ASP.NET2.0 生成缩略图_将anaconda3下的图片生成缩略图-优快云博客

本文链接：https://blog.youkuaiyun.com/codetian/article/details/1497297

本文介绍了一个ASP.NET中的图片上传及缩略图生成的方法。该方法首先验证上传文件是否为图片格式，然后生成原图和指定尺寸的缩略图，并采用高质量的插值法和平滑处理来确保图片质量。

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protected void btnUploadPicture_Click1(object sender, EventArgs e)
    {
        //检查上传文件的格式是否有效
        if (this.UploadFile.PostedFile.ContentType.ToLower().IndexOf("image") < 0)
        {
            Response.Write("上传图片格式无效！");
            return;
        }

        //生成原图
        Byte[] oFileByte = new byte[this.UploadFile.PostedFile.ContentLength];
        System.IO.Stream oStream = this.UploadFile.PostedFile.InputStream;
        Byte[] aa = this.UploadFile.FileBytes;
        System.Drawing.Image oImage = System.Drawing.Image.FromStream(oStream);

        int oWidth = oImage.Width; //原图宽度
        int oHeight = oImage.Height; //原图高度
        int tWidth = 100; //设置缩略图初始宽度
        int tHeight = 100; //设置缩略图初始高度

        //按比例计算出缩略图的宽度和高度
        if (oWidth >= oHeight)
        {
            tHeight = (int)Math.Floor(Convert.ToDouble(oHeight) * (Convert.ToDouble(tWidth) / Convert.ToDouble(oWidth)));
        }
        else
        {
            tWidth = (int)Math.Floor(Convert.ToDouble(oWidth) * (Convert.ToDouble(tHeight) / Convert.ToDouble(oHeight)));
        }

        //生成缩略原图
        Bitmap tImage = new Bitmap(tWidth, tHeight);
        Graphics g = Graphics.FromImage(tImage);
        g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High; //设置高质量插值法
        g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;//设置高质量,低速度呈现平滑程度
        g.Clear(Color.Transparent); //清空画布并以透明背景色填充
        g.DrawImage(oImage, new Rectangle(0, 0, tWidth, tHeight), new Rectangle(0, 0, oWidth, oHeight), GraphicsUnit.Pixel);

string oFullName = Server.MapPath(".") + "/" + "o" + DateTime.Now.ToShortDateString().Replace("-", "") + DateTime.Now.Hour.ToString() + DateTime.Now.Minute.ToString() + DateTime.Now.Second.ToString() + DateTime.Now.Millisecond.ToString() + ".jpg"; //保存原图的物理路径
string tFullName = Server.MapPath(".") + "/" + "t" + DateTime.Now.ToShortDateString().Replace("-", "") + DateTime.Now.Hour.ToString() + DateTime.Now.Minute.ToString() + DateTime.Now.Second.ToString() + DateTime.Now.Millisecond.ToString() + ".jpg"; //保存缩略图的物理路径

        try
        {
            //以JPG格式保存图片
            oImage.Save(oFullName, System.Drawing.Imaging.ImageFormat.Jpeg);
            tImage.Save(tFullName, System.Drawing.Imaging.ImageFormat.Jpeg);
            //Response.BinaryWrite(aa);
            //Response.WriteFile(oFullName);
            //Response.WriteFile(tFullName);
        }
        catch (Exception ex)
        {
            throw ex;
        }
        finally
        {
            //释放资源
            oImage.Dispose();
            g.Dispose();
            tImage.Dispose();
        }
    }