Pileus Git - ~andy/gtk/blob - gtk/gtkscrolledwindow.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 Library 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  * Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Library 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 #include "gtkscrolledwindow.h"
  20 #include "gtksignal.h"
  21
  22
  23 #define SCROLLBAR_SPACING(w) (GTK_SCROLLED_WINDOW_CLASS (GTK_OBJECT (w)->klass)->scrollbar_spacing)
  24
  25
  26 static void gtk_scrolled_window_class_init         (GtkScrolledWindowClass *klass);
  27 static void gtk_scrolled_window_init               (GtkScrolledWindow      *scrolled_window);
  28 static void gtk_scrolled_window_destroy            (GtkObject              *object);
  29 static void gtk_scrolled_window_finalize           (GtkObject              *object);
  30 static void gtk_scrolled_window_map                (GtkWidget              *widget);
  31 static void gtk_scrolled_window_unmap              (GtkWidget              *widget);
  32 static void gtk_scrolled_window_draw               (GtkWidget              *widget,
  33                                                     GdkRectangle           *area);
  34 static void gtk_scrolled_window_size_request       (GtkWidget              *widget,
  35                                                     GtkRequisition         *requisition);
  36 static void gtk_scrolled_window_size_allocate      (GtkWidget              *widget,
  37                                                     GtkAllocation          *allocation);
  38 static void gtk_scrolled_window_add                (GtkContainer           *container,
  39                                                     GtkWidget              *widget);
  40 static void gtk_scrolled_window_remove             (GtkContainer           *container,
  41                                                     GtkWidget              *widget);
  42 static void gtk_scrolled_window_foreach            (GtkContainer           *container,
  43                                                     GtkCallback             callback,
  44                                                     gpointer                callback_data);
  45 static void gtk_scrolled_window_viewport_allocate  (GtkWidget              *widget,
  46                                                     GtkAllocation          *allocation);
  47 static void gtk_scrolled_window_adjustment_changed (GtkAdjustment          *adjustment,
  48                                                     gpointer                data);
  49
  50
  51 static GtkContainerClass *parent_class = NULL;
  52
  53
  54 guint
  55 gtk_scrolled_window_get_type (void)
  56 {
  57   static guint scrolled_window_type = 0;
  58
  59   if (!scrolled_window_type)
  60     {
  61       GtkTypeInfo scrolled_window_info =
  62       {
  63         "GtkScrolledWindow",
  64         sizeof (GtkScrolledWindow),
  65         sizeof (GtkScrolledWindowClass),
  66         (GtkClassInitFunc) gtk_scrolled_window_class_init,
  67         (GtkObjectInitFunc) gtk_scrolled_window_init,
  68         (GtkArgSetFunc) NULL,
  69         (GtkArgGetFunc) NULL,
  70       };
  71
  72       scrolled_window_type = gtk_type_unique (gtk_container_get_type (), &scrolled_window_info);
  73     }
  74
  75   return scrolled_window_type;
  76 }
  77
  78 static void
  79 gtk_scrolled_window_class_init (GtkScrolledWindowClass *class)
  80 {
  81   GtkObjectClass *object_class;
  82   GtkWidgetClass *widget_class;
  83   GtkContainerClass *container_class;
  84
  85   object_class = (GtkObjectClass*) class;
  86   widget_class = (GtkWidgetClass*) class;
  87   container_class = (GtkContainerClass*) class;
  88
  89   parent_class = gtk_type_class (gtk_container_get_type ());
  90
  91   object_class->destroy = gtk_scrolled_window_destroy;
  92   object_class->finalize = gtk_scrolled_window_finalize;
  93
  94   widget_class->map = gtk_scrolled_window_map;
  95   widget_class->unmap = gtk_scrolled_window_unmap;
  96   widget_class->draw = gtk_scrolled_window_draw;
  97   widget_class->size_request = gtk_scrolled_window_size_request;
  98   widget_class->size_allocate = gtk_scrolled_window_size_allocate;
  99
 100   container_class->add = gtk_scrolled_window_add;
 101   container_class->remove = gtk_scrolled_window_remove;
 102   container_class->foreach = gtk_scrolled_window_foreach;
 103
 104   class->scrollbar_spacing = 5;
 105 }
 106
 107 static void
 108 gtk_scrolled_window_init (GtkScrolledWindow *scrolled_window)
 109 {
 110   GTK_WIDGET_SET_FLAGS (scrolled_window, GTK_NO_WINDOW);
 111
 112   gtk_container_set_resize_mode (GTK_CONTAINER (scrolled_window), GTK_RESIZE_QUEUE);
 113
 114   scrolled_window->hscrollbar = NULL;
 115   scrolled_window->vscrollbar = NULL;
 116   scrolled_window->hscrollbar_policy = GTK_POLICY_ALWAYS;
 117   scrolled_window->vscrollbar_policy = GTK_POLICY_ALWAYS;
 118 }
 119
 120 GtkWidget*
 121 gtk_scrolled_window_new (GtkAdjustment *hadjustment,
 122                          GtkAdjustment *vadjustment)
 123 {
 124   GtkWidget *scrolled_window;
 125
 126   scrolled_window = gtk_type_new (gtk_scrolled_window_get_type ());
 127
 128   gtk_scrolled_window_construct (GTK_SCROLLED_WINDOW (scrolled_window), hadjustment, vadjustment);
 129
 130   return scrolled_window;
 131 }
 132
 133 void
 134 gtk_scrolled_window_construct (GtkScrolledWindow *scrolled_window,
 135                                GtkAdjustment     *hadjustment,
 136                                GtkAdjustment     *vadjustment)
 137 {
 138   g_return_if_fail (scrolled_window != NULL);
 139   g_return_if_fail (GTK_IS_SCROLLED_WINDOW (scrolled_window));
 140   g_return_if_fail (scrolled_window->viewport == NULL);
 141
 142   scrolled_window->viewport = gtk_viewport_new (hadjustment, vadjustment);
 143   hadjustment = gtk_viewport_get_hadjustment (GTK_VIEWPORT (scrolled_window->viewport));
 144   vadjustment = gtk_viewport_get_vadjustment (GTK_VIEWPORT (scrolled_window->viewport));
 145   gtk_container_set_resize_mode (GTK_CONTAINER (scrolled_window->viewport), GTK_RESIZE_PARENT);
 146
 147   gtk_signal_connect (GTK_OBJECT (hadjustment), "changed",
 148                       (GtkSignalFunc) gtk_scrolled_window_adjustment_changed,
 149                       (gpointer) scrolled_window);
 150   gtk_signal_connect (GTK_OBJECT (vadjustment), "changed",
 151                       (GtkSignalFunc) gtk_scrolled_window_adjustment_changed,
 152                       (gpointer) scrolled_window);
 153
 154   scrolled_window->hscrollbar = gtk_hscrollbar_new (hadjustment);
 155   scrolled_window->vscrollbar = gtk_vscrollbar_new (vadjustment);
 156
 157   gtk_widget_set_parent (scrolled_window->viewport, GTK_WIDGET (scrolled_window));
 158   gtk_widget_set_parent (scrolled_window->hscrollbar, GTK_WIDGET (scrolled_window));
 159   gtk_widget_set_parent (scrolled_window->vscrollbar, GTK_WIDGET (scrolled_window));
 160
 161   gtk_widget_show (scrolled_window->viewport);
 162   gtk_widget_show (scrolled_window->hscrollbar);
 163   gtk_widget_show (scrolled_window->vscrollbar);
 164
 165   gtk_widget_ref (scrolled_window->viewport);
 166   gtk_widget_ref (scrolled_window->hscrollbar);
 167   gtk_widget_ref (scrolled_window->vscrollbar);
 168 }
 169
 170 GtkAdjustment*
 171 gtk_scrolled_window_get_hadjustment (GtkScrolledWindow *scrolled_window)
 172 {
 173   g_return_val_if_fail (scrolled_window != NULL, NULL);
 174   g_return_val_if_fail (GTK_IS_SCROLLED_WINDOW (scrolled_window), NULL);
 175
 176   return gtk_range_get_adjustment (GTK_RANGE (scrolled_window->hscrollbar));
 177 }
 178
 179 GtkAdjustment*
 180 gtk_scrolled_window_get_vadjustment (GtkScrolledWindow *scrolled_window)
 181 {
 182   g_return_val_if_fail (scrolled_window != NULL, NULL);
 183   g_return_val_if_fail (GTK_IS_SCROLLED_WINDOW (scrolled_window), NULL);
 184
 185   return gtk_range_get_adjustment (GTK_RANGE (scrolled_window->vscrollbar));
 186 }
 187
 188 void
 189 gtk_scrolled_window_set_policy (GtkScrolledWindow *scrolled_window,
 190                                 GtkPolicyType      hscrollbar_policy,
 191                                 GtkPolicyType      vscrollbar_policy)
 192 {
 193   g_return_if_fail (scrolled_window != NULL);
 194   g_return_if_fail (GTK_IS_SCROLLED_WINDOW (scrolled_window));
 195
 196   if ((scrolled_window->hscrollbar_policy != hscrollbar_policy) ||
 197       (scrolled_window->vscrollbar_policy != vscrollbar_policy))
 198     {
 199       scrolled_window->hscrollbar_policy = hscrollbar_policy;
 200       scrolled_window->vscrollbar_policy = vscrollbar_policy;
 201
 202       if (GTK_WIDGET (scrolled_window)->parent)
 203         gtk_widget_queue_resize (GTK_WIDGET (scrolled_window));
 204     }
 205 }
 206
 207
 208 static void
 209 gtk_scrolled_window_destroy (GtkObject *object)
 210 {
 211   GtkScrolledWindow *scrolled_window;
 212
 213   g_return_if_fail (object != NULL);
 214   g_return_if_fail (GTK_IS_SCROLLED_WINDOW (object));
 215
 216   scrolled_window = GTK_SCROLLED_WINDOW (object);
 217
 218   gtk_widget_destroy (scrolled_window->viewport);
 219   gtk_widget_destroy (scrolled_window->hscrollbar);
 220   gtk_widget_destroy (scrolled_window->vscrollbar);
 221
 222   if (GTK_OBJECT_CLASS (parent_class)->destroy)
 223     (* GTK_OBJECT_CLASS (parent_class)->destroy) (object);
 224 }
 225
 226 static void
 227 gtk_scrolled_window_finalize (GtkObject *object)
 228 {
 229   GtkScrolledWindow *scrolled_window;
 230
 231   scrolled_window = GTK_SCROLLED_WINDOW (object);
 232   gtk_widget_unref (scrolled_window->viewport);
 233   gtk_widget_unref (scrolled_window->hscrollbar);
 234   gtk_widget_unref (scrolled_window->vscrollbar);
 235
 236   GTK_OBJECT_CLASS (parent_class)->finalize (object);
 237 }
 238
 239 static void
 240 gtk_scrolled_window_map (GtkWidget *widget)
 241 {
 242   GtkScrolledWindow *scrolled_window;
 243
 244   g_return_if_fail (widget != NULL);
 245   g_return_if_fail (GTK_IS_SCROLLED_WINDOW (widget));
 246
 247   if (!GTK_WIDGET_MAPPED (widget))
 248     {
 249       GTK_WIDGET_SET_FLAGS (widget, GTK_MAPPED);
 250       scrolled_window = GTK_SCROLLED_WINDOW (widget);
 251
 252       if (GTK_WIDGET_VISIBLE (scrolled_window->viewport) &&
 253           !GTK_WIDGET_MAPPED (scrolled_window->viewport))
 254         gtk_widget_map (scrolled_window->viewport);
 255
 256       if (GTK_WIDGET_VISIBLE (scrolled_window->hscrollbar) &&
 257           !GTK_WIDGET_MAPPED (scrolled_window->hscrollbar))
 258         gtk_widget_map (scrolled_window->hscrollbar);
 259
 260       if (GTK_WIDGET_VISIBLE (scrolled_window->vscrollbar) &&
 261           !GTK_WIDGET_MAPPED (scrolled_window->vscrollbar))
 262         gtk_widget_map (scrolled_window->vscrollbar);
 263     }
 264 }
 265
 266 static void
 267 gtk_scrolled_window_unmap (GtkWidget *widget)
 268 {
 269   GtkScrolledWindow *scrolled_window;
 270
 271   g_return_if_fail (widget != NULL);
 272   g_return_if_fail (GTK_IS_SCROLLED_WINDOW (widget));
 273
 274   if (GTK_WIDGET_MAPPED (widget))
 275     {
 276       GTK_WIDGET_UNSET_FLAGS (widget, GTK_MAPPED);
 277       scrolled_window = GTK_SCROLLED_WINDOW (widget);
 278
 279       if (GTK_WIDGET_MAPPED (scrolled_window->viewport))
 280         gtk_widget_unmap (scrolled_window->viewport);
 281
 282       if (GTK_WIDGET_MAPPED (scrolled_window->hscrollbar))
 283         gtk_widget_unmap (scrolled_window->hscrollbar);
 284
 285       if (GTK_WIDGET_MAPPED (scrolled_window->vscrollbar))
 286         gtk_widget_unmap (scrolled_window->vscrollbar);
 287     }
 288 }
 289
 290 static void
 291 gtk_scrolled_window_draw (GtkWidget    *widget,
 292                           GdkRectangle *area)
 293 {
 294   GtkScrolledWindow *scrolled_window;
 295   GdkRectangle child_area;
 296
 297   g_return_if_fail (widget != NULL);
 298   g_return_if_fail (GTK_IS_SCROLLED_WINDOW (widget));
 299   g_return_if_fail (area != NULL);
 300
 301   if (GTK_WIDGET_DRAWABLE (widget))
 302     {
 303       scrolled_window = GTK_SCROLLED_WINDOW (widget);
 304
 305       if (gtk_widget_intersect (scrolled_window->viewport, area, &child_area))
 306         gtk_widget_draw (scrolled_window->viewport, &child_area);
 307
 308       if (gtk_widget_intersect (scrolled_window->hscrollbar, area, &child_area))
 309         gtk_widget_draw (scrolled_window->hscrollbar, &child_area);
 310
 311       if (gtk_widget_intersect (scrolled_window->vscrollbar, area, &child_area))
 312         gtk_widget_draw (scrolled_window->vscrollbar, &child_area);
 313     }
 314 }
 315
 316 static void
 317 gtk_scrolled_window_size_request (GtkWidget      *widget,
 318                                   GtkRequisition *requisition)
 319 {
 320   GtkScrolledWindow *scrolled_window;
 321   gint extra_height;
 322   gint extra_width;
 323
 324   g_return_if_fail (widget != NULL);
 325   g_return_if_fail (GTK_IS_SCROLLED_WINDOW (widget));
 326   g_return_if_fail (requisition != NULL);
 327
 328   scrolled_window = GTK_SCROLLED_WINDOW (widget);
 329
 330   requisition->width = 0;
 331   requisition->height = 0;
 332
 333   if (GTK_WIDGET_VISIBLE (scrolled_window->viewport))
 334     {
 335       gtk_widget_size_request (scrolled_window->viewport, &scrolled_window->viewport->requisition);
 336
 337       requisition->width += scrolled_window->viewport->requisition.width;
 338       requisition->height += scrolled_window->viewport->requisition.height;
 339     }
 340
 341   extra_width = 0;
 342   extra_height = 0;
 343
 344   if ((scrolled_window->hscrollbar_policy == GTK_POLICY_AUTOMATIC) ||
 345       GTK_WIDGET_VISIBLE (scrolled_window->hscrollbar))
 346     {
 347       gtk_widget_size_request (scrolled_window->hscrollbar,
 348                                &scrolled_window->hscrollbar->requisition);
 349
 350       requisition->width = MAX (requisition->width, scrolled_window->hscrollbar->requisition.width);
 351       extra_height = SCROLLBAR_SPACING (scrolled_window) + scrolled_window->hscrollbar->requisition.height;
 352     }
 353
 354   if ((scrolled_window->vscrollbar_policy == GTK_POLICY_AUTOMATIC) ||
 355       GTK_WIDGET_VISIBLE (scrolled_window->vscrollbar))
 356     {
 357       gtk_widget_size_request (scrolled_window->vscrollbar,
 358                                &scrolled_window->vscrollbar->requisition);
 359
 360       requisition->height = MAX (requisition->height, scrolled_window->vscrollbar->requisition.height);
 361       extra_width = SCROLLBAR_SPACING (scrolled_window) + scrolled_window->vscrollbar->requisition.width;
 362     }
 363
 364   requisition->width += GTK_CONTAINER (widget)->border_width * 2 + extra_width;
 365   requisition->height += GTK_CONTAINER (widget)->border_width * 2 + extra_height;
 366 }
 367
 368 static void
 369 gtk_scrolled_window_size_allocate (GtkWidget     *widget,
 370                                    GtkAllocation *allocation)
 371 {
 372   GtkScrolledWindow *scrolled_window;
 373   GtkAllocation viewport_allocation;
 374   GtkAllocation child_allocation;
 375   guint previous_hvis;
 376   guint previous_vvis;
 377   gint count;
 378
 379   g_return_if_fail (widget != NULL);
 380   g_return_if_fail (GTK_IS_SCROLLED_WINDOW (widget));
 381   g_return_if_fail (allocation != NULL);
 382
 383   scrolled_window = GTK_SCROLLED_WINDOW (widget);
 384   widget->allocation = *allocation;
 385
 386   if (scrolled_window->hscrollbar_policy == GTK_POLICY_ALWAYS)
 387     scrolled_window->hscrollbar_visible = TRUE;
 388   if (scrolled_window->vscrollbar_policy == GTK_POLICY_ALWAYS)
 389     scrolled_window->vscrollbar_visible = TRUE;
 390
 391   if (GTK_WIDGET_VISIBLE (scrolled_window->viewport))
 392     {
 393       count = 0;
 394
 395       do {
 396         gtk_scrolled_window_viewport_allocate (widget, &viewport_allocation);
 397
 398         child_allocation.x = viewport_allocation.x + allocation->x;
 399         child_allocation.y = viewport_allocation.y + allocation->y;
 400         child_allocation.width = viewport_allocation.width;
 401         child_allocation.height = viewport_allocation.height;
 402
 403         previous_hvis = scrolled_window->hscrollbar_visible;
 404         previous_vvis = scrolled_window->vscrollbar_visible;
 405
 406         gtk_widget_size_allocate (scrolled_window->viewport, &child_allocation);
 407         /* If, after the first iteration, the hscrollbar and the
 408          * vscrollbar flip visiblity, then we need both.
 409          */
 410         if ((count++) &&
 411             (previous_hvis != scrolled_window->hscrollbar_visible) &&
 412             (previous_vvis != scrolled_window->vscrollbar_visible))
 413           {
 414             scrolled_window->hscrollbar_visible = TRUE;
 415             scrolled_window->vscrollbar_visible = TRUE;
 416             break;
 417           }
 418
 419         count++;
 420       } while ((previous_hvis != scrolled_window->hscrollbar_visible) ||
 421                (previous_vvis != scrolled_window->vscrollbar_visible));
 422     }
 423
 424   if (scrolled_window->hscrollbar_visible)
 425     {
 426       if (!GTK_WIDGET_VISIBLE (scrolled_window->hscrollbar))
 427         gtk_widget_show (scrolled_window->hscrollbar);
 428
 429       child_allocation.x = viewport_allocation.x;
 430       child_allocation.y = viewport_allocation.y + viewport_allocation.height + SCROLLBAR_SPACING (scrolled_window);
 431       child_allocation.width = viewport_allocation.width;
 432       child_allocation.height = scrolled_window->hscrollbar->requisition.height;
 433       child_allocation.x += allocation->x;
 434       child_allocation.y += allocation->y;
 435
 436       gtk_widget_size_allocate (scrolled_window->hscrollbar, &child_allocation);
 437     }
 438   else
 439     {
 440       if (GTK_WIDGET_VISIBLE (scrolled_window->hscrollbar))
 441         gtk_widget_hide (scrolled_window->hscrollbar);
 442     }
 443
 444   if (scrolled_window->vscrollbar_visible)
 445     {
 446       if (!GTK_WIDGET_VISIBLE (scrolled_window->vscrollbar))
 447         gtk_widget_show (scrolled_window->vscrollbar);
 448
 449       child_allocation.x = viewport_allocation.x + viewport_allocation.width + SCROLLBAR_SPACING (scrolled_window);
 450       child_allocation.y = viewport_allocation.y;
 451       child_allocation.width = scrolled_window->vscrollbar->requisition.width;
 452       child_allocation.height = viewport_allocation.height;
 453       child_allocation.x += allocation->x;
 454       child_allocation.y += allocation->y;
 455
 456       gtk_widget_size_allocate (scrolled_window->vscrollbar, &child_allocation);
 457     }
 458   else
 459     {
 460       if (GTK_WIDGET_VISIBLE (scrolled_window->vscrollbar))
 461         gtk_widget_hide (scrolled_window->vscrollbar);
 462     }
 463 }
 464
 465 static void
 466 gtk_scrolled_window_add (GtkContainer *container,
 467                          GtkWidget    *widget)
 468 {
 469   GtkScrolledWindow *scrolled_window;
 470
 471   g_return_if_fail (container != NULL);
 472   g_return_if_fail (GTK_IS_SCROLLED_WINDOW (container));
 473   g_return_if_fail (widget != NULL);
 474
 475   scrolled_window = GTK_SCROLLED_WINDOW (container);
 476   gtk_container_add (GTK_CONTAINER (scrolled_window->viewport), widget);
 477 }
 478
 479 static void
 480 gtk_scrolled_window_remove (GtkContainer *container,
 481                             GtkWidget    *widget)
 482 {
 483   GtkScrolledWindow *scrolled_window;
 484
 485   g_return_if_fail (container != NULL);
 486   g_return_if_fail (GTK_IS_SCROLLED_WINDOW (container));
 487   g_return_if_fail (widget != NULL);
 488
 489   scrolled_window = GTK_SCROLLED_WINDOW (container);
 490
 491   if (scrolled_window->viewport == widget ||
 492       scrolled_window->hscrollbar == widget ||
 493       scrolled_window->vscrollbar == widget)
 494     {
 495       /* this happens during destroy */
 496       gtk_widget_unparent (widget);
 497     }
 498   else
 499     gtk_container_remove (GTK_CONTAINER (scrolled_window->viewport), widget);
 500 }
 501
 502 static void
 503 gtk_scrolled_window_foreach (GtkContainer *container,
 504                              GtkCallback   callback,
 505                              gpointer      callback_data)
 506 {
 507   GtkScrolledWindow *scrolled_window;
 508
 509   g_return_if_fail (container != NULL);
 510   g_return_if_fail (GTK_IS_SCROLLED_WINDOW (container));
 511   g_return_if_fail (callback != NULL);
 512
 513   scrolled_window = GTK_SCROLLED_WINDOW (container);
 514
 515   if (scrolled_window->viewport)
 516     (* callback) (scrolled_window->viewport, callback_data);
 517
 518   (* callback) (scrolled_window->vscrollbar, callback_data);
 519   (* callback) (scrolled_window->hscrollbar, callback_data);
 520 }
 521
 522 static void
 523 gtk_scrolled_window_viewport_allocate (GtkWidget     *widget,
 524                                        GtkAllocation *allocation)
 525 {
 526   GtkScrolledWindow *scrolled_window;
 527
 528   g_return_if_fail (widget != NULL);
 529   g_return_if_fail (allocation != NULL);
 530
 531   scrolled_window = GTK_SCROLLED_WINDOW (widget);
 532
 533   allocation->x = GTK_CONTAINER (widget)->border_width;
 534   allocation->y = GTK_CONTAINER (widget)->border_width;
 535   allocation->width = MAX (1, widget->allocation.width - allocation->x * 2);
 536   allocation->height = MAX (1, widget->allocation.height - allocation->y * 2);
 537
 538   if (scrolled_window->vscrollbar_visible)
 539     allocation->width = MAX (1,
 540       allocation->width - (scrolled_window->vscrollbar->requisition.width + SCROLLBAR_SPACING (scrolled_window)));
 541   if (scrolled_window->hscrollbar_visible)
 542     allocation->height = MAX (1,
 543       allocation->height - (scrolled_window->hscrollbar->requisition.height + SCROLLBAR_SPACING (scrolled_window)));
 544 }
 545
 546 static void
 547 gtk_scrolled_window_adjustment_changed (GtkAdjustment *adjustment,
 548                                         gpointer       data)
 549 {
 550   GtkScrolledWindow *scrolled_win;
 551
 552   g_return_if_fail (adjustment != NULL);
 553   g_return_if_fail (data != NULL);
 554
 555   scrolled_win = GTK_SCROLLED_WINDOW (data);
 556
 557   if (adjustment == gtk_range_get_adjustment (GTK_RANGE (scrolled_win->hscrollbar)))
 558     {
 559       if (scrolled_win->hscrollbar_policy == GTK_POLICY_AUTOMATIC)
 560         {
 561           scrolled_win->hscrollbar_visible =
 562             ((adjustment->upper - adjustment->lower) > adjustment->page_size);
 563         }
 564     }
 565   else if (adjustment == gtk_range_get_adjustment (GTK_RANGE (scrolled_win->vscrollbar)))
 566     {
 567       if (scrolled_win->vscrollbar_policy == GTK_POLICY_AUTOMATIC)
 568         {
 569           scrolled_win->vscrollbar_visible =
 570             ((adjustment->upper - adjustment->lower) > adjustment->page_size);
 571         }
 572     }
 573   else
 574     {
 575       g_warning ("could not determine which adjustment scrollbar received change signal for");
 576       return;
 577     }
 578 }