.net core 图片合并,图片水印,等比例缩小,SixLabors.ImageSharp

using SixLabors.ImageSharp;
using SixLabors.ImageSharp.Formats;
using SixLabors.ImageSharp.Processing;

/// <summary>
        /// 合并图片 小图片放在大图片上面
        /// </summary>
        /// <param name="TempleBase64Str">模板大图片base64</param>
        /// <param name="OutputBase64Str">模板小图片base64</param>
        /// <param name="x">X坐标</param>
        /// <param name="y">y坐标</param>
        /// <returns></returns>
        public ImageResponse MergeImage(string TempleBase64Str, string OutputBase64Str, int x, int y)
        {
            string strRet = null;
            if (string.IsNullOrEmpty(TempleBase64Str))
            {
                return new ImageResponse { success = false, errmsg = "请传入模板大图片base64" };
            }
            if (string.IsNullOrEmpty(OutputBase64Str))
            {
                return new ImageResponse { success = false, errmsg = "请传入模板小图片base64" };
            }
            if (x < 0 || y < 0)
            {
                return new ImageResponse { success = false, errmsg = "坐标不能传入负数" };
            }
            try
            {
                byte[] templebytes = Convert.FromBase64String(TempleBase64Str);
                byte[] outputbytes = Convert.FromBase64String(OutputBase64Str);
                IImageFormat format = null;
                var imagesTemle = SixLabors.ImageSharp.Image.Load(templebytes, out format);
                var outputImg = SixLabors.ImageSharp.Image.Load(outputbytes);
                
                if (imagesTemle.Height - (outputImg.Height + y) <= 0)
                {
                    return new ImageResponse { success = false, errmsg = "Y坐标高度超限" };
                }
                if (imagesTemle.Width - (outputImg.Width + x) <= 0)
                {
                    return new ImageResponse { success = false, errmsg = "X坐标宽度超限" };
                }
                //进行多图片处理
                imagesTemle.Mutate(a =>
                {
                    //还是合并 
                    a.DrawImage(outputImg, 1, new SixLabors.Primitives.Point(x, y));
                });
                strRet = imagesTemle.ToBase64String(format);
                return new ImageResponse { success = true, base64Str = strRet };
            }
            catch (Exception ex) 
            {
                return new ImageResponse { success = false, errmsg ="报错信息"+ex.Message };
            }
        }

using (Stream fs = new MemoryStream(bytes))
//路径参数
using(FileStream streamTemple=System.IO.File.OpenRead("c/图片路径"))
using(MemoryStream output=new MemoryStream())
{
    ...
    //保存图片
    imagesTemle.SaveAsJpeg(streamTemple);
    streamTemple.Close();
    ...
}