Method GetColor

IO/Image/vtkTIFFReader.cxx:713–784

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//------------------------------------------------------------------------------
void vtkTIFFReader::GetColor(
  int index, unsigned short* red, unsigned short* green, unsigned short* blue)
{
  *red = 0;
  *green = 0;
  *blue = 0;
  if (index < 0)
  {
    vtkErrorMacro("Color index has to be greater than 0");
    return;
  }
  if (this->TotalColors > 0 && this->ColorRed && this->ColorGreen && this->ColorBlue)
  {
    if (index >= this->TotalColors)
    {
      vtkErrorMacro(
        "Color index has to be less than number of colors (" << this->TotalColors << ")");
      return;
    }
    *red = *(this->ColorRed + index);
    *green = *(this->ColorGreen + index);
    *blue = *(this->ColorBlue + index);
    return;
  }

  unsigned short photometric;

  if (!TIFFGetField(this->InternalImage->Image, TIFFTAG_PHOTOMETRIC, &photometric))
  {
    if (this->InternalImage->Photometrics != PHOTOMETRIC_PALETTE)
    {
      vtkErrorMacro("You can only access colors for palette images");
      return;
    }
  }

  unsigned short *red_orig, *green_orig, *blue_orig;

  switch (this->InternalImage->BitsPerSample)
  {
    case 1:
    case 2:
    case 4:
    case 8:
    case 16:
      break;
    default:
      vtkErrorMacro(
        "Sorry, can not image with " << this->InternalImage->BitsPerSample << "-bit samples");
      return;
  }
  if (!TIFFGetField(
        this->InternalImage->Image, TIFFTAG_COLORMAP, &red_orig, &green_orig, &blue_orig))
  {
    vtkErrorMacro("Missing required \"Colormap\" tag");
    return;
  }
  this->TotalColors = (1L << this->InternalImage->BitsPerSample);