.net图片水印类

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Drawing.Drawing2D;

 namespace JillZhang
{
/// <summary>
/// 给图片添加水印得类的描述
/// </summary>
public class WaterMark
{
  private bool _textMark=false;
  private bool _imgMark=false;
  private string _text="";
private string _imgPath="";
  private int _markX=0;
private int _markY=0;
private float _transparency=1;
private string _fontFamily="宋体";
private Color _textColor=Color.Black;
private bool _textbold=false;
  int[] sizes=new int[]{48,32,16,8,6,4};
/// <summary>
/// 实例化一个水印类
  /// </summary>
  public WaterMark()
{
   
  }
  /// <summary>
  ///　初始化一个只添加文字水印得实例
  /// </summary>
  /// <param name="text">水印文字</param>
  /// <param name="fontFamily">文字字体</param>
  /// <param name="bold">是否粗体</param>
  /// <param name="color">字体颜色</param>
  /// <param name="markX">标记位置横坐标</param>
/// <param name="markY">标记位置纵坐标</param>
  public WaterMark(string text,string fontFamily,bool bold,Color color,int markX,int markY)
{
   this._imgMark=false;
   this._textMark=true;
   this._text=text;
   this._fontFamily=fontFamily;
   this._textbold=bold;
  this._textColor=color;
   this._markX=markX;
   this._markY=MarkY;
}
  /// <summary>
  /// 实例化一个只添加图片水印得实例
/// </summary>
/// <param name="imagePath">水印图片路径</param>
/// <param name="tranparence">透明度</param>
/// <param name="markX">标记位置横坐标</param>
/// <param name="markY">标记位置纵坐标</param>
public WaterMark(string imagePath,float tranparence,int markX,int markY)
{
this._textMark=false;
this._imgMark=true;
this._imgPath=imagePath;
this._markX=markX;
this._markY=MarkY;
  this._transparency=tranparence;
}
/// <summary>
/// 是否添加文字水印
/// </summary>
public bool TextMark
{
  get{return _textMark;}
  set{_textMark=value;}
}
/// <summary>
/// 是否添加图片水印
/// </summary>
public bool ImageMark
{
  get{return _imgMark;}
  set{_imgMark=value;}  
}
/// <summary>
/// 文字水印得内容
  /// </summary>
public string Text
{
  get{return _text;}
set{_text=value;}
}
/// <summary>
/// 图片水印得图片地址
/// </summary>
public string ImagePath
{
get{return _imgPath;}
set{_imgPath=value;}
}
/// <summary>
/// 添加水印位置得横坐标
/// </summary>
public int MarkX
{
get{return _markX;}
set{_markX=value;}
}
/// <summary>
/// 添加水印位置得纵坐标
/// </summary>
public int MarkY
{
get{return _markY;}
set{_markY=value;}
}
/// <summary>
/// 水印得透明度
/// </summary>
public float Transparency
{
get{
if(_transparency>1.0f)
  {
   _transparency=1.0f;
  }
  return _transparency;}
set{_transparency=value;}
}
/// <summary>
/// 水印文字得颜色
/// </summary>
public Color TextColor
{
get{return _textColor;}
  set{_textColor=value;}
}
/// <summary>
/// 水印文字得字体
/// </summary>
public string TextFontFamily
{
  get{return _fontFamily;}
  set{_fontFamily=value;}
}
/// <summary>
/// 水印文字是否加粗
/// </summary>
public bool Bold
{
  get{return _textbold;}
  set{_textbold=value;}
}
/// <summary>
/// 添加水印，此方法适用于gif格式得图片
/// </summary>
/// <param name="image">需要添加水印得图片</param>
/// <returns>添加水印之后得图片</returns>
public Image Mark(Image img)
{
try
  {
  //添加文字水印
   if(this.TextMark)
   {
    //根据源图片生成新的Bitmap对象作为作图区，为了给gif图片添加水印，才有此周折
    Bitmap newBitmap=new Bitmap(img.Width,img.Height,PixelFormat.Format24bppRgb); 
    //设置新建位图得分辨率
   newBitmap.SetResolution(img.HorizontalResolution,img.VerticalResolution);
   //创建Graphics对象，以对该位图进行操作
    Graphics g = Graphics.FromImage(newBitmap);
   //消除锯齿
    g.SmoothingMode=SmoothingMode.AntiAlias;
   //将原图拷贝到作图区
   g.DrawImage(img,new Rectangle(0,0,img.Width,img.Height),0,0,img.Width,img.Height,GraphicsUnit.Pixel);
   //声明字体对象
   Font cFont = null;
    //用来测试水印文本长度得尺子
   SizeF size=new SizeF();
   //探测出一个适合图片大小得字体大小，以适应水印文字大小得自适应
   for(int i=0;i<6;i++)
    {
     //创建一个字体对象
     cFont= new Font(this.TextFontFamily,sizes[i]);
     //是否加粗
    if(!this.Bold)
     {
     cFont= new Font(this.TextFontFamily,sizes[i],FontStyle.Regular);
     }
    else
    {
     cFont=new Font(this.TextFontFamily,sizes[i],FontStyle.Bold);
    }
    //测量文本大小
     size=g.MeasureString(this.Text,cFont);
     //匹配第一个符合要求得字体大小
    if((ushort)size.Width<(ushort)img.Width)
    {
    break;
     }
   }
    //创建刷子对象，准备给图片写上文字
   Brush brush= new SolidBrush(this.TextColor);
//在指定得位置写上文字
   g.DrawString(this.Text,cFont,brush,this.MarkX,this.MarkY);
    //释放Graphics对象
    g.Dispose();   
    //将生成得图片读入MemoryStream
   System.IO.MemoryStream ms = new System.IO.MemoryStream();
    newBitmap.Save(ms,ImageFormat.Jpeg);
   //重新生成Image对象
   img=System.Drawing.Image.FromStream(ms); 
    //返回新的Image对象
   return img;

   }
   //添加图像水印
   if(this.ImageMark)
   {
    //获得水印图像
   Image markImg = Image.FromFile(this.ImagePath);
    //创建颜色矩阵
    float[][] ptsArray ={ 
         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, this.Transparency, 0}, //注意：此处为0.0f为完全透明，1.0f为完全不透明
         new float[] {0, 0, 0, 0, 1}}; 
    ColorMatrix colorMatrix= new ColorMatrix(ptsArray);
    //新建一个Image属性
    ImageAttributes imageAttributes= new ImageAttributes();
    //将颜色矩阵添加到属性
    imageAttributes.SetColorMatrix(colorMatrix,ColorMatrixFlag.Default,
     ColorAdjustType.Default);
   //生成位图作图区
    Bitmap newBitmap=new Bitmap(img.Width,img.Height,PixelFormat.Format24bppRgb);
    //设置分辨率
    newBitmap.SetResolution(img.HorizontalResolution,img.VerticalResolution);
    //创建Graphics
    Graphics g = Graphics.FromImage(newBitmap);
    //消除锯齿
    g.SmoothingMode=SmoothingMode.AntiAlias;
   //拷贝原图到作图区
    g.DrawImage(img,new Rectangle(0,0,img.Width,img.Height),0,0,img.Width,img.Height,GraphicsUnit.Pixel);
    //如果原图过小
    if(markImg.Width>img.Width||markImg.Height>img.Height)
    {
     System.Drawing.Image.GetThumbnailImageAbort callb=null;
     //对水印图片生成缩略图,缩小到原图得1/4
     System.Drawing.Image new_img=markImg.GetThumbnailImage(img.Width/4,markImg.Height*img.Width/markImg.Width,callb,new System.IntPtr());
     //添加水印
     g.DrawImage(new_img,new Rectangle(this.MarkX,this.MarkY,new_img.Width,new_img.Height),0,0,new_img.Width,new_img.Height,GraphicsUnit.Pixel,imageAttributes);
    //释放缩略图
     new_img.Dispose();
     //释放Graphics
    g.Dispose();
     //将生成得图片读入MemoryStream
    System.IO.MemoryStream ms = new System.IO.MemoryStream();
    newBitmap.Save(ms,ImageFormat.Jpeg);
//返回新的Image对象
     img=Image.FromStream(ms);
     return img;
    }
     //原图足够大
    else
    {
     //添加水印
     g.DrawImage(markImg,new Rectangle(this.MarkX,this.MarkY,markImg.Width,markImg.Height),0,0,markImg.Width,markImg.Height,GraphicsUnit.Pixel,imageAttributes);
     //释放Graphics
    g.Dispose();
     //将生成得图片读入MemoryStream
    System.IO.MemoryStream ms = new System.IO.MemoryStream();
     newBitmap.Save(ms,ImageFormat.Jpeg);
     //返回新的Image对象
     img=Image.FromStream(ms);
     return img;
    }     
   }
   return img;
  }
  catch
  {
              return img;   
  }   
}
 
}
}