Pileus Git - ~andy/gtk/blob - gtk/gtkadjustment.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 "gtkadjustment.h"
  28 #include "gtkmarshalers.h"
  29
  30
  31 enum {
  32   CHANGED,
  33   VALUE_CHANGED,
  34   LAST_SIGNAL
  35 };
  36
  37
  38 static void gtk_adjustment_class_init (GtkAdjustmentClass *klass);
  39 static void gtk_adjustment_init       (GtkAdjustment      *adjustment);
  40
  41
  42 static guint adjustment_signals[LAST_SIGNAL] = { 0 };
  43
  44
  45 GType
  46 gtk_adjustment_get_type (void)
  47 {
  48   static GType adjustment_type = 0;
  49
  50   if (!adjustment_type)
  51     {
  52       static const GTypeInfo adjustment_info =
  53       {
  54         sizeof (GtkAdjustmentClass),
  55         NULL,           /* base_init */
  56         NULL,           /* base_finalize */
  57         (GClassInitFunc) gtk_adjustment_class_init,
  58         NULL,           /* class_finalize */
  59         NULL,           /* class_data */
  60         sizeof (GtkAdjustment),
  61         0,              /* n_preallocs */
  62         (GInstanceInitFunc) gtk_adjustment_init,
  63       };
  64
  65       adjustment_type =
  66         g_type_register_static (GTK_TYPE_OBJECT, "GtkAdjustment",
  67                                 &adjustment_info, 0);
  68     }
  69
  70   return adjustment_type;
  71 }
  72
  73 static void
  74 gtk_adjustment_class_init (GtkAdjustmentClass *class)
  75 {
  76   class->changed = NULL;
  77   class->value_changed = NULL;
  78
  79   adjustment_signals[CHANGED] =
  80     g_signal_new ("changed",
  81                   G_OBJECT_CLASS_TYPE (class),
  82                   G_SIGNAL_RUN_FIRST | G_SIGNAL_NO_RECURSE,
  83                   G_STRUCT_OFFSET (GtkAdjustmentClass, changed),
  84                   NULL, NULL,
  85                   _gtk_marshal_VOID__VOID,
  86                   G_TYPE_NONE, 0);
  87   adjustment_signals[VALUE_CHANGED] =
  88     g_signal_new ("value_changed",
  89                   G_OBJECT_CLASS_TYPE (class),
  90                   G_SIGNAL_RUN_FIRST | G_SIGNAL_NO_RECURSE,
  91                   G_STRUCT_OFFSET (GtkAdjustmentClass, value_changed),
  92                   NULL, NULL,
  93                   _gtk_marshal_VOID__VOID,
  94                   G_TYPE_NONE, 0);
  95 }
  96
  97 static void
  98 gtk_adjustment_init (GtkAdjustment *adjustment)
  99 {
 100   adjustment->value = 0.0;
 101   adjustment->lower = 0.0;
 102   adjustment->upper = 0.0;
 103   adjustment->step_increment = 0.0;
 104   adjustment->page_increment = 0.0;
 105   adjustment->page_size = 0.0;
 106 }
 107
 108 GtkObject*
 109 gtk_adjustment_new (gdouble value,
 110                     gdouble lower,
 111                     gdouble upper,
 112                     gdouble step_increment,
 113                     gdouble page_increment,
 114                     gdouble page_size)
 115 {
 116   GtkAdjustment *adjustment;
 117
 118   adjustment = g_object_new (GTK_TYPE_ADJUSTMENT, NULL);
 119
 120   adjustment->value = value;
 121   adjustment->lower = lower;
 122   adjustment->upper = upper;
 123   adjustment->step_increment = step_increment;
 124   adjustment->page_increment = page_increment;
 125   adjustment->page_size = page_size;
 126
 127   return GTK_OBJECT (adjustment);
 128 }
 129
 130 /**
 131  * gtk_adjustment_get_value:
 132  * @adjustment: a #GtkAdjustment
 133  *
 134  * Gets the current value of the adjustment. See
 135  * gtk_adjustment_set_value ().
 136  *
 137  * Return value: The current value of the adjustment.
 138  **/
 139 gdouble
 140 gtk_adjustment_get_value (GtkAdjustment *adjustment)
 141 {
 142   g_return_val_if_fail (GTK_IS_ADJUSTMENT (adjustment), 0.);
 143
 144   return adjustment->value;
 145 }
 146
 147 void
 148 gtk_adjustment_set_value (GtkAdjustment        *adjustment,
 149                           gdouble               value)
 150 {
 151   g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
 152
 153   value = CLAMP (value, adjustment->lower, adjustment->upper);
 154
 155   if (value != adjustment->value)
 156     {
 157       adjustment->value = value;
 158
 159       gtk_adjustment_value_changed (adjustment);
 160     }
 161 }
 162
 163 void
 164 gtk_adjustment_changed (GtkAdjustment        *adjustment)
 165 {
 166   g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
 167
 168   g_signal_emit (adjustment, adjustment_signals[CHANGED], 0);
 169 }
 170
 171 void
 172 gtk_adjustment_value_changed (GtkAdjustment        *adjustment)
 173 {
 174   g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
 175
 176   g_signal_emit (adjustment, adjustment_signals[VALUE_CHANGED], 0);
 177 }
 178
 179 void
 180 gtk_adjustment_clamp_page (GtkAdjustment *adjustment,
 181                            gdouble        lower,
 182                            gdouble        upper)
 183 {
 184   gboolean need_emission;
 185
 186   g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
 187
 188   lower = CLAMP (lower, adjustment->lower, adjustment->upper);
 189   upper = CLAMP (upper, adjustment->lower, adjustment->upper);
 190
 191   need_emission = FALSE;
 192
 193   if (adjustment->value + adjustment->page_size < upper)
 194     {
 195       adjustment->value = upper - adjustment->page_size;
 196       need_emission = TRUE;
 197     }
 198   if (adjustment->value > lower)
 199     {
 200       adjustment->value = lower;
 201       need_emission = TRUE;
 202     }
 203
 204   if (need_emission)
 205     gtk_adjustment_value_changed (adjustment);
 206 }