Method SetColorArray

Views/Infovis/vtkDendrogramItem.cxx:1143–1207

------------------------------------------------------------------------------

//------------------------------------------------------------------------------
void vtkDendrogramItem::SetColorArray(const char* arrayName)
{
  this->ColorArray =
    vtkArrayDownCast<vtkDoubleArray>(this->Tree->GetVertexData()->GetArray(arrayName));
  if (!this->ColorArray)
  {
    vtkErrorMacro("Could not downcast " << arrayName << " to a vtkDoubleArray");
    this->ColorTree = false;
    return;
  }

  this->ColorTree = true;

  double minValue = VTK_DOUBLE_MAX;
  double maxValue = VTK_DOUBLE_MIN;

  for (vtkIdType id = 0; id < this->ColorArray->GetNumberOfTuples(); ++id)
  {
    double d = this->ColorArray->GetValue(id);
    maxValue = std::max(d, maxValue);
    minValue = std::min(d, minValue);
  }

  // special case: when there is no range of values to display, all edges should
  // be drawn in grey.  Without this, all the edges would be drawn in either red
  // or blue.
  if (minValue == maxValue)
  {
    this->TreeLookupTable->SetNumberOfTableValues(1);
    this->TreeLookupTable->SetTableValue(0, 0.60, 0.60, 0.60);
    // this is done to prevent the legend from being drawn
    this->LegendPositionSet = true;
    return;
  }

  // how much we vary the colors from step to step
  double inc = 0.06;

  // setup the color lookup table.  It will contain 10 shades of red,
  // 10 shades of blue, and a grey neutral value.

  this->TreeLookupTable->SetNumberOfTableValues(21);
  if (fabs(maxValue) > fabs(minValue))
  {
    this->TreeLookupTable->SetRange(-maxValue, maxValue);
  }
  else
  {
    this->TreeLookupTable->SetRange(minValue, -minValue);
  }
  for (vtkIdType i = 0; i < 10; ++i)
  {
    this->TreeLookupTable->SetTableValue(i, 1.0, 0.25 + inc * i, 0.25 + inc * i);
  }
  this->TreeLookupTable->SetTableValue(10, 0.60, 0.60, 0.60);
  for (vtkIdType i = 11; i < 21; ++i)
  {
    this->TreeLookupTable->SetTableValue(i, 0.85 - inc * (i - 10), 0.85 - inc * (i - 10), 1.0);