gtk2/gtk/gtklinkbutton.c

/* GTK - The GIMP Toolkit
 * gtklinkbutton.c - an hyperlink-enabled button
 *
 * Copyright (C) 2006 Emmanuele Bassi <ebassi@gmail.com>
 * All rights reserved.
 *
 * Based on gnome-href code by:
 *      James Henstridge <james@daa.com.au>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * SECTION:gtklinkbutton
 * @Title: GtkLinkButton
 * @Short_description: Create buttons bound to a URL
 * @See_also: #GtkButton
 *
 * A GtkLinkButton is a #GtkButton with a hyperlink, similar to the one
 * used by web browsers, which triggers an action when clicked. It is useful
 * to show quick links to resources.
 *
 * A link button is created by calling either gtk_link_button_new() or
 * gtk_link_button_new_with_label(). If using the former, the URI you pass
 * to the constructor is used as a label for the widget.
 *
 * The URI bound to a GtkLinkButton can be set specifically using
 * gtk_link_button_set_uri(), and retrieved using gtk_link_button_get_uri().
 *
 * By default, GtkLinkButton calls gtk_show_uri() when the button is
 * clicked. This behaviour can be overridden by connecting to the
 * #GtkLinkButton::activate-link signal and returning %TRUE from the
 * signal handler.
 */

#include "config.h"

#include "gtklinkbutton.h"

#include <string.h>

#include "gtkclipboard.h"
#include "gtkdnd.h"
#include "gtklabel.h"
#include "gtkmain.h"
#include "gtkmarshalers.h"
#include "gtkmenu.h"
#include "gtkmenuitem.h"
#include "gtksizerequest.h"
#include "gtkshow.h"
#include "gtktooltip.h"
#include "gtkprivate.h"
#include "gtkintl.h"

#include "a11y/gtklinkbuttonaccessible.h"

struct _GtkLinkButtonPrivate
{
  gchar *uri;

  gboolean visited;

  GtkWidget *popup_menu;
};

enum
{
  PROP_0,
  PROP_URI,
  PROP_VISITED
};

enum
{
  ACTIVATE_LINK,

  LAST_SIGNAL
};

static void     gtk_link_button_finalize     (GObject          *object);
static void     gtk_link_button_get_property (GObject          *object,
					      guint             prop_id,
					      GValue           *value,
					      GParamSpec       *pspec);
static void     gtk_link_button_set_property (GObject          *object,
					      guint             prop_id,
					      const GValue     *value,
					      GParamSpec       *pspec);
static void     gtk_link_button_add          (GtkContainer     *container,
					      GtkWidget        *widget);
static gboolean gtk_link_button_button_press (GtkWidget        *widget,
					      GdkEventButton   *event);
static void     gtk_link_button_clicked      (GtkButton        *button);
static gboolean gtk_link_button_popup_menu   (GtkWidget        *widget);
static void     gtk_link_button_unrealize    (GtkWidget        *widget);
static gboolean gtk_link_button_enter_cb     (GtkWidget        *widget,
					      GdkEventCrossing *event,
					      gpointer          user_data);
static gboolean gtk_link_button_leave_cb     (GtkWidget        *widget,
					      GdkEventCrossing *event,
					      gpointer          user_data);
static void gtk_link_button_drag_data_get_cb (GtkWidget        *widget,
					      GdkDragContext   *context,
					      GtkSelectionData *selection,
					      guint             _info,
					      guint             _time,
					      gpointer          user_data);
static gboolean gtk_link_button_query_tooltip_cb (GtkWidget    *widget,
                                                  gint          x,
                                                  gint          y,
                                                  gboolean      keyboard_tip,
                                                  GtkTooltip   *tooltip,
                                                  gpointer      data);
static gboolean gtk_link_button_activate_link (GtkLinkButton *link_button);

static const GtkTargetEntry link_drop_types[] = {
  { "text/uri-list", 0, 0 },
  { "_NETSCAPE_URL", 0, 0 }
};

static guint link_signals[LAST_SIGNAL] = { 0, };

G_DEFINE_TYPE_WITH_PRIVATE (GtkLinkButton, gtk_link_button, GTK_TYPE_BUTTON)

static void
gtk_link_button_class_init (GtkLinkButtonClass *klass)
{
  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
  GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
  GtkContainerClass *container_class = GTK_CONTAINER_CLASS (klass);
  GtkButtonClass *button_class = GTK_BUTTON_CLASS (klass);
  
  gobject_class->set_property = gtk_link_button_set_property;
  gobject_class->get_property = gtk_link_button_get_property;
  gobject_class->finalize = gtk_link_button_finalize;
  
  widget_class->button_press_event = gtk_link_button_button_press;
  widget_class->popup_menu = gtk_link_button_popup_menu;
  widget_class->unrealize = gtk_link_button_unrealize;
  
  container_class->add = gtk_link_button_add;

  button_class->clicked = gtk_link_button_clicked;

  klass->activate_link = gtk_link_button_activate_link;

  /**
   * GtkLinkButton:uri:
   *
   * The URI bound to this button.
   *
   * Since: 2.10
   */
  g_object_class_install_property (gobject_class,
                                   PROP_URI,
                                   g_param_spec_string ("uri",
                                                        P_("URI"),
                                                        P_("The URI bound to this button"),
                                                        NULL,
                                                        GTK_PARAM_READWRITE));

  /**
   * GtkLinkButton:visited:
   *
   * The 'visited' state of this button. A visited link is drawn in a
   * different color.
   *
   * Since: 2.14
   */
  g_object_class_install_property (gobject_class,
                                   PROP_VISITED,
                                   g_param_spec_boolean ("visited",
                                                         P_("Visited"),
                                                         P_("Whether this link has been visited."),
                                                         FALSE,
                                                         GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY));

  /**
   * GtkLinkButton::activate-link:
   * @button: the #GtkLinkButton that emitted the signal
   *
   * The ::activate-link signal is emitted each time the #GtkLinkButton
   * has been clicked.
   *
   * The default handler will call gtk_show_uri() with the URI stored inside
   * the #GtkLinkButton:uri property.
   *
   * To override the default behavior, you can connect to the ::activate-link
   * signal and stop the propagation of the signal by returning %TRUE from
   * your handler.
   */
  link_signals[ACTIVATE_LINK] =
    g_signal_new (I_("activate-link"),
                  G_TYPE_FROM_CLASS (klass),
                  G_SIGNAL_RUN_LAST,
                  G_STRUCT_OFFSET (GtkLinkButtonClass, activate_link),
                  _gtk_boolean_handled_accumulator, NULL,
                  _gtk_marshal_BOOLEAN__VOID,
                  G_TYPE_BOOLEAN, 0);

  gtk_widget_class_set_accessible_type (widget_class, GTK_TYPE_LINK_BUTTON_ACCESSIBLE);
}

static void
gtk_link_button_init (GtkLinkButton *link_button)
{
  link_button->priv = gtk_link_button_get_instance_private (link_button);

  gtk_button_set_relief (GTK_BUTTON (link_button), GTK_RELIEF_NONE);
  gtk_widget_set_state_flags (GTK_WIDGET (link_button), GTK_STATE_FLAG_LINK, FALSE);

  g_signal_connect (link_button, "enter-notify-event",
  		    G_CALLBACK (gtk_link_button_enter_cb), NULL);
  g_signal_connect (link_button, "leave-notify-event",
  		    G_CALLBACK (gtk_link_button_leave_cb), NULL);
  g_signal_connect (link_button, "drag-data-get",
  		    G_CALLBACK (gtk_link_button_drag_data_get_cb), NULL);

  g_object_set (link_button, "has-tooltip", TRUE, NULL);
  g_signal_connect (link_button, "query-tooltip",
                    G_CALLBACK (gtk_link_button_query_tooltip_cb), NULL);

  /* enable drag source */
  gtk_drag_source_set (GTK_WIDGET (link_button),
  		       GDK_BUTTON1_MASK,
  		       link_drop_types, G_N_ELEMENTS (link_drop_types),
  		       GDK_ACTION_COPY);
}

static void
gtk_link_button_finalize (GObject *object)
{
  GtkLinkButton *link_button = GTK_LINK_BUTTON (object);
  
  g_free (link_button->priv->uri);
  
  G_OBJECT_CLASS (gtk_link_button_parent_class)->finalize (object);
}

static void
gtk_link_button_get_property (GObject    *object,
			      guint       prop_id,
			      GValue     *value,
			      GParamSpec *pspec)
{
  GtkLinkButton *link_button = GTK_LINK_BUTTON (object);
  
  switch (prop_id)
    {
    case PROP_URI:
      g_value_set_string (value, link_button->priv->uri);
      break;
    case PROP_VISITED:
      g_value_set_boolean (value, link_button->priv->visited);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
    }
}

static void
gtk_link_button_set_property (GObject      *object,
			      guint         prop_id,
			      const GValue *value,
			      GParamSpec   *pspec)
{
  GtkLinkButton *link_button = GTK_LINK_BUTTON (object);
  
  switch (prop_id)
    {
    case PROP_URI:
      gtk_link_button_set_uri (link_button, g_value_get_string (value));
      break;
    case PROP_VISITED:
      gtk_link_button_set_visited (link_button, g_value_get_boolean (value));
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
    }
}

static void
set_link_underline (GtkLinkButton *link_button)
{
  GtkWidget *label;
  
  label = gtk_bin_get_child (GTK_BIN (link_button));
  if (GTK_IS_LABEL (label))
    {
      PangoAttrList *attributes;
      PangoAttribute *uline;

      uline = pango_attr_underline_new (PANGO_UNDERLINE_SINGLE);
      uline->start_index = 0;
      uline->end_index = G_MAXUINT;
      attributes = pango_attr_list_new ();
      pango_attr_list_insert (attributes, uline); 
      gtk_label_set_attributes (GTK_LABEL (label), attributes);
      pango_attr_list_unref (attributes);
    }
}

static void
gtk_link_button_add (GtkContainer *container,
		     GtkWidget    *widget)
{
  GTK_CONTAINER_CLASS (gtk_link_button_parent_class)->add (container, widget);

  set_link_underline (GTK_LINK_BUTTON (container));
}

static void
set_hand_cursor (GtkWidget *widget,
		 gboolean   show_hand)
{
  GdkDisplay *display;
  GdkCursor *cursor;

  display = gtk_widget_get_display (widget);

  cursor = NULL;
  if (show_hand)
    cursor = gdk_cursor_new_for_display (display, GDK_HAND2);

  gdk_window_set_cursor (gtk_widget_get_window (widget), cursor);
  gdk_display_flush (display);

  if (cursor)
    g_object_unref (cursor);
}

static void
gtk_link_button_unrealize (GtkWidget *widget)
{
  set_hand_cursor (widget, FALSE);

  GTK_WIDGET_CLASS (gtk_link_button_parent_class)->unrealize (widget);
}

static void
popup_menu_detach (GtkWidget *attach_widget,
		   GtkMenu   *menu)
{
  GtkLinkButton *link_button = GTK_LINK_BUTTON (attach_widget);

  link_button->priv->popup_menu = NULL;
}

static void
popup_position_func (GtkMenu  *menu,
		     gint     *x,
		     gint     *y,
		     gboolean *push_in,
		     gpointer  user_data)
{
  GtkLinkButton *link_button = GTK_LINK_BUTTON (user_data);
  GtkLinkButtonPrivate *priv = link_button->priv;
  GtkAllocation allocation;
  GtkWidget *widget = GTK_WIDGET (link_button);
  GdkScreen *screen = gtk_widget_get_screen (widget);
  GtkRequisition req;
  gint monitor_num;
  GdkRectangle monitor;
  
  g_return_if_fail (gtk_widget_get_realized (widget));

  gdk_window_get_origin (gtk_widget_get_window (widget), x, y);

  gtk_widget_get_preferred_size (priv->popup_menu, &req, NULL);

  gtk_widget_get_allocation (widget, &allocation);
  *x += allocation.width / 2;
  *y += allocation.height;

  monitor_num = gdk_screen_get_monitor_at_point (screen, *x, *y);
  gtk_menu_set_monitor (menu, monitor_num);
  gdk_screen_get_monitor_workarea (screen, monitor_num, &monitor);

  *x = CLAMP (*x, monitor.x, monitor.x + MAX (0, monitor.width - req.width));
  *y = CLAMP (*y, monitor.y, monitor.y + MAX (0, monitor.height - req.height));

  *push_in = FALSE;
}

static void
copy_activate_cb (GtkWidget     *widget,
		  GtkLinkButton *link_button)
{
  GtkLinkButtonPrivate *priv = link_button->priv;
  
  gtk_clipboard_set_text (gtk_widget_get_clipboard (GTK_WIDGET (link_button),
			  			    GDK_SELECTION_CLIPBOARD),
		  	  priv->uri, -1);
}

static void
gtk_link_button_do_popup (GtkLinkButton  *link_button,
			  GdkEventButton *event)
{
  GtkLinkButtonPrivate *priv = link_button->priv;
  gint button;
  guint time;
  
  if (event)
    {
      button = event->button;
      time = event->time;
    }
  else
    {
      button = 0;
      time = gtk_get_current_event_time ();
    }

  if (gtk_widget_get_realized (GTK_WIDGET (link_button)))
    {
      GtkWidget *menu_item;

      if (priv->popup_menu)
	gtk_widget_destroy (priv->popup_menu);

      priv->popup_menu = gtk_menu_new ();
      gtk_style_context_add_class (gtk_widget_get_style_context (priv->popup_menu),
                                   GTK_STYLE_CLASS_CONTEXT_MENU);

      gtk_menu_attach_to_widget (GTK_MENU (priv->popup_menu),
		      		 GTK_WIDGET (link_button),
				 popup_menu_detach);

      menu_item = gtk_menu_item_new_with_mnemonic (_("Copy URL"));
      g_signal_connect (menu_item, "activate",
		        G_CALLBACK (copy_activate_cb), link_button);
      gtk_widget_show (menu_item);
      gtk_menu_shell_append (GTK_MENU_SHELL (priv->popup_menu), menu_item);

      if (button)
        gtk_menu_popup (GTK_MENU (priv->popup_menu), NULL, NULL,
		        NULL, NULL,
			button, time);
      else
        {
          gtk_menu_popup (GTK_MENU (priv->popup_menu), NULL, NULL,
			  popup_position_func, link_button,
			  button, time);
	  gtk_menu_shell_select_first (GTK_MENU_SHELL (priv->popup_menu), FALSE);
	}
    }
}

static gboolean
gtk_link_button_button_press (GtkWidget      *widget,
			      GdkEventButton *event)
{
  if (!gtk_widget_has_focus (widget))
    gtk_widget_grab_focus (widget);

  /* Don't popup the menu if there's no URI set,
   * otherwise the menu item will trigger a warning */
  if (gdk_event_triggers_context_menu ((GdkEvent *) event) &&
      GTK_LINK_BUTTON (widget)->priv->uri != NULL)
    {
      gtk_link_button_do_popup (GTK_LINK_BUTTON (widget), event);

      return TRUE;
    }

  if (GTK_WIDGET_CLASS (gtk_link_button_parent_class)->button_press_event)
    return GTK_WIDGET_CLASS (gtk_link_button_parent_class)->button_press_event (widget, event);
  
  return FALSE;
}

static gboolean
gtk_link_button_activate_link (GtkLinkButton *link_button)
{
  GdkScreen *screen;
  GError *error;

  if (gtk_widget_has_screen (GTK_WIDGET (link_button)))
    screen = gtk_widget_get_screen (GTK_WIDGET (link_button));
  else
    screen = NULL;

  error = NULL;
  gtk_show_uri (screen, link_button->priv->uri, GDK_CURRENT_TIME, &error);
  if (error)
    {
      g_warning ("Unable to show '%s': %s",
                 link_button->priv->uri,
                 error->message);
      g_error_free (error);

      return FALSE;
    }

  gtk_link_button_set_visited (link_button, TRUE);

  return TRUE;
}

static void
gtk_link_button_clicked (GtkButton *button)
{
  gboolean retval = FALSE;

  g_signal_emit (button, link_signals[ACTIVATE_LINK], 0, &retval);
}

static gboolean
gtk_link_button_popup_menu (GtkWidget *widget)
{
  gtk_link_button_do_popup (GTK_LINK_BUTTON (widget), NULL);

  return TRUE; 
}

static gboolean
gtk_link_button_enter_cb (GtkWidget        *widget,
			  GdkEventCrossing *crossing,
			  gpointer          user_data)
{
  set_hand_cursor (widget, TRUE);
  
  return FALSE;
}

static gboolean
gtk_link_button_leave_cb (GtkWidget        *widget,
			  GdkEventCrossing *crossing,
			  gpointer          user_data)
{
  set_hand_cursor (widget, FALSE);
  
  return FALSE;
}

static void
gtk_link_button_drag_data_get_cb (GtkWidget        *widget,
				  GdkDragContext   *context,
				  GtkSelectionData *selection,
				  guint             _info,
				  guint             _time,
				  gpointer          user_data)
{
  GtkLinkButton *link_button = GTK_LINK_BUTTON (widget);
  gchar *uri;
  
  uri = g_strdup_printf ("%s\r\n", link_button->priv->uri);
  gtk_selection_data_set (selection,
                          gtk_selection_data_get_target (selection),
  			  8,
  			  (guchar *) uri,
			  strlen (uri));
  
  g_free (uri);
}

/**
 * gtk_link_button_new:
 * @uri: a valid URI
 *
 * Creates a new #GtkLinkButton with the URI as its text.
 *
 * Returns: a new link button widget.
 *
 * Since: 2.10
 */
GtkWidget *
gtk_link_button_new (const gchar *uri)
{
  gchar *utf8_uri = NULL;
  GtkWidget *retval;
  
  g_return_val_if_fail (uri != NULL, NULL);
  
  if (g_utf8_validate (uri, -1, NULL))
    {
      utf8_uri = g_strdup (uri);
    }
  else
    {
      GError *conv_err = NULL;
    
      utf8_uri = g_locale_to_utf8 (uri, -1, NULL, NULL, &conv_err);
      if (conv_err)
        {
          g_warning ("Attempting to convert URI `%s' to UTF-8, but failed "
                     "with error: %s\n",
                     uri,
                     conv_err->message);
          g_error_free (conv_err);
        
          utf8_uri = g_strdup (_("Invalid URI"));
        }
    }
  
  retval = g_object_new (GTK_TYPE_LINK_BUTTON,
  			 "label", utf8_uri,
  			 "uri", uri,
  			 NULL);
  
  g_free (utf8_uri);
  
  return retval;
}

/**
 * gtk_link_button_new_with_label:
 * @uri: a valid URI
 * @label: (allow-none): the text of the button
 *
 * Creates a new #GtkLinkButton containing a label.
 *
 * Returns: (transfer none): a new link button widget.
 *
 * Since: 2.10
 */
GtkWidget *
gtk_link_button_new_with_label (const gchar *uri,
				const gchar *label)
{
  GtkWidget *retval;
  
  g_return_val_if_fail (uri != NULL, NULL);
  
  if (!label)
    return gtk_link_button_new (uri);

  retval = g_object_new (GTK_TYPE_LINK_BUTTON,
		         "label", label,
			 "uri", uri,
			 NULL);

  return retval;
}

static gboolean 
gtk_link_button_query_tooltip_cb (GtkWidget    *widget,
                                  gint          x,
                                  gint          y,
                                  gboolean      keyboard_tip,
                                  GtkTooltip   *tooltip,
                                  gpointer      data)
{
  GtkLinkButton *link_button = GTK_LINK_BUTTON (widget);
  const gchar *label, *uri;

  label = gtk_button_get_label (GTK_BUTTON (link_button));
  uri = link_button->priv->uri;

  if (!gtk_widget_get_tooltip_text (widget)
    && !gtk_widget_get_tooltip_markup (widget)
    && label && *label != '\0' && uri && strcmp (label, uri) != 0)
    {
      gtk_tooltip_set_text (tooltip, uri);
      return TRUE;
    }

  return FALSE;
}



/**
 * gtk_link_button_set_uri:
 * @link_button: a #GtkLinkButton
 * @uri: a valid URI
 *
 * Sets @uri as the URI where the #GtkLinkButton points. As a side-effect
 * this unsets the “visited” state of the button.
 *
 * Since: 2.10
 */
void
gtk_link_button_set_uri (GtkLinkButton *link_button,
			 const gchar   *uri)
{
  GtkLinkButtonPrivate *priv;

  g_return_if_fail (GTK_IS_LINK_BUTTON (link_button));
  g_return_if_fail (uri != NULL);

  priv = link_button->priv;

  g_free (priv->uri);
  priv->uri = g_strdup (uri);

  g_object_notify (G_OBJECT (link_button), "uri");

  gtk_link_button_set_visited (link_button, FALSE);
}

/**
 * gtk_link_button_get_uri:
 * @link_button: a #GtkLinkButton
 *
 * Retrieves the URI set using gtk_link_button_set_uri().
 *
 * Returns: a valid URI.  The returned string is owned by the link button
 *   and should not be modified or freed.
 *
 * Since: 2.10
 */
const gchar *
gtk_link_button_get_uri (GtkLinkButton *link_button)
{
  g_return_val_if_fail (GTK_IS_LINK_BUTTON (link_button), NULL);
  
  return link_button->priv->uri;
}

/**
 * gtk_link_button_set_visited:
 * @link_button: a #GtkLinkButton
 * @visited: the new “visited” state
 *
 * Sets the “visited” state of the URI where the #GtkLinkButton
 * points.  See gtk_link_button_get_visited() for more details.
 *
 * Since: 2.14
 */
void
gtk_link_button_set_visited (GtkLinkButton *link_button,
                             gboolean       visited)
{
  g_return_if_fail (GTK_IS_LINK_BUTTON (link_button));

  visited = visited != FALSE;

  if (link_button->priv->visited != visited)
    {
      link_button->priv->visited = visited;

      if (visited)
        {
          gtk_widget_unset_state_flags (GTK_WIDGET (link_button), GTK_STATE_FLAG_LINK);
          gtk_widget_set_state_flags (GTK_WIDGET (link_button), GTK_STATE_FLAG_VISITED, FALSE);
        }
      else
        {
          gtk_widget_unset_state_flags (GTK_WIDGET (link_button), GTK_STATE_FLAG_VISITED);
          gtk_widget_set_state_flags (GTK_WIDGET (link_button), GTK_STATE_FLAG_LINK, FALSE);
        }

      g_object_notify (G_OBJECT (link_button), "visited");
    }
}

/**
 * gtk_link_button_get_visited:
 * @link_button: a #GtkLinkButton
 *
 * Retrieves the “visited” state of the URI where the #GtkLinkButton
 * points. The button becomes visited when it is clicked. If the URI
 * is changed on the button, the “visited” state is unset again.
 *
 * The state may also be changed using gtk_link_button_set_visited().
 *
 * Returns: %TRUE if the link has been visited, %FALSE otherwise
 *
 * Since: 2.14
 */
gboolean
gtk_link_button_get_visited (GtkLinkButton *link_button)
{
  g_return_val_if_fail (GTK_IS_LINK_BUTTON (link_button), FALSE);
  
  return link_button->priv->visited;
}