Added DragCallback class to help dialog dragging support.

Introduced a new Widget::computeExtentsPositionInLocalCoordinates() method that intersects with a ray through mouse pointer and the extents of the widget.


git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@14429 16af8721-9629-0410-8352-f15c8da7e697

include/osgUI/Callbacks

@@ -0,0 +1,65 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2014 Robert Osfield
+ *
+ * This library is open source and may be redistributed and/or modified under
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ *
+ * 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
+ * OpenSceneGraph Public License for more details.
+*/
+
+#ifndef OSGUI_CALLBACKS
+#define OSGUI_CALLBACKS
+
+#include <osg/Callback>
+#include <osgGA/EventVisitor>
+
+#include <osgUI/Export>
+
+namespace osgUI
+{
+
+class OSGUI_EXPORT HandleCallback : public osg::CallbackObject
+{
+public:
+    HandleCallback();
+    HandleCallback(const HandleCallback& hc, const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY);
+    META_Object(osgUI, HandleCallback);
+
+    virtual bool run(osg::Object* object, osg::Parameters& inputParameters, osg::Parameters& outputParameters) const;
+    virtual bool handle(osgGA::EventVisitor* ev, osgGA::Event* event) const;
+
+protected:
+    virtual ~HandleCallback() {}
+};
+
+
+class OSGUI_EXPORT DragCallback : public HandleCallback
+{
+public:
+    DragCallback();
+    DragCallback(const DragCallback& dc, const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY);
+    META_Object(osgUI, DragCallback);
+
+    void setDragging(bool v) { _dragging = v; }
+    bool getDragging() const { return _dragging; }
+
+    void setPreviousPosition(const osg::Vec3d& position) { _previousPosition = position; }
+    const osg::Vec3d& getPreviousPosition() const { return _previousPosition; }
+
+    virtual bool handle(osgGA::EventVisitor* ev, osgGA::Event* event) const;
+
+protected:
+    virtual ~DragCallback() {}
+
+    bool        _dragging;
+    osg::Vec3d  _previousPosition;
+
+};
+
+}
+
+#endif