Method scrollTo

dw/iterator.cc:98–205

* \brief Scrolls the viewport, so that the region between \em it1 and * \em it2 is seen, according to \em hpos and \em vpos. * * The parameters \em start and \em end have the same meaning as in * dw::core::Iterator::getAllocation, \em start refers * to \em it1, while \em end rerers to \em it2. * * If \em it1 and \em it2 point to the same location (see code), only * \em it1 is regarded, and

 * \em it1 is regarded, and both belowstart and belowend refer to it.
 */
void Iterator::scrollTo (Iterator *it1, Iterator *it2, int start, int end,
                         HPosition hpos, VPosition vpos)
{
   Allocation alloc1, alloc2, alloc;
   int x1, x2, y1, y2;
   DeepIterator *eit1, *eit2, *eit3;
   int curStart, curEnd, cmp;
   bool atStart;

   if (it1->equals(it2)) {
      it1->getAllocation (start, end, &alloc);
      it1->getWidget()->getLayout()->scrollTo (hpos, vpos, alloc.x, alloc.y,
                                               alloc.width,
                                               alloc.ascent + alloc.descent);
   } else {
      // First, determine the rectangle all iterators from it1 and it2
      // allocate, i.e. the smallest rectangle containing all allocations of
      // these iterators.
      eit1 = new DeepIterator (it1);
      eit2 = new DeepIterator (it2);

      x1 = INT_MAX;
      x2 = INT_MIN;
      y1 = INT_MAX;
      y2 = INT_MIN;

      for (atStart = true, eit3 = (DeepIterator*)eit1->clone ();
           (cmp = eit3->compareTo (eit2)) <= 0;
           eit3->next (), atStart = false) {
         if (atStart)
            curStart = start;
         else
            curStart = 0;

         if (cmp == 0)
            curEnd = end;
         else
            curEnd = INT_MAX;

         eit3->getAllocation (curStart, curEnd, &alloc);
         x1 = misc::min (x1, alloc.x);
         x2 = misc::max (x2, alloc.x + alloc.width);
         y1 = misc::min (y1, alloc.y);
         y2 = misc::max (y2, alloc.y + alloc.ascent + alloc.descent);
      }

      delete eit3;
      delete eit2;
      delete eit1;

      it1->getAllocation (start, INT_MAX, &alloc1);
      it2->getAllocation (0, end, &alloc2);

      if (alloc1.x > alloc2.x) {
         //
         // This is due to a line break within the region. When the line is
         // longer than the viewport, and the region is actually quite short,
         // the user would not see anything of the region, as in this figure