Method Sort

Rendering/Image/vtkImageSliceCollection.cxx:89–149

------------------------------------------------------------------------------ Sorts the vtkImageSliceCollection by layer number. Smaller layer numbers are first. Layer numbers can be any integer value.

// Sorts the vtkImageSliceCollection by layer number.  Smaller layer
// numbers are first.  Layer numbers can be any integer value.
void vtkImageSliceCollection::Sort()
{
  // Create a temporary array of pointers to images
  int numElems = this->GetNumberOfItems();
  vtkImageSliceLayerPair defaultLayerArray[8];
  vtkImageSliceLayerPair* layerArray = defaultLayerArray;
  if (numElems > 8)
  {
    layerArray = new vtkImageSliceLayerPair[numElems];
  }

  // Start at the beginning of the collection
  vtkCollectionSimpleIterator ait;
  this->InitTraversal(ait);

  // Fill the image array with the items in the collection
  for (int ii = 0; ii < numElems; ii++)
  {
    vtkImageSlice* image = this->GetNextImage(ait);
    layerArray[ii].image = image;
    layerArray[ii].layer = image->GetProperty()->GetLayerNumber();
  }

  // The collection will be small (often with n=2) so do a brute-force
  // selection sort, which also keeps items with the same layer number
  // in the same order as before the sort.
  for (int i = 0; i < numElems - 1; i++)
  {
    int imin = i;
    int lmin = layerArray[imin].layer;
    int j = i + 1;

    do
    {
      int l = layerArray[j].layer;
      if (l < lmin)
      {
        imin = j;
        lmin = l;
      }
    } while (++j < numElems);

    vtkImageSliceLayerPair t = layerArray[imin];
    layerArray[imin] = layerArray[i];
    layerArray[i] = t;
  }

  // Now move the items around in the linked list -
  // keep the links the same, but swap around the items
  vtkCollectionElement* elem = this->Top;
  for (int jj = 0; jj < numElems; jj++)
  {
    elem->Item = layerArray[jj].image;
    elem = elem->Next;
  }

  if (layerArray != defaultLayerArray)
  {