Example #1
0
 /**
  * Removes all children from the given map. Note that we do not removes this node directly because
  * the corresponding Map.Entry is presumed already used by an other node.
  */
 private void removeFrom(final Map<Rectangle, SelectedNode> overlaps) {
   SelectedNode child = (SelectedNode) firstChildren();
   while (child != null) {
     child.removeFrom(overlaps);
     final SelectedNode existing = overlaps.remove(child);
     if (existing != null && existing != child) {
       overlaps.put(existing, existing);
     }
     child = (SelectedNode) child.nextSibling();
   }
 }
Example #2
0
 /**
  * Removes the nodes having the same bounding box than this tile, then process recursively for
  * children. If such matchs are found, they are probably tiles at a different resolution. Retains
  * the one which minimize the disk reading, and discards the other ones.
  *
  * <p>This check is not generic since we search for an exact match, but this case is common
  * enough. Handling it with a {@link java.util.HashMap} will help to reduce the amount of tiles to
  * handle in a more costly way later.
  *
  * <p>As a side effect, this method trims the bounding box of selected nodes to the tiles that
  * they contain.
  *
  * @param overlaps An initially empty map. Will be filled through recursive invocation of this
  *     method while we iterate down the tree.
  */
 final void removeTrivialOverlaps(final Map<Rectangle, SelectedNode> overlaps) {
   /*
    * Must process children first because if any of them are removed, it will lower
    * the cost and consequently can change the decision taken at the end of this method.
    */
   SelectedNode child = (SelectedNode) firstChildren();
   while (child != null) {
     // Must ask for next sibling before to filter since the later
     // may set it to null if the child is removed from the tree.
     final SelectedNode next = (SelectedNode) child.nextSibling();
     child.removeTrivialOverlaps(overlaps);
     child = next;
   }
   /*
    * If this node is just a container for other nodes, trims the bounding box to the tiles
    * that it contains. We would not need to do that if the size of parent nodes was always
    * a multiple of child nodes.  But sometime they are not, in which case some child nodes
    * may live on the boundary between two parent nodes. It is not easy to predict in which
    * parent such child will end up and what will be its bounding box since the computation
    * involves intersection, but the end result is that two parents may have identical bbox
    * while their child do not overlaps at all.
    *
    * We don't perform this computation if this node contains a tile, because in such case
    * we assume that the bounding box was carefully choosen by the user. This is different
    * than a null tile in which case the bounding box was calculated by our code.
    */
   if (tile == null) {
     child = (SelectedNode) firstChildren();
     if (child != null) {
       int xmin = x, ymin = y, w = width, h = height;
       width = height = -1;
       do {
         assert !child.isEmpty() : child;
         add(child);
         child = (SelectedNode) child.nextSibling();
       } while (child != null);
       if (x < xmin) {
         w -= (xmin - x);
         x = xmin;
       }
       if (y < ymin) {
         h -= (ymin - y);
         y = ymin;
       }
       if (width > w) width = w;
       if (height > h) height = h;
     }
   }
   /*
    * Now searchs for overlaps.
    */
   SelectedNode existing = overlaps.put(this, this);
   if (existing != null && existing != this) {
     if (!isCheaperThan(existing)) {
       /*
        * A cheaper tiles existed for the same bounds. Reinsert the previous tile in the
        * map. We will delete this node from the tree later, except if the previous node
        * is a children of this node. In the later case, we can't remove completly this
        * node since it would remove its children as well, so we just nullify the tile.
        */
       if (existing.getParent() == this) {
         if (tile != null) {
           tile = null;
           cost = childrenCost();
         }
         return;
       }
       overlaps.put(existing, existing);
       existing = this;
     }
     existing.remove();
     existing.removeFrom(overlaps);
     assert overlaps.get(existing) != existing;
   }
 }