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simgear/simgear/canvas/CanvasEventManager.cxx
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// Manage event handling inside a Canvas similar to the DOM Level 3 Event Model
//
// Copyright (C) 2012 Thomas Geymayer <tomgey@gmail.com>
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
#include "CanvasEventManager.hxx"
#include "MouseEvent.hxx"
#include <simgear/canvas/elements/CanvasElement.hxx>
namespace simgear
{
namespace canvas
{
const unsigned int drag_threshold = 8;
const double multi_click_timeout = 0.4;
//----------------------------------------------------------------------------
EventManager::StampedPropagationPath::StampedPropagationPath():
time(0)
{
}
//----------------------------------------------------------------------------
EventManager::StampedPropagationPath::StampedPropagationPath(
const EventPropagationPath& path,
double time
):
path(path),
time(time)
{
}
//----------------------------------------------------------------------------
void EventManager::StampedPropagationPath::clear()
{
path.clear();
time = 0;
}
//----------------------------------------------------------------------------
bool EventManager::StampedPropagationPath::valid() const
{
return !path.empty() && time > 0;
}
//----------------------------------------------------------------------------
EventManager::EventManager():
_current_click_count(0)
{
}
//----------------------------------------------------------------------------
bool EventManager::handleEvent( const MouseEventPtr& event,
const EventPropagationPath& path )
{
switch( event->type )
{
case Event::MOUSE_DOWN:
_last_mouse_down = StampedPropagationPath(path, event->getTime());
break;
case Event::MOUSE_UP:
{
if( _last_mouse_down.path.empty() )
// Ignore mouse up without any previous mouse down
return false;
// normal mouseup
propagateEvent(event, path);
// now handle click/dblclick
if( checkClickDistance(path, _last_mouse_down.path) )
handleClick(event, getCommonAncestor(_last_mouse_down.path, path));
_last_mouse_down.clear();
return true;
}
case Event::DRAG:
if( !_last_mouse_down.valid() )
return false;
else
return propagateEvent(event, _last_mouse_down.path);
case Event::MOUSE_MOVE:
handleMove(event, path);
break;
case Event::MOUSE_LEAVE:
// Mouse leaves window and therefore also current mouseover element
handleMove(event, EventPropagationPath());
return true;
case Event::WHEEL:
break;
default:
return false;
}
return propagateEvent(event, path);
}
//----------------------------------------------------------------------------
void EventManager::handleClick( const MouseEventPtr& event,
const EventPropagationPath& path )
{
MouseEventPtr click(new MouseEvent(*event));
click->type = Event::CLICK;
if( event->getTime() > _last_click.time + multi_click_timeout )
_current_click_count = 1;
else
{
// Maximum current click count is 3
_current_click_count = (_current_click_count % 3) + 1;
if( _current_click_count > 1 )
{
// Reset current click count if moved too far
if( !checkClickDistance(path, _last_click.path) )
_current_click_count = 1;
}
}
click->click_count = _current_click_count;
MouseEventPtr dbl_click;
if( _current_click_count == 2 )
{
dbl_click.reset(new MouseEvent(*click));
dbl_click->type = Event::DBL_CLICK;
}
propagateEvent(click, path);
if( dbl_click )
propagateEvent(dbl_click, getCommonAncestor(_last_click.path, path));
_last_click = StampedPropagationPath(path, event->getTime());
}
//----------------------------------------------------------------------------
void EventManager::handleMove( const MouseEventPtr& event,
const EventPropagationPath& path )
{
if( _last_mouse_over.path == path )
return;
if( !_last_mouse_over.path.empty() )
{
MouseEventPtr mouseout(new MouseEvent(*event));
mouseout->type = Event::MOUSE_OUT;
propagateEvent(mouseout, _last_mouse_over.path);
}
if( !path.empty() )
{
MouseEventPtr mouseover(new MouseEvent(*event));
mouseover->type = Event::MOUSE_OVER;
propagateEvent(mouseover, path);
}
_last_mouse_over.path = path;
}
//----------------------------------------------------------------------------
bool EventManager::propagateEvent( const EventPtr& event,
const EventPropagationPath& path )
{
event->target = path.back().element;
MouseEventPtr mouse_event = boost::dynamic_pointer_cast<MouseEvent>(event);
// Event propagation similar to DOM Level 3 event flow:
// http://www.w3.org/TR/DOM-Level-3-Events/#event-flow
// Capturing phase
// for( EventTargets::iterator it = _target_path.begin();
// it != _target_path.end();
// ++it )
// {
// if( it->element )
// std::cout << it->element->getProps()->getPath() << " "
// << "(" << it->local_pos.x() << "|" << it->local_pos.y() << ")\n";
// }
// Bubbling phase
for( EventPropagationPath::const_reverse_iterator
it = path.rbegin();
it != path.rend();
++it )
{
ElementPtr el = it->element.lock();
if( !el )
// Ignore element if it has been destroyed while traversing the event
// (eg. removed by another event handler)
continue;
// TODO provide functions to convert position and delta to local
// coordinates on demand. Events shouldn't contain informations in
// local coordinates as they might differe between different elements
// receiving the same event.
// if( mouse_event && event->type != Event::DRAG )
// {
// // TODO transform pos and delta for drag events. Maybe we should just
// // store the global coordinates and convert to local coordinates
// // on demand.
//
// // Position and delta are specified in local coordinate system of
// // current element
// mouse_event->pos = it->local_pos;
// mouse_event->delta = it->local_delta;
// }
el->callListeners(event);
if( event->propagation_stopped )
return true;
}
return true;
}
//----------------------------------------------------------------------------
bool
EventManager::checkClickDistance( const EventPropagationPath& path1,
const EventPropagationPath& path2 ) const
{
osg::Vec2 delta = path1.front().local_pos - path2.front().local_pos;
return delta.x() < drag_threshold
&& delta.y() < drag_threshold;
}
//----------------------------------------------------------------------------
EventPropagationPath
EventManager::getCommonAncestor( const EventPropagationPath& path1,
const EventPropagationPath& path2 ) const
{
if( path1.back().element.lock() == path2.back().element.lock() )
return path2;
EventPropagationPath path;
for( size_t i = 0; i < path1.size() && i < path2.size(); ++i )
{
if( path1[i].element.lock() != path2[i].element.lock() )
break;
path.push_back(path2[i]);
}
return path;
}
} // namespace canvas
} // namespace simgear