Method SetLabelPositions2D

Rendering/Annotation/vtkAxisActor.cxx:563–652

------------------------------------------------------------------------------ Determine and set scale factor and position for 2D labels. ------------------------------------------------------------------------------

// Determine and set scale factor and position for 2D labels.
//------------------------------------------------------------------------------
void vtkAxisActor::SetLabelPositions2D(vtkViewport* viewport, bool force)
{
  if (!force && (!this->LabelVisibility || this->NumberOfLabelsBuilt == 0))
  {
    return;
  }

  int xmult = 0;
  int ymult = 0;
  double xcoeff = 0.;
  double ycoeff = 0.;

  // we are in 2D mode, so no Z axis
  switch (this->AxisType)
  {
    case VTK_AXIS_TYPE_X:
      xmult = 0;
      ymult = vtkAxisActorMultiplierTable1[this->AxisPosition];
      xcoeff = 0.5;
      ycoeff = 1.0;
      break;
    case VTK_AXIS_TYPE_Y:
      xmult = vtkAxisActorMultiplierTable1[this->AxisPosition];
      ymult = 0;
      xcoeff = 1.0;
      ycoeff = 0.5;
      break;
    default:
      // shouldn't get here
      break;
  }

  //
  // xadjust & yadjust are used for positioning the label correctly
  // depending upon the 'orientation' of the axis as determined
  // by its position in view space (via transformed bounds).
  //
  double displayBounds[6] = { 0., 0., 0., 0., 0., 0. };
  this->TransformBounds(viewport, displayBounds);
  double xadjust = (displayBounds[0] > displayBounds[1] ? -1 : 1);
  double yadjust = (displayBounds[2] > displayBounds[3] ? -1 : 1);
  double transpos[3] = { 0., 0., 0. };
  double center[3], tick[3], pos[2];

  vtkTextRenderer* tren = vtkTextRenderer::GetInstance();
  if (!tren)
  {
    vtkErrorMacro(<< "Unable to obtain the vtkTextRenderer instance!");
    return;
  }

  vtkWindow* win = viewport->GetVTKWindow();
  if (!win)
  {
    vtkErrorMacro(<< "No render window available: cannot determine DPI.");
    return;
  }