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>
29 const unsigned int drag_threshold = 8;
30 const double multi_click_timeout = 0.4;
32 //----------------------------------------------------------------------------
33 EventManager::StampedPropagationPath::StampedPropagationPath():
39 //----------------------------------------------------------------------------
41 EventManager::StampedPropagationPath::StampedPropagationPath(
42 const EventPropagationPath& path,
51 //----------------------------------------------------------------------------
52 void EventManager::StampedPropagationPath::clear()
58 //----------------------------------------------------------------------------
59 bool EventManager::StampedPropagationPath::valid() const
61 return !path.empty() && time > 0;
64 //----------------------------------------------------------------------------
65 EventManager::EventManager():
66 _current_click_count(0)
71 //----------------------------------------------------------------------------
72 bool EventManager::handleEvent( const MouseEventPtr& event,
73 const EventPropagationPath& path )
78 case Event::MOUSE_DOWN:
79 _last_mouse_down = StampedPropagationPath(path, event->getTime());
83 // If the mouse has moved while a button was down (aka. dragging) we
84 // need to notify the original element that the mouse has left it, and
85 // the new element that it has been entered
86 if( _last_mouse_down.path != path )
87 handled |= handleMove(event, path);
90 handled |= propagateEvent(event, path);
92 if( _last_mouse_down.path.empty() )
93 // Ignore mouse up without any previous mouse down
96 // now handle click/dblclick
97 if( checkClickDistance(path, _last_mouse_down.path) )
99 handleClick(event, getCommonAncestor(_last_mouse_down.path, path));
101 _last_mouse_down.clear();
106 if( !_last_mouse_down.valid() )
109 return propagateEvent(event, _last_mouse_down.path);
110 case Event::MOUSE_MOVE:
111 handled |= handleMove(event, path);
113 case Event::MOUSE_LEAVE:
114 // Mouse leaves window and therefore also current mouseover element
115 handleMove(event, EventPropagationPath());
117 // Event is only send if mouse is moved outside the window or dragging
118 // has ended somewhere outside the window. In both cases a mouse button
119 // has been released, so no more mouse down or click...
120 _last_mouse_down.clear();
130 return handled | propagateEvent(event, path);
133 //----------------------------------------------------------------------------
134 bool EventManager::handleClick( const MouseEventPtr& event,
135 const EventPropagationPath& path )
137 MouseEventPtr click(new MouseEvent(*event));
138 click->type = Event::CLICK;
140 if( event->getTime() > _last_click.time + multi_click_timeout )
141 _current_click_count = 1;
144 // Maximum current click count is 3
145 _current_click_count = (_current_click_count % 3) + 1;
147 if( _current_click_count > 1 )
149 // Reset current click count if moved too far
150 if( !checkClickDistance(path, _last_click.path) )
151 _current_click_count = 1;
155 click->click_count = _current_click_count;
157 MouseEventPtr dbl_click;
158 if( _current_click_count == 2 )
160 dbl_click.reset(new MouseEvent(*click));
161 dbl_click->type = Event::DBL_CLICK;
164 bool handled = propagateEvent(click, path);
167 handled |= propagateEvent( dbl_click,
168 getCommonAncestor(_last_click.path, path) );
170 _last_click = StampedPropagationPath(path, event->getTime());
175 //----------------------------------------------------------------------------
176 bool EventManager::handleMove( const MouseEventPtr& event,
177 const EventPropagationPath& path )
179 EventPropagationPath& last_path = _last_mouse_over.path;
180 if( last_path == path )
183 bool handled = false;
186 if( !last_path.empty() )
188 MouseEventPtr mouseout(new MouseEvent(*event));
189 mouseout->type = Event::MOUSE_OUT;
190 handled |= propagateEvent(mouseout, last_path);
192 // Send a mouseleave event to all ancestors of the currently left element
193 // which are not ancestor of the new element currently entered
194 EventPropagationPath path_leave = last_path;
195 for(size_t i = path_leave.size() - 1; i > 0; --i)
197 if( i < path.size() && path[i] == path_leave[i] )
200 MouseEventPtr mouseleave(new MouseEvent(*event));
201 mouseleave->type = Event::MOUSE_LEAVE;
202 handled |= propagateEvent(mouseleave, path_leave);
204 path_leave.pop_back();
211 MouseEventPtr mouseover(new MouseEvent(*event));
212 mouseover->type = Event::MOUSE_OVER;
213 handled |= propagateEvent(mouseover, path);
215 // Send a mouseenter event to all ancestors of the currently entered
216 // element which are not ancestor of the old element currently being
218 EventPropagationPath path_enter;
219 for(size_t i = 0; i < path.size(); ++i)
221 path_enter.push_back(path[i]);
223 if( i < last_path.size() && path[i] == last_path[i] )
226 MouseEventPtr mouseenter(new MouseEvent(*event));
227 mouseenter->type = Event::MOUSE_ENTER;
228 handled |= propagateEvent(mouseenter, path_enter);
232 _last_mouse_over.path = path;
236 //----------------------------------------------------------------------------
237 bool EventManager::propagateEvent( const EventPtr& event,
238 const EventPropagationPath& path )
240 event->target = path.back().element;
241 MouseEventPtr mouse_event = boost::dynamic_pointer_cast<MouseEvent>(event);
243 // Event propagation similar to DOM Level 3 event flow:
244 // http://www.w3.org/TR/DOM-Level-3-Events/#event-flow
247 // for( EventPropagationPath::const_iterator it = path.begin();
251 // if( !it->element.expired() )
252 // std::cout << it->element.lock()->getProps()->getPath() << std::endl;
255 // Check if event supports bubbling
256 const Event::Type types_no_bubbling[] = {
260 const size_t num_types_no_bubbling = sizeof(types_no_bubbling)
261 / sizeof(types_no_bubbling[0]);
262 bool do_bubble = true;
263 for( size_t i = 0; i < num_types_no_bubbling; ++i )
264 if( event->type == types_no_bubbling[i] )
271 for( EventPropagationPath::const_reverse_iterator
276 ElementPtr el = it->element.lock();
280 // Ignore element if it has been destroyed while traversing the event
281 // (eg. removed by another event handler)
288 // TODO provide functions to convert delta to local coordinates on demand.
289 // Maybe also provide a clone method for events as local coordinates
290 // might differ between different elements receiving the same event.
291 if( mouse_event ) //&& event->type != Event::DRAG )
293 // TODO transform pos and delta for drag events. Maybe we should just
294 // store the global coordinates and convert to local coordinates
297 // Position and delta are specified in local coordinate system of
299 mouse_event->local_pos = it->local_pos;
300 //mouse_event->delta = it->local_delta;
303 event->current_target = el;
304 el->handleEvent(event);
306 if( event->propagation_stopped || !do_bubble )
313 //----------------------------------------------------------------------------
315 EventManager::checkClickDistance( const EventPropagationPath& path1,
316 const EventPropagationPath& path2 ) const
318 osg::Vec2 delta = path1.front().local_pos - path2.front().local_pos;
319 return std::fabs(delta.x()) < drag_threshold
320 && std::fabs(delta.y()) < drag_threshold;
323 //----------------------------------------------------------------------------
325 EventManager::getCommonAncestor( const EventPropagationPath& path1,
326 const EventPropagationPath& path2 ) const
328 if( path1.empty() || path2.empty() )
329 return EventPropagationPath();
331 if( path1.back().element.lock() == path2.back().element.lock() )
334 EventPropagationPath path;
336 for( size_t i = 0; i < path1.size() && i < path2.size(); ++i )
338 if( path1[i].element.lock() != path2[i].element.lock() )
341 path.push_back(path2[i]);
347 } // namespace canvas
348 } // namespace simgear