flightgear/src/GUI/WaypointList.cxx

#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif

#include "WaypointList.hxx"

#include <algorithm>
#include <boost/tuple/tuple.hpp>

#include <plib/puAux.h>

#include <simgear/structure/callback.hxx>
#include <simgear/sg_inlines.h>

#include <Main/globals.hxx>
#include <Main/fg_props.hxx>

#include <Navaids/positioned.hxx>
#include <Navaids/routePath.hxx>
#include <Autopilot/route_mgr.hxx>

// select if the widget grabs keys necessary to fly aircraft from the keyboard,
// or not. See http://code.google.com/p/flightgear-bugs/issues/detail?id=338
// for discussion about why / what is going on.
#define AVOID_FLIGHT_KEYS 1

using namespace flightgear;

enum {
  SCROLL_NO = 0,
  SCROLL_UP,
  SCROLL_DOWN
};
  
static const double BLINK_TIME = 0.3;
static const int DRAG_START_DISTANCE_PX = 5;
  
class FlightPlanWaypointModel : 
  public WaypointList::Model, 
  public SGPropertyChangeListener
{
public:
  FlightPlanWaypointModel(flightgear::FlightPlan* fp) :
    _fp(fp)
  {    
    SGPropertyNode* routeEdited = fgGetNode("/autopilot/route-manager/signals/edited", true);
    SGPropertyNode* flightplanChanged = fgGetNode("/autopilot/route-manager/signals/flightplan-changed", true);
    routeEdited->addChangeListener(this);
    flightplanChanged->addChangeListener(this);
  }
  
  ~FlightPlanWaypointModel()
  {
    SGPropertyNode* routeEdited = fgGetNode("/autopilot/route-manager/signals/edited", true);
    SGPropertyNode* flightplanChanged = fgGetNode("/autopilot/route-manager/signals/flightplan-changed", true);
    routeEdited->removeChangeListener(this);
    flightplanChanged->removeChangeListener(this);
  }
  
// implement WaypointList::Model
  virtual unsigned int numWaypoints() const
  {
    return _fp->numLegs();
  }
  
  virtual int currentWaypoint() const
  {
    return _fp->currentIndex();
  }
  
  virtual flightgear::Waypt* waypointAt(unsigned int index) const
  {
    if (index >= numWaypoints()) {
      return NULL;
    }
    
    return _fp->legAtIndex(index)->waypoint();
  }

  virtual flightgear::FlightPlan* flightplan() const
  {
    return _fp;
  }
  
  virtual void deleteAt(unsigned int index)
  {
    _fp->deleteIndex(index);
  }
  
  virtual void moveWaypointToIndex(unsigned int srcIndex, unsigned int destIndex)
  {
    SG_LOG(SG_GENERAL, SG_INFO, "moveWaypoint: from " << srcIndex << " to " << destIndex);
    if (destIndex > srcIndex) {
      --destIndex;
    }
    
     int currentWpIndex = currentWaypoint();
    
    WayptRef w = _fp->legAtIndex(srcIndex)->waypoint();
    _fp->deleteIndex(srcIndex);
    _fp->insertWayptAtIndex(w, destIndex);

    if ((signed int) srcIndex == currentWpIndex) {
        // current waypoint was moved
        _fp->setCurrentIndex(destIndex);
    }
  }
  
  virtual void setUpdateCallback(SGCallback* cb)
  {
    _cb = cb;
  }
    
// implement SGPropertyChangeListener
  void valueChanged(SGPropertyNode *prop)
  {
    if (prop->getNameString() == "edited") {
      if (_cb) {
        (*_cb)();
      }
    }
    
    if (prop->getNameString() == "flightplan-changed") {
      _fp = 
        static_cast<FGRouteMgr*>(globals->get_subsystem("route-manager"))->flightPlan();
    }
  }
private:
  flightgear::FlightPlan* _fp;
  SGCallback* _cb;
};

//////////////////////////////////////////////////////////////////////////////

static void drawClippedString(puFont& font, const char* s, int x, int y, int maxWidth)
{
  int fullWidth = font.getStringWidth(s);
  if (fullWidth <= maxWidth) { // common case, easy and efficent
    font.drawString(s, x, y);
    return;
  }
  
  std::string buf(s);
  int len = buf.size();
  do {
    buf.resize(--len);
    fullWidth = font.getStringWidth(buf.c_str());
  } while (fullWidth > maxWidth);
  
  font.drawString(buf.c_str(), x, y);
}

//////////////////////////////////////////////////////////////////////////////

WaypointList::WaypointList(int x, int y, int width, int height) :
  puFrame(x, y, width, height),
  GUI_ID(FGCLASS_WAYPOINTLIST),
  _scrollPx(0),
  _dragging(false),
  _dragScroll(SCROLL_NO),
  _showLatLon(false),
  _model(NULL),
  _updateCallback(NULL),
  _scrollCallback(NULL),
  _blink(false)
{
  // pretend to be a list, so fgPopup doesn't mess with our mouse events
  type |= PUCLASS_LIST;  
  flightgear::FlightPlan* fp = 
    static_cast<FGRouteMgr*>(globals->get_subsystem("route-manager"))->flightPlan();
  setModel(new FlightPlanWaypointModel(fp));
  setSize(width, height);
  setValue(-1);
  
  _blinkTimer.stamp();
}

WaypointList::~WaypointList()
{
  delete _model;
  delete _updateCallback;
  delete _scrollCallback;
}

void WaypointList::setUpdateCallback(SGCallback* cb)
{
  _updateCallback = cb;
}

void WaypointList::setScrollCallback(SGCallback* cb)
{
  _scrollCallback = cb;
}

void WaypointList::setSize(int width, int height)
{
  double scrollP = getVScrollPercent();
  _heightPx = height;
  puFrame::setSize(width, height);
  
  if (wantsVScroll()) {
    setVScrollPercent(scrollP);
  } else {
    _scrollPx = 0;
  }
}

int WaypointList::checkHit ( int button, int updown, int x, int y )
{
  if ( isHit( x, y ) || ( puActiveWidget () == this ) )
  {
    doHit ( button, updown, x, y ) ;
    return TRUE ;
  }

  return FALSE ;
}


void WaypointList::doHit( int button, int updown, int x, int y )
{
  puFrame::doHit(button, updown, x, y);  
  if (updown == PU_DRAG) {
    handleDrag(x, y);
    return;
  }
  
  if (button != active_mouse_button) {
    return;
  }
      
  if (updown == PU_UP) {
    puDeactivateWidget();
    if (_dragging) {
      doDrop(x, y);
      return;
    }
  } else if (updown == PU_DOWN) {
    puSetActiveWidget(this, x, y);
    _mouseDownX = x;
    _mouseDownY = y;
    return;
  }
  
// update selection
  int row = rowForY(y - abox.min[1]);
  if (row >= (int) _model->numWaypoints()) {
    row = -1; // 'no selection'
  }

  if (row == getSelected()) {
    _showLatLon = !_showLatLon;
    puPostRefresh();
    return;
  }
  
  setSelected(row);
}

void WaypointList::handleDrag(int x, int y)
{
  if (!_dragging) {
    // don't start drags immediately, require a certain mouse movement first
    int manhattanLength = abs(x - _mouseDownX) + abs(y - _mouseDownY);
    if (manhattanLength < DRAG_START_DISTANCE_PX) {
      return;
    }
    
    _dragSourceRow = rowForY(y - abox.min[1]);
    Waypt* wp = _model->waypointAt(_dragSourceRow);
    if (!wp || wp->flag(WPT_GENERATED) || (wp->type() == "discontinuity")) {
      return; // don't allow generated points to be dragged
    }
    
    _dragging = true;
    _dragScroll = SCROLL_NO;
  }
  
  if (y < abox.min[1]) {
    if (_dragScroll != SCROLL_DOWN) {
      _dragScroll = SCROLL_DOWN;
      _dragScrollTime.stamp();
    }
  } else if (y > abox.max[1]) {
    if (_dragScroll != SCROLL_UP) {
      _dragScroll = SCROLL_UP;
      _dragScrollTime.stamp();
    }
  } else {
    _dragScroll = SCROLL_NO;
    _dragTargetRow = rowForY(y - abox.min[1] - (rowHeightPx() / 2));
  }
}

void WaypointList::doDrop(int x, int y)
{
  _dragging = false;
  puDeactivateWidget();
  
  SG_LOG(SG_GENERAL, SG_INFO, "doDrop");
  
  if ((y < abox.min[1]) || (y >= abox.max[1])) {
    SG_LOG(SG_GENERAL, SG_INFO, "y out of bounds:" << y);
    return;
  }
  
  if (_dragSourceRow == _dragTargetRow) {
    SG_LOG(SG_GENERAL, SG_INFO, "source and target row match");
    return;
  }
  
  _model->moveWaypointToIndex(_dragSourceRow, _dragTargetRow);
  
  // keep row indexes linged up when moving an item down the list
  if (_dragSourceRow < _dragTargetRow) {
    --_dragTargetRow;
  }
  
  setSelected(_dragTargetRow);
}

void WaypointList::invokeDownCallback(void)
{
  _dragging = false;
  _dragScroll = SCROLL_NO;
  SG_LOG(SG_GENERAL, SG_INFO, "cancel drag");
}

int WaypointList::rowForY(int y) const
{
  if (!_model) {
    return -1;
  }
  
  // flip y to increase down, not up (as rows do)
  int flipY = _heightPx - y;
  int row = (flipY + _scrollPx) / rowHeightPx();
  return row;
}

void WaypointList::draw( int dx, int dy )
{
  puFrame::draw(dx, dy);

  if (!_model) {
    return;
  }

  if (_dragScroll != SCROLL_NO) {
    doDragScroll();
  }
  
  double dt = (SGTimeStamp::now() - _blinkTimer).toSecs();
  if (dt > BLINK_TIME) {
    _blinkTimer.stamp();
    _blink = !_blink;
  }
  
  glEnable(GL_SCISSOR_TEST);
  GLint sx = (int) abox.min[0],
    sy = abox.min[1];
  GLsizei w = (GLsizei) abox.max[0] - abox.min[0],
    h = _heightPx;
    
  sx += border_thickness;
  sy += border_thickness;
  w -= 2 * border_thickness;
  h -= 2 * border_thickness;
    
  glScissor(sx + dx, sy + dy, w, h);
  int row = firstVisibleRow(), 
    final = lastVisibleRow(),
    rowHeight = rowHeightPx(),
    y = rowHeight;
  
  y -= (_scrollPx % rowHeight); // partially draw the first row
  
  _arrowWidth = legendFont.getStringWidth(">");
  
  RoutePath path(_model->flightplan());
  
  for ( ; row <= final; ++row, y += rowHeight) {
    drawRow(dx, dy, row, y, path);
  } // of row drawing iteration
  
  glDisable(GL_SCISSOR_TEST);
    
  if (_dragging) {
    // draw the insert marker after the rows
    int insertY = (_dragTargetRow * rowHeight) - _scrollPx;
    SG_CLAMP_RANGE(insertY, 0, std::min(_heightPx, totalHeightPx()));
    
    glColor4f(1.0f, 0.5f, 0.0f, 0.8f);
    glLineWidth(3.0f);
    glBegin(GL_LINES);
      glVertex2f(dx + abox.min[0], dy + abox.max[1] - insertY);
      glVertex2f(dx + abox.max[0], dy + abox.max[1] - insertY);
    glEnd();
  }
}

void WaypointList::drawRow(int dx, int dy, int rowIndex, int y,
                           const RoutePath& path)
{
  flightgear::Waypt* wp(_model->waypointAt(rowIndex));
    
  bool isSelected = (rowIndex == getSelected());
  bool isCurrent = (rowIndex == _model->currentWaypoint());
  bool isDragSource = (_dragging && (rowIndex == _dragSourceRow));

  puBox bkgBox = abox;
  bkgBox.min[1] = abox.max[1] - y;
  bkgBox.max[1] = bkgBox.min[1] + rowHeightPx();
  
  puColour col;
  puFont* f = &legendFont;
  bool drawBox = false;
  
  if (wp->flag(WPT_MISS)) {
    drawBox = true;
    puSetColor(col, 1.0, 0.0, 0.0, 0.3);  // red
  } else if (wp->flag(WPT_ARRIVAL) || wp->flag(WPT_DEPARTURE)) {
    drawBox = true;
    puSetColor(col, 0.0, 0.0, 0.0, 0.3);
  } else if (wp->flag(WPT_APPROACH)) {
    drawBox = true;
    puSetColor(col, 0.0, 0.0, 0.1, 0.3);
  }
  
  if (isDragSource) {
    // draw later, on *top* of text string
  } else if (isSelected) { // -PLAIN means selected, apparently
    bkgBox.draw(dx, dy, -PUSTYLE_PLAIN, colour, false, 0);
  } else if (drawBox) {
    bkgBox.draw(dx, dy, PUSTYLE_PLAIN, &col, false, 0);
  }
  
  if (isCurrent) {
    glColor4f (1.0, 0.5, 0.0, 1.0) ;
  } else {
    glColor4fv ( colour [ PUCOL_LEGEND ] ) ;
  }
  
  int xx = dx + abox.min[0] + PUSTR_LGAP;
  int yy = dy + abox.max[1] - y ;
  yy += 4; // center text in row height
  
  if (isCurrent) {
    f->drawString(">", xx, yy);
  }
  
  int x = xx;
  x += _arrowWidth + PUSTR_LGAP;
    drawRowText(x, yy, rowIndex, path);


  if (isDragSource) {
    puSetColor(col, 1.0, 0.5, 0.0, 0.5);
    bkgBox.draw(dx, dy, PUSTYLE_PLAIN, &col, false, 0);
  }
}

void WaypointList::drawRowText(int x, int baseline, int rowIndex, const RoutePath& path)
{
    flightgear::Waypt* wp(_model->waypointAt(rowIndex));
    bool isDiscontinuity = (wp->type() == "discontinuity");

    char buffer[128];
    int count = ::snprintf(buffer, 128, "%03d   %-5s", rowIndex, wp->ident().c_str());

    FGPositioned* src = wp->source();
    if (src && !src->name().empty() && (src->name() != wp->ident())) {
      // append name if present, and different to id
      ::snprintf(buffer + count, 128 - count, " (%s)", src->name().c_str());
    }

    drawClippedString(legendFont, buffer, x, baseline, 300);
    x += 300 + PUSTR_LGAP;

    if (isDiscontinuity) {
        return;
    }

    if (_showLatLon) {
      // only show for non-dynamic waypoints
      if (!wp->flag(WPT_DYNAMIC)) {
        SGGeod p(wp->position());
        char ns = (p.getLatitudeDeg() > 0.0) ? 'N' : 'S';
        char ew = (p.getLongitudeDeg() > 0.0) ? 'E' : 'W';

        ::snprintf(buffer, 128 - count, "%4.2f%c %4.2f%c",
          fabs(p.getLongitudeDeg()), ew, fabs(p.getLatitudeDeg()), ns);
      } else {
        buffer[0] = 0;
      }
    } else if (rowIndex > 0) {
      double courseDeg = path.trackForIndex(rowIndex);
      double distanceM = path.distanceForIndex(rowIndex);
      ::snprintf(buffer, 128 - count, "%03.0f %5.1fnm",
        courseDeg, distanceM * SG_METER_TO_NM);
    }

    puFont* f = &legendFont;
  f->drawString(buffer, x, baseline);
  x += 100 + PUSTR_LGAP;

  if (wp->altitudeRestriction() != RESTRICT_NONE) {
    char aboveAtBelow = ' ';
    if (wp->altitudeRestriction() == RESTRICT_ABOVE) {
      aboveAtBelow = 'A';
    } else if (wp->altitudeRestriction() == RESTRICT_BELOW) {
      aboveAtBelow = 'B';
    }

    int altHundredFt = (wp->altitudeFt() + 50) / 100; // round to nearest 100ft
    if (altHundredFt < 100) {
      count = ::snprintf(buffer, 128, "%d'%c", altHundredFt * 100, aboveAtBelow);
    } else { // display as a flight-level
      count = ::snprintf(buffer, 128, "FL%d%c", altHundredFt, aboveAtBelow);
    }

    f->drawString(buffer, x, baseline);
  } // of valid wp altitude
  x += 60 + PUSTR_LGAP;

  if (wp->speedRestriction() == SPEED_RESTRICT_MACH) {
    count = ::snprintf(buffer, 126, "%03.2fM", wp->speedMach());
    f->drawString(buffer, x, baseline);
  } else if (wp->speedRestriction() != RESTRICT_NONE) {
    count = ::snprintf(buffer, 126, "%dKts", (int) wp->speedKts());
    f->drawString(buffer, x, baseline);
  }
}

const double SCROLL_PX_SEC = 200.0;

void WaypointList::doDragScroll()
{
  double dt = (SGTimeStamp::now() - _dragScrollTime).toSecs();
  _dragScrollTime.stamp();
  int deltaPx = (int)(dt * SCROLL_PX_SEC);
  
  if (_dragScroll == SCROLL_UP) {
    _scrollPx = _scrollPx - deltaPx;
    SG_CLAMP_RANGE(_scrollPx, 0, scrollRangePx());
    _dragTargetRow = firstVisibleRow();
  } else {
    _scrollPx = _scrollPx + deltaPx;
    SG_CLAMP_RANGE(_scrollPx, 0, scrollRangePx());
    _dragTargetRow = lastFullyVisibleRow() + 1;
  }
  
  if (_scrollCallback) {
    (*_scrollCallback)();
  }
}

int WaypointList::getSelected()
{
  return getIntegerValue();
}

void WaypointList::setSelected(int rowIndex)
{
  if (rowIndex == getSelected()) {
    return;
  }
  
  setValue(rowIndex);
  invokeCallback();
  if (rowIndex == -1) {
    return;
  }

  ensureRowVisible(rowIndex);
}

void WaypointList::ensureRowVisible(int rowIndex)
{
  if ((rowIndex >= firstFullyVisibleRow()) && (rowIndex <= lastFullyVisibleRow())) {
    return; // already visible, fine
  }
  
  // ideal position would place the desired row in the middle of the
  // visible section - hence subtract half the visible height.
  int targetScrollPx = (rowIndex * rowHeightPx()) - (_heightPx / 2);
  
  // clamp the scroll value to something valid
  SG_CLAMP_RANGE(targetScrollPx, 0, scrollRangePx());
  _scrollPx = targetScrollPx;
  
  puPostRefresh();
  if (_scrollCallback) { // keep scroll observers in sync
    (*_scrollCallback)();
  }
}

unsigned int WaypointList::numWaypoints() const
{
  if (!_model) {
    return 0;
  }
  
  return _model->numWaypoints();
}

bool WaypointList::wantsVScroll() const
{
  return totalHeightPx() > _heightPx;
}

float WaypointList::getVScrollPercent() const
{
  float scrollRange = scrollRangePx();
  if (scrollRange < 1.0f) {
    return 0.0;
  }
  
  return _scrollPx / scrollRange;
}

float WaypointList::getVScrollThumbPercent() const
{
  return _heightPx / (float) totalHeightPx();
}

void WaypointList::setVScrollPercent(float perc)
{
  float scrollRange = scrollRangePx();
  _scrollPx = (int)(scrollRange * perc);
}

int WaypointList::firstVisibleRow() const
{
  return _scrollPx / rowHeightPx();
}

int WaypointList::firstFullyVisibleRow() const
{
  int rh = rowHeightPx();
  return (_scrollPx + rh - 1) / rh;
}
  
int WaypointList::numVisibleRows() const
{
  int rh = rowHeightPx();
  int topOffset = _scrollPx % rh; // pixels of first visible row
  return (_heightPx - topOffset + rh - 1) / rh;

}

int WaypointList::numFullyVisibleRows() const
{
  int rh = rowHeightPx();
  int topOffset = _scrollPx % rh; // pixels of first visible row
  return (_heightPx - topOffset) / rh;
}

int WaypointList::rowHeightPx() const
{
  return legendFont.getStringHeight() + PUSTR_BGAP;
}

int WaypointList::scrollRangePx() const
{
  return std::max(0, totalHeightPx() - _heightPx);
}

int WaypointList::totalHeightPx() const
{
  if (!_model) {
    return 0;
  }
  
  return (int) _model->numWaypoints() * rowHeightPx();
}

int WaypointList::lastFullyVisibleRow() const
{
  int row = firstFullyVisibleRow() + numFullyVisibleRows();
  return std::min(row, (int) _model->numWaypoints() - 1);
}

int WaypointList::lastVisibleRow() const
{
  int row = firstVisibleRow() + numVisibleRows();
  return std::min(row, (int) _model->numWaypoints() - 1);
}

void WaypointList::setModel(Model* model)
{
  if (_model) {
    delete _model;
  }
  
  _model = model;
  _model->setUpdateCallback(make_callback(this, &WaypointList::modelUpdateCallback));
  
  puPostRefresh();
}

int WaypointList::checkKey (int key, int updown )
{
  if ((updown == PU_UP) || !isVisible () || !isActive () || (window != puGetWindow())) {
    return FALSE ;
  }

#ifdef AVOID_FLIGHT_KEYS
    return FALSE;
#endif
  
  switch (key)
  {
  case PU_KEY_HOME:
    setSelected(0);
    break;

  case PU_KEY_END:
    setSelected(_model->numWaypoints() - 1);
    break ;

  case PU_KEY_UP        :
  case PU_KEY_PAGE_UP   :
    if (getSelected() >= 0) {
      setSelected(getSelected() - 1);
    }
    break ;

  case PU_KEY_DOWN      :
  case PU_KEY_PAGE_DOWN : {
    int newSel = getSelected() + 1;
    if (newSel >= (int) _model->numWaypoints()) {
      setSelected(-1);
    } else {
      setSelected(newSel);
    }
    break ;
  }
  
  case '-':
    if (getSelected() >= 0) {
      Waypt* wp = _model->waypointAt(getSelected());
      if (wp->flag(WPT_GENERATED)) {
        break;
      }
      
      if (wp->altitudeRestriction() != RESTRICT_NONE) {
        int curAlt = (static_cast<int>(wp->altitudeFt()) + 50) / 100;
        if (curAlt <= 0) {
          wp->setAltitude(0, RESTRICT_NONE);
        } else {
          wp->setAltitude((curAlt - 10) * 100, wp->altitudeRestriction());
        }
      }
    }
    break;
    
  case '=':
    if (getSelected() >= 0) {
      flightgear::Waypt* wp = _model->waypointAt(getSelected());
      if (wp->flag(WPT_GENERATED)) {
        break;
      }
        
      if (wp->altitudeRestriction() == RESTRICT_NONE) {
        wp->setAltitude(1000, RESTRICT_AT);
      } else {
        int curAlt = (static_cast<int>(wp->altitudeFt()) + 50) / 100;
        wp->setAltitude((curAlt + 10) * 100, wp->altitudeRestriction());
      }
    }
    break;
  
  case 0x7f: // delete
    if (getSelected() >= 0) {
      int index = getSelected();
      Waypt* wp = _model->waypointAt(getSelected());
      if (wp->flag(WPT_GENERATED)) {
        break;
      }
      
      _model->deleteAt(index);
      setSelected(index - 1);
    }
    break;

  default :
    return FALSE;
  }

  return TRUE ;
}

void WaypointList::modelUpdateCallback()
{
  // local stuff
  
  if (_updateCallback) {
    (*_updateCallback)();
  }
}

//////////////////////////////////////////////////////////////////////////////


static void handle_scrollbar(puObject* scrollbar)
{
  ScrolledWaypointList* self = (ScrolledWaypointList*)scrollbar->getUserData();
  self->setScrollPercent(scrollbar->getFloatValue());
}

static void waypointListCb(puObject* wpl)
{
  ScrolledWaypointList* self = (ScrolledWaypointList*)wpl->getUserData();
  self->setValue(wpl->getIntegerValue());
  self->invokeCallback();
}

ScrolledWaypointList::ScrolledWaypointList(int x, int y, int width, int height) :
  puGroup(x,y),
  _scrollWidth(16)
{
  // ensure our type is compound, so fgPopup::applySize doesn't descend into
  // us, and try to cast our children's user-data to GUIInfo*.
  type |= PUCLASS_LIST;
  
  init(width, height);
}

void ScrolledWaypointList::setValue(float v)
{
  puGroup::setValue(v);
  _list->setValue(v);
}

void ScrolledWaypointList::setValue(int v)
{
  puGroup::setValue(v);
  _list->setValue(v);
}

void ScrolledWaypointList::init(int w, int h)
{
  _list = new WaypointList(0, 0, w, h);
  _list->setUpdateCallback(make_callback(this, &ScrolledWaypointList::modelUpdated));
  _hasVScroll = _list->wantsVScroll();
  _list->setUserData(this);
  _list->setCallback(waypointListCb);
  
  _list->setScrollCallback(make_callback(this, &ScrolledWaypointList::updateScroll));
  
  _scrollbar = new puaScrollBar(w - _scrollWidth, 0, h, 
    1 /*arrow*/, 1 /* vertical */, _scrollWidth);
  _scrollbar->setMinValue(0.0);
  _scrollbar->setMaxValue(1.0);
  _scrollbar->setUserData(this);
  _scrollbar->setCallback(handle_scrollbar);
  close(); // close the group
  
  setSize(w, h);
}

void ScrolledWaypointList::modelUpdated()
{  
  int w, h;
  getSize(&w, &h);
  updateWantsScroll(w, h);
}

void ScrolledWaypointList::setScrollPercent(float v)
{
  // slider's min is the bottom, so invert the value
  _list->setVScrollPercent(1.0f - v); 
}

void ScrolledWaypointList::setSize(int w, int h)
{
  updateWantsScroll(w, h);
  puGroup::setSize(w, h);
}

void ScrolledWaypointList::updateWantsScroll(int w, int h)
{
  _hasVScroll = _list->wantsVScroll();
  
  if (_hasVScroll) {
    _scrollbar->reveal();
    _scrollbar->setPosition(w - _scrollWidth, 0);
    _scrollbar->setSize(_scrollWidth, h);
    _list->setSize(w - _scrollWidth, h);
    updateScroll();
  } else {
    _scrollbar->hide();
    _list->setSize(w, h);
  }
}

void ScrolledWaypointList::updateScroll()
{
 // _scrollbar->setMaxValue(_list->numWaypoints());
  _scrollbar->setValue(1.0f - _list->getVScrollPercent());
  _scrollbar->setSliderFraction(_list->getVScrollThumbPercent());
}