

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

src/picom.c

@@ -502,9 +502,8 @@ static bool run_fade(session_t *ps, struct managed_win **_w, unsigned int steps)
 	          steps);
 	if (w->state == WSTATE_MAPPED || w->state == WSTATE_UNMAPPED) {
 		// We are not fading
-		assert(!animatable_is_animating(&w->opacity));
-		assert(!animatable_is_animating(&w->blur_opacity));
-		log_trace("|- not fading");
+		assert(w->number_of_animations == 0);
+		log_trace("|- not animated");
 		return false;
 	}
 
@@ -513,8 +512,7 @@ static bool run_fade(session_t *ps, struct managed_win **_w, unsigned int steps)
 		animatable_early_stop(&w->opacity);
 		animatable_early_stop(&w->blur_opacity);
 	}
-	if (!animatable_is_animating(&w->opacity) &&
-	    !animatable_is_animating(&w->blur_opacity)) {
+	if (w->number_of_animations == 0) {
 		// We have reached target opacity.
 		// We don't call win_check_fade_finished here because that could destroy
 		// the window, but we still need the damage info from this window
@@ -951,7 +949,7 @@ static bool paint_preprocess(session_t *ps, bool *fade_running, bool *animation,
 		// If was_painted == false, and to_paint is also false, we don't care
 		// If was_painted == false, but to_paint is true, damage will be added in
 		// the loop below
-		if (was_painted && animatable_is_animating(&w->opacity)) {
+		if (was_painted && w->number_of_animations != 0) {
 			add_damage_from_win(ps, w);
 		}
 

src/win.c

@@ -892,6 +892,11 @@ static double win_calc_opacity_target(session_t *ps, const struct managed_win *w
 	return opacity;
 }
 
+static void win_transition_callback(enum transition_event event attr_unused, void *data) {
+	auto w = (struct managed_win *)data;
+	w->number_of_animations--;
+}
+
 /// Call `animatable_set_target` on the opacity of a window, with appropriate
 /// target opacity and duration.
 ///
@@ -903,8 +908,9 @@ static inline unsigned int win_start_fade(session_t *ps, struct managed_win *w)
 	    target_opacity > current_opacity ? ps->o.fade_in_step : ps->o.fade_out_step;
 	unsigned int duration =
 	    (unsigned int)(fabs(target_opacity - current_opacity) / step_size);
+	w->number_of_animations++;
 	animatable_set_target(&w->opacity, target_opacity, duration,
-	                      NULL, NULL);
+	                      win_transition_callback, w);
 	return duration;
 }
 
@@ -2413,7 +2419,8 @@ void unmap_win_start(session_t *ps, struct managed_win *w) {
 	w->a.map_state = XCB_MAP_STATE_UNMAPPED;
 	w->state = WSTATE_UNMAPPING;
 	auto duration = win_start_fade(ps, w);
-	animatable_set_target(&w->blur_opacity, 0, duration, NULL, NULL);
+	w->number_of_animations++;
+	animatable_set_target(&w->blur_opacity, 0, duration, win_transition_callback, w);
 
 #ifdef CONFIG_DBUS
 	// Send D-Bus signal
@@ -2439,10 +2446,10 @@ void unmap_win_start(session_t *ps, struct managed_win *w) {
 bool win_maybe_finalize_fading(session_t *ps, struct managed_win *w) {
 	if (w->state == WSTATE_MAPPED || w->state == WSTATE_UNMAPPED) {
 		// No fading in progress
-		assert(!animatable_is_animating(&w->opacity));
+		assert(w->number_of_animations == 0);
 		return false;
 	}
-	if (!animatable_is_animating(&w->opacity)) {
+	if (w->number_of_animations == 0) {
 		switch (w->state) {
 		case WSTATE_UNMAPPING: unmap_win_finish(ps, w); return false;
 		case WSTATE_DESTROYING: destroy_win_finish(ps, &w->base); return true;
@@ -2461,7 +2468,7 @@ bool win_maybe_finalize_fading(session_t *ps, struct managed_win *w) {
 /// @return whether the window is destroyed and freed
 bool win_skip_fading(session_t *ps, struct managed_win *w) {
 	if (w->state == WSTATE_MAPPED || w->state == WSTATE_UNMAPPED) {
-		assert(!animatable_is_animating(&w->opacity));
+		assert(w->number_of_animations == 0);
 		return false;
 	}
 	log_debug("Skipping fading process of window %#010x (%s)", w->base.id, w->name);
@@ -2528,7 +2535,8 @@ void map_win_start(session_t *ps, struct managed_win *w) {
 	// iff `state` is MAPPED
 	w->state = WSTATE_MAPPING;
 	auto duration = win_start_fade(ps, w);
-	animatable_set_target(&w->blur_opacity, 1, duration, NULL, NULL);
+	w->number_of_animations++;
+	animatable_set_target(&w->blur_opacity, 1, duration, win_transition_callback, w);
 
 	log_debug("Window %#010x has opacity %f, opacity target is %f", w->base.id,
 	          animatable_get(&w->opacity), w->opacity.target);
@@ -2561,7 +2569,7 @@ void map_win_start(session_t *ps, struct managed_win *w) {
 void win_update_opacity_target(session_t *ps, struct managed_win *w) {
 	auto duration = win_start_fade(ps, w);
 
-	if (!animatable_is_animating(&w->opacity)) {
+	if (w->number_of_animations == 0) {
 		return;
 	}
 
@@ -2573,8 +2581,9 @@ void win_update_opacity_target(session_t *ps, struct managed_win *w) {
 	} else if (w->state == WSTATE_MAPPING) {
 		// Opacity target changed while fading in, keep the blur_opacity
 		// in lock step with the opacity
+		w->number_of_animations++;
 		animatable_set_target(&w->blur_opacity, w->blur_opacity.target, duration,
-		                      NULL, NULL);
+		                      win_transition_callback, w);
 		log_debug("Opacity changed while fading in");
 	} else if (w->state == WSTATE_FADING) {
 		// Opacity target changed while FADING.

src/win.h

@@ -282,6 +282,10 @@ struct managed_win {
 
 	struct c2_window_state c2_state;
 
+	// Animation related
+	/// Number of animations currently in progress
+	unsigned int number_of_animations;
+
 #ifdef CONFIG_OPENGL
 	/// Textures and FBO background blur use.
 	glx_blur_cache_t glx_blur_cache;