1 // Visitor for traversing a canvas element hierarchy similar to the traversal
2 // of the DOM Level 3 Event Model
4 // Copyright (C) 2012 Thomas Geymayer <tomgey@gmail.com>
6 // This library is free software; you can redistribute it and/or
7 // modify it under the terms of the GNU Library General Public
8 // License as published by the Free Software Foundation; either
9 // version 2 of the License, or (at your option) any later version.
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 // Library General Public License for more details.
16 // You should have received a copy of the GNU Library General Public
17 // License along with this library; if not, write to the Free Software
18 // Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
20 #include "CanvasEvent.hxx"
21 #include "CanvasEventVisitor.hxx"
22 #include <simgear/canvas/elements/CanvasElement.hxx>
30 //----------------------------------------------------------------------------
31 EventVisitor::EventVisitor( TraverseMode mode,
32 const osg::Vec2f& pos,
33 const osg::Vec2f& delta,
34 const ElementPtr& root ):
35 _traverse_mode( mode ),
38 if( mode == TRAVERSE_DOWN )
40 EventTarget target = {ElementWeakPtr(), pos, delta};
41 _target_path.push_back(target);
45 //----------------------------------------------------------------------------
46 EventVisitor::~EventVisitor()
51 //----------------------------------------------------------------------------
52 bool EventVisitor::traverse(Element& el)
54 if( _traverse_mode == TRAVERSE_UP )
55 return el.ascend(*this);
57 return el.traverse(*this);
60 //----------------------------------------------------------------------------
61 bool EventVisitor::apply(Element& el)
63 // We only need to check for hits while traversing down
64 if( _traverse_mode == TRAVERSE_DOWN )
66 // Transform event to local coordinates
67 const osg::Matrix& m = el.getMatrixTransform()->getInverseMatrix();
68 const osg::Vec2f& pos = _target_path.back().local_pos;
69 const osg::Vec2f local_pos
71 m(0, 0) * pos[0] + m(1, 0) * pos[1] + m(3, 0),
72 m(0, 1) * pos[0] + m(1, 1) * pos[1] + m(3, 1)
75 // Don't check specified root element for collision, as its purpose is to
76 // catch all events which have no target. This allows for example calling
77 // event listeners attached to the canvas itself (its root group) even if
78 // no element has been hit.
79 if( _root.get() != &el && !el.hitBound(pos, local_pos) )
82 const osg::Vec2f& delta = _target_path.back().local_delta;
83 const osg::Vec2f local_delta
85 m(0, 0) * delta[0] + m(1, 0) * delta[1],
86 m(0, 1) * delta[0] + m(1, 1) * delta[1]
89 EventTarget target = {el.getWeakPtr(), local_pos, local_delta};
90 _target_path.push_back(target);
92 if( el.traverse(*this) || &el == _root.get() )
95 _target_path.pop_back();
99 return el.ascend(*this);
102 //----------------------------------------------------------------------------
103 const EventPropagationPath& EventVisitor::getPropagationPath() const
108 } // namespace canvas
109 } // namespace simgear