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Learning_GTK4_tree/gtk/gtkdroptarget.c

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2023-12-12 11:36:42 +01:00
/* 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 "gtkdroptarget.h"
#include "gtkdropprivate.h"
#include "gtkeventcontrollerprivate.h"
#include "gtkmarshalers.h"
#include "gdk/gdkmarshalers.h"
#include "gtknative.h"
#include "gtkprivate.h"
#include "gtktypebuiltins.h"
/**
* GtkDropTarget:
*
* `GtkDropTarget` is an event controller to receive Drag-and-Drop operations.
*
* The most basic way to use a `GtkDropTarget` to receive drops on a
* widget is to create it via [ctor@Gtk.DropTarget.new], passing in the
* `GType` of the data you want to receive and connect to the
* [signal@Gtk.DropTarget::drop] signal to receive the data:
*
* ```c
* static gboolean
* on_drop (GtkDropTarget *target,
* const GValue *value,
* double x,
* double y,
* gpointer data)
* {
* MyWidget *self = data;
*
* // Call the appropriate setter depending on the type of data
* // that we received
* if (G_VALUE_HOLDS (value, G_TYPE_FILE))
* my_widget_set_file (self, g_value_get_object (value));
* else if (G_VALUE_HOLDS (value, GDK_TYPE_PIXBUF))
* my_widget_set_pixbuf (self, g_value_get_object (value));
* else
* return FALSE;
*
* return TRUE;
* }
*
* static void
* my_widget_init (MyWidget *self)
* {
* GtkDropTarget *target =
* gtk_drop_target_new (G_TYPE_INVALID, GDK_ACTION_COPY);
*
* // This widget accepts two types of drop types: GFile objects
* // and GdkPixbuf objects
* gtk_drop_target_set_gtypes (target, (GTypes [2]) {
* G_TYPE_FILE,
* GDK_TYPE_PIXBUF,
* }, 2);
*
* g_signal_connect (target, "drop", G_CALLBACK (on_drop), self);
* gtk_widget_add_controller (GTK_WIDGET (self), GTK_EVENT_CONTROLLER (target));
* }
* ```
*
* `GtkDropTarget` supports more options, such as:
*
* * rejecting potential drops via the [signal@Gtk.DropTarget::accept] signal
* and the [method@Gtk.DropTarget.reject] function to let other drop
* targets handle the drop
* * tracking an ongoing drag operation before the drop via the
* [signal@Gtk.DropTarget::enter], [signal@Gtk.DropTarget::motion] and
* [signal@Gtk.DropTarget::leave] signals
* * configuring how to receive data by setting the
* [property@Gtk.DropTarget:preload] property and listening for its
* availability via the [property@Gtk.DropTarget:value] property
*
* However, `GtkDropTarget` is ultimately modeled in a synchronous way
* and only supports data transferred via `GType`. If you want full control
* over an ongoing drop, the [class@Gtk.DropTargetAsync] object gives you
* this ability.
*
* While a pointer is dragged over the drop target's widget and the drop
* has not been rejected, that widget will receive the
* %GTK_STATE_FLAG_DROP_ACTIVE state, which can be used to style the widget.
*
* If you are not interested in receiving the drop, but just want to update
* UI state during a Drag-and-Drop operation (e.g. switching tabs), you can
* use [class@Gtk.DropControllerMotion].
*/
struct _GtkDropTarget
{
GtkEventController parent_object;
GdkContentFormats *formats;
GdkDragAction actions;
guint preload : 1;
guint dropping : 1;
graphene_point_t coords;
GdkDrop *drop;
GCancellable *cancellable; /* NULL unless doing a read of value */
GValue value;
};
struct _GtkDropTargetClass
{
GtkEventControllerClass parent_class;
gboolean (* accept) (GtkDropTarget *self,
GdkDrop *drop);
GdkDragAction (* enter) (GtkDropTarget *self,
double x,
double y);
GdkDragAction (* motion) (GtkDropTarget *self,
double x,
double y);
void (* leave) (GtkDropTarget *self,
GdkDrop *drop);
gboolean (* drop) (GtkDropTarget *self,
const GValue *value,
double x,
double y);
};
enum {
PROP_0,
PROP_ACTIONS,
PROP_CURRENT_DROP,
PROP_DROP,
PROP_FORMATS,
PROP_PRELOAD,
PROP_VALUE,
NUM_PROPERTIES
};
static GParamSpec *properties[NUM_PROPERTIES];
enum {
ACCEPT,
ENTER,
MOTION,
LEAVE,
DROP,
NUM_SIGNALS
};
static guint signals[NUM_SIGNALS];
G_DEFINE_TYPE (GtkDropTarget, gtk_drop_target, GTK_TYPE_EVENT_CONTROLLER);
static void
gtk_drop_target_end_drop (GtkDropTarget *self)
{
if (self->drop == NULL)
return;
g_object_freeze_notify (G_OBJECT (self));
if (self->dropping)
{
gdk_drop_finish (self->drop, 0);
self->dropping = FALSE;
}
g_clear_object (&self->drop);
g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_DROP]);
g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_CURRENT_DROP]);
if (G_IS_VALUE (&self->value))
{
g_value_unset (&self->value);
g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_VALUE]);
}
if (self->cancellable)
{
g_cancellable_cancel (self->cancellable);
g_clear_object (&self->cancellable);
}
gtk_widget_unset_state_flags (gtk_event_controller_get_widget (GTK_EVENT_CONTROLLER (self)),
GTK_STATE_FLAG_DROP_ACTIVE);
g_object_thaw_notify (G_OBJECT (self));
}
static GdkDragAction
make_action_unique (GdkDragAction actions)
{
if (actions & GDK_ACTION_COPY)
return GDK_ACTION_COPY;
if (actions & GDK_ACTION_MOVE)
return GDK_ACTION_MOVE;
if (actions & GDK_ACTION_LINK)
return GDK_ACTION_LINK;
return 0;
}
static void
gtk_drop_target_do_drop (GtkDropTarget *self)
{
gboolean success;
g_assert (self->dropping);
g_assert (G_IS_VALUE (&self->value));
g_signal_emit (self, signals[DROP], 0, &self->value, self->coords.x, self->coords.y, &success);
if (success)
gdk_drop_finish (self->drop, make_action_unique (self->actions & gdk_drop_get_actions (self->drop)));
else
gdk_drop_finish (self->drop, 0);
self->dropping = FALSE;
gtk_drop_target_end_drop (self);
}
static void
gtk_drop_target_load_done (GObject *source,
GAsyncResult *res,
gpointer data)
{
GtkDropTarget *self = data;
const GValue *value;
GError *error = NULL;
value = gdk_drop_read_value_finish (GDK_DROP (source), res, &error);
if (value == NULL)
{
/* If this happens, data/self is invalid */
if (g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
{
g_clear_error (&error);
return;
}
g_clear_object (&self->cancellable);
/* XXX: Should this be a warning? */
g_warning ("Failed to receive drop data: %s", error->message);
g_clear_error (&error);
gtk_drop_target_end_drop (self);
return;
}
g_clear_object (&self->cancellable);
g_value_init (&self->value, G_VALUE_TYPE (value));
g_value_copy (value, &self->value);
g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_VALUE]);
if (self->dropping)
gtk_drop_target_do_drop (self);
}
static gboolean
gtk_drop_target_load_local (GtkDropTarget *self,
GType type)
{
GdkDrag *drag;
drag = gdk_drop_get_drag (self->drop);
if (drag == NULL)
return FALSE;
g_value_init (&self->value, type);
if (gdk_content_provider_get_value (gdk_drag_get_content (drag),
&self->value,
NULL))
{
g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_VALUE]);
return TRUE;
}
g_value_unset (&self->value);
g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_VALUE]);
return FALSE;
}
static gboolean
gtk_drop_target_load (GtkDropTarget *self)
{
GType type;
g_assert (self->drop);
if (G_IS_VALUE (&self->value))
return TRUE;
if (self->cancellable)
return FALSE;
type = gdk_content_formats_match_gtype (self->formats, gdk_drop_get_formats (self->drop));
if (gtk_drop_target_load_local (self, type))
return TRUE;
self->cancellable = g_cancellable_new ();
gdk_drop_read_value_async (self->drop,
type,
G_PRIORITY_DEFAULT,
self->cancellable,
gtk_drop_target_load_done,
g_object_ref (self));
return FALSE;
}
static void
gtk_drop_target_start_drop (GtkDropTarget *self,
GdkDrop *drop)
{
g_object_freeze_notify (G_OBJECT (self));
gtk_drop_target_end_drop (self);
self->drop = g_object_ref (drop);
g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_DROP]);
g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_CURRENT_DROP]);
if (self->preload)
gtk_drop_target_load (self);
gtk_widget_set_state_flags (gtk_event_controller_get_widget (GTK_EVENT_CONTROLLER (self)),
GTK_STATE_FLAG_DROP_ACTIVE,
FALSE);
g_object_thaw_notify (G_OBJECT (self));
}
static gboolean
gtk_drop_target_accept (GtkDropTarget *self,
GdkDrop *drop)
{
if ((gdk_drop_get_actions (drop) & gtk_drop_target_get_actions (self)) == 0)
return FALSE;
if (self->formats == NULL)
return TRUE;
return gdk_content_formats_match_gtype (self->formats, gdk_drop_get_formats (drop)) != G_TYPE_INVALID;
}
static GdkDragAction
gtk_drop_target_enter (GtkDropTarget *self,
double x,
double y)
{
return make_action_unique (self->actions & gdk_drop_get_actions (self->drop));
}
static GdkDragAction
gtk_drop_target_motion (GtkDropTarget *self,
double x,
double y)
{
return make_action_unique (self->actions & gdk_drop_get_actions (self->drop));
}
static gboolean
gtk_drop_target_drop (GtkDropTarget *self,
const GValue *value,
double x,
double y)
{
return FALSE;
}
static gboolean
gtk_drop_target_filter_event (GtkEventController *controller,
GdkEvent *event)
{
switch ((int) gdk_event_get_event_type (event))
{
case GDK_DRAG_ENTER:
case GDK_DRAG_LEAVE:
case GDK_DRAG_MOTION:
case GDK_DROP_START:
return GTK_EVENT_CONTROLLER_CLASS (gtk_drop_target_parent_class)->filter_event (controller, event);
default:;
}
return TRUE;
}
static gboolean
gtk_drop_target_handle_event (GtkEventController *controller,
GdkEvent *event,
double x,
double y)
{
GtkDropTarget *self = GTK_DROP_TARGET (controller);
/* All drops have been rejected. New drops only arrive via crossing
* events, so we can: */
if (self->drop == NULL)
return FALSE;
switch ((int) gdk_event_get_event_type (event))
{
case GDK_DRAG_MOTION:
{
GtkWidget *widget = gtk_event_controller_get_widget (controller);
GdkDragAction preferred;
/* sanity check */
g_return_val_if_fail (self->drop == gdk_dnd_event_get_drop (event), FALSE);
graphene_point_init (&self->coords, x, y);
g_signal_emit (self, signals[MOTION], 0, x, y, &preferred);
if (!gdk_drag_action_is_unique (preferred))
{
g_critical ("Handler for GtkDropTarget::motion on %s %p did not return a unique preferred action",
G_OBJECT_TYPE_NAME (widget), widget);
preferred = make_action_unique (preferred);
}
if (preferred &&
gtk_drop_status (self->drop, self->actions, preferred))
{
gtk_widget_set_state_flags (widget, GTK_STATE_FLAG_DROP_ACTIVE, FALSE);
}
else
{
gtk_widget_unset_state_flags (widget, GTK_STATE_FLAG_DROP_ACTIVE);
}
}
return FALSE;
case GDK_DROP_START:
{
/* sanity check */
g_return_val_if_fail (self->drop == gdk_dnd_event_get_drop (event), FALSE);
graphene_point_init (&self->coords, x, y);
self->dropping = TRUE;
if (gtk_drop_target_load (self))
gtk_drop_target_do_drop (self);
return TRUE;
}
default:
return FALSE;
}
}
static void
gtk_drop_target_handle_crossing (GtkEventController *controller,
const GtkCrossingData *crossing,
double x,
double y)
{
GtkDropTarget *self = GTK_DROP_TARGET (controller);
GtkWidget *widget = gtk_event_controller_get_widget (controller);
if (crossing->type != GTK_CROSSING_DROP)
return;
/* sanity check */
g_warn_if_fail (self->drop == NULL || self->drop == crossing->drop);
if (crossing->direction == GTK_CROSSING_IN)
{
gboolean accept = FALSE;
GdkDragAction preferred;
if (self->drop != NULL)
return;
/* if we were a target already but self->drop == NULL, the drop
* was rejected already */
if (crossing->old_descendent != NULL ||
crossing->old_target == widget)
return;
g_signal_emit (self, signals[ACCEPT], 0, crossing->drop, &accept);
if (!accept)
return;
graphene_point_init (&self->coords, x, y);
gtk_drop_target_start_drop (self, crossing->drop);
/* start_drop ends w/ thaw_notify, where handler may reject, so recheck */
if (self->drop != NULL)
g_signal_emit (self, signals[ENTER], 0, x, y, &preferred);
else
preferred = 0;
if (!gdk_drag_action_is_unique (preferred))
{
g_critical ("Handler for GtkDropTarget::enter on %s %p did not return a unique preferred action",
G_OBJECT_TYPE_NAME (widget), widget);
preferred = make_action_unique (preferred);
}
if (preferred &&
gtk_drop_status (self->drop, self->actions, preferred))
{
gtk_widget_set_state_flags (widget, GTK_STATE_FLAG_DROP_ACTIVE, FALSE);
}
else
{
gtk_widget_unset_state_flags (widget, GTK_STATE_FLAG_DROP_ACTIVE);
}
}
else
{
if (crossing->new_descendent != NULL ||
crossing->new_target == widget)
return;
g_signal_emit (self, signals[LEAVE], 0);
if (!self->dropping)
gtk_drop_target_end_drop (self);
gtk_widget_unset_state_flags (widget, GTK_STATE_FLAG_DROP_ACTIVE);
}
}
static void
gtk_drop_target_finalize (GObject *object)
{
GtkDropTarget *self = GTK_DROP_TARGET (object);
g_clear_pointer (&self->formats, gdk_content_formats_unref);
G_OBJECT_CLASS (gtk_drop_target_parent_class)->finalize (object);
}
static void
gtk_drop_target_set_property (GObject *object,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
GtkDropTarget *self = GTK_DROP_TARGET (object);
switch (prop_id)
{
case PROP_ACTIONS:
gtk_drop_target_set_actions (self, g_value_get_flags (value));
break;
case PROP_FORMATS:
self->formats = g_value_dup_boxed (value);
if (self->formats == NULL)
self->formats = gdk_content_formats_new (NULL, 0);
break;
case PROP_PRELOAD:
gtk_drop_target_set_preload (self, g_value_get_boolean (value));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
}
}
static void
gtk_drop_target_get_property (GObject *object,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
GtkDropTarget *self = GTK_DROP_TARGET (object);
switch (prop_id)
{
case PROP_ACTIONS:
g_value_set_flags (value, self->actions);
break;
case PROP_DROP:
case PROP_CURRENT_DROP:
g_value_set_object (value, self->drop);
break;
case PROP_FORMATS:
g_value_set_boxed (value, self->formats);
break;
case PROP_PRELOAD:
g_value_set_boolean (value, self->preload);
break;
case PROP_VALUE:
if (G_IS_VALUE (&self->value))
g_value_set_boxed (value, &self->value);
else
g_value_set_boxed (value, NULL);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
}
}
static void
gtk_drop_target_class_init (GtkDropTargetClass *class)
{
GObjectClass *object_class = G_OBJECT_CLASS (class);
GtkEventControllerClass *controller_class = GTK_EVENT_CONTROLLER_CLASS (class);
object_class->finalize = gtk_drop_target_finalize;
object_class->set_property = gtk_drop_target_set_property;
object_class->get_property = gtk_drop_target_get_property;
controller_class->handle_event = gtk_drop_target_handle_event;
controller_class->filter_event = gtk_drop_target_filter_event;
controller_class->handle_crossing = gtk_drop_target_handle_crossing;
class->accept = gtk_drop_target_accept;
class->enter = gtk_drop_target_enter;
class->motion = gtk_drop_target_motion;
class->drop = gtk_drop_target_drop;
/**
* GtkDropTarget:actions: (attributes org.gtk.Property.get=gtk_drop_target_get_actions org.gtk.Property.set=gtk_drop_target_set_actions)
*
* The `GdkDragActions` that this drop target supports.
*/
properties[PROP_ACTIONS] =
g_param_spec_flags ("actions", NULL, NULL,
GDK_TYPE_DRAG_ACTION, 0,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS | G_PARAM_EXPLICIT_NOTIFY);
/**
* GtkDropTarget:drop: (attributes org.gtk.Property.get=gtk_drop_target_get_drop) (skip)
*
* The `GdkDrop` that is currently being performed.
*
* Deprecated: 4.4: Use [property@Gtk.DropTarget:current-drop] instead
*/
properties[PROP_DROP] =
g_param_spec_object ("drop", NULL, NULL,
GDK_TYPE_DROP,
GTK_PARAM_READABLE | G_PARAM_DEPRECATED);
/**
* GtkDropTarget:current-drop: (attributes org.gtk.Property.get=gtk_drop_target_get_current_drop)
*
* The `GdkDrop` that is currently being performed.
*
* Since: 4.4
*/
properties[PROP_CURRENT_DROP] =
g_param_spec_object ("current-drop", NULL, NULL,
GDK_TYPE_DROP,
GTK_PARAM_READABLE);
/**
* GtkDropTarget:formats: (attributes org.gtk.Property.get=gtk_drop_target_get_formats)
*
* The `GdkContentFormats` that determine the supported data formats.
*/
properties[PROP_FORMATS] =
g_param_spec_boxed ("formats", NULL, NULL,
GDK_TYPE_CONTENT_FORMATS,
GTK_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY);
/**
* GtkDropTarget:preload: (attributes org.gtk.Property.get=gtk_drop_target_get_preload org.gtk.Property.set=gtk_drop_target_set_preload)
*
* Whether the drop data should be preloaded when the pointer is only
* hovering over the widget but has not been released.
*
* Setting this property allows finer grained reaction to an ongoing
* drop at the cost of loading more data.
*
* The default value for this property is %FALSE to avoid downloading
* huge amounts of data by accident.
*
* For example, if somebody drags a full document of gigabytes of text
* from a text editor across a widget with a preloading drop target,
* this data will be downloaded, even if the data is ultimately dropped
* elsewhere.
*
* For a lot of data formats, the amount of data is very small (like
* %GDK_TYPE_RGBA), so enabling this property does not hurt at all.
* And for local-only Drag-and-Drop operations, no data transfer is done,
* so enabling it there is free.
*/
properties[PROP_PRELOAD] =
g_param_spec_boolean ("preload", NULL, NULL,
FALSE,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS | G_PARAM_EXPLICIT_NOTIFY);
/**
* GtkDropTarget:value: (attributes org.gtk.Property.get=gtk_drop_target_get_value)
*
* The value for this drop operation.
*
* This is %NULL if the data has not been loaded yet or no drop
* operation is going on.
*
* Data may be available before the [signal@Gtk.DropTarget::drop]
* signal gets emitted - for example when the [property@Gtk.DropTarget:preload]
* property is set. You can use the ::notify signal to be notified
* of available data.
*/
properties[PROP_VALUE] =
g_param_spec_boxed ("value", NULL, NULL,
G_TYPE_VALUE,
GTK_PARAM_READABLE);
g_object_class_install_properties (object_class, NUM_PROPERTIES, properties);
/**
* GtkDropTarget::accept:
* @self: the `GtkDropTarget`
* @drop: the `GdkDrop`
*
* Emitted on the drop site when a drop operation is about to begin.
*
* If the drop is not accepted, %FALSE will be returned and the drop target
* will ignore the drop. If %TRUE is returned, the drop is accepted for now
* but may be rejected later via a call to [method@Gtk.DropTarget.reject]
* or ultimately by returning %FALSE from a [signal@Gtk.DropTarget::drop]
* handler.
*
* The default handler for this signal decides whether to accept the drop
* based on the formats provided by the @drop.
*
* If the decision whether the drop will be accepted or rejected depends
* on the data, this function should return %TRUE, the
* [property@Gtk.DropTarget:preload] property should be set and the value
* should be inspected via the ::notify:value signal, calling
* [method@Gtk.DropTarget.reject] if required.
*
* Returns: %TRUE if @drop is accepted
*/
signals[ACCEPT] =
g_signal_new (I_("accept"),
G_TYPE_FROM_CLASS (class),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GtkDropTargetClass, accept),
g_signal_accumulator_first_wins, NULL,
_gdk_marshal_BOOLEAN__OBJECT,
G_TYPE_BOOLEAN, 1,
GDK_TYPE_DROP);
g_signal_set_va_marshaller (signals[ACCEPT],
GTK_TYPE_DROP_TARGET,
_gdk_marshal_BOOLEAN__OBJECTv);
/**
* GtkDropTarget::enter:
* @self: the `GtkDropTarget`
* @x: the x coordinate of the current pointer position
* @y: the y coordinate of the current pointer position
*
* Emitted on the drop site when the pointer enters the widget.
*
* It can be used to set up custom highlighting.
*
* Returns: Preferred action for this drag operation or 0 if
* dropping is not supported at the current @x,@y location.
*/
signals[ENTER] =
g_signal_new (I_("enter"),
G_TYPE_FROM_CLASS (class),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GtkDropTargetClass, enter),
g_signal_accumulator_first_wins, NULL,
_gtk_marshal_FLAGS__DOUBLE_DOUBLE,
GDK_TYPE_DRAG_ACTION, 2,
G_TYPE_DOUBLE, G_TYPE_DOUBLE);
g_signal_set_va_marshaller (signals[ENTER],
GTK_TYPE_DROP_TARGET,
_gtk_marshal_FLAGS__DOUBLE_DOUBLEv);
/**
* GtkDropTarget::motion:
* @self: the `GtkDropTarget`
* @x: the x coordinate of the current pointer position
* @y: the y coordinate of the current pointer position
*
* Emitted while the pointer is moving over the drop target.
*
* Returns: Preferred action for this drag operation or 0 if
* dropping is not supported at the current @x,@y location.
*/
signals[MOTION] =
g_signal_new (I_("motion"),
G_TYPE_FROM_CLASS (class),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GtkDropTargetClass, motion),
g_signal_accumulator_first_wins, NULL,
_gtk_marshal_FLAGS__DOUBLE_DOUBLE,
GDK_TYPE_DRAG_ACTION, 2,
G_TYPE_DOUBLE, G_TYPE_DOUBLE);
g_signal_set_va_marshaller (signals[MOTION],
GTK_TYPE_DROP_TARGET,
_gtk_marshal_FLAGS__DOUBLE_DOUBLEv);
/**
* GtkDropTarget::leave:
* @self: the `GtkDropTarget`
*
* Emitted on the drop site when the pointer leaves the widget.
*
* Its main purpose it to undo things done in
* [signal@Gtk.DropTarget::enter].
*/
signals[LEAVE] =
g_signal_new (I_("leave"),
G_TYPE_FROM_CLASS (class),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GtkDropTargetClass, leave),
NULL, NULL,
NULL,
G_TYPE_NONE, 0);
/**
* GtkDropTarget::drop:
* @self: the `GtkDropTarget`
* @value: the `GValue` being dropped
* @x: the x coordinate of the current pointer position
* @y: the y coordinate of the current pointer position
*
* Emitted on the drop site when the user drops the data onto the widget.
*
* The signal handler must determine whether the pointer position is in
* a drop zone or not. If it is not in a drop zone, it returns %FALSE
* and no further processing is necessary.
*
* Otherwise, the handler returns %TRUE. In this case, this handler will
* accept the drop. The handler is responsible for using the given @value
* and performing the drop operation.
*
* Returns: whether the drop was accepted at the given pointer position
*/
signals[DROP] =
g_signal_new (I_("drop"),
G_TYPE_FROM_CLASS (class),
G_SIGNAL_RUN_LAST,
0,
g_signal_accumulator_first_wins, NULL,
_gtk_marshal_BOOLEAN__BOXED_DOUBLE_DOUBLE,
G_TYPE_BOOLEAN, 3,
G_TYPE_VALUE, G_TYPE_DOUBLE, G_TYPE_DOUBLE);
g_signal_set_va_marshaller (signals[DROP],
GTK_TYPE_DROP_TARGET,
_gtk_marshal_BOOLEAN__BOXED_DOUBLE_DOUBLEv);
}
static void
gtk_drop_target_init (GtkDropTarget *self)
{
}
/**
* gtk_drop_target_new:
* @type: The supported type or %G_TYPE_INVALID
* @actions: the supported actions
*
* Creates a new `GtkDropTarget` object.
*
* If the drop target should support more than 1 type, pass
* %G_TYPE_INVALID for @type and then call
* [method@Gtk.DropTarget.set_gtypes].
*
* Returns: the new `GtkDropTarget`
*/
GtkDropTarget *
gtk_drop_target_new (GType type,
GdkDragAction actions)
{
GtkDropTarget *result;
GdkContentFormats *formats;
if (type != G_TYPE_INVALID)
formats = gdk_content_formats_new_for_gtype (type);
else
formats = NULL;
result = g_object_new (GTK_TYPE_DROP_TARGET,
"formats", formats,
"actions", actions,
NULL);
g_clear_pointer (&formats, gdk_content_formats_unref);
return result;
}
/**
* gtk_drop_target_get_formats: (attributes org.gtk.Method.get_property=formats)
* @self: a `GtkDropTarget`
*
* Gets the data formats that this drop target accepts.
*
* If the result is %NULL, all formats are expected to be supported.
*
* Returns: (nullable) (transfer none): the supported data formats
*/
GdkContentFormats *
gtk_drop_target_get_formats (GtkDropTarget *self)
{
g_return_val_if_fail (GTK_IS_DROP_TARGET (self), NULL);
return self->formats;
}
/**
* gtk_drop_target_set_gtypes:
* @self: a `GtkDropTarget`
* @types: (nullable) (transfer none) (array length=n_types): all supported `GType`s
* that can be dropped on the target
* @n_types: number of @types
*
* Sets the supported `GTypes` for this drop target.
*/
void
gtk_drop_target_set_gtypes (GtkDropTarget *self,
GType *types,
gsize n_types)
{
GdkContentFormatsBuilder *builder;
gsize i;
g_return_if_fail (GTK_IS_DROP_TARGET (self));
g_return_if_fail (n_types == 0 || types != NULL);
gdk_content_formats_unref (self->formats);
builder = gdk_content_formats_builder_new ();
for (i = 0; i < n_types; i++)
gdk_content_formats_builder_add_gtype (builder, types[i]);
self->formats = gdk_content_formats_builder_free_to_formats (builder);
g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_FORMATS]);
}
/**
* gtk_drop_target_get_gtypes:
* @self: a `GtkDropTarget`
* @n_types: (out) (optional): the number of `GType`s contained in the
* return value
*
* Gets the list of supported `GType`s that can be dropped on the target.
*
* If no types have been set, `NULL` will be returned.
*
* Returns: (transfer none) (nullable) (array length=n_types):
* the `G_TYPE_INVALID`-terminated array of types included in
* formats
*/
const GType *
gtk_drop_target_get_gtypes (GtkDropTarget *self,
gsize *n_types)
{
g_return_val_if_fail (GTK_IS_DROP_TARGET (self), NULL);
return gdk_content_formats_get_gtypes (self->formats, n_types);
}
/**
* gtk_drop_target_set_actions: (attributes org.gtk.Method.set_property=actions)
* @self: a `GtkDropTarget`
* @actions: the supported actions
*
* Sets the actions that this drop target supports.
*/
void
gtk_drop_target_set_actions (GtkDropTarget *self,
GdkDragAction actions)
{
g_return_if_fail (GTK_IS_DROP_TARGET (self));
if (self->actions == actions)
return;
self->actions = actions;
g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_ACTIONS]);
}
/**
* gtk_drop_target_get_actions: (attributes org.gtk.Method.get_property=actions)
* @self: a `GtkDropTarget`
*
* Gets the actions that this drop target supports.
*
* Returns: the actions that this drop target supports
*/
GdkDragAction
gtk_drop_target_get_actions (GtkDropTarget *self)
{
g_return_val_if_fail (GTK_IS_DROP_TARGET (self), 0);
return self->actions;
}
/**
* gtk_drop_target_set_preload: (attributes org.gtk.Method.set_property=preload)
* @self: a `GtkDropTarget`
* @preload: %TRUE to preload drop data
*
* Sets whether data should be preloaded on hover.
*/
void
gtk_drop_target_set_preload (GtkDropTarget *self,
gboolean preload)
{
g_return_if_fail (GTK_IS_DROP_TARGET (self));
if (self->preload == preload)
return;
self->preload = preload;
g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_PRELOAD]);
}
/**
* gtk_drop_target_get_preload: (attributes org.gtk.Method.get_property=preload)
* @self: a `GtkDropTarget`
*
* Gets whether data should be preloaded on hover.
*
* Returns: %TRUE if drop data should be preloaded
*/
gboolean
gtk_drop_target_get_preload (GtkDropTarget *self)
{
g_return_val_if_fail (GTK_IS_DROP_TARGET (self), 0);
return self->preload;
}
/**
* gtk_drop_target_get_drop: (attributes org.gtk.Method.get_property=drop)
* @self: a `GtkDropTarget`
*
* Gets the currently handled drop operation.
*
* If no drop operation is going on, %NULL is returned.
*
* Returns: (nullable) (transfer none): The current drop
*
* Deprecated: 4.4: Use [method@Gtk.DropTarget.get_current_drop] instead
*/
GdkDrop *
gtk_drop_target_get_drop (GtkDropTarget *self)
{
g_return_val_if_fail (GTK_IS_DROP_TARGET (self), NULL);
return self->drop;
}
/**
* gtk_drop_target_get_current_drop: (attributes org.gtk.Method.get_property=current-drop)
* @self: a `GtkDropTarget`
*
* Gets the currently handled drop operation.
*
* If no drop operation is going on, %NULL is returned.
*
* Returns: (nullable) (transfer none): The current drop
*
* Since: 4.4
*/
GdkDrop *
gtk_drop_target_get_current_drop (GtkDropTarget *self)
{
g_return_val_if_fail (GTK_IS_DROP_TARGET (self), NULL);
return self->drop;
}
/**
* gtk_drop_target_get_value: (attributes org.gtk.Method.get_property=value)
* @self: a `GtkDropTarget`
*
* Gets the current drop data, as a `GValue`.
*
* Returns: (nullable) (transfer none): The current drop data
*/
const GValue *
gtk_drop_target_get_value (GtkDropTarget *self)
{
g_return_val_if_fail (GTK_IS_DROP_TARGET (self), NULL);
if (!G_IS_VALUE (&self->value))
return NULL;
return &self->value;
}
/**
* gtk_drop_target_reject:
* @self: a `GtkDropTarget`
*
* Rejects the ongoing drop operation.
*
* If no drop operation is ongoing, i.e when [property@Gtk.DropTarget:current-drop]
* is %NULL, this function does nothing.
*
* This function should be used when delaying the decision
* on whether to accept a drag or not until after reading
* the data.
*/
void
gtk_drop_target_reject (GtkDropTarget *self)
{
g_return_if_fail (GTK_IS_DROP_TARGET (self));
if (self->drop == NULL)
return;
gtk_drop_target_end_drop (self);
}