Updated readme

ChangeLog

@@ -11,6 +11,8 @@
     - Experimental, testing/feedback needed
   - Icons (system tray, task buttons, launcher):
     - Changed rendering method to fix icon corruptions (please report any problems)
+  - System tray:
+    - Workaround for misbehaving applications leaving empty tray icons
   - Many bugfixes
 - New config options (see https://gitlab.com/o9000/tint2/wikis/Configure):
   - Panel:

README.md

@@ -1,14 +1,14 @@
-### New unstable release: 0.12-rc3
+### New unstable release: 0.12-rc4
 Changes: https://gitlab.com/o9000/tint2/blob/master/ChangeLog
 
 Documentation: https://gitlab.com/o9000/tint2/wikis/home
 
 Try it out with (see also [dependencies](https://gitlab.com/o9000/tint2/wikis/Install#dependencies)):
 ```
-mkdir tint2-0.12-rc3
-cd tint2-0.12-rc3
-wget 'https://gitlab.com/o9000/tint2/repository/archive.tar.gz?ref=v0.12-rc3' --output-document tint2-0.12-rc3.tar.gz
-tar -xzf tint2-0.12-rc3.tar.gz
+mkdir tint2-0.12-rc4
+cd tint2-0.12-rc4
+wget 'https://gitlab.com/o9000/tint2/repository/archive.tar.gz?ref=v0.12-rc4' --output-document tint2-0.12-rc4.tar.gz
+tar -xzf tint2-0.12-rc4.tar.gz
 cd tint2.git
 mkdir build
 cd build
@@ -49,7 +49,7 @@ tint2 is a simple panel/taskbar made for modern X window managers. It was specif
   * [Configure](https://gitlab.com/o9000/tint2/wikis/Configure)
   * [Add applet not supported by tint2](https://gitlab.com/o9000/tint2/wikis/ThirdPartyApplets)
   * [Other frequently asked questions](https://gitlab.com/o9000/tint2/wikis/FAQ)
-  * [Debug](https://gitlab.com/o9000/tint2/wikis/Debug)
+  * [Debug](https://gitlab.com/o9000/tint2/wikis/Debug)  
 
 ### How can I help out?
 

src/battery/battery.c

@@ -76,6 +76,9 @@ void update_battery_tick(void* arg)
 	int16_t old_hours = battery_state.time.hours;
 	int8_t old_minutes = battery_state.time.minutes;
 	
+	if (!battery_found) {
+		init_battery();
+	}
 	if (update_battery() != 0) {
 		// Reconfigure
 		init_battery();
@@ -103,15 +106,23 @@ void update_battery_tick(void* arg)
 
 	int i;
 	for (i = 0; i < nb_panel; i++) {
-		if (!battery_found && panel1[i].battery.area.on_screen == 1) {
-			hide(&panel1[i].battery.area);
-			panel_refresh = 1;
-		} else if (battery_state.percentage >= percentage_hide && panel1[i].battery.area.on_screen == 1) {
-			hide(&panel1[i].battery.area);
-			panel_refresh = 1;
-		} else if (battery_state.percentage < percentage_hide && panel1[i].battery.area.on_screen == 0) {
-			show(&panel1[i].battery.area);
-			panel_refresh = 1;
+		if (!battery_found) {
+			if (panel1[i].battery.area.on_screen == 1) {
+				hide(&panel1[i].battery.area);
+				panel_refresh = 1;
+			}
+		} else {
+			if (battery_state.percentage >= percentage_hide) {
+				if (panel1[i].battery.area.on_screen == 1) {
+					hide(&panel1[i].battery.area);
+					panel_refresh = 1;
+				}
+			} else {
+				if (panel1[i].battery.area.on_screen == 0) {
+					show(&panel1[i].battery.area);
+					panel_refresh = 1;
+				}
+			}
 		}
 		if (panel1[i].battery.area.on_screen == 1) {
 			panel1[i].battery.area.resize = 1;
@@ -279,7 +290,7 @@ void init_battery()
 #endif
 
 	if (!battery_timeout)
-		battery_timeout = add_timeout(10, 10000, update_battery_tick, 0, &battery_timeout);
+		battery_timeout = add_timeout(10, 30000, update_battery_tick, 0, &battery_timeout);
 }
 
 
@@ -474,7 +485,7 @@ int update_battery() {
 	battery_state.time.seconds = seconds;
 
 	if (energy_full > 0)
-		new_percentage = ((energy_now <= energy_full ? energy_now : energy_full) * 100) / energy_full;
+		new_percentage = 0.5 + ((energy_now <= energy_full ? energy_now : energy_full) * 100.0) / energy_full;
 
 	battery_state.percentage = new_percentage;
 

src/config.c

@@ -613,13 +613,13 @@ void add_entry (char *key, char *value)
 	}
 	else if (strcmp(key, "systray_sort") == 0) {
 		if (strcmp(value, "descending") == 0)
-			systray.sort = -1;
+			systray.sort = SYSTRAY_SORT_DESCENDING;
 		else if (strcmp(value, "ascending") == 0)
-			systray.sort = 1;
+			systray.sort = SYSTRAY_SORT_ASCENDING;
 		else if (strcmp(value, "left2right") == 0)
-			systray.sort = 2;
+			systray.sort = SYSTRAY_SORT_LEFT2RIGHT;
 		else  if (strcmp(value, "right2left") == 0)
-			systray.sort = 3;
+			systray.sort = SYSTRAY_SORT_RIGHT2LEFT;
 	}
 	else if (strcmp(key, "systray_icon_size") == 0) {
 		systray_max_icon_size = atoi(value);

src/launcher/icon-theme-common.c

@@ -536,6 +536,9 @@ char *get_icon_path_helper(GSList *themes, const char *icon_name, int size)
 	char *next_larger = NULL;
 	GSList *next_larger_theme = NULL;
 
+	int file_name_size = 4096;
+	char *file_name = calloc(file_name_size, 1);
+
 	for (theme = themes; theme; theme = g_slist_next(theme)) {
 		((IconTheme*)theme->data)->list_directories = g_slist_sort_with_data(((IconTheme*)theme->data)->list_directories,
 																			 compare_theme_directories,
@@ -560,8 +563,13 @@ char *get_icon_path_helper(GSList *themes, const char *icon_name, int size)
 					char *theme_name = ((IconTheme*)theme->data)->name;
 					char *dir_name = ((IconThemeDir*)dir->data)->name;
 					char *extension = (char*) ext->data;
-					char *file_name = calloc(strlen(base_name) + strlen(theme_name) +
-											 strlen(dir_name) + strlen(icon_name) + strlen(extension) + 100, 1);
+					if (strlen(base_name) + strlen(theme_name) +
+						strlen(dir_name) + strlen(icon_name) + strlen(extension) + 100 > file_name_size) {
+						file_name_size = strlen(base_name) + strlen(theme_name) +
+										 strlen(dir_name) + strlen(icon_name) + strlen(extension) + 100;
+						file_name = realloc(file_name, file_name_size);
+					}
+					file_name[0] = 0;
 					// filename = directory/$(themename)/subdirectory/iconname.extension
 					sprintf(file_name, "%s/%s/%s/%s%s", base_name, theme_name, dir_name, icon_name, extension);
 					if (DEBUG_ICON_SEARCH)
@@ -596,11 +604,12 @@ char *get_icon_path_helper(GSList *themes, const char *icon_name, int size)
 								printf("next_larger = %s; next_larger_size = %d\n", next_larger, next_larger_size);
 						}
 					}
-					free(file_name);
 				}
 			}
 		}
 	}
+	free(file_name);
+	file_name = NULL;
 	if (next_larger) {
 		g_slist_free(extensions);
 		free(best_file_name);

src/launcher/launcher.c

@@ -31,6 +31,8 @@
 #include <glib.h>
 #include <glib/gstdio.h>
 #include <gdk-pixbuf/gdk-pixbuf.h>
+#include <sys/types.h>
+#include <sys/wait.h>
 
 #ifdef HAVE_RSVG
 #include <librsvg/rsvg.h>
@@ -150,8 +152,7 @@ void cleanup_launcher_theme(Launcher *launcher)
 	for (l = launcher->list_icons; l ; l = l->next) {
 		LauncherIcon *launcherIcon = (LauncherIcon*)l->data;
 		if (launcherIcon) {
-			free_icon(launcherIcon->icon_scaled);
-			free_icon(launcherIcon->icon_original);
+			free_icon(launcherIcon->image);
 			free(launcherIcon->icon_name);
 			free(launcherIcon->icon_path);
 			free(launcherIcon->cmd);
@@ -186,7 +187,7 @@ int resize_launcher(void *obj)
 	// Resize icons if necessary
 	for (l = launcher->list_icons; l ; l = l->next) {
 		LauncherIcon *launcherIcon = (LauncherIcon *)l->data;
-		if (launcherIcon->icon_size != icon_size || !launcherIcon->icon_original) {
+		if (launcherIcon->icon_size != icon_size || !launcherIcon->image) {
 			launcherIcon->icon_size = icon_size;
 			launcherIcon->area.width = launcherIcon->icon_size;
 			launcherIcon->area.height = launcherIcon->icon_size;
@@ -195,69 +196,69 @@ int resize_launcher(void *obj)
 			char *new_icon_path = get_icon_path(launcher->list_themes, launcherIcon->icon_name, launcherIcon->icon_size);
 			if (!new_icon_path) {
 				// Draw a blank icon
-				free_icon(launcherIcon->icon_original);
-				launcherIcon->icon_original = NULL;
-				free_icon(launcherIcon->icon_scaled);
-				launcherIcon->icon_scaled = NULL;
+				free_icon(launcherIcon->image);
+				launcherIcon->image = NULL;
 				continue;
 			}
-			if (launcherIcon->icon_path && strcmp(new_icon_path, launcherIcon->icon_path) == 0) {
-				// If it's the same file just rescale
-				free_icon(launcherIcon->icon_scaled);
-				launcherIcon->icon_scaled = scale_icon(launcherIcon->icon_original, icon_size);
-				free(new_icon_path);
-				fprintf(stderr, "launcher.c %d: Using icon %s\n", __LINE__, launcherIcon->icon_path);
-			} else {
-				// Free the old files
-				free_icon(launcherIcon->icon_original);
-				free_icon(launcherIcon->icon_scaled);
-				launcherIcon->icon_original = launcherIcon->icon_scaled = NULL;
-				// Load the new file and scale
-				launcherIcon->icon_original = imlib_load_image_immediately(new_icon_path);
+
+			// Free the old files
+			free_icon(launcherIcon->image);
+			launcherIcon->image = NULL;
+			// Load the new file and scale
+			launcherIcon->image = imlib_load_image_immediately(new_icon_path);
 #ifdef HAVE_RSVG
-				if (!launcherIcon->icon_original && g_str_has_suffix(new_icon_path, ".svg")) {
+			if (!launcherIcon->image && g_str_has_suffix(new_icon_path, ".svg")) {
+				char suffix[128];
+				sprintf(suffix, "tmpicon-%d.png", getpid());
+				// We fork here because librsvg allocates memory like crazy
+				pid_t pid = fork();
+				if (pid == 0) {
+					// Child
 					GError* err = NULL;
 					RsvgHandle* svg = rsvg_handle_new_from_file(new_icon_path, &err);
 
 					if (err != NULL) {
 						fprintf(stderr, "Could not load svg image!: %s", err->message);
 						g_error_free(err);
-						launcherIcon->icon_original = NULL;
+						launcherIcon->image = NULL;
 					} else {
-						char suffix[128];
-						sprintf(suffix, "tmpicon-%d.png", getpid());
 						gchar *name = g_build_filename(g_get_user_config_dir(), "tint2", suffix, NULL);
 						GdkPixbuf *pixbuf = rsvg_handle_get_pixbuf(svg);
 						gdk_pixbuf_save(pixbuf, name, "png", NULL, NULL);
-						launcherIcon->icon_original = imlib_load_image_immediately_without_cache(name);
-						g_remove(name);
-						g_free(name);
-						g_object_unref(G_OBJECT(pixbuf));
-						g_object_unref(G_OBJECT(svg));
 					}
-				} else
-#endif
-				{
-					launcherIcon->icon_original = imlib_load_image_immediately(new_icon_path);
-				}
-				// On loading error, fallback to default
-				if (!launcherIcon->icon_original) {
-					free(new_icon_path);
-					new_icon_path = get_icon_path(launcher->list_themes, DEFAULT_ICON, launcherIcon->icon_size);
-					if (new_icon_path)
-						launcherIcon->icon_original = imlib_load_image_immediately(new_icon_path);
-				}
-
-				if (!launcherIcon->icon_original) {
-					// Loading default icon failed, draw a blank icon
-					free(new_icon_path);
+					exit(0);
 				} else {
-					// Loaded icon successfully
-					launcherIcon->icon_scaled = scale_icon(launcherIcon->icon_original, launcherIcon->icon_size);
-					free(launcherIcon->icon_path);
-					launcherIcon->icon_path = new_icon_path;
-					fprintf(stderr, "launcher.c %d: Using icon %s\n", __LINE__, launcherIcon->icon_path);
+					// Parent
+					waitpid(pid, 0, 0);
+					gchar *name = g_build_filename(g_get_user_config_dir(), "tint2", suffix, NULL);
+					launcherIcon->image = imlib_load_image_immediately_without_cache(name);
+					g_remove(name);
+					g_free(name);
 				}
+			} else
+#endif
+			{
+				launcherIcon->image = imlib_load_image_immediately(new_icon_path);
+			}
+			// On loading error, fallback to default
+			if (!launcherIcon->image) {
+				free(new_icon_path);
+				new_icon_path = get_icon_path(launcher->list_themes, DEFAULT_ICON, launcherIcon->icon_size);
+				if (new_icon_path)
+					launcherIcon->image = imlib_load_image_immediately(new_icon_path);
+			}
+
+			if (!launcherIcon->image) {
+				// Loading default icon failed, draw a blank icon
+				free(new_icon_path);
+			} else {
+				// Loaded icon successfully
+				Imlib_Image original = launcherIcon->image;
+				launcherIcon->image = scale_icon(launcherIcon->image, launcherIcon->icon_size);
+				free_icon(original);
+				free(launcherIcon->icon_path);
+				launcherIcon->icon_path = new_icon_path;
+				fprintf(stderr, "launcher.c %d: Using icon %s\n", __LINE__, launcherIcon->icon_path);
 			}
 		}
 	}
@@ -331,6 +332,7 @@ int resize_launcher(void *obj)
 			}
 		}
 	}
+
 	return 1;
 }
 
@@ -355,9 +357,8 @@ void draw_launcher_icon(void *obj, cairo_t *c)
 {
 	LauncherIcon *launcherIcon = (LauncherIcon*)obj;
 
-	Imlib_Image icon_scaled = launcherIcon->icon_scaled;
 	// Render
-	imlib_context_set_image(icon_scaled);
+	imlib_context_set_image(launcherIcon->image);
 	if (server.real_transparency) {
 		render_image(launcherIcon->area.pix, 0, 0);
 	} else {

src/launcher/launcher.h

@@ -23,8 +23,7 @@ typedef struct Launcher {
 typedef struct LauncherIcon {
 	// always start with area
 	Area area;
-	Imlib_Image icon_scaled;
-	Imlib_Image icon_original;
+	Imlib_Image image;
 	char *cmd;
 	char *icon_name;
 	char *icon_path;

src/server.c

@@ -98,6 +98,7 @@ void server_init_atoms ()
 	server.atom._NET_SYSTEM_TRAY_ORIENTATION = XInternAtom(server.dsp, "_NET_SYSTEM_TRAY_ORIENTATION", False);
 	server.atom._XEMBED = XInternAtom(server.dsp, "_XEMBED", False);
 	server.atom._XEMBED_INFO = XInternAtom(server.dsp, "_XEMBED_INFO", False);
+	server.atom._NET_WM_PID = XInternAtom(server.dsp, "_NET_WM_PID", True);
 
 	// drag 'n' drop
 	server.atom.XdndAware = XInternAtom(server.dsp, "XdndAware", False);

src/server.h

@@ -74,6 +74,7 @@ typedef struct Global_atom
 	Atom _NET_SYSTEM_TRAY_ORIENTATION;
 	Atom _XEMBED;
 	Atom _XEMBED_INFO;
+	Atom _NET_WM_PID;
 	Atom _XSETTINGS_SCREEN;
 	Atom _XSETTINGS_SETTINGS;
 	Atom XdndAware;

src/systray/systraybar.c

@@ -52,7 +52,7 @@ int refresh_systray;
 int systray_enabled;
 int systray_max_icon_size;
 int systray_monitor;
-
+int chrono;
 // background pixmap if we render ourselves the icons
 static Pixmap render_background;
 
@@ -61,8 +61,9 @@ void default_systray()
 {
 	memset(&systray, 0, sizeof(Systraybar));
 	render_background = 0;
+	chrono = 0;
 	systray.alpha = 100;
-	systray.sort = 3;
+	systray.sort = SYSTRAY_SORT_LEFT2RIGHT;
 	systray.area._draw_foreground = draw_systray;
 	systray.area._on_change_layout = on_change_systray;
 	systray.area.size_mode = SIZE_BY_CONTENT;
@@ -108,8 +109,9 @@ void init_systray_panel(void *p)
 	GSList *l;
 	int count = 0;
 	for (l = systray.list_icons; l ; l = l->next) {
-		if (!((TrayWindow*)l->data)->hide)
-			count++;
+		if (((TrayWindow*)l->data)->hide)
+			continue;
+		count++;
 	}
 	if (count == 0)
 		hide(&systray.area);
@@ -146,8 +148,9 @@ int resize_systray(void *obj)
 		sysbar->icon_size = systray_max_icon_size;
 	count = 0;
 	for (l = systray.list_icons; l ; l = l->next) {
-		if (!((TrayWindow*)l->data)->hide)
-			count++;
+		if (((TrayWindow*)l->data)->hide)
+			continue;
+		count++;
 	}
 	//printf("count %d\n", count);
 
@@ -194,11 +197,12 @@ void on_change_systray (void *obj)
 	GSList *l;
 	for (i=1, l = systray.list_icons; l ; i++, l = l->next) {
 		traywin = (TrayWindow*)l->data;
-		if (traywin->hide) continue;
+		if (traywin->hide)
+			continue;
 
 		traywin->y = posy;
 		traywin->x = posx;
-		//printf("systray %d : %d,%d\n", i, posx, posy);
+		// printf("systray %d : pos %d, %d\n", traywin->tray_id, posx, posy);
 		traywin->width = sysbar->icon_size;
 		traywin->height = sysbar->icon_size;
 		if (panel_horizontal) {
@@ -336,21 +340,39 @@ static gint compare_traywindows(gconstpointer a, gconstpointer b)
 {
 	const TrayWindow * traywin_a = (TrayWindow*)a;
 	const TrayWindow * traywin_b = (TrayWindow*)b;
-	XTextProperty name_a, name_b;
 
-	if(XGetWMName(server.dsp, traywin_a->tray_id, &name_a) == 0) {
-		return -1;
-	}
-	else if(XGetWMName(server.dsp, traywin_b->tray_id, &name_b) == 0) {
-		XFree(name_a.value);
+	if (traywin_a->empty && !traywin_b->empty)
 		return 1;
+	if (!traywin_a->empty && traywin_b->empty)
+		return -1;
+
+	if (systray.sort == SYSTRAY_SORT_ASCENDING ||
+		systray.sort == SYSTRAY_SORT_DESCENDING) {
+		XTextProperty name_a, name_b;
+
+		if (XGetWMName(server.dsp, traywin_a->tray_id, &name_a) == 0) {
+			return -1;
+		}
+		else if (XGetWMName(server.dsp, traywin_b->tray_id, &name_b) == 0) {
+			XFree(name_a.value);
+			return 1;
+		}
+		else {
+			gint retval = g_ascii_strncasecmp((char*)name_a.value, (char*)name_b.value, -1) *
+						  (systray.sort == SYSTRAY_SORT_ASCENDING ? 1 : -1);
+			XFree(name_a.value);
+			XFree(name_b.value);
+			return retval;
+		}
 	}
-	else {
-		gint retval = g_ascii_strncasecmp((char*)name_a.value, (char*)name_b.value, -1) * systray.sort;
-		XFree(name_a.value);
-		XFree(name_b.value);
-		return retval;
+
+	if (systray.sort == SYSTRAY_SORT_LEFT2RIGHT ||
+		systray.sort == SYSTRAY_SORT_RIGHT2LEFT) {
+		return (traywin_a->chrono - traywin_b->chrono) *
+				(systray.sort == SYSTRAY_SORT_LEFT2RIGHT ? 1 : -1);
 	}
+
+	return 0;
 }
 
 
@@ -361,12 +383,42 @@ gboolean add_icon(Window id)
 	Panel *panel = systray.area.panel;
 	int hide = 0;
 
+	int pid = 0;
+	{
+		Atom actual_type;
+		int actual_format;
+		unsigned long nitems;
+		unsigned long bytes_after;
+		unsigned char *prop = 0;
+		int ret = XGetWindowProperty(server.dsp, id, server.atom._NET_WM_PID, 0, 1024, False, AnyPropertyType, &actual_type, &actual_format, &nitems, &bytes_after, &prop);
+		if (ret == Success && prop) {
+			pid = prop[1] * 256;
+			pid += prop[0];
+		}
+	}
+
 	GSList *l;
+	int num_empty_same_pid = 0;
 	for (l = systray.list_icons; l; l = l->next) {
 		if (((TrayWindow*)l->data)->tray_id == id)
 			return FALSE;
+		if (pid && ((TrayWindow*)l->data)->pid == pid && ((TrayWindow*)l->data)->empty)
+			num_empty_same_pid++;
 	}
 
+	const int max_num_empty_same_pid = 0;
+	if (num_empty_same_pid > max_num_empty_same_pid) {
+		for (l = systray.list_icons; l; l = l->next) {
+			if (pid && ((TrayWindow*)l->data)->pid == pid && ((TrayWindow*)l->data)->empty) {
+				num_empty_same_pid++;
+				fprintf(stderr, "Removing tray icon %lu from misbehaving application with pid=%d\n", ((TrayWindow*)l->data)->tray_id, pid);
+				remove_icon((TrayWindow*)l->data);
+				break;
+			}
+		}
+	}
+	//printf("add_icon: %d, pid %d, %d\n", id, pid, num_empty_same_pid);
+
 	error = FALSE;
 	XWindowAttributes attr;
 	if ( XGetWindowAttributes(server.dsp, id, &attr) == False ) return FALSE;
@@ -445,16 +497,19 @@ gboolean add_icon(Window id)
 	traywin->hide = hide;
 	traywin->depth = attr.depth;
 	traywin->damage = 0;
+	traywin->empty = 0;
+	traywin->pid = pid;
+	traywin->chrono = chrono;
+	chrono++;
 
 	if (systray.area.on_screen == 0)
 		show(&systray.area);
 
-	if (systray.sort == 3)
+	if (systray.sort == SYSTRAY_SORT_RIGHT2LEFT)
 		systray.list_icons = g_slist_prepend(systray.list_icons, traywin);
-	else if (systray.sort == 2)
-		systray.list_icons = g_slist_append(systray.list_icons, traywin);
 	else
-		systray.list_icons = g_slist_insert_sorted(systray.list_icons, traywin, compare_traywindows);
+		systray.list_icons = g_slist_append(systray.list_icons, traywin);
+	systray.list_icons = g_slist_sort(systray.list_icons, compare_traywindows);
 	//printf("add_icon id %lx, %d\n", id, g_slist_length(systray.list_icons));
 
 	if (FORCE_COMPOSITED_RENDERING || server.real_transparency || systray.alpha != 100 || systray.brightness != 0 || systray.saturation != 0) {
@@ -481,7 +536,7 @@ void remove_icon(TrayWindow *traywin)
 
 	// remove from our list
 	systray.list_icons = g_slist_remove(systray.list_icons, traywin);
-	//printf("remove_icon id %lx, %d\n", traywin->id);
+	//printf("remove_icon: %d\n", traywin->tray_id);
 
 	XSelectInput(server.dsp, traywin->tray_id, NoEventMask);
 	if (traywin->damage)
@@ -503,8 +558,9 @@ void remove_icon(TrayWindow *traywin)
 	int count = 0;
 	GSList *l;
 	for (l = systray.list_icons; l; l = l->next) {
-		if (!((TrayWindow*)l->data)->hide)
-			count++;
+		if (((TrayWindow*)l->data)->hide)
+			continue;
+		count++;
 	}
 	if (count == 0)
 		hide(&systray.area);
@@ -546,6 +602,7 @@ void systray_render_icon_now(void* t)
 	// we end up in this function only in real transparency mode or if systray_task_asb != 100 0 0
 	// we made also sure, that we always have a 32 bit visual, i.e. we can safely create 32 bit pixmaps here
 	TrayWindow* traywin = t;
+
 	traywin->render_timeout = 0;
 	if ( traywin->width == 0 || traywin->height == 0 ) {
 		// reschedule rendering since the geometry information has not yet been processed (can happen on slow cpu)
@@ -553,6 +610,27 @@ void systray_render_icon_now(void* t)
 		return;
 	}
 
+	XImage *ximage = XGetImage(server.dsp, traywin->tray_id, 0, 0, traywin->width, traywin->height, AllPlanes, XYPixmap);
+	XColor color;
+	int x, y, empty = 1;
+	for (x = 0; empty && x < traywin->width; x++) {
+		for (y = 0; empty && y < traywin->height; y++) {
+			color.pixel = XGetPixel(ximage, x, y);
+			if (color.pixel != 0)
+				empty = 0;
+		}
+	}
+	XFree(ximage);
+	if (traywin->empty != empty) {
+		traywin->empty = empty;
+		systray.area.resize = 1;
+		panel_refresh = 1;
+		systray.list_icons = g_slist_sort(systray.list_icons, compare_traywindows);
+	}
+	//printf("systray_render_icon_now: %d empty %d\n", traywin->tray_id, empty);
+	if (empty)
+		return;
+
 	// good systray icons support 32 bit depth, but some icons are still 24 bit.
 	// We create a heuristic mask for these icons, i.e. we get the rgb value in the top left corner, and
 	// mask out all pixel with the same rgb value
@@ -636,7 +714,8 @@ void refresh_systray_icon()
 	GSList *l;
 	for (l = systray.list_icons; l ; l = l->next) {
 		traywin = (TrayWindow*)l->data;
-		if (traywin->hide) continue;
+		if (traywin->hide)
+			continue;
 		systray_render_icon(traywin);
 	}
 }

src/systray/systraybar.h

@@ -20,6 +20,7 @@
 // Flags for _XEMBED_INFO
 #define XEMBED_MAPPED		(1 << 0)
 
+enum { SYSTRAY_SORT_ASCENDING, SYSTRAY_SORT_DESCENDING, SYSTRAY_SORT_LEFT2RIGHT, SYSTRAY_SORT_RIGHT2LEFT };
 
 typedef struct {
 	// always start with area
@@ -43,6 +44,9 @@ typedef struct
 	int depth;
 	Damage damage;
 	timeout* render_timeout;
+	int empty;
+	int pid;
+	int chrono;
 } TrayWindow;