C#图片水印类
using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using System.IO;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
namespace ECHX.BLL
{
        /// <summary>
    /// WaterMark 的摘要说明
    /// </summary>
    /// 
    /// <param name="strCopyright">要加入的文字</param>
    /// <param name="strMarkPath">水印图片路径</param>
    /// <param name="strPhotoPath">要加水印的图片路径</param>
    /// <param name="strSavePath">处理后的图片路径</param>
    /// <param name="iMarkRightSpace">水印在修改图片中距左边的宽度</param>
    /// <param name="iMarkButtomSpace">水印在修改图片中距底部的高度</param>
    /// <param name="iDiaphaneity">水印图片的透明度</param>
    /// <param name="iFontRightSpace">文字</param>
    /// <param name="iFontButtomSpace">文字</param>
    /// <param name="iFontDiaphaneity">文字</param>
    /// <param name="bShowCopyright">是否显示文字</param>
    /// <param name="bShowMarkImage">是否显示水印图片</param>    public class WaterMark
    {
        #region  param
        private string strCopyright,strMarkPath,strPhotoPath,strSavePath;
        private int iMarkRightSpace, iMarkButtomSpace, iDiaphaneity;
        private int iFontRightSpace = 0, iFontButtomSpace = 0, iFontDiaphaneity=80;
        private int iFontSize = 10;
        private bool bShowCopyright=true, bShowMarkImage=true;
        #endregion        #region WaterMark
        public WaterMark()
        {
            this.strCopyright   = "";
            this.strMarkPath    = null;
            this.strPhotoPath   = null;
            this.strSavePath    = null;
            this.iDiaphaneity   = 70;
            this.iMarkRightSpace    = 0;
            this.iMarkButtomSpace   = 0;
        }        /// <summary>
        /// 主要用两样都加的
        /// </summary>
        public WaterMark(string copyright,string Path,string photoPath,string savePath)
        {
            this.strCopyright   = copyright;
            this.strMarkPath    = Path;
            this.strPhotoPath   = photoPath;
            this.strSavePath    = savePath;
            this.iDiaphaneity   =   70;
            this.iMarkRightSpace    = 0;
            this.iMarkButtomSpace   = 0; 
        }
        #endregion        #region property        /// <summary>
        /// 设置是否显示水印文字
        /// </summary>
        public bool ShowCopyright
        {
            set { this.bShowCopyright = value; }
        }        /// <summary>
        /// 设置是否显示水印图片
        /// </summary>
        public bool ShowMarkImage
        {
            set { this.bShowMarkImage = value; }
        }
        /// <summary>
        /// 获取或设置要加入的文字
        /// </summary>
        public string Copyright
        {
            set { this.strCopyright = value; }
        }        /// <summary>
        /// 获取或设置加水印后的图片路径
        /// </summary>
        public string SavePath
        {
            get { return this.strSavePath; }
            set { this.strSavePath = value; }
        }        /// <summary>
        /// 获取或设置水印图片路径
        /// </summary>
        public string MarkPath
        {
            get { return this.strMarkPath; }
            set { this.strMarkPath = value; }
        }        /// <summary>
        /// 获取或设置要加水印图片的路径
        /// </summary>
        public string PhotoPath
        {
            get { return this.strPhotoPath; }
            set { this.strPhotoPath = value; }
        }        /// <summary>
        /// 设置水印图片的透明度
        /// </summary>
        public int Diaphaneity
        {
            set { 
                if(value > 0 && value <= 100)
                    this.iDiaphaneity = value; 
            }
        }        /// <summary>
        /// 设置水印字体的透明度0-255
        /// </summary>
        public int FontDiaphaneity
        {
            set
            {
                if (value >= 0 && value <= 255)
                    this.iFontDiaphaneity = value;
            }
        }        /// <summary>
        /// 设置水印图片在修改图片中距左边的高度
        /// </summary>
        public int MarkRightSpace
        {
            set { this.iMarkRightSpace = value; }
        }        /// <summary>
        /// 设置水印图片在修改图片中距底部的高度
        /// </summary>
        public int MarkButtomSpace
        {
            set { this.iMarkButtomSpace = value; }
        }        /// <summary>
        /// 设置水印字体在修改图片中距左边的距离
        /// </summary>
        public int FontRightSpace
        {
            set { iFontRightSpace = value; }
        }        /// <summary>
        /// 设置水印字体在修改图片中距底部的高度
        /// </summary>
        public int FontButtomSpace
        {
            set { iFontButtomSpace = value; }
        }        #endregion       
        /// <summary>
        /// 生成水印图片
        /// </summary>
        /// <returns></returns>
        public void createMarkPhoto()
        {
            Bitmap bmWater = null;
            Image gPhoto = Image.FromFile(this.strPhotoPath);
            int PhotoWidth  = gPhoto.Width;
            int PhotoHeight = gPhoto.Height;
            Bitmap bitPhoto = new Bitmap(PhotoWidth, PhotoHeight,PixelFormat.Format24bppRgb);
            bitPhoto.SetResolution(gPhoto.HorizontalResolution,gPhoto.VerticalResolution);            try
            {
                if (bShowCopyright)
                {
                    Graphics grPhoto = Graphics.FromImage(bitPhoto);
                    grPhoto.SmoothingMode = SmoothingMode.AntiAlias;
                    grPhoto.DrawImage(gPhoto, new Rectangle(0, 0, PhotoWidth, PhotoHeight), 0, 0, PhotoWidth, PhotoHeight, GraphicsUnit.Pixel);                    Font crFont = new Font("楷体", iFontSize, FontStyle.Bold);
                    SizeF crSize = grPhoto.MeasureString(strCopyright, crFont);                    //设置字体在图片中的位置
                    float yPosFromBottom = PhotoHeight - iFontButtomSpace - (crSize.Height);                    //float xCenterOfImg = (phWidth/2);
                    float xCenterOfImg = PhotoWidth - iFontRightSpace - (crSize.Width / 2);
                    //设置字体居中                    StringFormat StrFormat = new StringFormat();
                    StrFormat.Alignment = StringAlignment.Center;                    //设置绘制文本的颜色和纹理 (Alpha=153)
                    SolidBrush semiTransBrush2 = new SolidBrush(Color.FromArgb(this.iFontDiaphaneity, 0, 0, 0));                    //将版权信息绘制到图象上
                    grPhoto.DrawString(strCopyright, crFont, semiTransBrush2, new PointF(xCenterOfImg, yPosFromBottom), StrFormat);                    gPhoto = bitPhoto;
                    grPhoto.Dispose();
                }                 if (bShowMarkImage)
                {
                    //创建一个需要填充水银的Image对象
                    Image imgWater = new Bitmap(strMarkPath);
                    int iMarkWidth = imgWater.Width;
                    int iMarkmHeight = imgWater.Height;                    Graphics grWater = null;
                    if (bShowCopyright)
                    {
                        //在原来修改过的bmPhoto上创建一个水银位图
                        bmWater = new Bitmap(bitPhoto);
                        bmWater.SetResolution(gPhoto.HorizontalResolution, gPhoto.VerticalResolution);
                    }
                    else
                    {
                        bmWater = new Bitmap(gPhoto);
                    }                    //将位图bmWater加载到Graphics对象
                    grWater = Graphics.FromImage(bmWater);
                    ImageAttributes imageAttributes = new ImageAttributes();                    ColorMap colorMap = new ColorMap();                    colorMap.OldColor = Color.FromArgb(255, 0, 255, 0);
                    colorMap.NewColor = Color.FromArgb(0, 0, 0, 0);                    ColorMap[] remapTable = { colorMap };                    imageAttributes.SetRemapTable(remapTable, ColorAdjustType.Bitmap);                    float[][] colorMatrixElements = { 
                    new float[] {1.0f, 0.0f, 0.0f, 0.0f, 0.0f}, 
                    new float[] {0.0f, 1.0f, 0.0f, 0.0f, 0.0f}, 
                    new float[] {0.0f, 0.0f, 1.0f, 0.0f, 0.0f}, 
                    new float[] {0.0f, 0.0f, 0.0f, (float)iDiaphaneity/100f, 0.0f}, 
                    new float[] {0.0f, 0.0f, 0.0f, 0.0f, 1.0f}};
                    ColorMatrix wmColorMatrix = new ColorMatrix(colorMatrixElements);                    imageAttributes.SetColorMatrix(wmColorMatrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap);                    grWater.DrawImage(imgWater, new Rectangle((PhotoWidth - iMarkRightSpace - (iMarkWidth / 2)), (PhotoHeight - iMarkButtomSpace - (iMarkmHeight/2)), iMarkWidth, iMarkmHeight), 0, 0, iMarkWidth, iMarkmHeight, GraphicsUnit.Pixel, imageAttributes);                    gPhoto = bmWater;
                    grWater.Dispose();
                    imgWater.Dispose();
                }
                gPhoto.Save(strSavePath, ImageFormat.Jpeg);
            }
            finally
            {              if (bitPhoto!=null)
                 bitPhoto.Dispose();             if (bmWater != null)
                bmWater.Dispose();             gPhoto.Dispose();
          }
             
        }
    }
}