Method BuildTitle

Rendering/Annotation/vtkAxisActor.cxx:658–771

------------------------------------------------------------------------------ Determines scale and position for the Title. Currently, title can only be centered with respect to its axis. ------------------------------------------------------------------------------

//  title can only be centered with respect to its axis.
//------------------------------------------------------------------------------
void vtkAxisActor::BuildTitle(bool force)
{
  this->NeedBuild2D = false;

  if (!force && !this->TitleVisibility)
  {
    return;
  }

  if (!force && this->TitleTextTime.GetMTime() < this->BuildTime.GetMTime() &&
    this->BoundsTime.GetMTime() < this->BuildTime.GetMTime() &&
    this->LabelBuildTime.GetMTime() < this->BuildTime.GetMTime())
  {
    return;
  }

  this->UpdateTitleActorProperty();

  // ---------- labels size ----------
  // local orientation (in the plane of the label)
  double labelAngle = vtkMath::RadiansFromDegrees(this->LabelTextProperty->GetOrientation());
  double labelCos = fabs(cos(labelAngle)), labelSin = fabs(sin(labelAngle));
  double labBounds[6];
  double offset[2] = { 0, this->TitleOffset[1] };

  // Side offset when not centered
  if (this->TitleAlignLocation == VTK_ALIGN_POINT1 || this->TitleAlignLocation == VTK_ALIGN_POINT2)
  {
    offset[0] += this->TitleOffset[0];
  }

  // find max height label (with the label text property considered)
  // only when title is on bottom
  if (this->LabelVisibility && this->TitleAlignLocation != VTK_ALIGN_TOP)
  {
    double labelMaxHeight, labHeight;
    labelMaxHeight = labHeight = 0;
    for (int i = 0; i < this->NumberOfLabelsBuilt; i++)
    {
      this->LabelProps[i]->GetBounds(labBounds);

      // labels actor aren't oriented yet, width and height are considered in
      // their local coordinate system
      // however, LabelTextProperty can orient it, but locally (in its plane)
      labHeight =
        (labBounds[1] - labBounds[0]) * labelSin + (labBounds[3] - labBounds[2]) * labelCos;
      labelMaxHeight = (labHeight > labelMaxHeight ? labHeight : labelMaxHeight);
    }
    offset[1] += this->LabelOffset + this->ScreenSize * labelMaxHeight;
  }

  // ---------- title size ----------
  double titleBounds[6];
  this->TitleProp->GetBounds(titleBounds);
  double halfTitleHeight = (titleBounds[3] - titleBounds[2]) * 0.5;
  double halfTitleWidth = (titleBounds[1] - titleBounds[0]) * 0.5;

  double* p1 = this->Point1Coordinate->GetValue();