Method DrawPath

IO/Export/vtkSVGContextDevice2D.cxx:2077–2182

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//------------------------------------------------------------------------------
void vtkSVGContextDevice2D::DrawPath(vtkPath* path, std::ostream& out)
{
  // The text renderer always uses floats to generate paths, so we'll optimize
  // a bit here:
  vtkFloatArray* points = vtkArrayDownCast<vtkFloatArray>(path->GetPoints()->GetData());
  vtkIntArray* codes = path->GetCodes();

  if (!points)
  {
    vtkErrorMacro("This method expects the path point precision to be floats.");
    return;
  }

  vtkIdType numTuples = points->GetNumberOfTuples();
  if (numTuples != codes->GetNumberOfTuples() || codes->GetNumberOfComponents() != 1 ||
    points->GetNumberOfComponents() != 3)
  {
    vtkErrorMacro("Invalid path data.");
    return;
  }

  if (numTuples == 0)
  { // Nothing to do.
    return;
  }

  // Use a lambda to invert the y positions for SVG:
  auto y = [](float yIn) -> float { return -yIn; };

  typedef vtkPath::ControlPointType CodeEnum;
  typedef vtkIntArray::ValueType CodeType;
  CodeType* code = codes->GetPointer(0);
  CodeType* codeEnd = code + numTuples;

  typedef vtkFloatArray::ValueType PointType;
  PointType* point = points->GetPointer(0);

  // These are only used in an assertion, ifdef silences warning on non-debug
  // builds
#ifndef NDEBUG
  PointType* pointBegin = point;
  CodeType* codeBegin = code;
#endif

  // Track the last code so we can save a little space by chaining draw commands
  int lastCode = -1;

  while (code < codeEnd)
  {
    assert("Sanity check" && (code - codeBegin) * 3 == point - pointBegin);

    switch (static_cast<CodeEnum>(*code))
    {
      case vtkPath::MOVE_TO:
        if (lastCode != *code)
        {
          lastCode = *code;
          out << "M";