Listing 2. Drawing the Points in Pixmap

/* Munch for a while on _points, until either we 
 * finish it off or run out of time.
 */
QPainter p;
p.begin(_buf);
struct timeval tv;
struct timezone tz;
gettimeofday(&tv, &tz);
double cur_time = double(tv.tv_sec)*1000.0 + 
   double(tv.tv_usec)/1000.0;
double deadline_time = cur_time + MAX_RENDER_TIME_MSEC;
bool dirty = false;   // true if _buf changed
while ((cur_time <= deadline_time) && (_pti < 
    _points->size())) {
  DoubPt newPt = (*_points)[_pti];
  if (rtpClip(_map.viewPort, &lastPt, &newPt)) {
    p.drawLine(rtpMap(_map, lastPt), rtpMap(_map,
        newPt));
    dirty = true;
  }
  lastPt = (*_points)[_pti++];
  gettimeofday(&tv, &tz);
  cur_time = double(tv.tv_sec)*1000.0 + 
      double(tv.tv_usec)/1000.0;
}
p.end();