Method RunLengthImage

Filters/Hybrid/vtkImageToPolyDataFilter.cxx:259–356

}

void vtkImageToPolyDataFilter::RunLengthImage(vtkUnsignedCharArray* pixels, int dims[3],
  double origin[3], double spacing[3], vtkPolyData* output)
{
  int i, j;
  vtkIdType pts[4], id;
  vtkPoints* newPts;
  vtkCellArray* newPolys;
  double x[3], minX, maxX, minY, maxY;
  vtkUnsignedCharArray* polyColors;
  unsigned char *colors = pixels->GetPointer(0), *color;

  // Setup data
  newPts = vtkPoints::New();
  newPolys = vtkCellArray::New();
  newPolys->AllocateEstimate(dims[0] * dims[1] / 10, 4);

  polyColors = vtkUnsignedCharArray::New();
  polyColors->Allocate(3 * dims[0] * dims[1] / 10); // for rgb
  polyColors->SetNumberOfComponents(3);

  // Loop over row-by-row generating quad polygons
  x[2] = 0.0;
  for (j = 0; j < dims[1]; j++)
  {
    if (j == 0)
    {
      minY = origin[1];
      maxY = origin[1] + 0.5 * spacing[1];
    }
    else if (j == (dims[1] - 1))
    {
      minY = origin[1] + j * spacing[1] - 0.5 * spacing[1];
      maxY = origin[1] + j * spacing[1];
    }
    else
    {
      minY = origin[1] + j * spacing[1] - 0.5 * spacing[1];
      maxY = origin[1] + j * spacing[1] + 0.5 * spacing[1];
    }

    for (i = 0; i < dims[0];)
    {
      if (i == 0)
      {
        minX = origin[0];
      }
      else
      {
        minX = origin[0] + i * spacing[0] - 0.5 * spacing[0];
      }
      color = colors + 3 * (i + j * dims[0]);
      while (i < dims[0])
      {
        unsigned char* ptr = colors + 3 * (i + j * dims[0]);
        if (!this->IsSameColor(color, ptr))
        {
          break;
        }