exported features
- set_drawable (d: DRAWABLE)
- point (x1: INTEGER_32, y1: INTEGER_32)
- line (x1: INTEGER_32, y1: INTEGER_32, x2: INTEGER_32, y2: INTEGER_32)
- rectangle (x1: INTEGER_32, y1: INTEGER_32, w: INTEGER_32, h: INTEGER_32)
- arc (x1: INTEGER_32, y1: INTEGER_32, w: INTEGER_32, h: INTEGER_32, angle1: REAL_64, angle2: REAL_64)
- arc_radius (x: INTEGER_32, y: INTEGER_32, r1: INTEGER_32, r2: INTEGER_32, angle1: REAL_64, angle2: REAL_64)
- fill_rectangle (x1: INTEGER_32, y1: INTEGER_32, w: INTEGER_32, h: INTEGER_32)
- fill_arc (x1: INTEGER_32, y1: INTEGER_32, w: INTEGER_32, h: INTEGER_32, angle1: REAL_64, angle2: REAL_64)
- fill_arc_radius (x: INTEGER_32, y: INTEGER_32, r1: INTEGER_32, r2: INTEGER_32, angle1: REAL_64, angle2: REAL_64)
- put_string (s: UNICODE_STRING, x: INTEGER_32, y: INTEGER_32)
- valid_drawable: BOOLEAN