Function gradient_fill

	static void CL_Draw::gradient_fill(
		CL_GraphicContext  gc,
		double x1,
		double y1,
		double x2,
		double y2,
		const CL_Gradient & color);

	static void CL_Draw::gradient_fill(
		CL_GraphicContext  gc,
		const CL_Pointd & start,
		const CL_Pointd & end,
		const CL_Gradient & gradient);

	static void CL_Draw::gradient_fill(
		CL_GraphicContext  gc,
		const CL_Rectd & rect,
		const CL_Gradient & gradient);