/* 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 . */ /* * 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 "gtkdragsource.h" #include "gtkgesturedrag.h" #include "gtkgesturesingleprivate.h" #include "gtkimagedefinitionprivate.h" #include "gtknative.h" #include "gtkwidgetprivate.h" #include "gtkintl.h" #include "gtkimageprivate.h" #include "gtkdragicon.h" #include "gtkprivate.h" #include "gtkmarshalers.h" #include "gtkicontheme.h" #include "gtkpicture.h" #include "gtksettingsprivate.h" #include "gtkgesturesingle.h" /** * SECTION:gtkdragsource * @Short_description: Event controller to initiate DND operations * @Title: GtkDragSource * * GtkDragSource is an auxiliary object that is used to initiate * Drag-And-Drop operations. It can be set up with the necessary * ingredients for a DND operation ahead of time. This includes * the source for the data that is being transferred, in the form * of a #GdkContentProvider, the desired action, and the icon to * use during the drag operation. After setting it up, the drag * source must be added to a widget as an event controller, using * gtk_widget_add_controller(). * * |[ * static void * my_widget_init (MyWidget *self) * { * GtkDragSource *drag_source = gtk_drag_source_new (); * * g_signal_connect (drag_source, "prepare", G_CALLBACK (on_drag_prepare), self); * g_signal_connect (drag_source, "drag-begin", G_CALLBACK (on_drag_begin), self); * * gtk_widget_add_controller (GTK_WIDGET (self), GTK_EVENT_CONTROLLER (drag_source)); * } * ]| * * Setting up the content provider and icon ahead of time only * makes sense when the data does not change. More commonly, you * will want to set them up just in time. To do so, #GtkDragSource * has #GtkDragSource::prepare and #GtkDragSource::drag-begin signals. * * The ::prepare signal is emitted before a drag is started, and * can be used to set the content provider and actions that the * drag should be started with. * * |[ * static GdkContentProvider * * on_drag_prepare (GtkDragSource *source, * double x, * double y, * MyWidget *self) * { * // This widget supports two types of content: GFile objects * // and GdkPixbuf objects; GTK will handle the serialization * // of these types automatically * GFile *file = my_widget_get_file (self); * GdkPixbuf *pixbuf = my_widget_get_pixbuf (self); * * return gdk_content_provider_new_union ((GdkContentProvider *[2]) { * gdk_content_provider_new_typed (G_TYPE_FILE, file), * gdk_content_provider_new_typed (GDK_TYPE_PIXBUF, pixbuf), * }, 2); * } * ]| * * The ::drag-begin signal is emitted after the #GdkDrag object has * been created, and can be used to set up the drag icon. * * |[ * static void * on_drag_begin (GtkDragSource *source, * GtkDrag *drag, * MyWidget *self) * { * // Set the widget as the drag icon * GdkPaintable *paintable = gtk_widget_paintable_new (GTK_WIDGET (self)); * gtk_drag_source_set_icon (source, paintable, 0, 0); * g_object_unref (paintable); * } * ]| * * During the DND operation, GtkDragSource emits signals that * can be used to obtain updates about the status of the operation, * but it is not normally necessary to connect to any signals, * except for one case: when the supported actions include * %GDK_ACTION_MOVE, you need to listen for the * #GtkDragSource::drag-end signal and delete the * data after it has been transferred. */ struct _GtkDragSource { GtkGestureSingle parent_instance; GdkContentProvider *content; GdkDragAction actions; GdkPaintable *paintable; int hot_x; int hot_y; double start_x; double start_y; GdkDrag *drag; }; struct _GtkDragSourceClass { GtkGestureSingleClass parent_class; GdkContentProvider *(* prepare) (GtkDragSource *source, double x, double y); }; enum { PROP_CONTENT = 1, PROP_ACTIONS, NUM_PROPERTIES }; static GParamSpec *properties[NUM_PROPERTIES]; enum { PREPARE, DRAG_BEGIN, DRAG_END, DRAG_CANCEL, NUM_SIGNALS }; static guint signals[NUM_SIGNALS]; static void gtk_drag_source_dnd_finished_cb (GdkDrag *drag, GtkDragSource *source); static void gtk_drag_source_cancel_cb (GdkDrag *drag, GdkDragCancelReason reason, GtkDragSource *source); static GdkContentProvider *gtk_drag_source_prepare (GtkDragSource *source, double x, double y); static void gtk_drag_source_drag_begin (GtkDragSource *source); G_DEFINE_TYPE (GtkDragSource, gtk_drag_source, GTK_TYPE_GESTURE_SINGLE); static void gtk_drag_source_init (GtkDragSource *source) { source->actions = GDK_ACTION_COPY; } static void gtk_drag_source_finalize (GObject *object) { GtkDragSource *source = GTK_DRAG_SOURCE (object); g_clear_object (&source->content); g_clear_object (&source->paintable); G_OBJECT_CLASS (gtk_drag_source_parent_class)->finalize (object); } static void gtk_drag_source_set_property (GObject *object, guint prop_id, const GValue *value, GParamSpec *pspec) { GtkDragSource *source = GTK_DRAG_SOURCE (object); switch (prop_id) { case PROP_CONTENT: gtk_drag_source_set_content (source, g_value_get_object (value)); break; case PROP_ACTIONS: gtk_drag_source_set_actions (source, g_value_get_flags (value)); break; default: G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec); } } static void gtk_drag_source_get_property (GObject *object, guint prop_id, GValue *value, GParamSpec *pspec) { GtkDragSource *source = GTK_DRAG_SOURCE (object); switch (prop_id) { case PROP_CONTENT: g_value_set_object (value, gtk_drag_source_get_content (source)); break; case PROP_ACTIONS: g_value_set_flags (value, gtk_drag_source_get_actions (source)); break; default: G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec); } } static gboolean gtk_drag_source_filter_event (GtkEventController *controller, GdkEvent *event) { /* Let touchpad swipe events go through, only if they match n-points */ if (gdk_event_get_event_type (event) == GDK_TOUCHPAD_SWIPE) { guint n_points; guint n_fingers; g_object_get (G_OBJECT (controller), "n-points", &n_points, NULL); n_fingers = gdk_touchpad_event_get_n_fingers (event); if (n_fingers == n_points) return FALSE; else return TRUE; } return GTK_EVENT_CONTROLLER_CLASS (gtk_drag_source_parent_class)->filter_event (controller, event); } static void gtk_drag_source_begin (GtkGesture *gesture, GdkEventSequence *sequence) { GtkDragSource *source = GTK_DRAG_SOURCE (gesture); GdkEventSequence *current; current = gtk_gesture_single_get_current_sequence (GTK_GESTURE_SINGLE (gesture)); gtk_gesture_get_point (gesture, current, &source->start_x, &source->start_y); } static void gtk_drag_source_update (GtkGesture *gesture, GdkEventSequence *sequence) { GtkDragSource *source = GTK_DRAG_SOURCE (gesture); GtkWidget *widget; double x, y; if (!gtk_gesture_is_recognized (gesture)) return; gtk_gesture_get_point (gesture, sequence, &x, &y); widget = gtk_event_controller_get_widget (GTK_EVENT_CONTROLLER (gesture)); if (gtk_drag_check_threshold (widget, source->start_x, source->start_y, x, y)) { gtk_drag_source_drag_begin (source); } } static void gtk_drag_source_class_init (GtkDragSourceClass *class) { GObjectClass *object_class = G_OBJECT_CLASS (class); GtkEventControllerClass *controller_class = GTK_EVENT_CONTROLLER_CLASS (class); GtkGestureClass *gesture_class = GTK_GESTURE_CLASS (class); object_class->finalize = gtk_drag_source_finalize; object_class->set_property = gtk_drag_source_set_property; object_class->get_property = gtk_drag_source_get_property; controller_class->filter_event = gtk_drag_source_filter_event; gesture_class->begin = gtk_drag_source_begin; gesture_class->update = gtk_drag_source_update; gesture_class->end = NULL; class->prepare = gtk_drag_source_prepare; /** * GtkDragSource:content: * * The data that is offered by drag operations from this source, * in the form of a #GdkContentProvider. */ properties[PROP_CONTENT] = g_param_spec_object ("content", P_("Content"), P_("The content provider for the dragged data"), GDK_TYPE_CONTENT_PROVIDER, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS | G_PARAM_EXPLICIT_NOTIFY); /** * GtkDragSource:actions: * * The actions that are supported by drag operations from the source. * * Note that you must handle the #GtkDragSource::drag-end signal * if the actions include %GDK_ACTION_MOVE. */ properties[PROP_ACTIONS] = g_param_spec_flags ("actions", P_("Actions"), P_("Supported actions"), GDK_TYPE_DRAG_ACTION, GDK_ACTION_COPY, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS | G_PARAM_EXPLICIT_NOTIFY); g_object_class_install_properties (object_class, NUM_PROPERTIES, properties); /** * GtkDragSource::prepare: * @source: the #GtkDragSource * @x: the X coordinate of the drag starting point * @y: the Y coordinate fo the drag starting point * * The ::prepare signal is emitted when a drag is about to be initiated. * It returns the * #GdkContentProvider to use for the drag that is about * to start. The default handler for this signal returns the value of * the #GtkDragSource:content property, so if you set up that property * ahead of time, you don't need to connect to this signal. * * Returns: (transfer full) (nullable): a #GdkContentProvider, or %NULL */ signals[PREPARE] = g_signal_new (I_("prepare"), G_TYPE_FROM_CLASS (class), G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GtkDragSourceClass, prepare), g_signal_accumulator_first_wins, NULL, NULL, GDK_TYPE_CONTENT_PROVIDER, 2, G_TYPE_DOUBLE, G_TYPE_DOUBLE); /** * GtkDragSource::drag-begin: * @source: the #GtkDragSource * @drag: the #GdkDrag object * * The ::drag-begin signal is emitted on the drag source when a drag * is started. It can be used to e.g. set a custom drag icon with * gtk_drag_source_set_icon(). */ signals[DRAG_BEGIN] = g_signal_new (I_("drag-begin"), G_TYPE_FROM_CLASS (class), G_SIGNAL_RUN_LAST, 0, NULL, NULL, NULL, G_TYPE_NONE, 1, GDK_TYPE_DRAG); /** * GtkDragSource::drag-end: * @source: the #GtkDragSource * @drag: the #GdkDrag object * @delete_data: %TRUE if the drag was performing %GDK_ACTION_MOVE, * and the data should be deleted * * The ::drag-end signal is emitted on the drag source when a drag is * finished. A typical reason to connect to this signal is to undo * things done in #GtkDragSource::prepare or #GtkDragSource::drag-begin. */ signals[DRAG_END] = g_signal_new (I_("drag-end"), G_TYPE_FROM_CLASS (class), G_SIGNAL_RUN_LAST, 0, NULL, NULL, NULL, G_TYPE_NONE, 2, GDK_TYPE_DRAG, G_TYPE_BOOLEAN); /** * GtkDragSource::drag-cancel: * @source: the #GtkDragSource * @drag: the #GdkDrag object * @reason: information on why the drag failed * * The ::drag-cancel signal is emitted on the drag source when a drag has * failed. The signal handler may handle a failed drag operation based on * the type of error. It should return %TRUE if the failure has been handled * and the default "drag operation failed" animation should not be shown. * * Returns: %TRUE if the failed drag operation has been already handled */ signals[DRAG_CANCEL] = g_signal_new (I_("drag-cancel"), G_TYPE_FROM_CLASS (class), G_SIGNAL_RUN_LAST, 0, _gtk_boolean_handled_accumulator, NULL, _gtk_marshal_BOOLEAN__OBJECT_ENUM, G_TYPE_BOOLEAN, 2, GDK_TYPE_DRAG, GDK_TYPE_DRAG_CANCEL_REASON); } static GdkContentProvider * gtk_drag_source_prepare (GtkDragSource *source, double x, double y) { if (source->actions == 0) return NULL; if (source->content == NULL) return NULL; return g_object_ref (source->content); } static void drag_end (GtkDragSource *source, gboolean success) { gboolean delete_data; g_signal_handlers_disconnect_by_func (source->drag, gtk_drag_source_dnd_finished_cb, source); g_signal_handlers_disconnect_by_func (source->drag, gtk_drag_source_cancel_cb, source); delete_data = success && gdk_drag_get_selected_action (source->drag) == GDK_ACTION_MOVE; g_signal_emit (source, signals[DRAG_END], 0, source->drag, delete_data); gdk_drag_drop_done (source->drag, success); g_clear_object (&source->drag); } static void gtk_drag_source_dnd_finished_cb (GdkDrag *drag, GtkDragSource *source) { drag_end (source, TRUE); } static void gtk_drag_source_cancel_cb (GdkDrag *drag, GdkDragCancelReason reason, GtkDragSource *source) { gboolean success = FALSE; g_signal_emit (source, signals[DRAG_CANCEL], 0, source->drag, reason, &success); drag_end (source, success); } static void gtk_drag_source_ensure_icon (GtkDragSource *self, GdkDrag *drag) { GdkContentProvider *provider; GtkWidget *icon, *child; GdkContentFormats *formats; const GType *types; gsize i, n_types; icon = gtk_drag_icon_get_for_drag (drag); /* If an icon has been set already, we don't need to set one. */ if (gtk_drag_icon_get_child (GTK_DRAG_ICON (icon))) return; if (self->paintable) { gtk_drag_icon_set_from_paintable (drag, self->paintable, self->hot_x, self->hot_y); return; } gdk_drag_set_hotspot (drag, -2, -2); provider = gdk_drag_get_content (drag); formats = gdk_content_provider_ref_formats (provider); types = gdk_content_formats_get_gtypes (formats, &n_types); for (i = 0; i < n_types; i++) { GValue value = G_VALUE_INIT; g_value_init (&value, types[i]); if (gdk_content_provider_get_value (provider, &value, NULL)) { child = gtk_drag_icon_create_widget_for_value (&value); if (child) { gtk_drag_icon_set_child (GTK_DRAG_ICON (icon), child); g_value_unset (&value); gdk_content_formats_unref (formats); return; } } g_value_unset (&value); } gdk_content_formats_unref (formats); child = gtk_image_new_from_icon_name ("text-x-generic"); gtk_image_set_icon_size (GTK_IMAGE (child), GTK_ICON_SIZE_LARGE); gtk_drag_icon_set_child (GTK_DRAG_ICON (icon), child); } static void gtk_drag_source_drag_begin (GtkDragSource *source) { GtkWidget *widget; GdkDevice *device, *pointer; GdkSeat *seat; double x, y; GtkNative *native; GdkSurface *surface; double px, py; int dx, dy; GdkContentProvider *content = NULL; widget = gtk_event_controller_get_widget (GTK_EVENT_CONTROLLER (source)); device = gtk_gesture_get_device (GTK_GESTURE (source)); seat = gdk_device_get_seat (device); if (device == gdk_seat_get_keyboard (seat)) pointer = gdk_seat_get_pointer (seat); else pointer = device; native = gtk_widget_get_native (widget); surface = gtk_native_get_surface (native); gtk_widget_translate_coordinates (widget, GTK_WIDGET (native), source->start_x, source->start_y, &x, &y); gdk_surface_get_device_position (surface, pointer, &px, &py, NULL); dx = round (px - x); dy = round (py - y); g_signal_emit (source, signals[PREPARE], 0, source->start_x, source->start_y, &content); if (!content) return; source->drag = gdk_drag_begin (surface, pointer, content, source->actions, dx, dy); g_object_unref (content); if (source->drag == NULL) return; gtk_widget_reset_controllers (widget); g_signal_emit (source, signals[DRAG_BEGIN], 0, source->drag); gtk_drag_source_ensure_icon (source, source->drag); g_signal_connect (source->drag, "dnd-finished", G_CALLBACK (gtk_drag_source_dnd_finished_cb), source); g_signal_connect (source->drag, "cancel", G_CALLBACK (gtk_drag_source_cancel_cb), source); } /** * gtk_drag_source_new: * * Creates a new #GtkDragSource object. * * Returns: the new #GtkDragSource */ GtkDragSource * gtk_drag_source_new (void) { return g_object_new (GTK_TYPE_DRAG_SOURCE, NULL); } /** * gtk_drag_source_get_content: * @source: a #GtkDragSource * * Gets the current content provider of a #GtkDragSource. * * Returns: (nullable) (transfer none): the #GdkContentProvider of @source */ GdkContentProvider * gtk_drag_source_get_content (GtkDragSource *source) { g_return_val_if_fail (GTK_IS_DRAG_SOURCE (source), NULL); return source->content; } /** * gtk_drag_source_set_content: * @source: a #GtkDragSource * @content: (nullable): a #GdkContentProvider, or %NULL * * Sets a content provider on a #GtkDragSource. * * When the data is requested in the cause of a * DND operation, it will be obtained from the * content provider. * * This function can be called before a drag is started, * or in a handler for the #GtkDragSource::prepare signal. * * You may consider setting the content provider back to * %NULL in a #GtkDragSource::drag-end signal handler. */ void gtk_drag_source_set_content (GtkDragSource *source, GdkContentProvider *content) { g_return_if_fail (GTK_IS_DRAG_SOURCE (source)); if (!g_set_object (&source->content, content)) return; g_object_notify_by_pspec (G_OBJECT (source), properties[PROP_CONTENT]); } /** * gtk_drag_source_get_actions: * @source: a #GtkDragSource * * Gets the actions that are currently set on the #GtkDragSource. * * Returns: the actions set on @source */ GdkDragAction gtk_drag_source_get_actions (GtkDragSource *source) { g_return_val_if_fail (GTK_IS_DRAG_SOURCE (source), 0); return source->actions; } /** * gtk_drag_source_set_actions: * @source: a #GtkDragSource * @actions: the actions to offer * * Sets the actions on the #GtkDragSource. * * During a DND operation, the actions are offered * to potential drop targets. If @actions include * %GDK_ACTION_MOVE, you need to listen to the * #GtkDragSource::drag-end signal and handle * @delete_data being %TRUE. * * This function can be called before a drag is started, * or in a handler for the #GtkDragSource::prepare signal. */ void gtk_drag_source_set_actions (GtkDragSource *source, GdkDragAction actions) { g_return_if_fail (GTK_IS_DRAG_SOURCE (source)); if (source->actions == actions) return; source->actions = actions; g_object_notify_by_pspec (G_OBJECT (source), properties[PROP_ACTIONS]); } /** * gtk_drag_source_set_icon: * @source: a #GtkDragSource * @paintable: (nullable): the #GdkPaintable to use as icon, or %NULL * @hot_x: the hotspot X coordinate on the icon * @hot_y: the hotspot Y coordinate on the icon * * Sets a paintable to use as icon during DND operations. * * The hotspot coordinates determine the point on the icon * that gets aligned with the hotspot of the cursor. * * If @paintable is %NULL, a default icon is used. * * This function can be called before a drag is started, or in * a #GtkDragSource::prepare or #GtkDragSource::drag-begin signal handler. */ void gtk_drag_source_set_icon (GtkDragSource *source, GdkPaintable *paintable, int hot_x, int hot_y) { g_return_if_fail (GTK_IS_DRAG_SOURCE (source)); g_set_object (&source->paintable, paintable); source->hot_x = hot_x; source->hot_y = hot_y; } /** * gtk_drag_source_get_drag: * @source: a #GtkDragSource * * Returns the underlying #GdkDrag object for an ongoing drag. * * Returns: (nullable) (transfer none): the #GdkDrag of the current drag operation, or %NULL */ GdkDrag * gtk_drag_source_get_drag (GtkDragSource *source) { g_return_val_if_fail (GTK_IS_DRAG_SOURCE (source), NULL); return source->drag; } /** * gtk_drag_source_drag_cancel: * @source: a #GtkDragSource * * Cancels a currently ongoing drag operation. */ void gtk_drag_source_drag_cancel (GtkDragSource *source) { g_return_if_fail (GTK_IS_DRAG_SOURCE (source)); if (source->drag) { gboolean success = FALSE; g_signal_emit (source, signals[DRAG_CANCEL], 0, source->drag, GDK_DRAG_CANCEL_ERROR, &success); drag_end (source, FALSE); } } /** * gtk_drag_check_threshold: (method) * @widget: a #GtkWidget * @start_x: X coordinate of start of drag * @start_y: Y coordinate of start of drag * @current_x: current X coordinate * @current_y: current Y coordinate * * Checks to see if a mouse drag starting at (@start_x, @start_y) and ending * at (@current_x, @current_y) has passed the GTK drag threshold, and thus * should trigger the beginning of a drag-and-drop operation. * * Returns: %TRUE if the drag threshold has been passed. */ gboolean gtk_drag_check_threshold (GtkWidget *widget, int start_x, int start_y, int current_x, int current_y) { int drag_threshold; g_return_val_if_fail (GTK_IS_WIDGET (widget), FALSE); drag_threshold = gtk_settings_get_dnd_drag_threshold (gtk_widget_get_settings (widget)); return (ABS (current_x - start_x) > drag_threshold || ABS (current_y - start_y) > drag_threshold); }