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);
101 case Event::MOUSE_MOVE:
102 handleMove(event, path);
104 case Event::MOUSE_LEAVE:
105 // Mouse leaves window and therefore also current mouseover element
106 handleMove(event, EventPropagationPath());
114 return propagateEvent(event, path);
117 //----------------------------------------------------------------------------
118 void EventManager::handleClick( const MouseEventPtr& event,
119 const EventPropagationPath& path )
121 MouseEventPtr click(new MouseEvent(*event));
122 click->type = Event::CLICK;
124 if( event->getTime() > _last_click.time + multi_click_timeout )
125 _current_click_count = 1;
128 // Maximum current click count is 3
129 _current_click_count = (_current_click_count % 3) + 1;
131 if( _current_click_count > 1 )
133 // Reset current click count if moved too far
134 if( !checkClickDistance(path, _last_click.path) )
135 _current_click_count = 1;
139 click->click_count = _current_click_count;
141 MouseEventPtr dbl_click;
142 if( _current_click_count == 2 )
144 dbl_click.reset(new MouseEvent(*click));
145 dbl_click->type = Event::DBL_CLICK;
148 propagateEvent(click, path);
151 propagateEvent(dbl_click, getCommonAncestor(_last_click.path, path));
153 _last_click = StampedPropagationPath(path, event->getTime());
156 //----------------------------------------------------------------------------
157 void EventManager::handleMove( const MouseEventPtr& event,
158 const EventPropagationPath& path )
160 if( _last_mouse_over.path == path )
163 if( !_last_mouse_over.path.empty() )
165 MouseEventPtr mouseout(new MouseEvent(*event));
166 mouseout->type = Event::MOUSE_OUT;
167 propagateEvent(mouseout, _last_mouse_over.path);
172 MouseEventPtr mouseover(new MouseEvent(*event));
173 mouseover->type = Event::MOUSE_OVER;
174 propagateEvent(mouseover, path);
177 _last_mouse_over.path = path;
180 //----------------------------------------------------------------------------
181 bool EventManager::propagateEvent( const EventPtr& event,
182 const EventPropagationPath& path )
184 event->target = path.back().element;
185 MouseEventPtr mouse_event = boost::dynamic_pointer_cast<MouseEvent>(event);
187 // Event propagation similar to DOM Level 3 event flow:
188 // http://www.w3.org/TR/DOM-Level-3-Events/#event-flow
191 // for( EventTargets::iterator it = _target_path.begin();
192 // it != _target_path.end();
196 // std::cout << it->element->getProps()->getPath() << " "
197 // << "(" << it->local_pos.x() << "|" << it->local_pos.y() << ")\n";
201 for( EventPropagationPath::const_reverse_iterator
206 ElementPtr el = it->element.lock();
209 // Ignore element if it has been destroyed while traversing the event
210 // (eg. removed by another event handler)
213 // TODO provide functions to convert position and delta to local
214 // coordinates on demand. Events shouldn't contain informations in
215 // local coordinates as they might differe between different elements
216 // receiving the same event.
217 // if( mouse_event && event->type != Event::DRAG )
219 // // TODO transform pos and delta for drag events. Maybe we should just
220 // // store the global coordinates and convert to local coordinates
223 // // Position and delta are specified in local coordinate system of
224 // // current element
225 // mouse_event->pos = it->local_pos;
226 // mouse_event->delta = it->local_delta;
229 el->callListeners(event);
231 if( event->propagation_stopped )
238 //----------------------------------------------------------------------------
240 EventManager::checkClickDistance( const EventPropagationPath& path1,
241 const EventPropagationPath& path2 ) const
243 osg::Vec2 delta = path1.front().local_pos - path2.front().local_pos;
244 return delta.x() < drag_threshold
245 && delta.y() < drag_threshold;
248 //----------------------------------------------------------------------------
250 EventManager::getCommonAncestor( const EventPropagationPath& path1,
251 const EventPropagationPath& path2 ) const
253 if( path1.back().element.lock() == path2.back().element.lock() )
256 EventPropagationPath path;
258 for( size_t i = 0; i < path1.size() && i < path2.size(); ++i )
260 if( path1[i].element.lock() != path2[i].element.lock() )
263 path.push_back(path2[i]);
269 } // namespace canvas
270 } // namespace simgear