Method BuildMinorTicks

Rendering/Annotation/vtkAxisActor.cxx:2014–2126

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//------------------------------------------------------------------------------
void vtkAxisActor::BuildMinorTicks(double p1[3], double p2[3], double localCoordSys[3][3])
{
  // (p2 - p1) vector
  double deltaVector[3];

  // inside point: point shifted toward x,y,z direction
  // outside points:  point shifted toward -x,-y,-z direction
  double vPointInside[3], vPointOutside[3], uPointInside[3], uPointOutside[3];

  int uMult = vtkAxisActorMultiplierTable1[this->AxisPosition];
  int vMult = vtkAxisActorMultiplierTable2[this->AxisPosition];

  double* axisVector = localCoordSys[0];
  double* uVector = localCoordSys[1];
  double* vVector = localCoordSys[2];

  // - Initialize all points to be on the axis
  for (int i = 0; i < 3; i++)
  {
    uPointInside[i] = vPointInside[i] = uPointOutside[i] = vPointOutside[i] = p1[i];
    deltaVector[i] = (p2[i] - p1[i]);
  }

  double axisLength = vtkMath::Norm(deltaVector);
  double rangeScale = axisLength / (this->Range[1] - this->Range[0]);

  // - Move outside points if needed (Axis -> Outside)
  if (this->TickLocation == VTK_TICKS_OUTSIDE || this->TickLocation == VTK_TICKS_BOTH)
  {
    for (int i = 0; i < 3; i++)
    {
      uPointOutside[i] += uVector[i] * uMult * this->MinorTickSize;
      vPointOutside[i] += vVector[i] * vMult * this->MinorTickSize;
    }
  }

  // - Move inside points if needed (Axis -> Inside)
  if (this->TickLocation == VTK_TICKS_INSIDE || this->TickLocation == VTK_TICKS_BOTH)
  {
    for (int i = 0; i < 3; i++)
    {
      uPointInside[i] -= uVector[i] * uMult * this->MinorTickSize;
      vPointInside[i] -= vVector[i] * vMult * this->MinorTickSize;
    }
  }

  // - Add the initial shift if any
  double axisShift = (this->MinorRangeStart - this->Range[0]) * rangeScale;
  axisLength -= axisShift;
  for (int i = 0; i < 3; i++)
  {
    uPointInside[i] += axisVector[i] * axisShift;
    vPointInside[i] += axisVector[i] * axisShift;
    uPointOutside[i] += axisVector[i] * axisShift;
    vPointOutside[i] += axisVector[i] * axisShift;
  }

  // - Reduce the deltaVector to correspond to a tick step