@@ -68,6 +68,7 @@ src/taskbar/taskbarname.c
              src/tooltip/tooltip.c
              src/util/area.c
              src/util/common.c
+             src/util/strnatcmp.c
              src/util/timer.c
              src/util/window.c )
 

@@ -503,6 +503,15 @@ }
 	else if (strcmp (key, "taskbar_hide_different_monitor") == 0) {
 		hide_task_diff_monitor = atoi (value);
 	}
+	else if (strcmp (key, "taskbar_sort_order") == 0) {
+		if (strcmp(value, "center") == 0) {
+			taskbar_sort_method = TASKBAR_SORT_CENTER;
+		} else if (strcmp(value, "title") == 0) {
+			taskbar_sort_method = TASKBAR_SORT_TITLE;
+		} else {
+			taskbar_sort_method = TASKBAR_NOSORT;
+		}
+	}
 
 	/* Task */
 	else if (strcmp (key, "task_text") == 0)

@@ -184,7 +184,10 @@ {
 	Panel *panel = tsk->area.panel;
 	char *title, *name;
 
-	if (!panel->g_task.text && !panel->g_task.tooltip_enabled) return 0;
+	if (!panel->g_task.text &&
+		!panel->g_task.tooltip_enabled &&
+		taskbar_sort_method != TASKBAR_SORT_TITLE)
+		return 0;
 
 	name = server_get_property (tsk->win, server.atom._NET_WM_VISIBLE_NAME, server.atom.UTF8_STRING, 0);
 	if (!name || !strlen(name)) {

@@ -31,6 +31,7 @@ #include "taskbar.h"
 #include "server.h"
 #include "window.h"
 #include "panel.h"
+#include "strnatcmp.h"
 
 
 /* win_to_task_table holds for every Window an array of tasks. Usually the array contains only one
@@ -45,7 +46,7 @@ int taskbar_enabled;
 int taskbar_distribute_size;
 int hide_inactive_tasks;
 int hide_task_diff_monitor;
-int sort_tasks_method;
+int taskbar_sort_method;
 
 guint win_hash(gconstpointer key) { return (guint)*((Window*)key); }
 gboolean win_compare(gconstpointer a, gconstpointer b) { return (*((Window*)a) == *((Window*)b)); }
@@ -61,7 +62,7 @@ taskbar_enabled = 0;
 	taskbar_distribute_size = 0;
 	hide_inactive_tasks = 0;
 	hide_task_diff_monitor = 0;
-	sort_tasks_method = TASKBAR_NOSORT;
+	taskbar_sort_method = TASKBAR_NOSORT;
 	default_taskbarname();
 }
 
@@ -410,10 +411,9 @@ }
 	panel_refresh = 1;
 }
 
-gint compare_tasks(Task *a, Task *b, Taskbar *taskbar)
+#define NONTRIVIAL 2
+gint compare_tasks_trivial(Task *a, Task *b, Taskbar *taskbar)
 {
-	int a_horiz_c, a_vert_c, b_horiz_c, b_vert_c;
-
 	if (a == b)
 		return 0;
 	if (taskbarname_enabled) {
@@ -422,6 +422,15 @@ return -1;
 		if (b == taskbar->area.list->data)
 			return 1;
 	}
+	return NONTRIVIAL;
+}
+
+gint compare_task_centers(Task *a, Task *b, Taskbar *taskbar)
+{
+	int trivial = compare_tasks_trivial(a, b, taskbar);
+	if (trivial != NONTRIVIAL)
+		return trivial;
+	int a_horiz_c, a_vert_c, b_horiz_c, b_vert_c;
 	a_horiz_c = a->win_x + a->win_w / 2;
 	b_horiz_c = b->win_x + b->win_w / 2;
 	a_vert_c = a->win_y + a->win_h / 2;
@@ -439,17 +448,38 @@ return a_horiz_c - b_horiz_c;
 	}
 }
 
+gint compare_task_titles(Task *a, Task *b, Taskbar *taskbar)
+{
+	int trivial = compare_tasks_trivial(a, b, taskbar);
+	if (trivial != NONTRIVIAL)
+		return trivial;
+	return strnatcasecmp(a->title ? a->title : "", b->title ? b->title : "");
+}
+
+gint compare_tasks(Task *a, Task *b, Taskbar *taskbar)
+{
+	int trivial = compare_tasks_trivial(a, b, taskbar);
+	if (trivial != NONTRIVIAL)
+		return trivial;
+	if (taskbar_sort_method == TASKBAR_NOSORT) {
+		return 0;
+	} else if (taskbar_sort_method == TASKBAR_SORT_CENTER) {
+		return compare_task_centers(a, b, taskbar);
+	} else if (taskbar_sort_method == TASKBAR_SORT_TITLE) {
+		return compare_task_titles(a, b, taskbar);
+	}
+	return 0;
+}
+
 int taskbar_needs_sort(Taskbar *taskbar)
 {
-	if (sort_tasks_method == TASKBAR_NOSORT)
+	if (taskbar_sort_method == TASKBAR_NOSORT)
 		return 0;
 
-	if (sort_tasks_method == TASKBAR_SORT_POSITION) {
-		GSList *i, *j;
-		for (i = taskbar->area.list, j = i ? i->next : NULL; i && j; i = i->next, j = j->next) {
-			if (compare_tasks(i->data, j->data, taskbar) > 0) {
-				return 1;
-			}
+	GSList *i, *j;
+	for (i = taskbar->area.list, j = i ? i->next : NULL; i && j; i = i->next, j = j->next) {
+		if (compare_tasks(i->data, j->data, taskbar) > 0) {
+			return 1;
 		}
 	}
 
@@ -460,34 +490,35 @@ void sort_tasks(Taskbar *taskbar)
 {
 	if (!taskbar)
 		return;
-	if (!taskbar_needs_sort(taskbar))
+	if (!taskbar_needs_sort(taskbar)) {
 		return;
-	if (sort_tasks_method == TASKBAR_SORT_POSITION) {
-		taskbar->area.list = g_slist_sort_with_data(taskbar->area.list, (GCompareDataFunc)compare_tasks, taskbar);
-		taskbar->area.resize = 1;
-		panel_refresh = 1;
 	}
+	taskbar->area.list = g_slist_sort_with_data(taskbar->area.list, (GCompareDataFunc)compare_tasks, taskbar);
+	taskbar->area.resize = 1;
+	panel_refresh = 1;
+	((Panel*)taskbar->area.panel)->area.resize = 1;
 }
 
 
 void sort_taskbar_for_win(Window win)
 {
-	if (sort_tasks_method == TASKBAR_SORT_POSITION) {
-		GPtrArray* task_group = task_get_tasks(win);
-		if (task_group) {
-			int i;
-			Task* tsk0 = g_ptr_array_index(task_group, 0);
-			if (tsk0) {
-				window_get_coordinates(win, &tsk0->win_x, &tsk0->win_y, &tsk0->win_w, &tsk0->win_h);
-			}
-			for (i = 0; i < task_group->len; ++i) {
-				Task* tsk = g_ptr_array_index(task_group, i);
-				tsk->win_x = tsk0->win_x;
-				tsk->win_y = tsk0->win_y;
-				tsk->win_w = tsk0->win_w;
-				tsk->win_h = tsk0->win_h;
-				sort_tasks(tsk->area.parent);
-			}
+	if (taskbar_sort_method == TASKBAR_NOSORT)
+		return;
+
+	GPtrArray* task_group = task_get_tasks(win);
+	if (task_group) {
+		int i;
+		Task* tsk0 = g_ptr_array_index(task_group, 0);
+		if (tsk0) {
+			window_get_coordinates(win, &tsk0->win_x, &tsk0->win_y, &tsk0->win_w, &tsk0->win_h);
+		}
+		for (i = 0; i < task_group->len; ++i) {
+			Task* tsk = g_ptr_array_index(task_group, i);
+			tsk->win_x = tsk0->win_x;
+			tsk->win_y = tsk0->win_y;
+			tsk->win_w = tsk0->win_w;
+			tsk->win_h = tsk0->win_h;
+			sort_tasks(tsk->area.parent);
 		}
 	}
 }

@@ -19,8 +19,8 @@ extern int taskbar_enabled;
 extern int taskbar_distribute_size;
 extern int hide_inactive_tasks;
 extern int hide_task_diff_monitor;
-enum { TASKBAR_NOSORT, TASKBAR_SORT_POSITION };
-extern int sort_tasks_method;
+enum { TASKBAR_NOSORT, TASKBAR_SORT_CENTER, TASKBAR_SORT_TITLE };
+extern int taskbar_sort_method;
 
 typedef struct {
 	// always start with area

@@ -462,7 +462,7 @@ Task * event_task = click_task(panel, e->xbutton.x, e->xbutton.y);
 
 	// If the event takes place on the same taskbar as the task being dragged
 	if(event_taskbar == task_drag->area.parent)	{
-		if (sort_tasks_method == TASKBAR_SORT_POSITION) {
+		if (taskbar_sort_method != TASKBAR_NOSORT) {
 			sort_tasks(event_taskbar);
 		} else {
 			// Swap the task_drag with the task on the event's location (if they differ)
@@ -500,7 +500,7 @@ task_drag->desktop = event_taskbar->desktop;
 
 		windows_set_desktop(task_drag->win, event_taskbar->desktop);
 
-		if (sort_tasks_method == TASKBAR_SORT_POSITION) {
+		if (taskbar_sort_method != TASKBAR_NOSORT) {
 			sort_tasks(event_taskbar);
 		}
 
@@ -751,6 +751,8 @@ if (g_tooltip.mapped && (g_tooltip.area == (Area*)tsk)) {
 					tooltip_copy_text((Area*)tsk);
 					tooltip_update();
 				}
+				if (taskbar_sort_method == TASKBAR_SORT_TITLE)
+					sort_taskbar_for_win(win);
 				panel_refresh = 1;
 			}
 		}

@@ -0,0 +1,178 @@ 
+/* -*- mode: c; c-file-style: "k&r" -*-
+
+  strnatcmp.c -- Perform 'natural order' comparisons of strings in C.
+  Copyright (C) 2000, 2004 by Martin Pool <mbp sourcefrog net>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+
+/* partial change history:
+ *
+ * 2004-10-10 mbp: Lift out character type dependencies into macros.
+ *
+ * Eric Sosman pointed out that ctype functions take a parameter whose
+ * value must be that of an unsigned int, even on platforms that have
+ * negative chars in their default char type.
+ */
+
+#include <ctype.h>
+#include <string.h>
+#include <assert.h>
+#include <stdio.h>
+
+#include "strnatcmp.h"
+
+
+/* These are defined as macros to make it easier to adapt this code to
+ * different characters types or comparison functions. */
+static inline int
+nat_isdigit(nat_char a)
+{
+     return isdigit((unsigned char) a);
+}
+
+
+static inline int
+nat_isspace(nat_char a)
+{
+     return isspace((unsigned char) a);
+}
+
+
+static inline nat_char
+nat_toupper(nat_char a)
+{
+     return toupper((unsigned char) a);
+}
+
+
+
+static int
+compare_right(nat_char const *a, nat_char const *b)
+{
+     int bias = 0;
+     
+     /* The longest run of digits wins.  That aside, the greatest
+	value wins, but we can't know that it will until we've scanned
+	both numbers to know that they have the same magnitude, so we
+	remember it in BIAS. */
+     for (;; a++, b++) {
+	  if (!nat_isdigit(*a)  &&  !nat_isdigit(*b))
+	       return bias;
+	  else if (!nat_isdigit(*a))
+	       return -1;
+	  else if (!nat_isdigit(*b))
+	       return +1;
+	  else if (*a < *b) {
+	       if (!bias)
+		    bias = -1;
+	  } else if (*a > *b) {
+	       if (!bias)
+		    bias = +1;
+	  } else if (!*a  &&  !*b)
+	       return bias;
+     }
+
+     return 0;
+}
+
+
+static int
+compare_left(nat_char const *a, nat_char const *b)
+{
+     /* Compare two left-aligned numbers: the first to have a
+        different value wins. */
+     for (;; a++, b++) {
+	  if (!nat_isdigit(*a)  &&  !nat_isdigit(*b))
+	       return 0;
+	  else if (!nat_isdigit(*a))
+	       return -1;
+	  else if (!nat_isdigit(*b))
+	       return +1;
+	  else if (*a < *b)
+	       return -1;
+	  else if (*a > *b)
+	       return +1;
+     }
+	  
+     return 0;
+}
+
+
+static int strnatcmp0(nat_char const *a, nat_char const *b, int fold_case)
+{
+     int ai, bi;
+     nat_char ca, cb;
+     int fractional, result;
+     
+     assert(a && b);
+     ai = bi = 0;
+     while (1) {
+	  ca = a[ai]; cb = b[bi];
+
+	  /* skip over leading spaces or zeros */
+	  while (nat_isspace(ca))
+	       ca = a[++ai];
+
+	  while (nat_isspace(cb))
+	       cb = b[++bi];
+
+	  /* process run of digits */
+	  if (nat_isdigit(ca)  &&  nat_isdigit(cb)) {
+	       fractional = (ca == '0' || cb == '0');
+
+	       if (fractional) {
+		    if ((result = compare_left(a+ai, b+bi)) != 0)
+			 return result;
+	       } else {
+		    if ((result = compare_right(a+ai, b+bi)) != 0)
+			 return result;
+	       }
+	  }
+
+	  if (!ca && !cb) {
+	       /* The strings compare the same.  Perhaps the caller
+                  will want to call strcmp to break the tie. */
+	       return 0;
+	  }
+
+	  if (fold_case) {
+	       ca = nat_toupper(ca);
+	       cb = nat_toupper(cb);
+	  }
+	  
+	  if (ca < cb)
+	       return -1;
+	  else if (ca > cb)
+	       return +1;
+
+	  ++ai; ++bi;
+     }
+}
+
+
+
+int strnatcmp(nat_char const *a, nat_char const *b) {
+     return strnatcmp0(a, b, 0);
+}
+
+
+/* Compare, recognizing numeric string and ignoring case. */
+int strnatcasecmp(nat_char const *a, nat_char const *b) {
+     return strnatcmp0(a, b, 1);
+}

@@ -0,0 +1,31 @@ 
+/* -*- mode: c; c-file-style: "k&r" -*-
+
+  strnatcmp.c -- Perform 'natural order' comparisons of strings in C.
+  Copyright (C) 2000, 2004 by Martin Pool <mbp sourcefrog net>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+
+/* CUSTOMIZATION SECTION
+ *
+ * You can change this typedef, but must then also change the inline
+ * functions in strnatcmp.c */
+typedef char nat_char;
+
+int strnatcmp(nat_char const *a, nat_char const *b);
+int strnatcasecmp(nat_char const *a, nat_char const *b);