Pileus Git - ~andy/gtk/blob - gtk/gtkbin.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, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 /*
  19  * Modified by the GTK+ Team and others 1997-2000.  See the AUTHORS
  20  * file for a list of people on the GTK+ Team.  See the ChangeLog
  21  * files for a list of changes.  These files are distributed with
  22  * GTK+ at ftp://ftp.gtk.org/pub/gtk/.
  23  */
  24
  25 /**
  26  * SECTION:gtkbin
  27  * @Short_description: A container with just one child
  28  * @Title: GtkBin
  29  *
  30  * The #GtkBin widget is a container with just one child.
  31  * It is not very useful itself, but it is useful for deriving subclasses,
  32  * since it provides common code needed for handling a single child widget.
  33  *
  34  * Many GTK+ widgets are subclasses of #GtkBin, including #GtkWindow,
  35  * #GtkButton, #GtkFrame, #GtkHandleBox or #GtkScrolledWindow.
  36  */
  37
  38 #include "config.h"
  39 #include "gtkbin.h"
  40 #include "gtksizerequest.h"
  41 #include "gtkintl.h"
  42
  43
  44 struct _GtkBinPrivate
  45 {
  46   GtkWidget *child;
  47 };
  48
  49 static void gtk_bin_add         (GtkContainer   *container,
  50                                  GtkWidget      *widget);
  51 static void gtk_bin_remove      (GtkContainer   *container,
  52                                  GtkWidget      *widget);
  53 static void gtk_bin_forall      (GtkContainer   *container,
  54                                  gboolean       include_internals,
  55                                  GtkCallback     callback,
  56                                  gpointer        callback_data);
  57 static GType gtk_bin_child_type (GtkContainer   *container);
  58
  59
  60 static void               gtk_bin_get_preferred_width_for_height  (GtkWidget           *widget,
  61                                                                    gint                 height,
  62                                                                    gint                *minimum_width,
  63                                                                    gint                *natural_width);
  64 static void               gtk_bin_get_preferred_height_for_width  (GtkWidget           *widget,
  65                                                                    gint                 width,
  66                                                                    gint                *minimum_height,
  67                                                                    gint                *natural_height);
  68
  69 G_DEFINE_ABSTRACT_TYPE (GtkBin, gtk_bin, GTK_TYPE_CONTAINER)
  70
  71 static void
  72 gtk_bin_class_init (GtkBinClass *class)
  73 {
  74   GtkWidgetClass *widget_class = (GtkWidgetClass*) class;
  75   GtkContainerClass *container_class = (GtkContainerClass*) class;
  76
  77   widget_class->get_preferred_width_for_height = gtk_bin_get_preferred_width_for_height;
  78   widget_class->get_preferred_height_for_width = gtk_bin_get_preferred_height_for_width;
  79
  80   container_class->add = gtk_bin_add;
  81   container_class->remove = gtk_bin_remove;
  82   container_class->forall = gtk_bin_forall;
  83   container_class->child_type = gtk_bin_child_type;
  84
  85   g_type_class_add_private (class, sizeof (GtkBinPrivate));
  86 }
  87
  88 static void
  89 gtk_bin_init (GtkBin *bin)
  90 {
  91   GtkBinPrivate *priv;
  92
  93   bin->priv = G_TYPE_INSTANCE_GET_PRIVATE (bin,
  94                                            GTK_TYPE_BIN,
  95                                            GtkBinPrivate);
  96   priv = bin->priv;
  97
  98   gtk_widget_set_has_window (GTK_WIDGET (bin), FALSE);
  99
 100   priv->child = NULL;
 101 }
 102
 103
 104 static GType
 105 gtk_bin_child_type (GtkContainer *container)
 106 {
 107   GtkBinPrivate *priv = GTK_BIN (container)->priv;
 108
 109   if (!priv->child)
 110     return GTK_TYPE_WIDGET;
 111   else
 112     return G_TYPE_NONE;
 113 }
 114
 115 static void
 116 gtk_bin_add (GtkContainer *container,
 117              GtkWidget    *child)
 118 {
 119   GtkBin *bin = GTK_BIN (container);
 120   GtkBinPrivate *priv = bin->priv;
 121
 122   if (priv->child != NULL)
 123     {
 124       g_warning ("Attempting to add a widget with type %s to a %s, "
 125                  "but as a GtkBin subclass a %s can only contain one widget at a time; "
 126                  "it already contains a widget of type %s",
 127                  g_type_name (G_OBJECT_TYPE (child)),
 128                  g_type_name (G_OBJECT_TYPE (bin)),
 129                  g_type_name (G_OBJECT_TYPE (bin)),
 130                  g_type_name (G_OBJECT_TYPE (priv->child)));
 131       return;
 132     }
 133
 134   gtk_widget_set_parent (child, GTK_WIDGET (bin));
 135   priv->child = child;
 136 }
 137
 138 static void
 139 gtk_bin_remove (GtkContainer *container,
 140                 GtkWidget    *child)
 141 {
 142   GtkBin *bin = GTK_BIN (container);
 143   GtkBinPrivate *priv = bin->priv;
 144   gboolean widget_was_visible;
 145
 146   g_return_if_fail (priv->child == child);
 147
 148   widget_was_visible = gtk_widget_get_visible (child);
 149
 150   gtk_widget_unparent (child);
 151   priv->child = NULL;
 152
 153   /* queue resize regardless of gtk_widget_get_visible (container),
 154    * since that's what is needed by toplevels, which derive from GtkBin.
 155    */
 156   if (widget_was_visible)
 157     gtk_widget_queue_resize (GTK_WIDGET (container));
 158 }
 159
 160 static void
 161 gtk_bin_forall (GtkContainer *container,
 162                 gboolean      include_internals,
 163                 GtkCallback   callback,
 164                 gpointer      callback_data)
 165 {
 166   GtkBin *bin = GTK_BIN (container);
 167   GtkBinPrivate *priv = bin->priv;
 168
 169   if (priv->child)
 170     (* callback) (priv->child, callback_data);
 171 }
 172
 173
 174 /* GtkBin widgets define the padding and borders independantly so
 175  * we cannot provide a generic get_size() for the same reason
 176  * we never implemented size_request() here.
 177  *
 178  * But for cases where the GtkBin class's padding is constant and
 179  * does not vary based on allocation (most cases), we can at least
 180  * deduce a common code path for the get_width_for_height()/get_height_for_width()
 181  * cases by using the delta of the base size requsts.
 182  */
 183 static void
 184 get_child_padding_delta (GtkBin *bin,
 185                          gint   *delta_h,
 186                          gint   *delta_v)
 187 {
 188   GtkBinPrivate *priv = bin->priv;
 189   gint hmin, vmin, hnat, vnat, child_hmin, child_vmin;
 190
 191   /* we can't use gtk_widget_get_preferred_width() wrapper
 192    * because we want our "original" request, not any external
 193    * adjustments from set_size_request() or whatever.  we have
 194    * to ask for natural also because NULL isn't allowed for the
 195    * direct vfuncs
 196    */
 197   GTK_WIDGET_GET_CLASS (bin)->get_preferred_width (GTK_WIDGET (bin), &hmin, &hnat);
 198   GTK_WIDGET_GET_CLASS (bin)->adjust_size_request (GTK_WIDGET (bin),
 199                                                    GTK_ORIENTATION_HORIZONTAL, &hmin, &hnat);
 200
 201   GTK_WIDGET_GET_CLASS (bin)->get_preferred_height (GTK_WIDGET (bin), &vmin, &vnat);
 202   GTK_WIDGET_GET_CLASS (bin)->adjust_size_request (GTK_WIDGET (bin),
 203                                                    GTK_ORIENTATION_VERTICAL, &vmin, &vnat);
 204
 205   gtk_widget_get_preferred_width (priv->child, &child_hmin, NULL);
 206   gtk_widget_get_preferred_height (priv->child, &child_vmin, NULL);
 207
 208   *delta_h = hmin - child_hmin;
 209   *delta_v = vmin - child_vmin;
 210 }
 211
 212 static void
 213 gtk_bin_get_preferred_width_for_height (GtkWidget *widget,
 214                                         gint       height,
 215                                         gint      *minimum_width,
 216                                         gint      *natural_width)
 217 {
 218   GtkBin *bin = GTK_BIN (widget);
 219   GtkBinPrivate *priv = bin->priv;
 220   gint    hdelta, vdelta, child_min, child_nat;
 221
 222   if (priv->child)
 223     {
 224       get_child_padding_delta (bin, &hdelta, &vdelta);
 225
 226       gtk_widget_get_preferred_width_for_height (priv->child,
 227                                                  height - vdelta,
 228                                                  &child_min, &child_nat);
 229
 230       if (minimum_width)
 231         *minimum_width = child_min + hdelta;
 232
 233       if (natural_width)
 234         *natural_width = child_nat + hdelta;
 235     }
 236   else
 237     GTK_WIDGET_GET_CLASS (widget)->get_preferred_width (widget, minimum_width, natural_width);
 238 }
 239
 240 static void
 241 gtk_bin_get_preferred_height_for_width  (GtkWidget *widget,
 242                                          gint       width,
 243                                          gint      *minimum_height,
 244                                          gint      *natural_height)
 245 {
 246   GtkBin *bin = GTK_BIN (widget);
 247   GtkBinPrivate *priv = bin->priv;
 248   gint    hdelta, vdelta, child_min, child_nat;
 249
 250   if (priv->child)
 251     {
 252       get_child_padding_delta (bin, &hdelta, &vdelta);
 253
 254       gtk_widget_get_preferred_height_for_width (priv->child,
 255                                                  width - hdelta,
 256                                                  &child_min, &child_nat);
 257
 258       if (minimum_height)
 259         *minimum_height = child_min + vdelta;
 260
 261       if (natural_height)
 262         *natural_height = child_nat + vdelta;
 263     }
 264   else
 265     GTK_WIDGET_GET_CLASS (widget)->get_preferred_height (widget, minimum_height, natural_height);
 266 }
 267
 268
 269 /**
 270  * gtk_bin_get_child:
 271  * @bin: a #GtkBin
 272  *
 273  * Gets the child of the #GtkBin, or %NULL if the bin contains
 274  * no child widget. The returned widget does not have a reference
 275  * added, so you do not need to unref it.
 276  *
 277  * Return value: (transfer none): pointer to child of the #GtkBin
 278  **/
 279 GtkWidget*
 280 gtk_bin_get_child (GtkBin *bin)
 281 {
 282   g_return_val_if_fail (GTK_IS_BIN (bin), NULL);
 283
 284   return bin->priv->child;
 285 }
 286
 287 void
 288 _gtk_bin_set_child (GtkBin    *bin,
 289                     GtkWidget *widget)
 290 {
 291   bin->priv->child = widget;
 292 }