class Gtk::DragSource

• Gtk::DragSource
• Gtk::GestureSingle
• Gtk::Gesture
• Gtk::EventController
• GObject::Object
• Reference
• Object

Overview

Gtk::DragSource is an event controller to initiate Drag-And-Drop operations.

Gtk::DragSource 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 Gdk::ContentProvider, 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.

WARNING ⚠️ The following code is in c ⚠️

static void
my_widget_init (MyWidget *self)
{
  Gtk::DragSource *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, Gtk::DragSource has Gtk::DragSource::#prepare and [signal@Gtk.DragSource::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.

WARNING ⚠️ The following code is in c ⚠️

static Gdk::ContentProvider *
on_drag_prepare (Gtk::DragSource *source,
                 double         x,
                 double         y,
                 MyWidget      *self)
{
  // This widget supports two types of content: GFile objects
  // and Gdk::Pixbuf objects; GTK will handle the serialization
  // of these types automatically
  GFile *file = my_widget_get_file (self);
  Gdk::Pixbuf *pixbuf = my_widget_get_pixbuf (self);

  return gdk_content_provider_new_union ((Gdk::ContentProvider *[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 Gdk::Drag object has been created, and can be used to set up the drag icon.

WARNING ⚠️ The following code is in c ⚠️

static void
on_drag_begin (Gtk::DragSource *source,
               Gdk::Drag       *drag,
               MyWidget      *self)
{
  // Set the widget as the drag icon
  Gdk::Paintable *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, Gtk::DragSource 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 [signal@Gtk.DragSource::drag-end] signal and delete the data after it has been transferred.

Defined in:

Constructors

• .new : self

  Creates a new Gtk::DragSource object.

• .new(*, actions : Gdk::DragAction | Nil = nil, button : UInt32 | Nil = nil, content : Gdk::ContentProvider | Nil = nil, exclusive : Bool | Nil = nil, n_points : UInt32 | Nil = nil, name : String | Nil = nil, propagation_limit : Gtk::PropagationLimit | Nil = nil, propagation_phase : Gtk::PropagationPhase | Nil = nil, touch_only : Bool | Nil = nil, widget : Gtk::Widget | Nil = nil)

Class Method Summary

• .g_type : UInt64

  Returns the type id (GType) registered in GLib type system.

Instance Method Summary

• #==(other : self)

  Returns true if this reference is the same as other.

• #actions : Gdk::DragAction

  Gets the actions that are currently set on the Gtk::DragSource.

• #actions=(actions : Gdk::DragAction) : Nil

  Sets the actions on the Gtk::DragSource.

• #content : Gdk::ContentProvider | Nil

  Gets the current content provider of a Gtk::DragSource.

• #content=(content : Gdk::ContentProvider | Nil) : Nil

  Sets a content provider on a Gtk::DragSource.

• #drag : Gdk::Drag | Nil

  Returns the underlying Gdk::Drag object for an ongoing drag.

• #drag_begin_signal
• #drag_cancel : Nil

  Cancels a currently ongoing drag operation.

• #drag_cancel_signal
• #drag_end_signal
• #hash(hasher)

  See Object#hash(hasher)

• #prepare_signal
• #set_icon(paintable : Gdk::Paintable | Nil, hot_x : Int32, hot_y : Int32) : Nil

  Sets a paintable to use as icon during DND operations.

Constructor Detail

Class Method Detail

Instance Method Detail