asp.net 生成缩略图、为图片添加文字水印、图片水印等功能

最近挺嫌的荒，不知道写点什么好，就在网上找了个类似的例子，自己重新写了一遍,稍微改了一下。希望对大家有用

实现了生成缩略图、为图片添加文字水印、图片水印等功能

源代码打包下载:https://files.cnblogs.com/ywqu/ThumPicture.rar

前台代码：

Code
<%@ Page Language="C#" AutoEventWireup="true"  CodeFile="Default.aspx.cs" Inherits="_Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div style="text-align: center">
        &nbsp;<table>
            <tr>
                <td style="width: 100px">
                    <asp:FileUpload ID="FileUpload1" runat="server" /></td>
                <td style="width: 100px">
                    <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Button" /></td>
            </tr>
            <tr>
                <td style="height: 20px"></td>
                <td style="height: 20px"></td>
            </tr>
            <tr>
                <td style="height: 20px;" colspan="2">
                    <asp:Label ID="Label1" runat="server" ForeColor="Red" Text="Label"></asp:Label></td>
            </tr>
            <tr>
                <td style="width: 100px">
                    </td>
                <td style="width: 100px">
                    </td>
            </tr>
        </table>
    
        
    </div>
    </form>
</body>
</html>

后台代码

Code
protected void Button1_Click(object sender, EventArgs e)
    {
        if (FileUpload1.HasFile)
        {
            string fileType = FileUpload1.PostedFile.ContentType;
            if (fileType == "image/bmp" || fileType == "image/gif" || fileType == "image/jpg")
            {
                string name = FileUpload1.PostedFile.FileName;  //文件路径
                FileInfo fileInfo = new FileInfo(name);
                string fileName = fileInfo.Name;                //文件名称
                string sFileName = "x_" + fileName;             //缩略图文件名 
                string syFileNameText = "text_" + fileName;     //水印图文件名(文字) 
                string syFileNamePic = "pic_" + fileName;       //水印图文件名(图片)

                string filePath = Server.MapPath("ImgUpLoad/" + fileName);    //服务器端文件路径
                string sFilePath = Server.MapPath("ImgUpLoad/" + sFileName);//缩略图文件路径
                string syFileTextPath = Server.MapPath("ImgUpLoad/" + syFileNameText);//带水印的的图片路径（文字）
                string syFilePicPath = Server.MapPath("ImgUpLoad/" + syFileNamePic);
                string syPic = Server.MapPath("hello36.png");

                if (!File.Exists(filePath))
                {
                    try
                    {
                        FileUpload1.SaveAs(filePath);
                        ThumNail.AddWaterWord(filePath, syFileTextPath);
                        ThumNail.AddWaterPic(filePath, syPic, syFilePicPath);
                        ThumNail.MakeThumNail(filePath, sFilePath, 130, 130, "Cut");
                        Label1.Text = "图片操做：生成缩略图、添加水印成功！";
                        
                    }
                    catch (Exception ex)
                    {

                         Label1.Text = "文件操作失败，失败原因：" + ex.Message;
                    }
                }
                else
                {
                    Label1.Text = "文件已经存在，请重新命名后上传！";
                }
            }
            else
            {
                Label1.Text = "文件格式不符，允许的格式：.gif .jpg .bmp";
            }
        }
        Label1.Visible = true;
    }

生成缩略图、为图片添加文字水印、图片水印等功能单独放到一个类（ThumNail.cs）里面了

Code
using System;
using System.Data;
using System.Configuration;
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;

/// <summary>
/// 生成缩略图、为图片添加文字水印、图片水印的类
/// </summary>
public class ThumNail
{
    public ThumNail()
    {
        //
        // TODO: Add constructor logic here
        //
    }
    /// <summary>
    /// 生成缩略图
    /// </summary>
    /// <param name="orginalImagePat">原图片地址</param>
    /// <param name="thumNailPath">缩略图地址</param>
    /// <param name="width">缩略图宽度</param>
    /// <param name="height">缩略图高度</param>
    /// <param name="model">生成缩略的模式</param>
    public static void MakeThumNail(string originalImagePath,string thumNailPath,int width,int height,string model)
    {
        System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath);

        int thumWidth = width;      //缩略图的宽度
        int thumHeight = height;    //缩略图的高度

        int x = 0;
        int y = 0;

        int originalWidth = originalImage.Width;    //原始图片的宽度
        int originalHeight = originalImage.Height;  //原始图片的高度

        switch (model)
        {
            case "HW":      //指定高宽缩放,可能变形
                break;
            case "W":       //指定宽度,高度按照比例缩放
                thumHeight = originalImage.Height * width / originalImage.Width;
                break;
            case "H":       //指定高度,宽度按照等比例缩放
                thumWidth = originalImage.Width * height / originalImage.Height;
                break;
            case "Cut":
                if ((double)originalImage.Width / (double)originalImage.Height > (double)thumWidth / (double)thumHeight)
                {
                    originalHeight = originalImage.Height;
                    originalWidth = originalImage.Height * thumWidth / thumHeight;
                    y = 0;
                    x = (originalImage.Width - originalWidth) / 2;
                }
                else
                {
                    originalWidth = originalImage.Width;
                    originalHeight = originalWidth * height / thumWidth;
                    x = 0;
                    y = (originalImage.Height - originalHeight) / 2;
                }
                break;
            default:
                break;
        }

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

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

        //设置高质量查值法
        graphic.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;

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

        //清空画布并以透明背景色填充
        graphic.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
        graphic.DrawImage(originalImage, new System.Drawing.Rectangle(0, 0, thumWidth, thumHeight), new System.Drawing.Rectangle(x, y, originalWidth, originalHeight), System.Drawing.GraphicsUnit.Pixel);

        try
        {
            bitmap.Save(thumNailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
        }
        catch (Exception ex)
        {

            throw ex;
        }
        finally
        {
            originalImage.Dispose();
            bitmap.Dispose();
            graphic.Dispose();
        }

    }

    /// <summary>
    /// 在图片上添加文字水印
    /// </summary>
    /// <param name="path">要添加水印的图片路径</param>
    /// <param name="syPath">生成的水印图片存放的位置</param>
    public static void AddWaterWord(string path,string syPath)
    {
        string syWord = "http://www.hello36.cn";
        System.Drawing.Image image = System.Drawing.Image.FromFile(path);

        //新建一个画板
        System.Drawing.Graphics graphic = System.Drawing.Graphics.FromImage(image);
        graphic.DrawImage(image,0,0,image.Width,image.Height);

        //设置字体
        System.Drawing.Font f = new System.Drawing.Font("Verdana",60);                            

        //设置字体颜色
        System.Drawing.Brush b = new System.Drawing.SolidBrush(System.Drawing.Color.Green);

        graphic.DrawString(syWord, f, b, 35, 35);
        graphic.Dispose();

        //保存文字水印图片
        image.Save(syPath);
        image.Dispose();

    }

    /// <summary>
    /// 在图片上添加图片水印
    /// </summary>
    /// <param name="path">原服务器上的图片路径</param>
    /// <param name="syPicPath">水印图片的路径</param>
    /// <param name="waterPicPath">生成的水印图片存放路径</param>
    public static void AddWaterPic(string path, string syPicPath, string waterPicPath)
    {
        System.Drawing.Image image = System.Drawing.Image.FromFile(path);
        System.Drawing.Image waterImage = System.Drawing.Image.FromFile(syPicPath);
        System.Drawing.Graphics graphic = System.Drawing.Graphics.FromImage(image);
        graphic.DrawImage(waterImage,new System.Drawing.Rectangle(image.Width-waterImage.Width,image.Height-waterImage.Height,waterImage.Width,waterImage.Height),0,0,waterImage.Width,waterImage.Height,System.Drawing.GraphicsUnit.Pixel);
        graphic.Dispose();

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

}