namespace Gtkmm2ext {
-class DnDTreeView : public Gtk::TreeView
-{
+template<class DataType>
+struct SerializedObjectPointers {
+ uint32_t size;
+ uint32_t cnt;
+ char type[32];
+ DataType data[0];
+};
+class DnDTreeViewBase : public Gtk::TreeView
+{
private:
public:
- DnDTreeView ();
- ~DnDTreeView() {}
+ DnDTreeViewBase ();
+ ~DnDTreeViewBase() {}
- /* this is the structure pointed to if add_object_drag() is called
- and a drop happens on a destination which has declared itself
- willing to accept a target of the type named in the call
- to add_object_drag().
- */
-
- struct SerializedObjectPointers {
- uint32_t size;
- uint32_t cnt;
- char type[32];
- void* ptr[0];
- };
-
void add_drop_targets (std::list<Gtk::TargetEntry>&);
void add_object_drag (int column, std::string type_name);
- sigc::signal<void,std::string,uint32_t,void**> signal_object_drop;
- void on_drag_begin(const Glib::RefPtr<Gdk::DragContext>& context) {
- TreeView::on_drag_begin (context);
- }
- void on_drag_end(const Glib::RefPtr<Gdk::DragContext>& context) {
- TreeView::on_drag_end (context);
- }
- void on_drag_data_delete(const Glib::RefPtr<Gdk::DragContext>& context) {
- TreeView::on_drag_data_delete (context);
- }
void on_drag_leave(const Glib::RefPtr<Gdk::DragContext>& context, guint time) {
- suggested_action = context->get_suggested_action();
- TreeView::on_drag_leave (context, 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);
- void on_drag_data_get(const Glib::RefPtr<Gdk::DragContext>& context, Gtk::SelectionData& selection_data, guint info, guint time);
- void on_drag_data_received(const Glib::RefPtr<Gdk::DragContext>& context, int x, int y, const Gtk::SelectionData& selection_data, guint info, guint time);
- private:
+ protected:
std::list<Gtk::TargetEntry> draggable;
Gdk::DragAction suggested_action;
int data_column;
-
- SerializedObjectPointers* serialize_pointers (Glib::RefPtr<Gtk::TreeModel> m,
- Gtk::TreeSelection::ListHandle_Path*,
- Glib::ustring type);
+};
+
+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
projects / ardour.git / blobdiff