贴段上传图片代码，截取缩略图

最新推荐文章于 2024-05-31 19:39:39 发布

转载最新推荐文章于 2024-05-31 19:39:39 发布 · 116 阅读

0 ·

CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/zhoudemo/archive/2012/01/12/2320288.html

本文介绍了一种图片上传和处理的方法，通过将大尺寸图片切割并生成缩略图，有效提高了网页加载速度。同时，文章提供了详细的代码实现，展示了如何使用C#进行图片的上传、压缩和存储。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

[PS:原创，如转载，请注明转载出处，谢谢]

这段代码杂用？有啥用？能干什么？

最近在做一个图片网，你说能干嘛用呢？？呵呵。。。

一张高清图，最少都是一MB以上的，看了这个之后，你还在用原来的，只保存一张图片？？？

那你显示列表页的时候，不卡死了才怪了，一个页面显示60张图片，一张图片来个不多，1MB，整个列表下来是60MB。。。老大，强悍。。。牛B哇。。。嘿嘿

搞啥？不搞啥，切出来后，在搞，显示缩略图，弄成几十K的大小，显示一张比例为800*600的图，用到详细页面去，在搞个原图，用来点击查看原图用，这样就不用当心了吧？速度自然就上去了

View Code

using System.IO;
using System.Drawing;

/// <summary>
/// 图片上传
/// </summary>
/// <param name="uname">用户名，用于生成图片名称</param>
/// <param name="file">HttpPostedFile</param>
/// <returns>图片路径</returns>
    public string[] ImgUpLoad(string uname, HttpPostedFile file)
    {
string[] returnImg = new string[3];
int intThumbWidth = 160;
int intThumbHeight = 160;

string sFilename = "";
        HttpPostedFile myFile = file;
int nFileLen = myFile.ContentLength;
if (nFileLen == 0)
return null;
//获取upImage选择文件的扩展名
        string extendName = System.IO.Path.GetExtension(myFile.FileName).ToLower();
//判断是否为图片格式
        if (extendName != ".jpg" && extendName != ".jpge" && extendName != ".gif" && extendName != ".bmp" && extendName != ".png")
return null;

byte[] myData = new Byte[nFileLen];
        myFile.InputStream.Read(myData, 0, nFileLen);
        sFilename = System.IO.Path.GetFileName(myFile.FileName);

//生成目录名称
        string dirName = DateTime.Now.Year.ToString() + DateTime.Now.Month.ToString();
if (!Directory.Exists(System.Web.HttpContext.Current.Server.MapPath("~/PhotoUploadFile/ShowPhoto/" + dirName + "/")))
        {
            Directory.CreateDirectory(System.Web.HttpContext.Current.Server.MapPath("~/PhotoUploadFile/ShowPhoto/" + dirName + "/"));
        }

//----生成未处理原图存放目录名称
        string dirNameSrc = DateTime.Now.Year.ToString() + DateTime.Now.Month.ToString();
if (!Directory.Exists(System.Web.HttpContext.Current.Server.MapPath("~/PhotoUploadFile/Photo/" + dirNameSrc + "/")))
        {
            Directory.CreateDirectory(System.Web.HttpContext.Current.Server.MapPath("~/PhotoUploadFile/Photo/" + dirNameSrc + "/"));
        }

        DateTime dtime = DateTime.Now;
//生成图片文件名称
        string fileName = dtime.Year.ToString()
            + dtime.Month.ToString()
            + dtime.Day.ToString()
            + dtime.Hour.ToString()
            + dtime.Minute.ToString()
            + dtime.Second.ToString()
            + dtime.Millisecond.ToString() + extendName;
        fileName = uname + fileName;

//处理完显示图片
        string savePath = "~/PhotoUploadFile/ShowPhoto/" + dirName + "/";
string dirPath = dirName + "/";

//----未处理原图路径与目录
        string savePathSrc = "~/PhotoUploadFile/Photo/" + dirNameSrc + "/";
string dirPathSrc = dirNameSrc + "/";

//----保存未处理原图
        System.IO.FileStream newFileSrc
            = new System.IO.FileStream(System.Web.HttpContext.Current.Server.MapPath(savePathSrc) + fileName,
            System.IO.FileMode.Create, System.IO.FileAccess.Write);
        newFileSrc.Write(myData, 0, myData.Length);
        newFileSrc.Close();
        returnImg[0] = savePathSrc + fileName;
//以上为上传原图

try
        {
//原图加载 
            using (System.Drawing.Image sourceImage = System.Drawing.Image.FromFile(System.Web.HttpContext.Current.Server.MapPath(savePathSrc + fileName)))
            {
//原图宽度和高度
                int width = sourceImage.Width;
int height = sourceImage.Height;
int smallWidth;
int smallHeight;

//获取第一张绘制图的大小,(比较 原图的宽/缩略图的宽   和 原图的高/缩略图的高) 
                if (((decimal)width) / height <= ((decimal)intThumbWidth) / intThumbHeight)
                {
//smallWidth = width/(height/intThumbHeight);
                    smallWidth = width * intThumbHeight / height;
                    smallHeight = intThumbHeight;
                }
else
                {
                    smallWidth = intThumbWidth;
//smallHeight = height/(width/intThumbWidth);
                    smallHeight = height * intThumbWidth / width;
                }

//生成目录名称
                dirName = DateTime.Now.Year.ToString() + DateTime.Now.Month.ToString();
if (!Directory.Exists(System.Web.HttpContext.Current.Server.MapPath("~/PhotoUploadFile/Thumb/" + dirName + "/")))
                {
                    Directory.CreateDirectory(System.Web.HttpContext.Current.Server.MapPath("~/PhotoUploadFile/Thumb/" + dirName + "/"));
                }

                dtime = DateTime.Now;

                savePath = "~/PhotoUploadFile/Thumb/" + dirName + "/";
string dirPath2 = dirName + "/";


//缩略图保存的绝对路径 
                string smallImagePath = System.Web.HttpContext.Current.Server.MapPath(savePath) + fileName;

//新建一个图板,以最小等比例压缩大小绘制原图 
                 using (System.Drawing.Image bitmap3 = new System.Drawing.Bitmap(smallWidth, smallHeight))
                {
//绘制中间图 
                    using (System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap3))
                    {

//高清,平滑 
                        g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
                        g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                        g.Clear(Color.Black);
                        g.DrawImage(
                        sourceImage,
new System.Drawing.Rectangle(0, 0, smallWidth, smallHeight),
new System.Drawing.Rectangle(0, 0, width, height),
                        System.Drawing.GraphicsUnit.Pixel
                        );
                    }
//新建一个图板,以缩略图大小绘制中间图 
                    using (System.Drawing.Image bitmap1 = new System.Drawing.Bitmap(intThumbWidth, intThumbHeight))
                    {
//绘制缩略图 
                        using (System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap1))
                        {
//高清,平滑 
                            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
                            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                            g.Clear(Color.Black);
int lwidth = (smallWidth - intThumbWidth) / 2;
int bheight = (smallHeight - intThumbHeight) / 2;
                            g.DrawImage(bitmap3, new Rectangle(0, 0, intThumbWidth, intThumbHeight), lwidth, bheight, intThumbWidth, intThumbHeight, GraphicsUnit.Pixel);

                            g.Dispose();
                            bitmap1.Save(smallImagePath, System.Drawing.Imaging.ImageFormat.Jpeg);
                            returnImg[1] = savePath + fileName;
                        }
                    }
                }

//生成显示图片 ShowPhoto
                intThumbWidth = 800;
                intThumbHeight = 600;
string equalSavePath = "~/PhotoUploadFile/ShowPhoto/" + dirName + "/";
string showSrcPath = equalSavePath;
                equalSavePath = System.Web.HttpContext.Current.Server.MapPath(equalSavePath) + fileName;
if (((decimal)width) / height <= ((decimal)intThumbWidth) / intThumbHeight)
                {
//smallWidth = width/(height/intThumbHeight);
                    smallWidth = width * intThumbHeight / height;
                    smallHeight = intThumbHeight;
                }
else
                {
                    smallWidth = intThumbWidth;
//smallHeight = height/(width/intThumbWidth);
                    smallHeight = height * intThumbWidth / width;
                }
if (width <= 800 && height <= 600)
                {
                    smallWidth = width;
                    smallHeight = height;
                }
//if (height < 800 && width < 600)
//{
//    smallWidth = height;
//    smallHeight = width;
//}
//if (width <= 800) {
//    smallWidth = width;
//}
//if (height <= 600) {
//    smallHeight = height;
//}

//新建一个图板,以最小等比例压缩大小绘制原图 
                using (System.Drawing.Image bitmap3 = new System.Drawing.Bitmap(smallWidth, smallHeight))
                {
//绘制中间图 
                    using (System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap3))
                    {

//高清,平滑 
                        g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
                        g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                        g.Clear(Color.Black);
                        g.DrawImage(
                        sourceImage,
new System.Drawing.Rectangle(0, 0, smallWidth, smallHeight),
new System.Drawing.Rectangle(0, 0, width, height),
                        System.Drawing.GraphicsUnit.Pixel
                        );
                    }
//新建一个图板,以缩略图大小绘制中间图 
                    using (System.Drawing.Image bitmap1 = new System.Drawing.Bitmap(intThumbWidth, intThumbHeight))
                    {
//绘制缩略图 
                        using (System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap1))
                        {
//高清,平滑 
                            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
                            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                            g.Clear(Color.Black);
int lwidth = (smallWidth - intThumbWidth) / 2;
int bheight = (smallHeight - intThumbHeight) / 2;
                            g.DrawImage(bitmap3, new Rectangle(0, 0, intThumbWidth, intThumbHeight), lwidth, bheight, intThumbWidth, intThumbHeight, GraphicsUnit.Pixel);

                            g.Dispose();
                            bitmap1.Save(equalSavePath, System.Drawing.Imaging.ImageFormat.Jpeg);
                            returnImg[2] = showSrcPath + fileName;
                        }
                    }
                }
            }
        }
catch (Exception ex)
        {
//出错则删除
//System.IO.File.Delete(System.Web.HttpContext.Current.Server.MapPath(savePath));
            throw ex;
        }

return returnImg;
    }

转载于:https://www.cnblogs.com/zhoudemo/archive/2012/01/12/2320288.html