Pileus Git - ~andy/gtk/blob - gtk/gtkbox.c

   1 /* GTK - The GIMP Toolkit
   2  * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  */
  19
  20 /*
  21  * Modified by the GTK+ Team and others 1997-2000.  See the AUTHORS
  22  * file for a list of people on the GTK+ Team.  See the ChangeLog
  23  * files for a list of changes.  These files are distributed with
  24  * GTK+ at ftp://ftp.gtk.org/pub/gtk/.
  25  */
  26
  27 #include "gtkbox.h"
  28
  29 enum {
  30   ARG_0,
  31   ARG_SPACING,
  32   ARG_HOMOGENEOUS
  33 };
  34
  35 enum {
  36   CHILD_ARG_0,
  37   CHILD_ARG_EXPAND,
  38   CHILD_ARG_FILL,
  39   CHILD_ARG_PADDING,
  40   CHILD_ARG_PACK_TYPE,
  41   CHILD_ARG_POSITION
  42 };
  43
  44 static void gtk_box_class_init (GtkBoxClass    *klass);
  45 static void gtk_box_init       (GtkBox         *box);
  46 static void gtk_box_get_arg    (GtkObject      *object,
  47                                 GtkArg         *arg,
  48                                 guint           arg_id);
  49 static void gtk_box_set_arg    (GtkObject      *object,
  50                                 GtkArg         *arg,
  51                                 guint           arg_id);
  52 static void gtk_box_map        (GtkWidget      *widget);
  53 static void gtk_box_unmap      (GtkWidget      *widget);
  54 static gint gtk_box_expose     (GtkWidget      *widget,
  55                                 GdkEventExpose *event);
  56 static void gtk_box_add        (GtkContainer   *container,
  57                                 GtkWidget      *widget);
  58 static void gtk_box_remove     (GtkContainer   *container,
  59                                 GtkWidget      *widget);
  60 static void gtk_box_forall     (GtkContainer   *container,
  61                                 gboolean        include_internals,
  62                                 GtkCallback     callback,
  63                                 gpointer        callback_data);
  64 static void gtk_box_set_child_arg (GtkContainer   *container,
  65                                    GtkWidget      *child,
  66                                    GtkArg         *arg,
  67                                    guint           arg_id);
  68 static void gtk_box_get_child_arg (GtkContainer   *container,
  69                                    GtkWidget      *child,
  70                                    GtkArg         *arg,
  71                                    guint           arg_id);
  72 static GtkType gtk_box_child_type (GtkContainer   *container);
  73
  74
  75 static GtkContainerClass *parent_class = NULL;
  76
  77
  78 GtkType
  79 gtk_box_get_type (void)
  80 {
  81   static GtkType box_type = 0;
  82
  83   if (!box_type)
  84     {
  85       static const GtkTypeInfo box_info =
  86       {
  87         "GtkBox",
  88         sizeof (GtkBox),
  89         sizeof (GtkBoxClass),
  90         (GtkClassInitFunc) gtk_box_class_init,
  91         (GtkObjectInitFunc) gtk_box_init,
  92         /* reserved_1 */ NULL,
  93         /* reserved_2 */ NULL,
  94         (GtkClassInitFunc) NULL,
  95       };
  96
  97       box_type = gtk_type_unique (GTK_TYPE_CONTAINER, &box_info);
  98     }
  99
 100   return box_type;
 101 }
 102
 103 static void
 104 gtk_box_class_init (GtkBoxClass *class)
 105 {
 106   GtkObjectClass *object_class;
 107   GtkWidgetClass *widget_class;
 108   GtkContainerClass *container_class;
 109
 110   object_class = (GtkObjectClass*) class;
 111   widget_class = (GtkWidgetClass*) class;
 112   container_class = (GtkContainerClass*) class;
 113
 114   parent_class = gtk_type_class (GTK_TYPE_CONTAINER);
 115
 116   gtk_object_add_arg_type ("GtkBox::spacing", GTK_TYPE_INT, GTK_ARG_READWRITE, ARG_SPACING);
 117   gtk_object_add_arg_type ("GtkBox::homogeneous", GTK_TYPE_BOOL, GTK_ARG_READWRITE, ARG_HOMOGENEOUS);
 118   gtk_container_add_child_arg_type ("GtkBox::expand", GTK_TYPE_BOOL, GTK_ARG_READWRITE, CHILD_ARG_EXPAND);
 119   gtk_container_add_child_arg_type ("GtkBox::fill", GTK_TYPE_BOOL, GTK_ARG_READWRITE, CHILD_ARG_FILL);
 120   gtk_container_add_child_arg_type ("GtkBox::padding", GTK_TYPE_UINT, GTK_ARG_READWRITE, CHILD_ARG_PADDING);
 121   gtk_container_add_child_arg_type ("GtkBox::pack_type", GTK_TYPE_PACK_TYPE, GTK_ARG_READWRITE, CHILD_ARG_PACK_TYPE);
 122   gtk_container_add_child_arg_type ("GtkBox::position", GTK_TYPE_INT, GTK_ARG_READWRITE, CHILD_ARG_POSITION);
 123
 124   object_class->set_arg = gtk_box_set_arg;
 125   object_class->get_arg = gtk_box_get_arg;
 126
 127   widget_class->map = gtk_box_map;
 128   widget_class->unmap = gtk_box_unmap;
 129   widget_class->expose_event = gtk_box_expose;
 130
 131   container_class->add = gtk_box_add;
 132   container_class->remove = gtk_box_remove;
 133   container_class->forall = gtk_box_forall;
 134   container_class->child_type = gtk_box_child_type;
 135   container_class->set_child_arg = gtk_box_set_child_arg;
 136   container_class->get_child_arg = gtk_box_get_child_arg;
 137 }
 138
 139 static void
 140 gtk_box_init (GtkBox *box)
 141 {
 142   GTK_WIDGET_SET_FLAGS (box, GTK_NO_WINDOW);
 143
 144   box->children = NULL;
 145   box->spacing = 0;
 146   box->homogeneous = FALSE;
 147 }
 148
 149 static void
 150 gtk_box_set_arg (GtkObject    *object,
 151                  GtkArg       *arg,
 152                  guint         arg_id)
 153 {
 154   GtkBox *box;
 155
 156   box = GTK_BOX (object);
 157
 158   switch (arg_id)
 159     {
 160     case ARG_SPACING:
 161       gtk_box_set_spacing (box, GTK_VALUE_INT (*arg));
 162       break;
 163     case ARG_HOMOGENEOUS:
 164       gtk_box_set_homogeneous (box, GTK_VALUE_BOOL (*arg));
 165       break;
 166     default:
 167       break;
 168     }
 169 }
 170
 171 static void
 172 gtk_box_get_arg (GtkObject    *object,
 173                  GtkArg       *arg,
 174                  guint         arg_id)
 175 {
 176   GtkBox *box;
 177
 178   box = GTK_BOX (object);
 179
 180   switch (arg_id)
 181     {
 182     case ARG_SPACING:
 183       GTK_VALUE_INT (*arg) = box->spacing;
 184       break;
 185     case ARG_HOMOGENEOUS:
 186       GTK_VALUE_BOOL (*arg) = box->homogeneous;
 187       break;
 188     default:
 189       arg->type = GTK_TYPE_INVALID;
 190       break;
 191     }
 192 }
 193
 194 static GtkType
 195 gtk_box_child_type      (GtkContainer   *container)
 196 {
 197   return GTK_TYPE_WIDGET;
 198 }
 199
 200 static void
 201 gtk_box_set_child_arg (GtkContainer   *container,
 202                        GtkWidget      *child,
 203                        GtkArg         *arg,
 204                        guint           arg_id)
 205 {
 206   gboolean expand = 0;
 207   gboolean fill = 0;
 208   guint padding = 0;
 209   GtkPackType pack_type = 0;
 210
 211   if (arg_id != CHILD_ARG_POSITION)
 212     gtk_box_query_child_packing (GTK_BOX (container),
 213                                  child,
 214                                  &expand,
 215                                  &fill,
 216                                  &padding,
 217                                  &pack_type);
 218
 219   switch (arg_id)
 220     {
 221     case CHILD_ARG_EXPAND:
 222       gtk_box_set_child_packing (GTK_BOX (container),
 223                                  child,
 224                                  GTK_VALUE_BOOL (*arg),
 225                                  fill,
 226                                  padding,
 227                                  pack_type);
 228       break;
 229     case CHILD_ARG_FILL:
 230       gtk_box_set_child_packing (GTK_BOX (container),
 231                                  child,
 232                                  expand,
 233                                  GTK_VALUE_BOOL (*arg),
 234                                  padding,
 235                                  pack_type);
 236       break;
 237     case CHILD_ARG_PADDING:
 238       gtk_box_set_child_packing (GTK_BOX (container),
 239                                  child,
 240                                  expand,
 241                                  fill,
 242                                  GTK_VALUE_UINT (*arg),
 243                                  pack_type);
 244       break;
 245     case CHILD_ARG_PACK_TYPE:
 246       gtk_box_set_child_packing (GTK_BOX (container),
 247                                  child,
 248                                  expand,
 249                                  fill,
 250                                  padding,
 251                                  GTK_VALUE_ENUM (*arg));
 252       break;
 253     case CHILD_ARG_POSITION:
 254       gtk_box_reorder_child (GTK_BOX (container),
 255                              child,
 256                              GTK_VALUE_INT (*arg));
 257       break;
 258     default:
 259       break;
 260     }
 261 }
 262
 263 static void
 264 gtk_box_get_child_arg (GtkContainer   *container,
 265                        GtkWidget      *child,
 266                        GtkArg         *arg,
 267                        guint           arg_id)
 268 {
 269   gboolean expand = 0;
 270   gboolean fill = 0;
 271   guint padding = 0;
 272   GtkPackType pack_type = 0;
 273   GList *list;
 274
 275   if (arg_id != CHILD_ARG_POSITION)
 276     gtk_box_query_child_packing (GTK_BOX (container),
 277                                  child,
 278                                  &expand,
 279                                  &fill,
 280                                  &padding,
 281                                  &pack_type);
 282
 283   switch (arg_id)
 284     {
 285     case CHILD_ARG_EXPAND:
 286       GTK_VALUE_BOOL (*arg) = expand;
 287       break;
 288     case CHILD_ARG_FILL:
 289       GTK_VALUE_BOOL (*arg) = fill;
 290       break;
 291     case CHILD_ARG_PADDING:
 292       GTK_VALUE_UINT (*arg) = padding;
 293       break;
 294     case CHILD_ARG_PACK_TYPE:
 295       GTK_VALUE_ENUM (*arg) = pack_type;
 296       break;
 297     case CHILD_ARG_POSITION:
 298       GTK_VALUE_INT (*arg) = 0;
 299       for (list = GTK_BOX (container)->children; list; list = list->next)
 300         {
 301           GtkBoxChild *child_entry;
 302
 303           child_entry = list->data;
 304           if (child_entry->widget == child)
 305             break;
 306           GTK_VALUE_INT (*arg)++;
 307         }
 308       if (!list)
 309         GTK_VALUE_INT (*arg) = -1;
 310       break;
 311     default:
 312       arg->type = GTK_TYPE_INVALID;
 313       break;
 314     }
 315 }
 316
 317 void
 318 gtk_box_pack_start (GtkBox    *box,
 319                     GtkWidget *child,
 320                     gboolean   expand,
 321                     gboolean   fill,
 322                     guint      padding)
 323 {
 324   GtkBoxChild *child_info;
 325
 326   g_return_if_fail (box != NULL);
 327   g_return_if_fail (GTK_IS_BOX (box));
 328   g_return_if_fail (child != NULL);
 329   g_return_if_fail (child->parent == NULL);
 330
 331   child_info = g_new (GtkBoxChild, 1);
 332   child_info->widget = child;
 333   child_info->padding = padding;
 334   child_info->expand = expand ? TRUE : FALSE;
 335   child_info->fill = fill ? TRUE : FALSE;
 336   child_info->pack = GTK_PACK_START;
 337
 338   box->children = g_list_append (box->children, child_info);
 339
 340   gtk_widget_set_parent (child, GTK_WIDGET (box));
 341
 342   if (GTK_WIDGET_REALIZED (box))
 343     gtk_widget_realize (child);
 344
 345   if (GTK_WIDGET_VISIBLE (box) && GTK_WIDGET_VISIBLE (child))
 346     {
 347       if (GTK_WIDGET_MAPPED (box))
 348         gtk_widget_map (child);
 349
 350       gtk_widget_queue_resize (child);
 351     }
 352 }
 353
 354 void
 355 gtk_box_pack_end (GtkBox    *box,
 356                   GtkWidget *child,
 357                   gboolean   expand,
 358                   gboolean   fill,
 359                   guint      padding)
 360 {
 361   GtkBoxChild *child_info;
 362
 363   g_return_if_fail (box != NULL);
 364   g_return_if_fail (GTK_IS_BOX (box));
 365   g_return_if_fail (child != NULL);
 366   g_return_if_fail (child->parent == NULL);
 367
 368   child_info = g_new (GtkBoxChild, 1);
 369   child_info->widget = child;
 370   child_info->padding = padding;
 371   child_info->expand = expand ? TRUE : FALSE;
 372   child_info->fill = fill ? TRUE : FALSE;
 373   child_info->pack = GTK_PACK_END;
 374
 375   box->children = g_list_append (box->children, child_info);
 376
 377   gtk_widget_set_parent (child, GTK_WIDGET (box));
 378
 379   if (GTK_WIDGET_REALIZED (box))
 380     gtk_widget_realize (child);
 381
 382   if (GTK_WIDGET_VISIBLE (box) && GTK_WIDGET_VISIBLE (child))
 383     {
 384       if (GTK_WIDGET_MAPPED (box))
 385         gtk_widget_map (child);
 386
 387       gtk_widget_queue_resize (child);
 388     }
 389 }
 390
 391 void
 392 gtk_box_pack_start_defaults (GtkBox    *box,
 393                              GtkWidget *child)
 394 {
 395   g_return_if_fail (box != NULL);
 396   g_return_if_fail (GTK_IS_BOX (box));
 397   g_return_if_fail (child != NULL);
 398
 399   gtk_box_pack_start (box, child, TRUE, TRUE, 0);
 400 }
 401
 402 void
 403 gtk_box_pack_end_defaults (GtkBox    *box,
 404                            GtkWidget *child)
 405 {
 406   g_return_if_fail (box != NULL);
 407   g_return_if_fail (GTK_IS_BOX (box));
 408   g_return_if_fail (child != NULL);
 409
 410   gtk_box_pack_end (box, child, TRUE, TRUE, 0);
 411 }
 412
 413 void
 414 gtk_box_set_homogeneous (GtkBox  *box,
 415                          gboolean homogeneous)
 416 {
 417   g_return_if_fail (box != NULL);
 418   g_return_if_fail (GTK_IS_BOX (box));
 419
 420   if ((homogeneous ? TRUE : FALSE) != box->homogeneous)
 421     {
 422       box->homogeneous = homogeneous ? TRUE : FALSE;
 423       gtk_widget_queue_resize (GTK_WIDGET (box));
 424     }
 425 }
 426
 427 void
 428 gtk_box_set_spacing (GtkBox *box,
 429                      gint    spacing)
 430 {
 431   g_return_if_fail (box != NULL);
 432   g_return_if_fail (GTK_IS_BOX (box));
 433
 434   if (spacing != box->spacing)
 435     {
 436       box->spacing = spacing;
 437       gtk_widget_queue_resize (GTK_WIDGET (box));
 438     }
 439 }
 440
 441 /**
 442  * gtk_box_get_spacing:
 443  * @box: a #GtkBox
 444  *
 445  * Gets the value set by gtk_box_set_spacing().
 446  *
 447  * Return value: spacing between children
 448  **/
 449 gint
 450 gtk_box_get_spacing (GtkBox *box)
 451 {
 452   g_return_if_fail (GTK_IS_BOX (box));
 453
 454   return box->spacing;
 455 }
 456
 457 void
 458 gtk_box_reorder_child (GtkBox                   *box,
 459                        GtkWidget                *child,
 460                        gint                      position)
 461 {
 462   GList *list;
 463
 464   g_return_if_fail (box != NULL);
 465   g_return_if_fail (GTK_IS_BOX (box));
 466   g_return_if_fail (child != NULL);
 467
 468   list = box->children;
 469   while (list)
 470     {
 471       GtkBoxChild *child_info;
 472
 473       child_info = list->data;
 474       if (child_info->widget == child)
 475         break;
 476
 477       list = list->next;
 478     }
 479
 480   if (list && box->children->next)
 481     {
 482       GList *tmp_list;
 483
 484       if (list->next)
 485         list->next->prev = list->prev;
 486       if (list->prev)
 487         list->prev->next = list->next;
 488       else
 489         box->children = list->next;
 490
 491       tmp_list = box->children;
 492       while (position && tmp_list->next)
 493         {
 494           position--;
 495           tmp_list = tmp_list->next;
 496         }
 497
 498       if (position)
 499         {
 500           tmp_list->next = list;
 501           list->prev = tmp_list;
 502           list->next = NULL;
 503         }
 504       else
 505         {
 506           if (tmp_list->prev)
 507             tmp_list->prev->next = list;
 508           else
 509             box->children = list;
 510           list->prev = tmp_list->prev;
 511           tmp_list->prev = list;
 512           list->next = tmp_list;
 513         }
 514
 515       if (GTK_WIDGET_VISIBLE (child) && GTK_WIDGET_VISIBLE (box))
 516         gtk_widget_queue_resize (child);
 517     }
 518 }
 519
 520 void
 521 gtk_box_query_child_packing (GtkBox             *box,
 522                              GtkWidget          *child,
 523                              gboolean           *expand,
 524                              gboolean           *fill,
 525                              guint              *padding,
 526                              GtkPackType        *pack_type)
 527 {
 528   GList *list;
 529   GtkBoxChild *child_info = NULL;
 530
 531   g_return_if_fail (box != NULL);
 532   g_return_if_fail (GTK_IS_BOX (box));
 533   g_return_if_fail (child != NULL);
 534
 535   list = box->children;
 536   while (list)
 537     {
 538       child_info = list->data;
 539       if (child_info->widget == child)
 540         break;
 541
 542       list = list->next;
 543     }
 544
 545   if (list)
 546     {
 547       if (expand)
 548         *expand = child_info->expand;
 549       if (fill)
 550         *fill = child_info->fill;
 551       if (padding)
 552         *padding = child_info->padding;
 553       if (pack_type)
 554         *pack_type = child_info->pack;
 555     }
 556 }
 557
 558 void
 559 gtk_box_set_child_packing (GtkBox               *box,
 560                            GtkWidget            *child,
 561                            gboolean              expand,
 562                            gboolean              fill,
 563                            guint                 padding,
 564                            GtkPackType           pack_type)
 565 {
 566   GList *list;
 567   GtkBoxChild *child_info = NULL;
 568
 569   g_return_if_fail (box != NULL);
 570   g_return_if_fail (GTK_IS_BOX (box));
 571   g_return_if_fail (child != NULL);
 572
 573   list = box->children;
 574   while (list)
 575     {
 576       child_info = list->data;
 577       if (child_info->widget == child)
 578         break;
 579
 580       list = list->next;
 581     }
 582
 583   if (list)
 584     {
 585       child_info->expand = expand != FALSE;
 586       child_info->fill = fill != FALSE;
 587       child_info->padding = padding;
 588       if (pack_type == GTK_PACK_END)
 589         child_info->pack = GTK_PACK_END;
 590       else
 591         child_info->pack = GTK_PACK_START;
 592
 593       if (GTK_WIDGET_VISIBLE (child) && GTK_WIDGET_VISIBLE (box))
 594         gtk_widget_queue_resize (child);
 595     }
 596 }
 597
 598 static void
 599 gtk_box_map (GtkWidget *widget)
 600 {
 601   GtkBox *box;
 602   GtkBoxChild *child;
 603   GList *children;
 604
 605   g_return_if_fail (widget != NULL);
 606   g_return_if_fail (GTK_IS_BOX (widget));
 607
 608   box = GTK_BOX (widget);
 609   GTK_WIDGET_SET_FLAGS (box, GTK_MAPPED);
 610
 611   children = box->children;
 612   while (children)
 613     {
 614       child = children->data;
 615       children = children->next;
 616
 617       if (GTK_WIDGET_VISIBLE (child->widget) &&
 618           !GTK_WIDGET_MAPPED (child->widget))
 619         gtk_widget_map (child->widget);
 620     }
 621 }
 622
 623 static void
 624 gtk_box_unmap (GtkWidget *widget)
 625 {
 626   GtkBox *box;
 627   GtkBoxChild *child;
 628   GList *children;
 629
 630   g_return_if_fail (widget != NULL);
 631   g_return_if_fail (GTK_IS_BOX (widget));
 632
 633   box = GTK_BOX (widget);
 634   GTK_WIDGET_UNSET_FLAGS (box, GTK_MAPPED);
 635
 636   children = box->children;
 637   while (children)
 638     {
 639       child = children->data;
 640       children = children->next;
 641
 642       if (GTK_WIDGET_VISIBLE (child->widget) &&
 643           GTK_WIDGET_MAPPED (child->widget))
 644         gtk_widget_unmap (child->widget);
 645     }
 646 }
 647
 648 static gint
 649 gtk_box_expose (GtkWidget      *widget,
 650                 GdkEventExpose *event)
 651 {
 652   GtkBox *box;
 653   GtkBoxChild *child;
 654   GdkEventExpose child_event;
 655   GList *children;
 656
 657   g_return_val_if_fail (widget != NULL, FALSE);
 658   g_return_val_if_fail (GTK_IS_BOX (widget), FALSE);
 659   g_return_val_if_fail (event != NULL, FALSE);
 660
 661   if (GTK_WIDGET_DRAWABLE (widget))
 662     {
 663       box = GTK_BOX (widget);
 664
 665       child_event = *event;
 666
 667       children = box->children;
 668       while (children)
 669         {
 670           child = children->data;
 671           children = children->next;
 672
 673           if (GTK_WIDGET_DRAWABLE (child->widget) &&
 674               GTK_WIDGET_NO_WINDOW (child->widget) &&
 675               gtk_widget_intersect (child->widget, &event->area, &child_event.area))
 676             gtk_widget_event (child->widget, (GdkEvent*) &child_event);
 677         }
 678     }
 679
 680   return FALSE;
 681 }
 682
 683 static void
 684 gtk_box_add (GtkContainer *container,
 685              GtkWidget    *widget)
 686 {
 687   g_return_if_fail (container != NULL);
 688   g_return_if_fail (GTK_IS_BOX (container));
 689   g_return_if_fail (widget != NULL);
 690
 691   gtk_box_pack_start_defaults (GTK_BOX (container), widget);
 692 }
 693
 694 static void
 695 gtk_box_remove (GtkContainer *container,
 696                 GtkWidget    *widget)
 697 {
 698   GtkBox *box;
 699   GtkBoxChild *child;
 700   GList *children;
 701
 702   g_return_if_fail (container != NULL);
 703   g_return_if_fail (GTK_IS_BOX (container));
 704   g_return_if_fail (widget != NULL);
 705
 706   box = GTK_BOX (container);
 707
 708   children = box->children;
 709   while (children)
 710     {
 711       child = children->data;
 712
 713       if (child->widget == widget)
 714         {
 715           gboolean was_visible;
 716
 717           was_visible = GTK_WIDGET_VISIBLE (widget);
 718           gtk_widget_unparent (widget);
 719
 720           box->children = g_list_remove_link (box->children, children);
 721           g_list_free (children);
 722           g_free (child);
 723
 724           /* queue resize regardless of GTK_WIDGET_VISIBLE (container),
 725            * since that's what is needed by toplevels.
 726            */
 727           if (was_visible)
 728             gtk_widget_queue_resize (GTK_WIDGET (container));
 729
 730           break;
 731         }
 732
 733       children = children->next;
 734     }
 735 }
 736
 737 static void
 738 gtk_box_forall (GtkContainer *container,
 739                 gboolean      include_internals,
 740                 GtkCallback   callback,
 741                 gpointer      callback_data)
 742 {
 743   GtkBox *box;
 744   GtkBoxChild *child;
 745   GList *children;
 746
 747   g_return_if_fail (container != NULL);
 748   g_return_if_fail (GTK_IS_BOX (container));
 749   g_return_if_fail (callback != NULL);
 750
 751   box = GTK_BOX (container);
 752
 753   children = box->children;
 754   while (children)
 755     {
 756       child = children->data;
 757       children = children->next;
 758
 759       if (child->pack == GTK_PACK_START)
 760         (* callback) (child->widget, callback_data);
 761     }
 762
 763   children = g_list_last (box->children);
 764   while (children)
 765     {
 766       child = children->data;
 767       children = children->prev;
 768
 769       if (child->pack == GTK_PACK_END)
 770         (* callback) (child->widget, callback_data);
 771     }
 772 }