Method PlaceAxes

Rendering/Annotation/vtkBarChartActor.cxx:331–574

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//------------------------------------------------------------------------------
int vtkBarChartActor::PlaceAxes(vtkViewport* viewport, const int* vtkNotUsed(size))
{
  vtkIdType i;
  vtkDataObject* input = this->GetInput();
  vtkFieldData* field = input->GetFieldData();
  double v = 0.0;

  this->Initialize();

  if (!field)
  {
    return 0;
  }

  // Retrieve the appropriate data array
  vtkDataArray* da = field->GetArray(this->ArrayNumber);
  if (!da)
  {
    return 0;
  }

  // Determine the number of independent variables
  this->N = da->GetNumberOfTuples();
  if (this->N <= 0 || this->N >= VTK_ID_MAX)
  {
    this->N = 0;
    vtkErrorMacro(<< "No field data to plot");
    return 0;
  }

  // We need to loop over the field to determine the total
  this->Heights = new double[this->N];
  this->MaxHeight = -VTK_FLOAT_MAX;
  this->MinHeight = VTK_FLOAT_MAX;
  for (i = 0; i < this->N; i++)
  {
    v = fabs(da->GetComponent(i, this->ComponentNumber));
    this->Heights[i] = v;
    this->MinHeight = (v < this->MinHeight ? v : this->MinHeight);
    this->MaxHeight = (v > this->MaxHeight ? v : this->MaxHeight);
  }
  if (this->MaxHeight > 0.0)
  {
    // compress the heights into the (0.10->1.0) range for aesthetic reasons
    // (i.e., you always want to see the minimum bar).
    for (i = 0; i < this->N; i++)
    {
      this->Heights[i] =
        0.10 + 0.90 * (this->Heights[i] - this->MinHeight) / (this->MaxHeight - this->MinHeight);
    }
    this->MinHeight -= 0.10 * (this->MaxHeight - this->MinHeight);
  }

  // Get the location of the corners of the box; make sure they are sane
  double* p1 = this->PositionCoordinate->GetComputedDoubleViewportValue(viewport);
  double* p2 = this->Position2Coordinate->GetComputedDoubleViewportValue(viewport);
  this->P1[0] = (p1[0] < p2[0] ? p1[0] : p2[0]);
  this->P1[1] = (p1[1] < p2[1] ? p1[1] : p2[1]);