gtk2/gtk/gtkdragdest.c

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/* GTK - The GIMP Toolkit
* Copyright (C) 1995-1999 Peter Mattis, Spencer Kimball and Josh MacDonald
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* Modified by the GTK+ Team and others 1997-2000. See the AUTHORS
* file for a list of people on the GTK+ Team. See the ChangeLog
* files for a list of changes. These files are distributed with
* GTK+ at ftp://ftp.gtk.org/pub/gtk/.
*/
#include "config.h"
#include "gtkdragdest.h"
#include "gtkdnd.h"
#include "gtkdndprivate.h"
#include "gtkintl.h"
static void
gtk_drag_dest_realized (GtkWidget *widget)
{
GtkWidget *toplevel = gtk_widget_get_toplevel (widget);
if (gtk_widget_is_toplevel (toplevel))
gdk_surface_register_dnd (gtk_widget_get_surface (toplevel));
}
static void
gtk_drag_dest_hierarchy_changed (GtkWidget *widget,
GtkWidget *previous_toplevel)
{
GtkWidget *toplevel = gtk_widget_get_toplevel (widget);
if (gtk_widget_is_toplevel (toplevel) && gtk_widget_get_realized (toplevel))
gdk_surface_register_dnd (gtk_widget_get_surface (toplevel));
}
static void
gtk_drag_dest_site_destroy (gpointer data)
{
GtkDragDestSite *site = data;
if (site->target_list)
gdk_content_formats_unref (site->target_list);
g_slice_free (GtkDragDestSite, site);
}
static void
gtk_drag_dest_set_internal (GtkWidget *widget,
GtkDragDestSite *site)
{
GtkDragDestSite *old_site;
old_site = g_object_get_data (G_OBJECT (widget), I_("gtk-drag-dest"));
if (old_site)
{
g_signal_handlers_disconnect_by_func (widget,
gtk_drag_dest_realized,
old_site);
g_signal_handlers_disconnect_by_func (widget,
gtk_drag_dest_hierarchy_changed,
old_site);
site->track_motion = old_site->track_motion;
}
if (gtk_widget_get_realized (widget))
gtk_drag_dest_realized (widget);
g_signal_connect (widget, "realize",
G_CALLBACK (gtk_drag_dest_realized), site);
g_signal_connect (widget, "hierarchy-changed",
G_CALLBACK (gtk_drag_dest_hierarchy_changed), site);
g_object_set_data_full (G_OBJECT (widget), I_("gtk-drag-dest"),
site, gtk_drag_dest_site_destroy);
}
/**
* gtk_drag_dest_set: (method)
* @widget: a #GtkWidget
* @flags: which types of default drag behavior to use
* @targets: (allow-none): the drop types that this @widget will
* accept, or %NULL. Later you can access the list with
* gtk_drag_dest_get_target_list() and gtk_drag_dest_find_target().
* @actions: a bitmask of possible actions for a drop onto this @widget.
*
* Sets a widget as a potential drop destination, and adds default behaviors.
*
* The default behaviors listed in @flags have an effect similar
* to installing default handlers for the widgets drag-and-drop signals
* (#GtkWidget::drag-motion, #GtkWidget::drag-drop, ...). They all exist
* for convenience. When passing #GTK_DEST_DEFAULT_ALL for instance it is
* sufficient to connect to the widgets #GtkWidget::drag-data-received
* signal to get primitive, but consistent drag-and-drop support.
*
* Things become more complicated when you try to preview the dragged data,
* as described in the documentation for #GtkWidget::drag-motion. The default
* behaviors described by @flags make some assumptions, that can conflict
* with your own signal handlers. For instance #GTK_DEST_DEFAULT_DROP causes
* invokations of gdk_drag_status() in the context of #GtkWidget::drag-motion,
* and invokations of gdk_drag_finish() in #GtkWidget::drag-data-received.
* Especially the later is dramatic, when your own #GtkWidget::drag-motion
* handler calls gtk_drag_get_data() to inspect the dragged data.
*
* Theres no way to set a default action here, you can use the
* #GtkWidget::drag-motion callback for that. Heres an example which selects
* the action to use depending on whether the control key is pressed or not:
* |[<!-- language="C" -->
* static void
* drag_motion (GtkWidget *widget,
* GdkDragContext *context,
* gint x,
* gint y,
* guint time)
* {
* GdkModifierType mask;
*
* gdk_surface_get_pointer (gtk_widget_get_surface (widget),
* NULL, NULL, &mask);
* if (mask & GDK_CONTROL_MASK)
* gdk_drag_status (context, GDK_ACTION_COPY, time);
* else
* gdk_drag_status (context, GDK_ACTION_MOVE, time);
* }
* ]|
*/
void
gtk_drag_dest_set (GtkWidget *widget,
GtkDestDefaults flags,
GdkContentFormats *targets,
GdkDragAction actions)
{
GtkDragDestSite *site;
g_return_if_fail (GTK_IS_WIDGET (widget));
site = g_slice_new0 (GtkDragDestSite);
site->flags = flags;
site->have_drag = FALSE;
if (targets)
site->target_list = gdk_content_formats_ref (targets);
else
site->target_list = NULL;
site->actions = actions;
site->track_motion = FALSE;
gtk_drag_dest_set_internal (widget, site);
}
/**
* gtk_drag_dest_unset: (method)
* @widget: a #GtkWidget
*
* Clears information about a drop destination set with
* gtk_drag_dest_set(). The widget will no longer receive
* notification of drags.
*/
void
gtk_drag_dest_unset (GtkWidget *widget)
{
GtkDragDestSite *old_site;
g_return_if_fail (GTK_IS_WIDGET (widget));
old_site = g_object_get_data (G_OBJECT (widget), I_("gtk-drag-dest"));
if (old_site)
{
g_signal_handlers_disconnect_by_func (widget,
gtk_drag_dest_realized,
old_site);
g_signal_handlers_disconnect_by_func (widget,
gtk_drag_dest_hierarchy_changed,
old_site);
}
g_object_set_data (G_OBJECT (widget), I_("gtk-drag-dest"), NULL);
}
/**
* gtk_drag_dest_get_target_list: (method)
* @widget: a #GtkWidget
*
* Returns the list of targets this widget can accept from
* drag-and-drop.
*
* Returns: (nullable) (transfer none): the #GdkContentFormats, or %NULL if none
*/
GdkContentFormats *
gtk_drag_dest_get_target_list (GtkWidget *widget)
{
GtkDragDestSite *site;
g_return_val_if_fail (GTK_IS_WIDGET (widget), NULL);
site = g_object_get_data (G_OBJECT (widget), I_("gtk-drag-dest"));
return site ? site->target_list : NULL;
}
/**
* gtk_drag_dest_set_target_list: (method)
* @widget: a #GtkWidget thats a drag destination
* @target_list: (allow-none): list of droppable targets, or %NULL for none
*
* Sets the target types that this widget can accept from drag-and-drop.
* The widget must first be made into a drag destination with
* gtk_drag_dest_set().
*/
void
gtk_drag_dest_set_target_list (GtkWidget *widget,
GdkContentFormats *target_list)
{
GtkDragDestSite *site;
g_return_if_fail (GTK_IS_WIDGET (widget));
site = g_object_get_data (G_OBJECT (widget), I_("gtk-drag-dest"));
if (!site)
{
g_warning ("Can't set a target list on a widget until you've called gtk_drag_dest_set() "
"to make the widget into a drag destination");
return;
}
if (target_list)
gdk_content_formats_ref (target_list);
if (site->target_list)
gdk_content_formats_unref (site->target_list);
site->target_list = target_list;
}
/**
* gtk_drag_dest_add_text_targets: (method)
* @widget: a #GtkWidget thats a drag destination
*
* Add the text targets supported by #GtkSelectionData to
* the target list of the drag destination. The targets
* are added with @info = 0. If you need another value,
* use gtk_target_list_add_text_targets() and
* gtk_drag_dest_set_target_list().
*/
void
gtk_drag_dest_add_text_targets (GtkWidget *widget)
{
GdkContentFormats *target_list;
target_list = gtk_drag_dest_get_target_list (widget);
if (target_list)
gdk_content_formats_ref (target_list);
else
target_list = gdk_content_formats_new (NULL, 0);
target_list = gtk_content_formats_add_text_targets (target_list);
gtk_drag_dest_set_target_list (widget, target_list);
gdk_content_formats_unref (target_list);
}
/**
* gtk_drag_dest_add_image_targets: (method)
* @widget: a #GtkWidget thats a drag destination
*
* Add the image targets supported by #GtkSelectionData to
* the target list of the drag destination. The targets
* are added with @info = 0. If you need another value,
* use gtk_target_list_add_image_targets() and
* gtk_drag_dest_set_target_list().
*/
void
gtk_drag_dest_add_image_targets (GtkWidget *widget)
{
GdkContentFormats *target_list;
target_list = gtk_drag_dest_get_target_list (widget);
if (target_list)
gdk_content_formats_ref (target_list);
else
target_list = gdk_content_formats_new (NULL, 0);
target_list = gtk_content_formats_add_image_targets (target_list, FALSE);
gtk_drag_dest_set_target_list (widget, target_list);
gdk_content_formats_unref (target_list);
}
/**
* gtk_drag_dest_add_uri_targets: (method)
* @widget: a #GtkWidget thats a drag destination
*
* Add the URI targets supported by #GtkSelectionData to
* the target list of the drag destination. The targets
* are added with @info = 0. If you need another value,
* use gtk_target_list_add_uri_targets() and
* gtk_drag_dest_set_target_list().
*/
void
gtk_drag_dest_add_uri_targets (GtkWidget *widget)
{
GdkContentFormats *target_list;
target_list = gtk_drag_dest_get_target_list (widget);
if (target_list)
gdk_content_formats_ref (target_list);
else
target_list = gdk_content_formats_new (NULL, 0);
target_list = gtk_content_formats_add_uri_targets (target_list);
gtk_drag_dest_set_target_list (widget, target_list);
gdk_content_formats_unref (target_list);
}
/**
* gtk_drag_dest_set_track_motion: (method)
* @widget: a #GtkWidget thats a drag destination
* @track_motion: whether to accept all targets
*
* Tells the widget to emit #GtkWidget::drag-motion and
* #GtkWidget::drag-leave events regardless of the targets and the
* %GTK_DEST_DEFAULT_MOTION flag.
*
* This may be used when a widget wants to do generic
* actions regardless of the targets that the source offers.
*/
void
gtk_drag_dest_set_track_motion (GtkWidget *widget,
gboolean track_motion)
{
GtkDragDestSite *site;
g_return_if_fail (GTK_IS_WIDGET (widget));
site = g_object_get_data (G_OBJECT (widget), I_("gtk-drag-dest"));
g_return_if_fail (site != NULL);
site->track_motion = track_motion != FALSE;
}
/**
* gtk_drag_dest_get_track_motion: (method)
* @widget: a #GtkWidget thats a drag destination
*
* Returns whether the widget has been configured to always
* emit #GtkWidget::drag-motion signals.
*
* Returns: %TRUE if the widget always emits
* #GtkWidget::drag-motion events
*/
gboolean
gtk_drag_dest_get_track_motion (GtkWidget *widget)
{
GtkDragDestSite *site;
g_return_val_if_fail (GTK_IS_WIDGET (widget), FALSE);
site = g_object_get_data (G_OBJECT (widget), I_("gtk-drag-dest"));
if (site)
return site->track_motion;
return FALSE;
}
/**
* gtk_drag_dest_find_target: (method)
* @widget: drag destination widget
* @drop: #GdkDrop
* @target_list: (allow-none): list of droppable targets, or %NULL to use
* gtk_drag_dest_get_target_list (@widget).
*
* Looks for a match between the supported targets of @drop and the
* @dest_target_list, returning the first matching target, otherwise
* returning %NULL. @dest_target_list should usually be the return
* value from gtk_drag_dest_get_target_list(), but some widgets may
* have different valid targets for different parts of the widget; in
* that case, they will have to implement a drag_motion handler that
* passes the correct target list to this function.
*
* Returns: (transfer none) (nullable): first target that the source offers
* and the dest can accept, or %NULL
*/
const char *
gtk_drag_dest_find_target (GtkWidget *widget,
GdkDrop *drop,
GdkContentFormats *target_list)
{
g_return_val_if_fail (GTK_IS_WIDGET (widget), NULL);
g_return_val_if_fail (GDK_IS_DROP (drop), NULL);
if (target_list == NULL)
target_list = gtk_drag_dest_get_target_list (widget);
if (target_list == NULL)
return NULL;
return gdk_content_formats_match_mime_type (target_list,
gdk_drop_get_formats (drop));
}