C# 添加图片水印类

来源：互联网发布：一人一首成名曲网络篇编辑：程序博客网时间：2024/05/01 11:43

using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using System.IO;
using System.Drawing.Imaging;
using System.Web;
using System.Drawing.Drawing2D;
using System.Reflection;

namespace Chen
{
    public class warterPic
    {
        /// <summary>
        /// 给图片上水印
        /// </summary>
        /// <param name="filepath">原图片地址</param>
        /// <param name="waterfile">水印图片地址</param>
        ///
        public void markwater(string filepath, string waterfile)
        {

            //gif不水印
            int i = filepath.LastIndexOf(".");
            string ex = filepath.Substring(i, filepath.Length - i);
            if (string.Compare(ex, ".gif", true) == 0)
            {
                return;
            }
            string modifyimagepath = filepath;//修改的图像路径
            int lucencypercent = 25;
            Image modifyimage = null;
            Image drawedimage = null;
            Graphics g = null;
            try
            {
                //建立图形对象
                modifyimage = Image.FromFile(modifyimagepath, true);
                drawedimage = Image.FromFile(waterfile, true);

                g = Graphics.FromImage(modifyimage);
                //获取要绘制图形坐标
                int x = modifyimage.Width - drawedimage.Width;
                int y = modifyimage.Height - drawedimage.Height; //设置颜色矩阵
                float[][] matrixitems ={ new float[] { 1, 0, 0, 0, 0 }, new float[] { 0, 1, 0, 0, 0 }, new float[] { 0, 0, 1, 0, 0 }, new float[] { 0, 0, 0, (float)lucencypercent / 100f, 0 }, new float[] { 0, 0, 0, 0, 1 } };

                ColorMatrix colormatrix = new ColorMatrix(matrixitems);
                ImageAttributes imgattr = new ImageAttributes();
                imgattr.SetColorMatrix(colormatrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap); //绘制阴影图像
                g.DrawImage(drawedimage, new Rectangle(x, y, drawedimage.Width, drawedimage.Height), 10, 10, drawedimage.Width, drawedimage.Height, GraphicsUnit.Pixel, imgattr); //保存文件
                string[] allowimagetype ={ ".jpg", ".gif", ".png", ".bmp", ".tiff", ".wmf", ".ico" };
                FileInfo fi = new FileInfo(modifyimagepath);

                ImageFormat imagetype = ImageFormat.Gif;
                switch (fi.Extension.ToLower())
                {
                    case ".jpg":
                        imagetype = ImageFormat.Jpeg;
                        break;
                    case ".gif":
                        imagetype = ImageFormat.Gif;
                        break;
                    case ".png":
                        imagetype = ImageFormat.Png;
                        break;
                    case ".bmp":
                        imagetype = ImageFormat.Bmp;
                        break;
                    case ".tif":
                        imagetype = ImageFormat.Tiff;
                        break;
                    case ".wmf":
                        imagetype = ImageFormat.Wmf;
                        break;
                    case ".ico":
                        imagetype = ImageFormat.Icon;
                        break;
                    default: break;
                }
                MemoryStream ms = new MemoryStream();

                modifyimage.Save(ms, imagetype);
                byte[] imgdata = ms.ToArray();
                modifyimage.Dispose();

                drawedimage.Dispose();
                g.Dispose();
                FileStream fs = null;
                //File.Delete(modifyimagepath);
                fs = new FileStream(modifyimagepath, FileMode.Create, FileAccess.Write);
                if (fs != null)
                {
                    fs.Write(imgdata, 0, imgdata.Length);
                    fs.Close();
                }
            }
            finally
            {
                try
                {
                    drawedimage.Dispose();
                    modifyimage.Dispose();
                    g.Dispose();
                }
                catch
                { }
            }
        }
    }
}

如果提示访问权限不够：
在web.config中
<system.web>中加

<identity impersonate="true"/> 提高权限