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asp.net上传图片并生成缩略图

时间:2013-11-23 11:35 | 来源:网胜培训中心
选择图片上传成功后,取得已经存在服务器的文件生成缩略图,并且判断是否是图片类型的文件,这个的判断可以在程序中修改。

实现过程:选择图片上传成功后,取得已经存在服务器的文件生成缩略图,并且判断是否是图片类型的文件,这个的判断可以在程序中修改,本程序只是判断了“image/bmp”、“image/gif”、“image/pjpeg”三种类型。
    代码如下:
    upfile.aspx文件

upfile.aspx.cs文件
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;

public partial class upfile_upfile : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    { }

    protected void Button1_Click(object sender, EventArgs e)
    {
        if (FileUpload1.HasFile)
        {
            string fileContentType = FileUpload1.PostedFile.ContentType;
            if (fileContentType == "image/bmp" || fileContentType == "image/gif" || fileContentType == "image/pjpeg")
            {
                string name = FileUpload1.PostedFile.FileName;                  // 客户端文件路径

                FileInfo file = new FileInfo(name);
                string fileName = file.Name;                                    // 文件名称
                string fileName_s = "s_" + file.Name;                           // 缩略图文件名称
                string fileName_sy = "sy_" + file.Name;                         // 水印图文件名称(文字)
                string fileName_syp = "syp_" + file.Name;                       // 水印图文件名称(图片)
                string webFilePath = Server.MapPath("file/" + fileName);        // 服务器端文件路径
                string webFilePath_s = Server.MapPath("file/" + fileName_s);  // 服务器端缩略图路径
                string webFilePath_sy = Server.MapPath("file/" + fileName_sy); // 服务器端带水印图路径(文字)
                string webFilePath_syp = Server.MapPath("file/" + fileName_syp); // 服务器端带水印图路径(图片)
                string webFilePath_sypf = Server.MapPath("file/shuiyin.jpg"); // 服务器端水印图路径(图片)

                if (!File.Exists(webFilePath))
                {
                    try
                    {
                        FileUpload1.SaveAs(webFilePath);                               

                        AddShuiYinWord(webFilePath, webFilePath_sy);
                        AddShuiYinPic(webFilePath, webFilePath_syp, webFilePath_sypf);
                        MakeThumbnail(webFilePath, webFilePath_s, 130, 130, "Cut");     // 生成缩略图方法
                        Label1.Text = "提示:文件“" + fileName + "”成功上传,并生成“" + fileName_s + "”缩略图,文件类型为:" + FileUpload1.PostedFile.ContentType + ",文件大小为:" + FileUpload1.PostedFile.ContentLength + "B";
                    }
                    catch (Exception ex)
                    {
                        Label1.Text = "提示:文件上传失败,失败原因:" + ex.Message;
                    }
                }
                else
                {
                    Label1.Text = "提示:文件已经存在,请重命名后上传";
                }
            }
            else
            {
                Label1.Text = "提示:文件类型不符";
            }
        }
    }
    /**////


    /// 生成缩略图
    ///
    /// 源图路径(物理路径)
    /// 缩略图路径(物理路径)
    /// 缩略图宽度
    /// 缩略图高度
    /// 生成缩略图的方式   
    public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode)
    {
        System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath);

        int towidth = width;
        int toheight = height;

        int x = 0;
        int y = 0;
        int ow = originalImage.Width;
        int oh = originalImage.Height;

        switch (mode)
        {
            case "HW"://指定高宽缩放(可能变形)               
                break;
            case "W"://指定宽,高按比例                   
                toheight = originalImage.Height * width / originalImage.Width;
                break;
            case "H"://指定高,宽按比例
                towidth = originalImage.Width * height / originalImage.Height;
                break;
            case "Cut"://指定高宽裁减(不变形)               
                if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
                {
                    oh = originalImage.Height;
                    ow = originalImage.Height * towidth / toheight;
                    y = 0;
                    x = (originalImage.Width - ow) / 2;
                }
                else
                {
                    ow = originalImage.Width;
                    oh = originalImage.Width * height / towidth;
                    x = 0;
                    y = (originalImage.Height - oh) / 2;
                }
                break;
            default:
                break;
        }

        //新建一个bmp图片
        System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);

        //新建一个画板
        System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);

        //设置高质量插值法
        g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;

        //设置高质量,低速度呈现平滑程度
        g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

        //清空画布并以透明背景色填充
        g.Clear(System.Drawing.Color.Transparent);

        //在指定位置并且按指定大小绘制原图片的指定部分
        g.DrawImage(originalImage, new System.Drawing.Rectangle(0, 0, towidth, toheight),
            new System.Drawing.Rectangle(x, y, ow, oh),
            System.Drawing.GraphicsUnit.Pixel);

        try
        {
            //以jpg格式保存缩略图
            bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
        }
        catch (System.Exception e)
        {
            throw e;
        }
        finally
        {
            originalImage.Dispose();
            bitmap.Dispose();
            g.Dispose();
        }
    }

    /**////


    /// 在图片上增加文字水印
    ///
    /// 原服务器图片路径
    /// 生成的带文字水印的图片路径
    protected void AddShuiYinWord(string Path, string Path_sy)
    {
        string addText = "测试水印";
        System.Drawing.Image image = System.Drawing.Image.FromFile(Path);
        System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image);
        g.DrawImage(image, 0, 0, image.Width, image.Height);
        System.Drawing.Font f = new System.Drawing.Font("Verdana", 16);
        System.Drawing.Brush b = new System.Drawing.SolidBrush(System.Drawing.Color.Blue);

        g.DrawString(addText, f, b, 15, 15);
        g.Dispose();

        image.Save(Path_sy);
        image.Dispose();
    }

    /**////


    /// 在图片上生成图片水印
    ///
    /// 原服务器图片路径
    /// 生成的带图片水印的图片路径
    /// 水印图片路径
    protected void AddShuiYinPic(string Path, string Path_syp, string Path_sypf)
    {
        System.Drawing.Image image = System.Drawing.Image.FromFile(Path);
        System.Drawing.Image copyImage = System.Drawing.Image.FromFile(Path_sypf);
        System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image);
        g.DrawImage(copyImage, new System.Drawing.Rectangle(image.Width - copyImage.Width, image.Height - copyImage.Height, copyImage.Width, copyImage.Height), 0, 0, copyImage.Width,copyImage.Height, System.Drawing.GraphicsUnit.Pixel);
        g.Dispose();

        image.Save(Path_syp);
        image.Dispose();
    }
}
 


关键词:asp.net上传图片并生成缩略图
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