VerticalScan_FloodFill

///Scr_FloodFill( ds_grid , scan_xstart , scan_ystart , value_fill )
   var grid , grd_w , grd_h , val_r , val_f , scn_x , scn_y;
   grid = argument[ 0 ];
   grd_w = ds_grid_width( grid );
   grd_h = ds_grid_height( grid );
   scn_x = argument[ 1 ];
   scn_y = argument[ 2 ];
   val_f = argument[ 3 ];
   val_r = ds_grid_get( grid , scn_x , scn_y );

   var map_x , map_y;
   map_x = ds_map_create();
   map_y = ds_map_create();

   ds_map_add( map_x , ( scn_y * grd_w ) + scn_x , scn_x );
   ds_map_add( map_y , ( scn_y * grd_w ) + scn_x , scn_y );

   if ( val_f == val_r ) {
      ds_map_destroy( map_x );
      ds_map_destroy( map_y );
      return 0;
   };

   while( ds_map_size( map_x ) > 0 && ds_map_size( map_y ) > 0 ) {
      var cell , prg_y = scn_y , scn_m = 0;

      while( scn_m < 2 ) {
         switch( scn_m ) {
            case 0:
               prg_y = scn_y;

               while( true ) {
                  cell = ( prg_y * grd_w ) + scn_x;
                  if ( cell < 0 || cell >= ( grd_w * grd_h ) || ( ds_grid_get( grid , scn_x , prg_y ) != val_r ) ) { break; };

                  cell = ( prg_y * grd_w ) + ( scn_x + 1 );
                  if ( cell > 0 && cell < ( grd_w * grd_h ) && ds_grid_get( grid , scn_x + 1 , prg_y ) == val_r ) {
                     ds_map_add( map_x , cell , scn_x + 1 );
                     ds_map_add( map_y , cell , prg_y );
                  };

                  cell = ( prg_y * grd_w ) + ( scn_x - 1 );
                  if ( cell > 0 && cell < ( grd_w * grd_h ) && ds_grid_get( grid , scn_x - 1 , prg_y ) == val_r ) {
                     ds_map_add( map_x , cell , scn_x - 1 );
                     ds_map_add( map_y , cell , prg_y );
                  };

                  cell = ( prg_y * grd_w ) + scn_x;
                  if ( prg_y != scn_y ) {
                     ds_map_delete( map_x , cell );
                     ds_map_delete( map_y , cell );
                  };

                  ds_grid_set( grid , scn_x , prg_y , val_f );
                  prg_y --;
               };

               scn_m = 1;
            break;
            case 1:
               prg_y = scn_y + 1;

               while( true ) {
                  cell = ( prg_y * grd_w ) + scn_x;
                  if ( ( cell < 0 ) || ( cell >= ( grd_w * grd_h ) ) || ( ds_grid_get( grid , scn_x , prg_y ) != val_r ) ) { break; };

                  cell = ( prg_y * grd_w ) + ( scn_x + 1 );
                  if ( cell >= 0 && cell < ( grd_w * grd_h ) && ds_grid_get( grid , scn_x + 1 , prg_y ) == val_r ) {
                     ds_map_add( map_x , cell , scn_x + 1 );
                     ds_map_add( map_y , cell , prg_y );
                  };

                  cell = ( prg_y * grd_w ) + ( scn_x - 1 );
                  if ( cell >= 0 && cell < ( grd_w * grd_h ) && ds_grid_get( grid , scn_x - 1 , prg_y ) == val_r ) {
                     ds_map_add( map_x , cell , scn_x - 1 );
                     ds_map_add( map_y , cell , prg_y );
                  };

                  cell = ( prg_y * grd_w ) + scn_x;
                  if ( prg_y != scn_y ) {
                     ds_map_delete( map_x , cell );
                     ds_map_delete( map_y , cell );
                  };

                  ds_grid_set( grid , scn_x , prg_y , val_f );
                  prg_y ++;
               };

               scn_m = 2;
            break;
            default: break;
         };
      };

      cell = ( scn_y * grd_w ) + scn_x;
      if ( cell >= 0 && cell <= ( grd_w * grd_h ) ) {
         ds_map_delete( map_x , cell );
         ds_map_delete( map_y , cell );
      };

      scn_x = ds_map_find_value( map_x , ds_map_find_first( map_x ) );
      scn_y = ds_map_find_value( map_y , ds_map_find_first( map_x ) );
   };

   ds_map_destroy( map_x );
   ds_map_destroy( map_y );
   return 0;