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 )
77 case Event::MOUSE_DOWN:
78 _last_mouse_down = StampedPropagationPath(path, event->getTime());
82 // If the mouse has moved while a button was down (aka. dragging) we
83 // need to notify the original element that the mouse has left it, and
84 // the new element that it has been entered
85 if( _last_mouse_down.path != path )
86 handled |= handleMove(event, path);
89 handled |= propagateEvent(event, path);
91 if( _last_mouse_down.path.empty() )
92 // Ignore mouse up without any previous mouse down
95 // now handle click/dblclick
96 if( checkClickDistance(path, _last_mouse_down.path) )
98 handleClick(event, getCommonAncestor(_last_mouse_down.path, path));
100 _last_mouse_down.clear();
105 if( !_last_mouse_down.valid() )
108 return propagateEvent(event, _last_mouse_down.path);
109 case Event::MOUSE_MOVE:
110 handled |= handleMove(event, path);
112 case Event::MOUSE_LEAVE:
113 // Mouse leaves window and therefore also current mouseover element
114 handleMove(event, EventPropagationPath());
116 // Event is only send if mouse is moved outside the window or dragging
117 // has ended somewhere outside the window. In both cases a mouse button
118 // has been released, so no more mouse down or click...
119 _last_mouse_down.clear();
129 return handled | propagateEvent(event, path);
132 //----------------------------------------------------------------------------
133 bool EventManager::handleClick( const MouseEventPtr& event,
134 const EventPropagationPath& path )
136 MouseEventPtr click(new MouseEvent(*event));
137 click->type = Event::CLICK;
139 if( event->getTime() > _last_click.time + multi_click_timeout )
140 _current_click_count = 1;
143 // Maximum current click count is 3
144 _current_click_count = (_current_click_count % 3) + 1;
146 if( _current_click_count > 1 )
148 // Reset current click count if moved too far
149 if( !checkClickDistance(path, _last_click.path) )
150 _current_click_count = 1;
154 click->click_count = _current_click_count;
156 MouseEventPtr dbl_click;
157 if( _current_click_count == 2 )
159 dbl_click.reset(new MouseEvent(*click));
160 dbl_click->type = Event::DBL_CLICK;
163 bool handled = propagateEvent(click, path);
166 handled |= propagateEvent( dbl_click,
167 getCommonAncestor(_last_click.path, path) );
169 _last_click = StampedPropagationPath(path, event->getTime());
174 //----------------------------------------------------------------------------
175 bool EventManager::handleMove( const MouseEventPtr& event,
176 const EventPropagationPath& path )
178 EventPropagationPath& last_path = _last_mouse_over.path;
179 if( last_path == path )
182 bool handled = false;
185 if( !last_path.empty() )
187 MouseEventPtr mouseout(new MouseEvent(*event));
188 mouseout->type = Event::MOUSE_OUT;
189 handled |= propagateEvent(mouseout, last_path);
191 // Send a mouseleave event to all ancestors of the currently left element
192 // which are not ancestor of the new element currently entered
193 EventPropagationPath path_leave = last_path;
194 for(size_t i = path_leave.size() - 1; i > 0; --i)
196 if( i < path.size() && path[i] == path_leave[i] )
199 MouseEventPtr mouseleave(new MouseEvent(*event));
200 mouseleave->type = Event::MOUSE_LEAVE;
201 handled |= propagateEvent(mouseleave, path_leave);
203 path_leave.pop_back();
210 MouseEventPtr mouseover(new MouseEvent(*event));
211 mouseover->type = Event::MOUSE_OVER;
212 handled |= propagateEvent(mouseover, path);
214 // Send a mouseenter event to all ancestors of the currently entered
215 // element which are not ancestor of the old element currently being
217 EventPropagationPath path_enter;
218 for(size_t i = 0; i < path.size(); ++i)
220 path_enter.push_back(path[i]);
222 if( i < last_path.size() && path[i] == last_path[i] )
225 MouseEventPtr mouseenter(new MouseEvent(*event));
226 mouseenter->type = Event::MOUSE_ENTER;
227 handled |= propagateEvent(mouseenter, path_enter);
231 _last_mouse_over.path = path;
235 //----------------------------------------------------------------------------
236 bool EventManager::propagateEvent( const EventPtr& event,
237 const EventPropagationPath& path )
239 event->target = path.back().element;
240 MouseEventPtr mouse_event = boost::dynamic_pointer_cast<MouseEvent>(event);
242 // Event propagation similar to DOM Level 3 event flow:
243 // http://www.w3.org/TR/DOM-Level-3-Events/#event-flow
246 // for( EventPropagationPath::const_iterator it = path.begin();
250 // if( !it->element.expired() )
251 // std::cout << it->element.lock()->getProps()->getPath() << std::endl;
254 // Check if event supports bubbling
255 const Event::Type types_no_bubbling[] = {
259 const size_t num_types_no_bubbling = sizeof(types_no_bubbling)
260 / sizeof(types_no_bubbling[0]);
261 bool do_bubble = true;
262 for( size_t i = 0; i < num_types_no_bubbling; ++i )
263 if( event->type == types_no_bubbling[i] )
270 for( EventPropagationPath::const_reverse_iterator
275 ElementPtr el = it->element.lock();
279 // Ignore element if it has been destroyed while traversing the event
280 // (eg. removed by another event handler)
287 // TODO provide functions to convert delta to local coordinates on demand.
288 // Maybe also provide a clone method for events as local coordinates
289 // might differ between different elements receiving the same event.
290 if( mouse_event ) //&& event->type != Event::DRAG )
292 // TODO transform pos and delta for drag events. Maybe we should just
293 // store the global coordinates and convert to local coordinates
296 // Position and delta are specified in local coordinate system of
298 mouse_event->local_pos = it->local_pos;
299 //mouse_event->delta = it->local_delta;
302 event->current_target = el;
303 el->handleEvent(event);
305 if( event->propagation_stopped || !do_bubble )
312 //----------------------------------------------------------------------------
314 EventManager::checkClickDistance( const EventPropagationPath& path1,
315 const EventPropagationPath& path2 ) const
317 osg::Vec2 delta = path1.front().local_pos - path2.front().local_pos;
318 return std::fabs(delta.x()) < drag_threshold
319 && std::fabs(delta.y()) < drag_threshold;
322 //----------------------------------------------------------------------------
324 EventManager::getCommonAncestor( const EventPropagationPath& path1,
325 const EventPropagationPath& path2 ) const
327 if( path1.empty() || path2.empty() )
328 return EventPropagationPath();
330 if( path1.back().element.lock() == path2.back().element.lock() )
333 EventPropagationPath path;
335 for( size_t i = 0; i < path1.size() && i < path2.size(); ++i )
337 if( path1[i].element.lock() != path2[i].element.lock() )
340 path.push_back(path2[i]);
346 } // namespace canvas
347 } // namespace simgear