libnautilus-private/nautilus-keep-last-vertical-box.c

   1 /* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */
   2
   3 /* nautilus-keep-last-vertical-box.c: Subclass of GtkVBox that clips off
   4                                       items that don't fit, except the last one.
   5
   6    Copyright (C) 2000 Eazel, Inc.
   7
   8    The Gnome Library is free software; you can redistribute it and/or
   9    modify it under the terms of the GNU Library General Public License as
  10    published by the Free Software Foundation; either version 2 of the
  11    License, or (at your option) any later version.
  12
  13    The Gnome Library is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16    Library General Public License for more details.
  17
  18    You should have received a copy of the GNU Library General Public
  19    License along with the Gnome Library; see the file COPYING.LIB.  If not,
  20    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.
  22
  23    Author: John Sullivan <sullivan@eazel.com>,
  24  */
  25
  26 #include <config.h>
  27 #include "nautilus-keep-last-vertical-box.h"
  28
  29 #include <eel/eel-gtk-macros.h>
  30
  31 static void     nautilus_keep_last_vertical_box_class_init  (NautilusKeepLastVerticalBoxClass *class);
  32 static void     nautilus_keep_last_vertical_box_init        (NautilusKeepLastVerticalBox      *box);
  33 static void     nautilus_keep_last_vertical_box_size_allocate     (GtkWidget                        *widget,
  34                                                                    GtkAllocation                    *allocation);
  35
  36 EEL_CLASS_BOILERPLATE (NautilusKeepLastVerticalBox, nautilus_keep_last_vertical_box, GTK_TYPE_VBOX)
  37
  38 /* Standard class initialization function */
  39 static void
  40 nautilus_keep_last_vertical_box_class_init (NautilusKeepLastVerticalBoxClass *klass)
  41 {
  42         GtkWidgetClass *widget_class;
  43
  44         widget_class = (GtkWidgetClass *) klass;
  45
  46         widget_class->size_allocate = nautilus_keep_last_vertical_box_size_allocate;
  47 }
  48
  49 /* Standard object initialization function */
  50 static void
  51 nautilus_keep_last_vertical_box_init (NautilusKeepLastVerticalBox *box)
  52 {
  53 }
  54
  55
  56 /* nautilus_keep_last_vertical_box_new:
  57  *
  58  * Create a new vertical box that clips off items from the end that don't
  59  * fit, except the last item, which is always kept. When packing this widget
  60  * into another vbox, use TRUE for expand and TRUE for fill or this class's
  61  * special clipping magic won't work because this widget's allocation might
  62  * be larger than the available space.
  63  *
  64  * @spacing: Vertical space between items.
  65  *
  66  * Return value: A new NautilusKeepLastVerticalBox
  67  */
  68 GtkWidget *
  69 nautilus_keep_last_vertical_box_new (gint spacing)
  70 {
  71         NautilusKeepLastVerticalBox *box;
  72
  73         box = NAUTILUS_KEEP_LAST_VERTICAL_BOX (gtk_widget_new (nautilus_keep_last_vertical_box_get_type (), NULL));
  74
  75         GTK_BOX (box)->spacing = spacing;
  76
  77         /* If homogeneous is TRUE and there are too many items to fit
  78          * naturally, they will be squashed together to fit in the space.
  79          * We want the ones that don't fit to be not shown at all, so
  80          * we set homogeneous to FALSE.
  81          */
  82         GTK_BOX (box)->homogeneous = FALSE;
  83
  84         return GTK_WIDGET (box);
  85 }
  86
  87 static void
  88 nautilus_keep_last_vertical_box_size_allocate (GtkWidget *widget,
  89                                                GtkAllocation *allocation)
  90 {
  91         GtkBox *box;
  92         GtkBoxChild *last_child, *child;
  93         GList *children;
  94         GtkAllocation last_child_allocation, child_allocation, tiny_allocation;
  95
  96         g_return_if_fail (NAUTILUS_IS_KEEP_LAST_VERTICAL_BOX (widget));
  97         g_return_if_fail (allocation != NULL);
  98
  99         EEL_CALL_PARENT (GTK_WIDGET_CLASS, size_allocate, (widget, allocation));
 100
 101         box = GTK_BOX (widget);
 102         children = g_list_last (box->children);
 103
 104         if (children != NULL) {
 105                 last_child = children->data;
 106                 children = children->prev;
 107
 108                 last_child_allocation = last_child->widget->allocation;
 109
 110                 /* If last child doesn't fit vertically, prune items from the end of the
 111                  * list one at a time until it does.
 112                  */
 113                 if (last_child_allocation.y + last_child_allocation.height >
 114                     allocation->y + allocation->height) {
 115
 116                         while (children != NULL) {
 117                                 child = children->data;
 118                                 children = children->prev;
 119
 120                                 child_allocation = child->widget->allocation;
 121
 122                                 /* Reallocate this child's position so that it does not appear.
 123                                  * Setting the width & height to 0 is not enough, as
 124                                  * one pixel is still drawn. Must also move it outside
 125                                  * visible range. For the cases I've seen, -1, -1 works fine.
 126                                  * This might not work in all future cases. Alternatively, the
 127                                  * items that don't fit could be hidden, but that would interfere
 128                                  * with having other hidden children.
 129                                  *
 130                                  * Note that these children are having their size allocated twice,
 131                                  * once by gtk_vbox_size_allocate and then again here. I don't
 132                                  * know of any problems with this, but holler if you do.
 133                                  */
 134                                 tiny_allocation.x = tiny_allocation.y = -1;
 135                                 tiny_allocation.height = tiny_allocation.width = 0;
 136                                 gtk_widget_size_allocate (child->widget, &tiny_allocation);
 137
 138                                 /* We're done if the special last item fits now. */
 139                                 if (child_allocation.y + last_child_allocation.height <=
 140                                     allocation->y + allocation->height) {
 141                                         last_child_allocation.y = child_allocation.y;
 142                                         gtk_widget_size_allocate (last_child->widget, &last_child_allocation);
 143                                         break;
 144                                 }
 145
 146                                 /* If the special last item still doesn't fit, but we've
 147                                  * run out of earlier items, then the special last item is
 148                                  * just too darn tall. Let's squash it down to fit in the box's
 149                                  * allocation.
 150                                  */
 151                                 if (children == NULL) {
 152                                         last_child_allocation.y = allocation->y;
 153                                         last_child_allocation.height = allocation->height;
 154                                         gtk_widget_size_allocate (last_child->widget, &last_child_allocation);
 155                                 }
 156                         }
 157                 }
 158         }
 159 }