protected:
DitherColorModel& cm_;
virtual void update();
virtual void disable() { method_ = &PseudoWindowRenderer::dither_null; }
virtual void disable() { method_ = &DitherWindowRenderer::dither_null; }
DitherMethod method_;
void dither_422(const u_char* frm, u_int off, u_int x,
u_int width, u_int height) const;