gtkmm: Gtk::DropTarget Class Reference

Event controller to receive DND drops. More...

#include <gtkmm/droptarget.h>

Inheritance diagram for Gtk::DropTarget:

[legend]

Public Member Functions
	DropTarget (DropTarget &&src) noexcept

DropTarget &	operator= (DropTarget &&src) noexcept

	~DropTarget () noexcept override

GtkDropTarget *	gobj ()
	Provides access to the underlying C GObject.

const GtkDropTarget *	gobj () const
	Provides access to the underlying C GObject.

GtkDropTarget *	gobj_copy ()
	Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.

void	set_gtypes (const std::vector< GType > & types)
	Sets the supported Types for this drop target.

std::vector< GType >	get_gtypes () const
	Gets a vector of supported Types.

Glib::RefPtr< Gdk::ContentFormats >	get_formats ()
	Gets the data formats that this drop target accepts.

Glib::RefPtr< const Gdk::ContentFormats >	get_formats () const
	Gets the data formats that this drop target accepts.

void	set_actions (Gdk::DragAction actions)
	Sets the actions that this drop target supports.

Gdk::DragAction	get_actions () const
	Gets the actions that this drop target supports.

void	set_preload (bool preload=true)
	Sets whether data should be preloaded on hover.

bool	get_preload () const
	Gets whether data should be preloaded on hover.

Glib::RefPtr< Gdk::Drop >	get_drop ()
	Gets the currently handled drop operation.

Glib::RefPtr< const Gdk::Drop >	get_drop () const
	Gets the currently handled drop operation.

Glib::RefPtr< Gdk::Drop >	get_current_drop ()
	Gets the currently handled drop operation.

Glib::RefPtr< const Gdk::Drop >	get_current_drop () const
	Gets the currently handled drop operation.

Glib::ValueBase	get_value () const
	Gets the current drop data, as a `Glib::Value`.

void	reject ()
	Rejects the ongoing drop operation.

Glib::PropertyProxy< Gdk::DragAction >	property_actions ()
	The `Gdk::DragActions` that this drop target supports.

Glib::PropertyProxy_ReadOnly< Gdk::DragAction >	property_actions () const
	The `Gdk::DragActions` that this drop target supports.

Glib::PropertyProxy_ReadOnly< Glib::RefPtr< Gdk::Drop > >	property_drop () const
	The `Gdk::Drop` that is currently being performed.

Glib::PropertyProxy_ReadOnly< Glib::RefPtr< Gdk::Drop > >	property_current_drop () const
	The `Gdk::Drop` that is currently being performed.

Glib::PropertyProxy_ReadOnly< Glib::RefPtr< Gdk::ContentFormats > >	property_formats () const
	The `Gdk::ContentFormats` that determine the supported data formats.

Glib::PropertyProxy< bool >	property_preload ()
	Whether the drop data should be preloaded when the pointer is only hovering over the widget but has not been released.

Glib::PropertyProxy_ReadOnly< bool >	property_preload () const
	Whether the drop data should be preloaded when the pointer is only hovering over the widget but has not been released.

Glib::PropertyProxy_ReadOnly< GValue * >	property_value () const
	The value for this drop operation.

Glib::SignalProxy< bool(const Glib::RefPtr< Gdk::Drop > &)>	signal_accept ()
	Only one signal handler is called.

Glib::SignalProxy< Gdk::DragAction(double, double)>	signal_enter ()
	Only one signal handler is called.

Glib::SignalProxy< Gdk::DragAction(double, double)>	signal_motion ()
	Only one signal handler is called.

Glib::SignalProxy< void()>	signal_leave ()

Glib::SignalProxy< bool(const Glib::ValueBase &, double, double)>	signal_drop ()
	Only one signal handler is called.

Public Member Functions inherited from Gtk::EventController
	EventController (EventController &&src) noexcept

EventController &	operator= (EventController &&src) noexcept

	~EventController () noexcept override

GtkEventController *	gobj ()
	Provides access to the underlying C GObject.

const GtkEventController *	gobj () const
	Provides access to the underlying C GObject.

GtkEventController *	gobj_copy ()
	Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.

Widget *	get_widget ()
	Returns the `Gtk::Widget` this controller relates to.

const Widget *	get_widget () const
	Returns the `Gtk::Widget` this controller relates to.

void	reset ()
	Resets the controller to a clean state.

PropagationPhase	get_propagation_phase () const
	Gets the propagation phase at which controller handles events.

void	set_propagation_phase (PropagationPhase phase)
	Sets the propagation phase at which a controller handles events.

PropagationLimit	get_propagation_limit () const
	Gets the propagation limit of the event controller.

void	set_propagation_limit (PropagationLimit limit)
	Sets the event propagation limit on the event controller.

Glib::ustring	get_name () const
	Gets the name of controller.

void	set_name (const Glib::ustring & name)
	Sets a name on the controller that can be used for debugging.

Glib::RefPtr< const Gdk::Event >	get_current_event () const
	Returns the event that is currently being handled by the controller.

guint32	get_current_event_time () const
	Returns the timestamp of the event that is currently being handled by the controller.

Glib::RefPtr< Gdk::Device >	get_current_event_device ()
	Returns the device of the event that is currently being handled by the controller.

Glib::RefPtr< const Gdk::Device >	get_current_event_device () const
	Returns the event that is currently being handled by the controller.

Gdk::ModifierType	get_current_event_state () const
	Returns the modifier state of the event that is currently being handled by the controller.

Glib::PropertyProxy_ReadOnly< Widget * >	property_widget () const
	The widget receiving the `Gdk::Events` that the controller will handle.

Glib::PropertyProxy< PropagationPhase >	property_propagation_phase ()
	The propagation phase at which this controller will handle events.

Glib::PropertyProxy_ReadOnly< PropagationPhase >	property_propagation_phase () const
	The propagation phase at which this controller will handle events.

Glib::PropertyProxy< PropagationLimit >	property_propagation_limit ()
	The limit for which events this controller will handle.

Glib::PropertyProxy_ReadOnly< PropagationLimit >	property_propagation_limit () const
	The limit for which events this controller will handle.

Glib::PropertyProxy< Glib::ustring >	property_name ()
	The name for this controller, typically used for debugging purposes.

Glib::PropertyProxy_ReadOnly< Glib::ustring >	property_name () const
	The name for this controller, typically used for debugging purposes.

Static Public Member Functions
static GType	get_type ()
	Get the GType for this class, for use with the underlying GObject type system.

static Glib::RefPtr< DropTarget >	create (GType type, Gdk::DragAction actions)
	Creates a new `Gtk::DropTarget` object.

Static Public Member Functions inherited from Gtk::EventController
static GType	get_type ()
	Get the GType for this class, for use with the underlying GObject type system.

Related Symbols
(Note that these are not member symbols.)
Glib::RefPtr< Gtk::DropTarget >	wrap (GtkDropTarget *object, bool take_copy=false)
	A Glib::wrap() method for this object.

Related Symbols inherited from Gtk::EventController
Glib::RefPtr< Gtk::EventController >	wrap (GtkEventController *object, bool take_copy=false)
	A Glib::wrap() method for this object.

Additional Inherited Members
Protected Member Functions inherited from Gtk::EventController
	EventController ()
	There is no create() method that corresponds to this constructor, because only derived classes shall be created.

Detailed Description

Event controller to receive DND drops.

Gtk::DropTarget is an event controller implementing a simple way to receive Drag-and-Drop operations.

The most basic way to use a Gtk::DropTarget to receive drops on a widget is to create it via create() passing in the GType of the data you want to receive and connect to signal_drop() to receive the data.

Gtk::DropTarget supports more options, such as:

rejecting potential drops via signal_accept() and the reject() method to let other drop targets handle the drop
tracking an ongoing drag operation before the drop via signal_enter(), signal_motion() and signal_leave()
configuring how to receive data by setting property_preload() and listening for its availability via property_value()

However, Gtk::DropTarget is ultimately modeled in a synchronous way and only supports data transferred via GType.
If you want full control over an ongoing drop, the 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::StateFlags::DROP_ACTIVE state, which can be used to style the widget.

Since gtkmm 3.96:

Constructor & Destructor Documentation

◆ DropTarget()

Gtk::DropTarget::DropTarget ( DropTarget && src )

noexcept

◆ ~DropTarget()

Gtk::DropTarget::~DropTarget ( )

overridenoexcept

Member Function Documentation

◆ create()

static Glib::RefPtr< DropTarget > Gtk::DropTarget::create	(	GType	type,
		Gdk::DragAction	actions
	)

static

Creates a new Gtk::DropTarget object.

If the drop target should support more than 1 type, pass G_TYPE_INVALID for type and then call set_gtypes().

Parameters

type	The supported type or G_TYPE_INVALID.
actions	The supported actions.

Returns: The new Gtk::DropTarget.

◆ get_actions()

Gdk::DragAction Gtk::DropTarget::get_actions ( ) const

Gets the actions that this drop target supports.

Returns: The actions that this drop target supports.

◆ get_current_drop() [1/2]

Glib::RefPtr< Gdk::Drop > Gtk::DropTarget::get_current_drop ( )

Gets the currently handled drop operation.

If no drop operation is going on, nullptr is returned.

Since gtkmm 4.4:

Returns: The current drop.

◆ get_current_drop() [2/2]

Glib::RefPtr< const Gdk::Drop > Gtk::DropTarget::get_current_drop ( ) const

Gets the currently handled drop operation.

If no drop operation is going on, nullptr is returned.

Since gtkmm 4.4:

Returns: The current drop.

◆ get_drop() [1/2]

Glib::RefPtr< Gdk::Drop > Gtk::DropTarget::get_drop ( )

Gets the currently handled drop operation.

If no drop operation is going on, nullptr is returned.

Deprecated: 4.4: Use get_current_drop() instead

Deprecated:: Use get_current_drop() instead.

Returns: The current drop.

◆ get_drop() [2/2]

Glib::RefPtr< const Gdk::Drop > Gtk::DropTarget::get_drop ( ) const

Gets the currently handled drop operation.

If no drop operation is going on, nullptr is returned.

Deprecated: 4.4: Use get_current_drop() instead

Deprecated:: Use get_current_drop() instead.

Returns: The current drop.

◆ get_formats() [1/2]

Glib::RefPtr< Gdk::ContentFormats > Gtk::DropTarget::get_formats ( )

Gets the data formats that this drop target accepts.

If the result is nullptr, all formats are expected to be supported.

Returns: The supported data formats.

◆ get_formats() [2/2]

Glib::RefPtr< const Gdk::ContentFormats > Gtk::DropTarget::get_formats ( ) const

Gets the data formats that this drop target accepts.

If the result is nullptr, all formats are expected to be supported.

Returns: The supported data formats.

◆ get_gtypes()

std::vector< GType > Gtk::DropTarget::get_gtypes ( ) const

Gets a vector of supported Types.

If no type have been set, an empty vector will be returned.

Returns: Vector of types.

◆ get_preload()

bool Gtk::DropTarget::get_preload ( ) const

Gets whether data should be preloaded on hover.

Returns: true if drop data should be preloaded.

◆ get_type()

static GType Gtk::DropTarget::get_type ( )

static

Get the GType for this class, for use with the underlying GObject type system.

◆ get_value()

Glib::ValueBase Gtk::DropTarget::get_value ( ) const

Gets the current drop data, as a Glib::Value.

Returns: The current drop data.

◆ gobj() [1/2]

GtkDropTarget * Gtk::DropTarget::gobj ( )

inline

Provides access to the underlying C GObject.

◆ gobj() [2/2]

const GtkDropTarget * Gtk::DropTarget::gobj ( ) const

inline

Provides access to the underlying C GObject.

◆ gobj_copy()

GtkDropTarget * Gtk::DropTarget::gobj_copy ( )

Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.

◆ operator=()

DropTarget & Gtk::DropTarget::operator= ( DropTarget && src )

noexcept

◆ property_actions() [1/2]

Glib::PropertyProxy< Gdk::DragAction > Gtk::DropTarget::property_actions ( )

The Gdk::DragActions that this drop target supports.

Default value: 0

Returns: A PropertyProxy that allows you to get or set the value of the property, or receive notification when the value of the property changes.

◆ property_actions() [2/2]

Glib::PropertyProxy_ReadOnly< Gdk::DragAction > Gtk::DropTarget::property_actions ( ) const

The Gdk::DragActions that this drop target supports.

Default value: 0

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ property_current_drop()

Glib::PropertyProxy_ReadOnly< Glib::RefPtr< Gdk::Drop > > Gtk::DropTarget::property_current_drop ( ) const

The Gdk::Drop that is currently being performed.

Since gtkmm 4.4:

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ property_drop()

Glib::PropertyProxy_ReadOnly< Glib::RefPtr< Gdk::Drop > > Gtk::DropTarget::property_drop ( ) const

The Gdk::Drop that is currently being performed.

Deprecated: 4.4: Use property_current_drop() instead

Deprecated:: Use property_current_drop() instead.

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ property_formats()

Glib::PropertyProxy_ReadOnly< Glib::RefPtr< Gdk::ContentFormats > > Gtk::DropTarget::property_formats ( ) const

The Gdk::ContentFormats that determine the supported data formats.

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ property_preload() [1/2]

Glib::PropertyProxy< bool > Gtk::DropTarget::property_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.

Default value: false

Returns: A PropertyProxy that allows you to get or set the value of the property, or receive notification when the value of the property changes.

◆ property_preload() [2/2]

Glib::PropertyProxy_ReadOnly< bool > Gtk::DropTarget::property_preload ( ) const

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.

Default value: false

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ property_value()

Glib::PropertyProxy_ReadOnly< GValue * > Gtk::DropTarget::property_value ( ) const

The value for this drop operation.

This is nullptr if the data has not been loaded yet or no drop operation is going on.

Data may be available before the signal_drop() signal gets emitted - for example when the property_preload() property is set. You can use the signal_notify() signal to be notified of available data.

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ reject()

void Gtk::DropTarget::reject ( )

Rejects the ongoing drop operation.

If no drop operation is ongoing, i.e when property_current_drop() is nullptr, 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.

◆ set_actions()

void Gtk::DropTarget::set_actions ( Gdk::DragAction actions )

Sets the actions that this drop target supports.

Parameters

actions The supported actions.

◆ set_gtypes()

void Gtk::DropTarget::set_gtypes ( const std::vector< GType > & types )

Sets the supported Types for this drop target.

Parameters

types All supported Types that can be dropped.

◆ set_preload()

void Gtk::DropTarget::set_preload ( bool preload = true )

Sets whether data should be preloaded on hover.

Parameters

preload true to preload drop data.

◆ signal_accept()

Glib::SignalProxy< bool(const Glib::RefPtr< Gdk::Drop > &)> Gtk::DropTarget::signal_accept ( )

Only one signal handler is called.

If you connect a handler, it must be called before (instead of) the default handler, otherwise it won't be called. Set the after parameter in connect() to false.

Slot Prototype:: bool on_my_accept(const Glib::RefPtr<Gdk::Drop>& drop)

Flags: Run Last

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 Gtk::DropTarget::reject() or ultimately by returning false from a signal_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_preload() property should be set and the value should be inspected via the notify:value signal, calling Gtk::DropTarget::reject() if required.

Parameters

drop	The `Gdk::Drop`.

Returns: true if drop is accepted.

◆ signal_drop()

Glib::SignalProxy< bool(const Glib::ValueBase &, double, double)> Gtk::DropTarget::signal_drop ( )

Only one signal handler is called.

If you connect a handler, it must be called before (instead of) the default handler, otherwise it won't be called. Set the after parameter in connect() to false.

Slot Prototype:: bool on_my_drop(const Glib::ValueBase& value, double x, double y)

Flags: Run Last

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.

Parameters

value	The `Glib::Value` being dropped.
x	The x coordinate of the current pointer position.
y	The y coordinate of the current pointer position.

Returns: Whether the drop was accepted at the given pointer position.

◆ signal_enter()

Glib::SignalProxy< Gdk::DragAction(double, double)> Gtk::DropTarget::signal_enter ( )

Only one signal handler is called.

If you connect a handler, it must be called before (instead of) the default handler, otherwise it won't be called. Set the after parameter in connect() to false.

Slot Prototype:: Gdk::DragAction on_my_enter(double x, double y)

Flags: Run Last

Emitted on the drop site when the pointer enters the widget.

It can be used to set up custom highlighting.

Parameters

x	The x coordinate of the current pointer position.
y	The y coordinate of the current pointer position.

Returns: Preferred action for this drag operation or 0 if dropping is not supported at the current x, y location.

◆ signal_leave()

Glib::SignalProxy< void()> Gtk::DropTarget::signal_leave ( )

Slot Prototype:: void on_my_leave()

Flags: Run Last

Emitted on the drop site when the pointer leaves the widget.

Its main purpose it to undo things done in signal_enter().

◆ signal_motion()

Glib::SignalProxy< Gdk::DragAction(double, double)> Gtk::DropTarget::signal_motion ( )

Only one signal handler is called.

If you connect a handler, it must be called before (instead of) the default handler, otherwise it won't be called. Set the after parameter in connect() to false.

Slot Prototype:: Gdk::DragAction on_my_motion(double x, double y)

Flags: Run Last

Emitted while the pointer is moving over the drop target.

Parameters

x	The x coordinate of the current pointer position.
y	The y coordinate of the current pointer position.

Returns: Preferred action for this drag operation or 0 if dropping is not supported at the current x, y location.

Friends And Related Symbol Documentation

◆ wrap()

Glib::RefPtr< Gtk::DropTarget > wrap	(	GtkDropTarget *	object,
		bool	take_copy = `false`
	)

A Glib::wrap() method for this object.

Parameters

object	The C instance.
take_copy	False if the result should take ownership of the C instance. True if it should take a new copy or ref.

Returns: A C++ instance that wraps this C instance.

Public Member Functions

Static Public Member Functions

Related Symbols

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ DropTarget()

◆ ~DropTarget()

Member Function Documentation

◆ create()

◆ get_actions()

◆ get_current_drop() [1/2]

◆ get_current_drop() [2/2]

◆ get_drop() [1/2]

◆ get_drop() [2/2]

◆ get_formats() [1/2]

◆ get_formats() [2/2]

◆ get_gtypes()

◆ get_preload()

◆ get_type()

◆ get_value()

◆ gobj() [1/2]

◆ gobj() [2/2]

◆ gobj_copy()

◆ operator=()

◆ property_actions() [1/2]

◆ property_actions() [2/2]

◆ property_current_drop()

◆ property_drop()

◆ property_formats()

◆ property_preload() [1/2]

◆ property_preload() [2/2]

◆ property_value()

◆ reject()

◆ set_actions()

◆ set_gtypes()

◆ set_preload()

◆ signal_accept()

◆ signal_drop()

◆ signal_enter()

◆ signal_leave()

◆ signal_motion()

Friends And Related Symbol Documentation

◆ wrap()