The TDrawRect structure.

 // DrawRect
 TDrawRect      struct
  Result                sbyte      // The function call result. NO_ERR means it succeeded.
  Location      TLocation  // The top left corner location.
  Size          TSize      // The width and height of the rectangle.
  Options       dword          // The options to use when writing to the LCD.
 TDrawRect      ends

See Drawing option constants for valid Options values.