Experimental backends: fade/hide blur-texture for transparent windows

.gitignore

@@ -52,3 +52,5 @@ doxygen/
 /src/backtrace-symbols.[ch]
 /compton*.trace
 *.orig
+/tests/log
+/tests/testcases/__pycache__/

src/backend/backend.c

@@ -204,16 +204,34 @@ void paint_all_new(session_t *ps, struct managed_win *t, bool ignore_damage) {
 			// itself is not opaque, only the frame is.
 
 			double blur_opacity = 1;
-			if (w->state == WSTATE_MAPPING) {
+			if (w->opacity < (1.0 / MAX_ALPHA)) {
+				// Hide blur for fully transparent windows.
+				blur_opacity = 0;
+			} else if (w->state == WSTATE_MAPPING) {
 				// Gradually increase the blur intensity during
 				// fading in.
+				assert(w->opacity <= w->opacity_target);
 				blur_opacity = w->opacity / w->opacity_target;
 			} else if (w->state == WSTATE_UNMAPPING ||
 			           w->state == WSTATE_DESTROYING) {
 				// Gradually decrease the blur intensity during
 				// fading out.
-				blur_opacity =
-				    w->opacity / win_calc_opacity_target(ps, w, true);
+				assert(w->opacity <= w->opacity_target_old);
+				blur_opacity = w->opacity / w->opacity_target_old;
+			} else if (w->state == WSTATE_FADING) {
+				if (w->opacity < w->opacity_target &&
+				    w->opacity_target_old < (1.0 / MAX_ALPHA)) {
+					// Gradually increase the blur intensity during
+					// fading in.
+					assert(w->opacity <= w->opacity_target);
+					blur_opacity = w->opacity / w->opacity_target;
+				} else if (w->opacity > w->opacity_target &&
+				           w->opacity_target < (1.0 / MAX_ALPHA)) {
+					// Gradually decrease the blur intensity during
+					// fading out.
+					assert(w->opacity <= w->opacity_target_old);
+					blur_opacity = w->opacity / w->opacity_target_old;
+				}
 			}
 			assert(blur_opacity >= 0 && blur_opacity <= 1);
 

src/event.c

@@ -287,7 +287,7 @@ static inline void ev_map_notify(session_t *ps, xcb_map_notify_event_t *ev) {
 		return;
 	}
 
-	win_queue_update(w, WIN_UPDATE_MAP);
+	win_set_flags(w, WIN_FLAGS_MAPPED);
 
 	// FocusIn/Out may be ignored when the window is unmapped, so we must
 	// recheck focus here
@@ -482,14 +482,7 @@ static inline void ev_property_notify(session_t *ps, xcb_property_notify_event_t
 			win_update_opacity_prop(ps, w);
 			// we cannot receive OPACITY change when window is destroyed
 			assert(w->state != WSTATE_DESTROYING);
-			w->opacity_target = win_calc_opacity_target(ps, w, false);
-			if (w->state == WSTATE_MAPPED) {
-				// See the winstate_t transition table
-				w->state = WSTATE_FADING;
-			}
-			if (!ps->redirected) {
-				CHECK(!win_skip_fading(ps, w));
-			}
+			win_update_opacity_target(ps, w);
 		}
 	}
 

src/picom.c

@@ -1309,12 +1309,6 @@ static void handle_new_windows(session_t *ps) {
 }
 
 static void refresh_windows(session_t *ps) {
-	win_stack_foreach_managed_safe(w, &ps->window_stack) {
-		win_process_updates(ps, w);
-	}
-}
-
-static void refresh_stale_images(session_t *ps) {
 	win_stack_foreach_managed(w, &ps->window_stack) {
 		win_process_flags(ps, w);
 	}
@@ -1351,7 +1345,13 @@ static void handle_pending_updates(EV_P_ struct session *ps) {
 		// Call fill_win on new windows
 		handle_new_windows(ps);
 
-		// Process window updates
+		// Handle screen changes
+		// This HAS TO be called before refresh_windows, as handle_root_flags
+		// could call configure_root, which will release images and mark them
+		// stale.
+		handle_root_flags(ps);
+
+		// Process window flags
 		refresh_windows(ps);
 
 		{
@@ -1363,15 +1363,6 @@ static void handle_pending_updates(EV_P_ struct session *ps) {
 			free(r);
 		}
 
-		// Handle screen changes
-		// This HAS TO be called before refresh_stale_images, as handle_root_flags
-		// could call configure_root, which will release images and mark them
-		// stale.
-		handle_root_flags(ps);
-
-		// Refresh pixmaps and shadows
-		refresh_stale_images(ps);
-
 		e = xcb_request_check(ps->c, xcb_ungrab_server_checked(ps->c));
 		if (e) {
 			log_fatal_x_error(e, "failed to ungrab x server");