--- /dev/null
+/*
+ Copyright (C) 2000-2007 Paul Davis
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program 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 General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#ifndef __gtkmm2ext_dndtreeview_h__
+#define __gtkmm2ext_dndtreeview_h__
+
+#include <stdint.h>
+#include <string>
+#include <gtkmm/treeview.h>
+#include <gtkmm/treeselection.h>
+#include <gtkmm/selectiondata.h>
+
+namespace Gtkmm2ext {
+
+template<class DataType>
+struct SerializedObjectPointers {
+ uint32_t size;
+ uint32_t cnt;
+ char type[32];
+ DataType data[0];
+};
+
+class DnDTreeViewBase : public Gtk::TreeView
+{
+ private:
+ public:
+ DnDTreeViewBase ();
+ ~DnDTreeViewBase() {}
+
+ void add_drop_targets (std::list<Gtk::TargetEntry>&);
+ void add_object_drag (int column, std::string type_name);
+
+ void on_drag_leave(const Glib::RefPtr<Gdk::DragContext>& context, guint time) {
+ suggested_action = context->get_suggested_action();
+ TreeView::on_drag_leave (context, time);
+ }
+
+ bool on_drag_motion(const Glib::RefPtr<Gdk::DragContext>& context, int x, int y, guint time) {
+ suggested_action = context->get_suggested_action();
+ return TreeView::on_drag_motion (context, x, y, time);
+ }
+
+ bool on_drag_drop(const Glib::RefPtr<Gdk::DragContext>& context, int x, int y, guint time);
+
+ protected:
+ std::list<Gtk::TargetEntry> draggable;
+ Gdk::DragAction suggested_action;
+ int data_column;
+};
+
+template<class DataType>
+class DnDTreeView : public DnDTreeViewBase
+{
+ public:
+ DnDTreeView() {}
+ ~DnDTreeView() {}
+
+ sigc::signal<void,std::string,uint32_t,const DataType*> signal_object_drop;
+
+ void on_drag_data_get(const Glib::RefPtr<Gdk::DragContext>& context, Gtk::SelectionData& selection_data, guint info, guint time) {
+ if (selection_data.get_target() == "GTK_TREE_MODEL_ROW") {
+
+ TreeView::on_drag_data_get (context, selection_data, info, time);
+
+ } else if (data_column >= 0) {
+
+ Gtk::TreeSelection::ListHandle_Path selection = get_selection()->get_selected_rows ();
+ SerializedObjectPointers<DataType>* sr = serialize_pointers (get_model(), &selection, selection_data.get_target());
+ selection_data.set (8, (guchar*)sr, sr->size);
+ }
+ }
+
+ void on_drag_data_received(const Glib::RefPtr<Gdk::DragContext>& context, int x, int y, const Gtk::SelectionData& selection_data, guint info, guint time) {
+ if (suggested_action) {
+ /* this is a drag motion callback. just update the status to
+ say that we are still dragging, and that's it.
+ */
+ suggested_action = Gdk::DragAction (0);
+ TreeView::on_drag_data_received (context, x, y, selection_data, info, time);
+ return;
+ }
+
+ if (selection_data.get_target() == "GTK_TREE_MODEL_ROW") {
+
+ TreeView::on_drag_data_received (context, x, y, selection_data, info, time);
+
+ } else if (data_column >= 0) {
+
+ /* object D-n-D */
+
+ const void* data = selection_data.get_data();
+ const SerializedObjectPointers<DataType>* sr = reinterpret_cast<const SerializedObjectPointers<DataType> *>(data);
+
+ if (sr) {
+ signal_object_drop (sr->type, sr->cnt, sr->data);
+ }
+
+ } else {
+ /* some kind of target type added by the app, which will be handled by a signal handler */
+ }
+ }
+
+ private:
+
+ SerializedObjectPointers<DataType>* serialize_pointers (Glib::RefPtr<Gtk::TreeModel> model,
+ Gtk::TreeSelection::ListHandle_Path* selection,
+ Glib::ustring type) {
+
+ /* this nasty chunk of code is here because X's DnD protocol (probably other graphics UI's too)
+ requires that we package up the entire data collection for DnD in a single contiguous region
+ (so that it can be trivially copied between address spaces). We don't know the type of DataType so
+ we have to mix-and-match C and C++ programming techniques here to get the right result.
+
+ The C trick is to use the "someType foo[0];" declaration trick to create a zero-sized array at the
+ end of a SerializedObjectPointers<DataType object. Then we allocate a raw memory buffer that extends
+ past that array and thus provides space for however many DataType items we actually want to pass
+ around.
+
+ The C++ trick is to use the placement operator new() syntax to initialize that extra
+ memory properly.
+ */
+
+ uint32_t cnt = selection->size();
+ uint32_t sz = (sizeof (DataType) * cnt) + sizeof (SerializedObjectPointers<DataType>);
+
+ char* buf = new char[sz];
+ SerializedObjectPointers<DataType>* sr = (SerializedObjectPointers<DataType>*) buf;
+
+ for (uint32_t i = 0; i < cnt; ++i) {
+ new ((void *) &sr->data[i]) DataType ();
+ }
+
+ sr->cnt = cnt;
+ sr->size = sz;
+ snprintf (sr->type, sizeof (sr->type), "%s", type.c_str());
+
+ cnt = 0;
+
+ for (Gtk::TreeSelection::ListHandle_Path::iterator x = selection->begin(); x != selection->end(); ++x, ++cnt) {
+ model->get_iter (*x)->get_value (data_column, sr->data[cnt]);
+ }
+
+ return sr;
+ }
+};
+
+} // namespace
+
+#endif /* __gtkmm2ext_dndtreeview_h__ */
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