// Version 1 (dereferenced by index)
        for ( y = Math.Max( 0, Area.y ); y < Area.y + Area.height; y++ ) {
          off_y = y - Area.y;
          ptr = baseptr + y * _line + area_x * 4;
          for ( x = area_x; x < Area.x + Area.width; x++ ) {
            off_x = x - Area.x;
            if ( ptr[3] != 0xFF ) {
              CurrentPixel = _base[i].pixels[off_x, off_y];
              alphaf = CurrentPixel.a;
              if ( alphaf == 1.0f ) {
                ptr[0] = ( byte )( CurrentPixel.b * 255 );
                ptr[1] = ( byte )( CurrentPixel.g * 255 );
                ptr[2] = ( byte )( CurrentPixel.r * 255 );
                ptr[3] = ( byte )( alphaf * 255 );
              } else if ( alphaf != 0.0f ) {
                alpha = ( byte )( alphaf * 255 );
                ptr[3] = alpha > ptr[3] ? alpha : ptr[3];
                ptr[2] = ( byte )( ptr[2] + alphaf * ( ( byte )( CurrentPixel.r * 255 ) - ptr[2] ) );
                ptr[1] = ( byte )( ptr[1] + alphaf * ( ( byte )( CurrentPixel.g * 255 ) - ptr[1] ) );
                ptr[0] = ( byte )( ptr[0] + alphaf * ( ( byte )( CurrentPixel.b * 255 ) - ptr[0] ) );
              }
            }
            ptr += 4;
          }
        }

// Version 2 (dereferenced directly)
        for ( y = Math.Max( 0, Area.y ); y < Area.y + Area.height; y++ ) {
          off_y = y - Area.y;
          ptr = baseptr + y * _line + area_x * 4;
          for ( x = area_x; x < Area.x + Area.width; x++ ) {
            off_x = x - Area.x;
            if ( ptr[3] != 0xFF ) {
              CurrentPixel = _base[i].pixels[off_x, off_y];
              alphaf = CurrentPixel.a;
              if ( alphaf == 1.0f ) {
                *ptr++ = ( byte )( CurrentPixel.b * 255 );
                *ptr++ = ( byte )( CurrentPixel.g * 255 );
                *ptr++ = ( byte )( CurrentPixel.r * 255 );
                *ptr++ = ( byte )( alphaf * 255 );
              } else if ( alphaf != 0.0f ) {
                alpha = ( byte )( alphaf * 255 );
                *ptr++ = ( byte )( *ptr + alphaf * ( ( byte )( CurrentPixel.b * 255 ) - *ptr ) );
                *ptr++ = ( byte )( *ptr + alphaf * ( ( byte )( CurrentPixel.g * 255 ) - *ptr ) );
                *ptr++ = ( byte )( *ptr + alphaf * ( ( byte )( CurrentPixel.r * 255 ) - *ptr ) );
                *ptr++ = alpha > ptr[3] ? alpha : ptr[3];
              } else {
                ptr += 4;
              }
            }
          }