INTERFACE VBTDrawContext;
IMPORT DrawContext;
IMPORT VBT, PaintOp;
TYPE
  T <: Public;
  Public = DrawContext.T OBJECT METHODS
    init(v: VBT.Leaf; bgColor := PaintOp.Bg): T;
    erase();   (* erase region that was set using setClip *)
  END;
END VBTDrawContext.