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 "gtksignal.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 GtkType
  46 gtk_adjustment_get_type (void)
  47 {
  48   static GtkType adjustment_type = 0;
  49
  50   if (!adjustment_type)
  51     {
  52       static const GtkTypeInfo adjustment_info =
  53       {
  54         "GtkAdjustment",
  55         sizeof (GtkAdjustment),
  56         sizeof (GtkAdjustmentClass),
  57         (GtkClassInitFunc) gtk_adjustment_class_init,
  58         (GtkObjectInitFunc) gtk_adjustment_init,
  59         /* reserved_1 */ NULL,
  60         /* reserved_2 */ NULL,
  61         (GtkClassInitFunc) NULL,
  62       };
  63
  64       adjustment_type = gtk_type_unique (GTK_TYPE_OBJECT, &adjustment_info);
  65     }
  66
  67   return adjustment_type;
  68 }
  69
  70 static void
  71 gtk_adjustment_class_init (GtkAdjustmentClass *class)
  72 {
  73   GtkObjectClass *object_class;
  74
  75   object_class = (GtkObjectClass*) class;
  76
  77   class->changed = NULL;
  78   class->value_changed = NULL;
  79
  80   adjustment_signals[CHANGED] =
  81     gtk_signal_new ("changed",
  82                     GTK_RUN_FIRST | GTK_RUN_NO_RECURSE,
  83                     GTK_CLASS_TYPE (object_class),
  84                     GTK_SIGNAL_OFFSET (GtkAdjustmentClass, changed),
  85                     gtk_marshal_VOID__VOID,
  86                     GTK_TYPE_NONE, 0);
  87   adjustment_signals[VALUE_CHANGED] =
  88     gtk_signal_new ("value_changed",
  89                     GTK_RUN_FIRST | GTK_RUN_NO_RECURSE,
  90                     GTK_CLASS_TYPE (object_class),
  91                     GTK_SIGNAL_OFFSET (GtkAdjustmentClass, value_changed),
  92                     gtk_marshal_VOID__VOID,
  93                     GTK_TYPE_NONE, 0);
  94 }
  95
  96 static void
  97 gtk_adjustment_init (GtkAdjustment *adjustment)
  98 {
  99   adjustment->value = 0.0;
 100   adjustment->lower = 0.0;
 101   adjustment->upper = 0.0;
 102   adjustment->step_increment = 0.0;
 103   adjustment->page_increment = 0.0;
 104   adjustment->page_size = 0.0;
 105 }
 106
 107 GtkObject*
 108 gtk_adjustment_new (gdouble value,
 109                     gdouble lower,
 110                     gdouble upper,
 111                     gdouble step_increment,
 112                     gdouble page_increment,
 113                     gdouble page_size)
 114 {
 115   GtkAdjustment *adjustment;
 116
 117   adjustment = gtk_type_new (gtk_adjustment_get_type ());
 118
 119   adjustment->value = value;
 120   adjustment->lower = lower;
 121   adjustment->upper = upper;
 122   adjustment->step_increment = step_increment;
 123   adjustment->page_increment = page_increment;
 124   adjustment->page_size = page_size;
 125
 126   return GTK_OBJECT (adjustment);
 127 }
 128
 129 /**
 130  * gtk_adjustment_get_value:
 131  * @adjustment: a #GtkAdjustment
 132  *
 133  * Gets the current value of the adjustment. See
 134  * gtk_adjustment_set_value ().
 135  *
 136  * Return value: The current value of the adjustment.
 137  **/
 138 gdouble
 139 gtk_adjustment_get_value (GtkAdjustment *adjustment)
 140 {
 141   g_return_val_if_fail (GTK_IS_ADJUSTMENT (adjustment), 0.);
 142
 143   return adjustment->value;
 144 }
 145
 146 void
 147 gtk_adjustment_set_value (GtkAdjustment        *adjustment,
 148                           gdouble               value)
 149 {
 150   g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
 151
 152   value = CLAMP (value, adjustment->lower, adjustment->upper);
 153
 154   if (value != adjustment->value)
 155     {
 156       adjustment->value = value;
 157
 158       gtk_adjustment_value_changed (adjustment);
 159     }
 160 }
 161
 162 void
 163 gtk_adjustment_changed (GtkAdjustment        *adjustment)
 164 {
 165   g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
 166
 167   gtk_signal_emit (GTK_OBJECT (adjustment), adjustment_signals[CHANGED]);
 168 }
 169
 170 void
 171 gtk_adjustment_value_changed (GtkAdjustment        *adjustment)
 172 {
 173   g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
 174
 175   gtk_signal_emit (GTK_OBJECT (adjustment), adjustment_signals[VALUE_CHANGED]);
 176 }
 177
 178 void
 179 gtk_adjustment_clamp_page (GtkAdjustment *adjustment,
 180                            gdouble        lower,
 181                            gdouble        upper)
 182 {
 183   gboolean need_emission;
 184
 185   g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
 186
 187   lower = CLAMP (lower, adjustment->lower, adjustment->upper);
 188   upper = CLAMP (upper, adjustment->lower, adjustment->upper);
 189
 190   need_emission = FALSE;
 191
 192   if (adjustment->value + adjustment->page_size < upper)
 193     {
 194       adjustment->value = upper - adjustment->page_size;
 195       need_emission = TRUE;
 196     }
 197   if (adjustment->value > lower)
 198     {
 199       adjustment->value = lower;
 200       need_emission = TRUE;
 201     }
 202
 203   if (need_emission)
 204     gtk_adjustment_value_changed (adjustment);
 205 }