图片添加图片水印

当图片为PNG格式的透明图片时,会添加透明水印;非PNG格式的图片时添加不透明水印.

using System;
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;
namespace IPImage
{
    public class ImgMask
    {
        /// <summary> 
        /// 在图片上加入图片版权信息 
        /// </summary> 
        /// <param name="strFileName">输入图片(绝对路径)</param> 
        /// <param name="strOutfileName">输出图片(绝对路径)</param> 
        /// <param name="strCopyRightFile">水印图片(绝对路径)</param> 
        /// <param name="StrPlace">水印位置</param> 
        /// <param name="bolFileName">是否删除输入图片</param> 
        public static void CreateCopyRightImage(string strFileName, string strOutfileName, string strCopyRightFile, string StrPlace, bool bolFileName) 
        { 
            System.Drawing.Image MyImage     = System.Drawing.Image.FromFile( strFileName ); 
            System.Drawing.Image CopyMyImage = System.Drawing.Image.FromFile( strCopyRightFile ); 
            System.Drawing.Bitmap OutPut     = new System.Drawing.Bitmap( MyImage ); 
            System.Drawing.Graphics GImage   = System.Drawing.Graphics.FromImage( OutPut ); 

            int IntX = 0; 
            int IntY = 0; 
            if (StrPlace == "1")   // 在左上 
            { 
                IntX = 0; 
                IntY = 0; 
            } 
            else if (StrPlace == "2")  // 在正上 
            { 
                IntX = (MyImage.Width-CopyMyImage.Width)/2; 
                IntY = 0; 
            } 
            else if (StrPlace == "3")  // 在右上 
            { 
                IntX = MyImage.Width-CopyMyImage.Width; 
                IntY = 0; 
            } 
            else if (StrPlace == "4")  // 在正左 
            { 
                IntX = 0; 
                IntY = (MyImage.Height-CopyMyImage.Height)/2; 
            } 
            else if (StrPlace == "5")  // 在中间 
            {
                IntX = (MyImage.Width-CopyMyImage.Width)/2; 
                IntY = (MyImage.Height-CopyMyImage.Height)/2; 
            } 
            else if (StrPlace == "6")  // 在正右 
            { 
                IntX = MyImage.Width-CopyMyImage.Width; 
                IntY = (MyImage.Height-CopyMyImage.Height)/2; 
            } 
            else if (StrPlace == "7")  // 在左下 
            { 
                IntX = 0; 
                IntY = MyImage.Height-CopyMyImage.Height; 
            } 
            else if (StrPlace == "8")  // 在正下 
            { 
                IntX = (MyImage.Width-CopyMyImage.Width)/2; 
                IntY = MyImage.Height-CopyMyImage.Height; 
            } 
            else if (StrPlace == "9")  // 在右下 
            { 
                IntX = MyImage.Width-CopyMyImage.Width; 
                IntY = MyImage.Height-CopyMyImage.Height; 
            } 
            else 
            { 
                IntX = MyImage.Width-CopyMyImage.Width-10; 
                IntY = MyImage.Height-CopyMyImage.Height-10; 
            } 

            // 画出水印的位置 
            GImage.DrawImage(CopyMyImage, IntX, IntY, CopyMyImage.Width, CopyMyImage.Height); 
            string strExtend = strFileName.Substring(strFileName.LastIndexOf(".") + 1).ToLower(); 

            switch ( strExtend ) 
            { 
            case "bmp" : 
                OutPut.Save(strOutfileName, System.Drawing.Imaging.ImageFormat.Bmp); 
                break; 
            case "jpg" : 
                OutPut.Save(strOutfileName, System.Drawing.Imaging.ImageFormat.Jpeg); 
                break; 
            case "gif" : 
                OutPut.Save(strOutfileName, System.Drawing.Imaging.ImageFormat.Gif); 
                break; 
            case "icon" : 
                OutPut.Save(strOutfileName, System.Drawing.Imaging.ImageFormat.Icon);
                break; 
            case "png" : 
                OutPut.Save(strOutfileName, System.Drawing.Imaging.ImageFormat.Png); 
                break; 
            case "tif" : 
                OutPut.Save(strOutfileName, System.Drawing.Imaging.ImageFormat.Tiff); 
                break; 
            default : 
                OutPut.Save(strOutfileName, System.Drawing.Imaging.ImageFormat.Jpeg); 
                break; 
            } 

            GImage.Dispose(); 
            OutPut.Dispose(); 
            MyImage.Dispose(); 
            CopyMyImage.Dispose(); 

            if( bolFileName ) 
                File.Delete( strFileName ); 
        }  
    }
}

透明图片效果:

附源码:下载