Files
simgear/simgear/canvas/CanvasEventManager.cxx
2018-03-02 09:07:01 +01:00

359 lines
11 KiB
C++

///@file
/// 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 <simgear_config.h>
#include "CanvasEventManager.hxx"
#include "elements/CanvasElement.hxx"
#include "events/MouseEvent.hxx"
#include <cmath>
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;
}
//----------------------------------------------------------------------------
void EventManager::MouseEventInfo::set( const MouseEventPtr& event,
const EventPropagationPath& p )
{
path = p;
time = event->time;
button = event->button;
pos = event->screen_pos;
}
//----------------------------------------------------------------------------
EventManager::EventManager():
_current_click_count(0)
{
}
//----------------------------------------------------------------------------
bool EventManager::handleEvent( const MouseEventPtr& event,
const EventPropagationPath& path )
{
bool handled = false;
switch( event->type )
{
case Event::MOUSE_DOWN:
_last_mouse_down.set(event, path);
break;
case Event::MOUSE_UP:
{
// If the mouse has moved while a button was down (aka. dragging) we
// need to notify the original element that the mouse has left it, and
// the new element that it has been entered
if( _last_mouse_down.path != path )
handled |= handleMove(event, path);
// normal mouseup
handled |= propagateEvent(event, path);
if( !_last_mouse_down.valid() )
// Ignore mouse up without any previous mouse down
return handled;
// now handle click/dblclick
if( checkClickDistance(event->screen_pos, _last_mouse_down.pos) )
handled |=
handleClick(event, getCommonAncestor(_last_mouse_down.path, path));
_last_mouse_down.clear();
return handled;
}
case Event::DRAG:
case Event::DRAG_START:
case Event::DRAG_END:
if( !_last_mouse_down.valid() )
return false;
else
{
// OSG does not set button for drag events.
event->button = _last_mouse_down.button;
return propagateEvent(event, _last_mouse_down.path);
}
case Event::MOUSE_MOVE:
handled |= handleMove(event, path);
break;
case Event::MOUSE_LEAVE:
// Mouse leaves window and therefore also current mouseover element
handleMove(event, EventPropagationPath());
// Event is only send if mouse is moved outside the window or dragging
// has ended somewhere outside the window. In both cases a mouse button
// has been released, so no more mouse down or click...
_last_mouse_down.clear();
_last_click.clear();
return true;
case Event::WHEEL:
break;
default:
return false;
}
return handled | propagateEvent(event, path);
}
//----------------------------------------------------------------------------
bool EventManager::propagateEvent( const EventPtr& event,
const EventPropagationPath& path )
{
event->target = path.back().element;
MouseEventPtr mouse_event = dynamic_cast<MouseEvent*>(event.get());
// Event propagation similar to DOM Level 3 event flow:
// http://www.w3.org/TR/DOM-Level-3-Events/#event-flow
// Position update only needed for drag event (as event needs to be
// delivered to element of initial mousedown, but with update positions)
if( mouse_event && mouse_event->type == MouseEvent::DRAG )
{
osg::Vec2f local_pos = mouse_event->client_pos;
// Capturing phase (currently just update position)
for( EventPropagationPath::const_iterator it = path.begin();
it != path.end();
++it )
{
ElementPtr el = it->element.lock();
if( !el )
continue;
it->local_pos = local_pos = el->posToLocal(local_pos);
}
}
bool const do_bubble = event->canBubble();
// 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)
if( do_bubble )
continue;
else
break;
}
// TODO provide functions to convert delta to local coordinates on demand.
// Maybe also provide a clone method for events as local coordinates
// might differ between different elements receiving the same event.
if( mouse_event )
mouse_event->local_pos = it->local_pos;
event->current_target = el;
el->handleEvent(event);
if( event->propagation_stopped || !do_bubble )
return true;
}
return true;
}
//----------------------------------------------------------------------------
bool 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 or different button has
// been clicked
if( !checkClickDistance(event->screen_pos, _last_click.pos)
|| _last_click.button != event->button )
_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;
}
bool handled = propagateEvent(click, path);
if( dbl_click )
handled |= propagateEvent( dbl_click,
getCommonAncestor(_last_click.path, path) );
_last_click.set(event, path);
return handled;
}
//----------------------------------------------------------------------------
bool EventManager::handleMove( const MouseEventPtr& event,
const EventPropagationPath& path )
{
EventPropagationPath& last_path = _last_mouse_over.path;
if( last_path == path )
return false;
bool handled = false;
// Leave old element
if( !last_path.empty() )
{
MouseEventPtr mouseout(new MouseEvent(*event));
mouseout->type = Event::MOUSE_OUT;
handled |= propagateEvent(mouseout, last_path);
// Send a mouseleave event to all ancestors of the currently left element
// which are not ancestor of the new element currently entered
EventPropagationPath path_leave = last_path;
for(size_t i = path_leave.size() - 1; i > 0; --i)
{
if( i < path.size() && path[i] == path_leave[i] )
break;
MouseEventPtr mouseleave(new MouseEvent(*event));
mouseleave->type = Event::MOUSE_LEAVE;
handled |= propagateEvent(mouseleave, path_leave);
path_leave.pop_back();
}
}
// Enter new element
if( !path.empty() )
{
MouseEventPtr mouseover(new MouseEvent(*event));
mouseover->type = Event::MOUSE_OVER;
handled |= propagateEvent(mouseover, path);
// Send a mouseenter event to all ancestors of the currently entered
// element which are not ancestor of the old element currently being
// left
EventPropagationPath path_enter;
for(size_t i = 0; i < path.size(); ++i)
{
path_enter.push_back(path[i]);
if( i < last_path.size() && path[i] == last_path[i] )
continue;
MouseEventPtr mouseenter(new MouseEvent(*event));
mouseenter->type = Event::MOUSE_ENTER;
handled |= propagateEvent(mouseenter, path_enter);
}
}
_last_mouse_over.path = path;
return handled;
}
//----------------------------------------------------------------------------
bool
EventManager::checkClickDistance( const osg::Vec2f& pos1,
const osg::Vec2f& pos2 ) const
{
osg::Vec2 delta = pos1 - pos2;
return std::fabs(delta.x()) < drag_threshold
&& std::fabs(delta.y()) < drag_threshold;
}
//----------------------------------------------------------------------------
EventPropagationPath
EventManager::getCommonAncestor( const EventPropagationPath& path1,
const EventPropagationPath& path2 ) const
{
if( path1.empty() || path2.empty() )
return EventPropagationPath();
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