vcs.maemo.org Git - hildon/blob - src/hildon-text-view.c

   1 /*
   2  * This file is a part of hildon
   3  *
   4  * Copyright (C) 2008 Nokia Corporation, all rights reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU Lesser Public License as published by
   8  * the Free Software Foundation; version 2 of the license.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU Lesser Public License for more details.
  14  *
  15  */
  16
  17 /**
  18  * SECTION:hildon-text-view
  19  * @short_description: Widget representing a text view in the Hildon framework.
  20  *
  21  * The #HildonTextView is a GTK widget which represents a text
  22  * view. It is derived from the #GtkTextView widget and provides
  23  * additional commodities specific to the Hildon framework.
  24  *
  25  * Besides all the features inherited from #GtkTextView, a
  26  * #HildonTextView can also have a placeholder text. This text will be
  27  * shown if the text view is empty and doesn't have the input focus,
  28  * but it's otherwise ignored. Thus, calls to
  29  * hildon_text_view_get_buffer() will never return the placeholder
  30  * text, not even when it's being displayed.
  31  *
  32  * Although #HildonTextView is derived from #GtkTextView,
  33  * gtk_text_view_get_buffer() and gtk_text_view_set_buffer() must
  34  * never be used to get/set the buffer in this
  35  * widget. hildon_text_view_get_buffer() and
  36  * hildon_text_view_set_buffer() must be used instead.
  37  *
  38  * <example>
  39  * <title>Creating a HildonTextView with a placeholder</title>
  40  * <programlisting>
  41  * GtkWidget *
  42  * create_text_view (void)
  43  * {
  44  *     GtkWidget *text_view;
  45  * <!-- -->
  46  *     text_view = hildon_text_view_new ();
  47  *     hildon_text_view_set_placeholder (HILDON_TEXT_VIEW (text_view),
  48  *                                       "Type some text here");
  49  * <!-- -->
  50  *     return text_view;
  51  * }
  52  * </programlisting>
  53  * </example>
  54  */
  55
  56 #include                                        "hildon-text-view.h"
  57
  58 G_DEFINE_TYPE                                   (HildonTextView, hildon_text_view, GTK_TYPE_TEXT_VIEW);
  59
  60 #define                                         HILDON_TEXT_VIEW_GET_PRIVATE(obj) \
  61                                                 (G_TYPE_INSTANCE_GET_PRIVATE ((obj), \
  62                                                 HILDON_TYPE_TEXT_VIEW, HildonTextViewPrivate));
  63
  64 typedef struct                                  _HildonTextViewPrivate HildonTextViewPrivate;
  65
  66 struct                                          _HildonTextViewPrivate
  67 {
  68     GtkTextBuffer *main_buffer;                   /* Used to show the "real" contents */
  69     GtkTextBuffer *placeholder_buffer;   /* Internal, used to display the placeholder */
  70     gulong changed_id;               /* ID of the main_buffer::changed signal handler */
  71 };
  72
  73 static const gchar *placeholder_widget_name     = "hildon-text-view-placeholder";
  74
  75 /* Function used to decide whether to show the placeholder or not */
  76 static void
  77 hildon_text_view_refresh_contents               (GtkWidget *text_view)
  78 {
  79     HildonTextViewPrivate *priv = HILDON_TEXT_VIEW_GET_PRIVATE (text_view);
  80     gint bufsize = gtk_text_buffer_get_char_count (priv->main_buffer);
  81
  82     if ((bufsize > 0) || GTK_WIDGET_HAS_FOCUS (text_view)) {
  83         /* Display the main buffer if it contains text or the widget is focused */
  84         gtk_widget_set_name (text_view, NULL);
  85         gtk_text_view_set_buffer (GTK_TEXT_VIEW (text_view), priv->main_buffer);
  86     } else {
  87         /* Otherwise, display the placeholder */
  88         gtk_widget_set_name (text_view, placeholder_widget_name);
  89         gtk_text_view_set_buffer (GTK_TEXT_VIEW (text_view), priv->placeholder_buffer);
  90     }
  91 }
  92
  93 /**
  94  * hildon_text_view_set_buffer:
  95  * @text_view: a #HildonTextView
  96  * @buffer: a #GtkTextBuffer
  97  *
  98  * Sets @buffer as the buffer being displayed by @text_view. The
  99  * previous buffer displayed by the text view is unreferenced, and a
 100  * reference is added to @buffer. If you owned a reference to @buffer
 101  * before passing it to this function, you must remove that reference
 102  * yourself
 103  *
 104  * Note that you must never use gtk_text_view_set_buffer() to set the
 105  * buffer of a #HildonTextView.
 106  */
 107 void
 108 hildon_text_view_set_buffer                     (HildonTextView *text_view,
 109                                                  GtkTextBuffer  *buffer)
 110 {
 111     HildonTextViewPrivate *priv;
 112
 113     g_return_if_fail (HILDON_IS_TEXT_VIEW (text_view));
 114     g_return_if_fail (GTK_IS_TEXT_BUFFER (buffer));
 115
 116     priv = HILDON_TEXT_VIEW_GET_PRIVATE (text_view);
 117
 118     /* If this is the same buffer, don't do anything */
 119     if (buffer == priv->main_buffer)
 120         return;
 121
 122     /* Disconnect the signal handler from the old buffer */
 123     g_signal_handler_disconnect (priv->main_buffer, priv->changed_id);
 124
 125     /* Replace the old buffer with the new one */
 126     g_object_unref (priv->main_buffer);
 127     priv->main_buffer = g_object_ref (buffer);
 128
 129     /* Attach a callback to the new text buffer */
 130     priv->changed_id =
 131         g_signal_connect_swapped (priv->main_buffer, "changed",
 132                                   G_CALLBACK (hildon_text_view_refresh_contents), text_view);
 133
 134     /* Refresh textview contents */
 135     hildon_text_view_refresh_contents (GTK_WIDGET (text_view));
 136 }
 137
 138 /**
 139  * hildon_text_view_get_buffer:
 140  * @text_view: a #HildonTextView
 141  *
 142  * Returns the text buffer in @text_view. The reference count is not
 143  * incremented; the caller of this function won't own a new reference.
 144  *
 145  * Note that you must never use gtk_text_view_get_buffer() to get the
 146  * buffer from a #HildonTextView.
 147  *
 148  * Also note that placeholder text (set using
 149  * hildon_text_view_set_placeholder()) is never contained in this
 150  * buffer.
 151  *
 152  * Returns: a #GtkTextBuffer
 153  */
 154 GtkTextBuffer *
 155 hildon_text_view_get_buffer                     (HildonTextView *text_view)
 156 {
 157     HildonTextViewPrivate *priv;
 158
 159     g_return_val_if_fail (HILDON_IS_TEXT_VIEW (text_view), NULL);
 160
 161     priv = HILDON_TEXT_VIEW_GET_PRIVATE (text_view);
 162
 163     /* Always return priv->main_buffer even if the placeholder is
 164      * being displayed */
 165     return priv->main_buffer;
 166 }
 167
 168 /**
 169  * hildon_text_view_set_placeholder:
 170  * @text_view: a #HildonTextView
 171  * @text: the new text
 172  *
 173  * Sets the placeholder text in @text_view to @text.
 174  */
 175 void
 176 hildon_text_view_set_placeholder                (HildonTextView *text_view,
 177                                                  const gchar    *text)
 178 {
 179     HildonTextViewPrivate *priv;
 180
 181     g_return_if_fail (HILDON_IS_TEXT_VIEW (text_view) && text != NULL);
 182
 183     priv = HILDON_TEXT_VIEW_GET_PRIVATE (text_view);
 184
 185     gtk_text_buffer_set_text (priv->placeholder_buffer, text, -1);
 186 }
 187
 188 /**
 189  * hildon_text_view_new:
 190  *
 191  * Creates a new text view.
 192  *
 193  * Returns: a new #HildonTextView
 194  */
 195 GtkWidget *
 196 hildon_text_view_new                            (void)
 197 {
 198     GtkWidget *entry = g_object_new (HILDON_TYPE_TEXT_VIEW, NULL);
 199
 200     return entry;
 201 }
 202
 203 static gboolean
 204 hildon_text_view_focus_in_event                 (GtkWidget     *widget,
 205                                                  GdkEventFocus *event)
 206 {
 207     hildon_text_view_refresh_contents (widget);
 208
 209     if (GTK_WIDGET_CLASS (hildon_text_view_parent_class)->focus_in_event) {
 210         return GTK_WIDGET_CLASS (hildon_text_view_parent_class)->focus_in_event (widget, event);
 211     } else {
 212         return FALSE;
 213     }
 214 }
 215
 216 static gboolean
 217 hildon_text_view_focus_out_event                (GtkWidget     *widget,
 218                                                  GdkEventFocus *event)
 219 {
 220     hildon_text_view_refresh_contents (widget);
 221
 222     if (GTK_WIDGET_CLASS (hildon_text_view_parent_class)->focus_out_event) {
 223         return GTK_WIDGET_CLASS (hildon_text_view_parent_class)->focus_out_event (widget, event);
 224     } else {
 225         return FALSE;
 226     }
 227 }
 228
 229 static void
 230 hildon_text_view_finalize                       (GObject *object)
 231 {
 232     HildonTextViewPrivate *priv = HILDON_TEXT_VIEW_GET_PRIVATE (object);
 233
 234     g_signal_handler_disconnect (priv->main_buffer, priv->changed_id);
 235     g_object_unref (priv->main_buffer);
 236     g_object_unref (priv->placeholder_buffer);
 237
 238     if (G_OBJECT_CLASS (hildon_text_view_parent_class)->finalize)
 239         G_OBJECT_CLASS (hildon_text_view_parent_class)->finalize (object);
 240 }
 241
 242 static void
 243 hildon_text_view_class_init                     (HildonTextViewClass *klass)
 244 {
 245     GObjectClass *gobject_class = (GObjectClass *)klass;
 246     GtkWidgetClass *widget_class = (GtkWidgetClass *)klass;
 247
 248     gobject_class->finalize = hildon_text_view_finalize;
 249     widget_class->focus_in_event = hildon_text_view_focus_in_event;
 250     widget_class->focus_out_event = hildon_text_view_focus_out_event;
 251
 252     g_type_class_add_private (klass, sizeof (HildonTextViewPrivate));
 253 }
 254
 255 static void
 256 hildon_text_view_init                           (HildonTextView *self)
 257 {
 258     HildonTextViewPrivate *priv = HILDON_TEXT_VIEW_GET_PRIVATE (self);
 259
 260     priv->main_buffer = gtk_text_buffer_new (NULL);
 261     priv->placeholder_buffer = gtk_text_buffer_new (NULL);
 262
 263     hildon_text_view_refresh_contents (GTK_WIDGET (self));
 264
 265     priv->changed_id =
 266         g_signal_connect_swapped (priv->main_buffer, "changed",
 267                                   G_CALLBACK (hildon_text_view_refresh_contents), self);
 268 }