2007.08.13 22:43 "[Tiff] 16-bit palette image", by Christian Henning

Hi there, can somebody tell what am I doing wrong when creating a 16-bit palette image. For some reason none picture viewer can read the file.

Please consider the following code creating a dummy tiff file.

int main()
{
   tsize_t width = 100;
   tsize_t height = 100;

   tsize_t bits_per_sample = 16;

   tsize_t samples_per_pixel = 1;

   tsize_t palette_size = 65536;

TIFF* file = TIFFOpen( "palette.tif", "w" );

   TIFFSetField( file, TIFFTAG_IMAGEWIDTH     , width               );
   TIFFSetField( file, TIFFTAG_IMAGELENGTH    , height              );
   TIFFSetField( file, TIFFTAG_BITSPERSAMPLE  , bits_per_sample     );
   TIFFSetField( file, TIFFTAG_SAMPLESPERPIXEL, samples_per_pixel   );
   TIFFSetField( file, TIFFTAG_ROWSPERSTRIP   , height              );

   TIFFSetField( file, TIFFTAG_PHOTOMETRIC    , PHOTOMETRIC_PALETTE );
   TIFFSetField( file, TIFFTAG_COMPRESSION    , COMPRESSION_LZW     );
   TIFFSetField( file, TIFFTAG_PLANARCONFIG   , PLANARCONFIG_CONTIG );

std::vector< short > palette( palette_size ); std::fill( palette.begin(), palette.end(), 0 );

   TIFFSetField( file
               , TIFFTAG_COLORMAP
               , &palette.front()
               , &palette.front()
               , &palette.front() );

   std::vector<short> buffer( width );
   std::fill( buffer.begin(), buffer.end(), 0 );

   for( int row = 0; row < height; ++row )
   {
      int res = TIFFWriteScanline( file
                                 , &buffer.front()
                                 , row
                                 , 0 );

      assert( res != -1 );
   }

   TIFFClose( file );
}

Thanks ahead,

Christian