gtkDragDestSet {RGtk2}R Documentation

gtkDragDestSet

Description

Sets a widget as a potential drop destination, and adds default behaviors.

Usage

gtkDragDestSet(object, flags, targets, actions)

Arguments

object

a GtkWidget

flags

which types of default drag behavior to use

targets

a pointer to a list of GtkTargetEntrys indicating the drop types that this widget will accept, or NULL. Later you can access the list with gtkDragDestGetTargetList and gtkDragDestFindTarget. [ allow-none ][ array length=n_targets]

actions

a bitmask of possible actions for a drop onto this widget.

Details

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 gdkDragStatus in the context of 
"drag-motion"
, and invokations of gtkDragFinish in 
"drag-data-received"
. Especially the later is dramatic, when your own 
"drag-motion"
handler calls gtkDragGetData to inspect the dragged data. There's no way to set a default action here, you can use the 
"drag-motion"
callback for that. Here's an example which selects the action to use depending on whether the control key is pressed or not: 
static void
drag_motion (GtkWidget *widget,
             GdkDragContext *context,
             gint x,
             gint y,
             guint time)
{
  GdkModifierType mask;

  gdk_window_get_pointer (gtk_widget_get_window (widget),
                          NULL, NULL, &mask);
  if (mask & GDK_CONTROL_MASK)
    gdk_drag_status (context, GDK_ACTION_COPY, time);
  else
    gdk_drag_status (context, GDK_ACTION_MOVE, time);
}

Author(s)

Derived by RGtkGen from GTK+ documentation

[Package RGtk2 version 2.20.21 Index]