[TD]add extensions for drag and drop

src/Mod/TechDraw/Gui/ViewProviderDrawingViewExtension.cpp

@@ -0,0 +1,108 @@
+/***************************************************************************
+ *   Copyright (c) 2022 WandererFan <wandererfan@gmail.com>                *
+ *                                                                         *
+ *   This file is part of the FreeCAD CAx development system.              *
+ *                                                                         *
+ *   This library is free software; you can redistribute it and/or         *
+ *   modify it under the terms of the GNU Library General Public           *
+ *   License as published by the Free Software Foundation; either          *
+ *   version 2 of the License, or (at your option) any later version.      *
+ *                                                                         *
+ *   This library  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 Library General Public License for more details.                  *
+ *                                                                         *
+ *   You should have received a copy of the GNU Library General Public     *
+ *   License along with this library; see the file COPYING.LIB. If not,    *
+ *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
+ *   Suite 330, Boston, MA  02111-1307, USA                                *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "PreCompiled.h"
+
+#ifndef _PreComp_
+# include <QMessageBox>
+#endif
+
+#include <App/Document.h>
+#include <App/DocumentObject.h>
+#include <Base/Console.h>
+#include <Base/Tools.h>
+
+#include <Mod/TechDraw/App/DrawPage.h>
+#include <Mod/TechDraw/App/DrawTemplate.h>
+
+#include "ViewProviderDrawingViewExtension.h"
+#include "ViewProviderDrawingView.h"
+#include "ViewProviderPage.h"
+
+using namespace TechDrawGui;
+
+EXTENSION_PROPERTY_SOURCE(TechDrawGui::ViewProviderDrawingViewExtension, Gui::ViewProviderExtension)
+
+ViewProviderDrawingViewExtension::ViewProviderDrawingViewExtension()
+{
+    initExtensionType(ViewProviderDrawingViewExtension::getExtensionClassTypeId());
+}
+
+ViewProviderDrawingViewExtension::~ViewProviderDrawingViewExtension()
+{
+}
+
+bool ViewProviderDrawingViewExtension::extensionCanDragObjects() const {
+    return true;
+}
+
+//we don't support dragging children of Views (Dimensions, Balloons, Hatches, etc) now, but we don't want another
+//extension to drag our children and cause problems
+bool ViewProviderDrawingViewExtension::extensionCanDragObject(App::DocumentObject* docObj) const {
+    (void)docObj;
+    return true;
+}
+
+//the default drag will remove the object from the document until it is dropped and re-added, so we claim
+//to do the dragging.
+void ViewProviderDrawingViewExtension::extensionDragObject(App::DocumentObject* obj) {
+    (void)obj;
+}
+
+//we don't support dropping of new children of Views (Dimensions, Balloons, Hatches, etc) now, but we don't want another
+//extension to try to drop on us and cause problems
+bool ViewProviderDrawingViewExtension::extensionCanDropObjects() const {
+    return true;
+}
+
+//let the page have any drops we receive
+bool ViewProviderDrawingViewExtension::extensionCanDropObject(App::DocumentObject* obj) const {
+    return getViewProviderDrawingView()->getViewProviderPage()->getVPPExtension()->extensionCanDropObject(obj);
+}
+
+//let the page have any drops we receive
+void ViewProviderDrawingViewExtension::extensionDropObject(App::DocumentObject* obj) {
+    getViewProviderDrawingView()->getViewProviderPage()->getVPPExtension()->extensionDropObject(obj);
+}
+
+const ViewProviderDrawingView* ViewProviderDrawingViewExtension::getViewProviderDrawingView() const
+{
+    return dynamic_cast<const ViewProviderDrawingView*>(getExtendedViewProvider());
+}
+
+const char*  ViewProviderDrawingViewExtension::whoAmI() const
+{
+    auto parent = getViewProviderDrawingView();
+    if (parent) {
+        return parent->whoAmI();
+    }
+    return nullptr;
+}
+
+namespace Gui {
+EXTENSION_PROPERTY_SOURCE_TEMPLATE(ViewProviderDrawingViewExtensionPython, ViewProviderDrawingViewExtension)
+
+// explicit template instantiation
+template class GuiExport ViewProviderExtensionPythonT<ViewProviderDrawingViewExtension>;
+}
+
+