1 // Manage event handling inside a Canvas similar to the DOM Level 3 Event Model
3 // Copyright (C) 2012 Thomas Geymayer <tomgey@gmail.com>
5 // This library is free software; you can redistribute it and/or
6 // modify it under the terms of the GNU Library General Public
7 // License as published by the Free Software Foundation; either
8 // version 2 of the License, or (at your option) any later version.
10 // This library is distributed in the hope that it will be useful,
11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 // Library General Public License for more details.
15 // You should have received a copy of the GNU Library General Public
16 // License along with this library; if not, write to the Free Software
17 // Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
19 #include "CanvasEventManager.hxx"
20 #include "MouseEvent.hxx"
21 #include <simgear/canvas/elements/CanvasElement.hxx>
28 const unsigned int drag_threshold = 8;
29 const double multi_click_timeout = 0.4;
31 //----------------------------------------------------------------------------
32 EventManager::StampedPropagationPath::StampedPropagationPath():
38 //----------------------------------------------------------------------------
40 EventManager::StampedPropagationPath::StampedPropagationPath(
41 const EventPropagationPath& path,
50 //----------------------------------------------------------------------------
51 void EventManager::StampedPropagationPath::clear()
57 //----------------------------------------------------------------------------
58 bool EventManager::StampedPropagationPath::valid() const
60 return !path.empty() && time > 0;
63 //----------------------------------------------------------------------------
64 EventManager::EventManager():
65 _current_click_count(0)
70 //----------------------------------------------------------------------------
71 bool EventManager::handleEvent( const MouseEventPtr& event,
72 const EventPropagationPath& path )
76 case Event::MOUSE_DOWN:
77 _last_mouse_down = StampedPropagationPath(path, event->getTime());
81 if( _last_mouse_down.path.empty() )
82 // Ignore mouse up without any previous mouse down
86 propagateEvent(event, path);
88 // now handle click/dblclick
89 if( checkClickDistance(path, _last_mouse_down.path) )
90 handleClick(event, getCommonAncestor(_last_mouse_down.path, path));
92 _last_mouse_down.clear();
97 if( !_last_mouse_down.valid() )
100 return propagateEvent(event, _last_mouse_down.path);
102 case Event::MOUSE_MOVE:
108 return propagateEvent(event, path);
111 //----------------------------------------------------------------------------
112 void EventManager::handleClick( const MouseEventPtr& event,
113 const EventPropagationPath& path )
115 MouseEventPtr click(new MouseEvent(*event));
116 click->type = Event::CLICK;
118 if( event->getTime() > _last_click.time + multi_click_timeout )
119 _current_click_count = 1;
122 // Maximum current click count is 3
123 _current_click_count = (_current_click_count % 3) + 1;
125 if( _current_click_count > 1 )
127 // Reset current click count if moved too far
128 if( !checkClickDistance(path, _last_click.path) )
129 _current_click_count = 1;
133 click->click_count = _current_click_count;
135 MouseEventPtr dbl_click;
136 if( _current_click_count == 2 )
138 dbl_click.reset(new MouseEvent(*click));
139 dbl_click->type = Event::DBL_CLICK;
142 propagateEvent(click, path);
145 propagateEvent(dbl_click, getCommonAncestor(_last_click.path, path));
147 _last_click = StampedPropagationPath(path, event->getTime());
150 //----------------------------------------------------------------------------
151 bool EventManager::propagateEvent( const EventPtr& event,
152 const EventPropagationPath& path )
154 event->target = path.back().element;
155 MouseEventPtr mouse_event = boost::dynamic_pointer_cast<MouseEvent>(event);
157 // Event propagation similar to DOM Level 3 event flow:
158 // http://www.w3.org/TR/DOM-Level-3-Events/#event-flow
161 // for( EventTargets::iterator it = _target_path.begin();
162 // it != _target_path.end();
166 // std::cout << it->element->getProps()->getPath() << " "
167 // << "(" << it->local_pos.x() << "|" << it->local_pos.y() << ")\n";
171 for( EventPropagationPath::const_reverse_iterator
176 ElementPtr el = it->element.lock();
179 // Ignore element if it has been destroyed while traversing the event
180 // (eg. removed by another event handler)
183 if( mouse_event && event->type != Event::DRAG )
185 // TODO transform pos and delta for drag events. Maybe we should just
186 // store the global coordinates and convert to local coordinates
189 // Position and delta are specified in local coordinate system of
191 mouse_event->pos = it->local_pos;
192 mouse_event->delta = it->local_delta;
195 el->callListeners(event);
197 if( event->propagation_stopped )
204 //----------------------------------------------------------------------------
206 EventManager::checkClickDistance( const EventPropagationPath& path1,
207 const EventPropagationPath& path2 ) const
209 osg::Vec2 delta = path1.front().local_pos - path2.front().local_pos;
210 return delta.x() < drag_threshold
211 && delta.y() < drag_threshold;
214 //----------------------------------------------------------------------------
216 EventManager::getCommonAncestor( const EventPropagationPath& path1,
217 const EventPropagationPath& path2 ) const
219 if( path1.back().element.lock() == path2.back().element.lock() )
222 EventPropagationPath path;
224 for( size_t i = 0; i < path1.size() && i < path2.size(); ++i )
226 if( path1[i].element.lock() != path2[i].element.lock() )
229 path.push_back(path2[i]);
235 } // namespace canvas
236 } // namespace simgear