Method DrawSegment

Imaging/Sources/vtkImageCanvasSource2D.cxx:829–878

------------------------------------------------------------------------------ Draw a Segment from point a to point b.

//------------------------------------------------------------------------------
// Draw a Segment from point a to point b.
void vtkImageCanvasSource2D::DrawSegment(int a0, int a1, int b0, int b1)
{
  int* extent;
  void* ptr;
  int z = this->DefaultZ;

  vtkDebugMacro(<< "Drawing a segment: " << a0 << ", " << a1 << " to " << b0 << ", " << b1);

  // Pre-multiply coords if needed
  if (this->Ratio[0] != 1.0)
  {
    a0 = static_cast<int>(static_cast<double>(a0) * this->Ratio[0]);
    b0 = static_cast<int>(static_cast<double>(b0) * this->Ratio[0]);
  }
  if (this->Ratio[1] != 1.0)
  {
    a1 = static_cast<int>(static_cast<double>(a1) * this->Ratio[1]);
    b1 = static_cast<int>(static_cast<double>(b1) * this->Ratio[1]);
  }
  if (this->Ratio[2] != 1.0)
  {
    z = static_cast<int>(static_cast<double>(z) * this->Ratio[2]);
  }

  // check to make sure line segment is in bounds.
  extent = this->ImageData->GetExtent();
  z = (z < extent[4]) ? extent[4] : z;
  z = (z > extent[5]) ? extent[5] : z;
  if (a0 < extent[0] || a0 > extent[1] || b0 < extent[0] || b0 > extent[1] || a1 < extent[2] ||
    a1 > extent[3] || b1 < extent[2] || b1 > extent[3])
  {
    if (!this->ClipSegment(a0, a1, b0, b1))
    {
      // non of the segment is in the data.
      return;
    }
  }

  ptr = this->ImageData->GetScalarPointer(b0, b1, z);
  a0 -= b0;
  a1 -= b1;
  switch (this->ImageData->GetScalarType())
  {
    vtkTemplateMacro(vtkImageCanvasSource2DDrawSegment(
      this->ImageData, this->DrawColor, static_cast<VTK_TT*>(ptr), a0, a1));
    default:
      vtkErrorMacro(<< "DrawSegment: Cannot handle ScalarType.");
  }
  this->Modified();
}

//------------------------------------------------------------------------------
// Clips a line segment so it will be in bounds.