Interfacing Raku to Gnome GTK+

Gnome::Gtk3::DragDest

Description

GTK+ has a rich set of functions for doing inter-process communication via the drag-and-drop metaphor.

This module defines the drag destination manipulations

Synopsis

Declaration

unit class Gnome::Gtk3::DragDest;

Types

enum GtkDestDefaults

The Gnome::Gtk3::DestDefaults enumeration specifies the various types of action that will be taken on behalf of the user for a drag destination site.

  • GTK_DEST_DEFAULT_NONE: (=0) to select no default.

  • GTK-DEST-DEFAULT-MOTION: If set for a widget, GTK+, during a drag over this widget will check if the drag matches this widget’s list of possible targets and actions. GTK+ will then call gdk-drag-status() as appropriate.

  • GTK-DEST-DEFAULT-HIGHLIGHT: If set for a widget, GTK+ will draw a highlight on this widget as long as a drag is over this widget and the widget drag format and action are acceptable.

  • GTK-DEST-DEFAULT-DROP: If set for a widget, when a drop occurs, GTK+ will will check if the drag matches this widget’s list of possible targets and actions. If so, GTK+ will call gtk-drag-get-data() on behalf of the widget. Whether or not the drop is successful, GTK+ will call gtk-drag-finish(). If the action was a move, then if the drag was successful, then True will be passed for the delete parameter to gtk-drag-finish().

  • GTK-DEST-DEFAULT-ALL: If set, specifies that all default actions should be taken.

Methods

new

default, no options

Create a new DragDest object.

multi method new ( )

This object does not wrap a native object into this Raku object because it does not need one. Therefore no option like :native-object is needed.

add-image-targets

Add the image targets supported by Gnome::Gtk3::SelectionData 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 set-target-list().

method add-image-targets ( N-GObject() $widget )
  • $widget; a native Gnome::Gtk3::Widget that’s a drag destination

add-text-targets

Add the text targets supported by Gnome::Gtk3::SelectionData 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 set-target-list().

method add-text-targets ( N-GObject() $widget )
  • $widget; a Gnome::Gtk3::Widget that’s a drag destination

add-uri-targets

Add the URI targets supported by Gnome::Gtk3::SelectionData 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 set-target-list().

method add-uri-targets ( N-GObject() $widget )
  • $widget; a Gnome::Gtk3::Widget that’s a drag destination

find-target

Looks for a match between the supported targets of context and the dest-target-list, returning the first matching target, otherwise returning GDK-NONE. dest-target-list should usually be the return value from 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: first target that the source offers and the dest can accept, or GDK-NONE

method find-target (
  N-GObject() $widget, N-GObject() $context,
  N-GObject() $target-list?
  --> N-GObject
)

  • $widget; drag destination widget

  • $context; drag context

  • $target-list; list of droppable targets, or undefined to use get-target-list($widget).

Previously, it returned a Gnome::Gdk3::Atom. To confirm with latest ideas about coercing, the routine now returns a native object. To cope with the change, write the following instead, for example;

my Gnome::Gdk3::Atom() $target-atom = $!destination.find-target(…);

Note the () tacked on the Gnome::Gdk3::Atom type! Sorry that I cannot give a deprecation warning because of multis not looking for return types.

get-target-list

Returns the list of targets this widget can accept from drag-and-drop.

Returns: the Gnome::Gtk3::TargetList, or undefined if none

method get-target-list ( N-GObject() $widget --> N-GObject )
  • $widget; a Gnome::Gtk3::Widget

get-track-motion

Returns whether the widget has been configured to always emit drag-motion signals.

Returns: True if the widget always emits drag-motion events

method get-track-motion ( N-GObject $widget --> Bool )
  • $widget; a Gnome::Gtk3::Widget that’s a drag destination

set

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 widget’s drag-and-drop signals ( drag-motion, drag-drop, …). They all exist for convenience. When passing GTK-DEST-DEFAULT-ALL for instance it is sufficient to connect to the widget’s 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 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 drag-motion, and invokations of gtk-drag-finish() in drag-data-received. Especially the later is dramatic, when your own drag-motion handler calls gtk-drag-get-data() to inspect the dragged data.

There’s no way to set a default action here, you can use the drag-motion callback for that.

The method API is

multi method set (
  N-GObject() $widget, Int() $flags,
  Array[N-GtkTargetEntry] $targets, Int() $actions
)

  • $widget; a Gnome::Gtk3::Widget

  • $flags; which types of default drag behavior to use. Bits are from enum GtkDestDefaults.

  • $targets; an array of native Gnome::Gtk3::TargetEntry targets indicating the drop types that this widget will accept. Later you can access the list with get-target-list() and find-target(), or an empty array.

  • $actions; a bitmask of possible actions for a drop onto this widget. Bits are from enum GdkDragAction defined in Gnome::Gdk3::DragContext.

set-target-list

Sets the target types that this widget can accept from drag-and-drop. The widget must first be made into a drag destination with set().

method set-target-list ( N-GObject() $widget, N-GtkTargetList $target-list )

  • $widget; a Gnome::Gtk3::Widget that’s a drag destination

  • $target-list; list of droppable targets, or undefined for none

set-track-motion

Tells the widget to emit drag-motion and 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.

method set-track-motion ( N-GObject() $widget, Bool $track_motion )

  • $widget; a Gnome::Gtk3::Widget that’s a drag destination

  • $track_motion; whether to accept all targets

unset

Clears information about a drop destination set with set(). The widget will no longer receive notification of drags.

method unset ( N-GObject() $widget )
  • $widget; a Gnome::Gtk3::Widget