C#从大图中截取一部分图片

#region 从大图中截取一部分图片
        /// <summary>
        /// 从大图中截取一部分图片
        /// </summary>
        /// <param name="fromImagePath">来源图片地址</param>
        /// <param name="offsetX">从偏移X坐标位置开始截取</param>
        /// <param name="offsetY">从偏移Y坐标位置开始截取</param>
        /// <param name="toImagePath">保存图片地址</param>
        /// <param name="width">保存图片的宽度</param>
        /// <param name="height">保存图片的高度</param>
        /// <returns></returns>
        public void CaptureImage(string fromImagePath, int offsetX,int offsetY, string toImagePath, int width, int height)
        {
            //原图片文件
            Image fromImage = Image.FromFile(fromImagePath);
            //创建新图位图
            Bitmap bitmap = new Bitmap(width, height);
            //创建作图区域
            Graphics graphic = Graphics.FromImage(bitmap);
            //截取原图相应区域写入作图区
            graphic.DrawImage(fromImage, , , new Rectangle(offsetX, offsetY, width, height), GraphicsUnit.Pixel);
            //从作图区生成新图
            Image saveImage = Image.FromHbitmap(bitmap.GetHbitmap());
            //保存图片
            saveImage.Save(toImagePath, ImageFormat.Png);
            //释放资源
            saveImage.Dispose();
            graphic.Dispose();
            bitmap.Dispose();
        }
        #endregion