C#.NET 图片水印添加代码

本文实例为大家分享了c#.net添加 图片水印的方法，供大家参考，具体内容如下

using system;
using system.drawing;
using system.drawing.drawing2d;
using system.drawing.imaging;
using system.io;

namespace pub.class
{
 /// <summary>
 /// 添加水印类 只支持添加图片水印
 /// </summary>
 public class watermark
 {
  #region 私有成员
  private string modifyimagepath=null;
 private string drawedimagepath=null;
 private int rightspace;
 private int bottoamspace;
 private int lucencypercent=70;
 private string outpath=null;
  #endregion

  #region 构造器
  /// <summary>
  /// 构造函数
  /// </summary>
  public watermark() { }
  #endregion

  #region 属性
  /// <summary>
 /// 获取或设置要修改的图像路径
 /// </summary>
 public string modifyimagepath
 {
 get{return this.modifyimagepath;}
 set{this.modifyimagepath=value;}
 }
 /// <summary>
 /// 获取或设置在画的图片路径(水印图片)
 /// </summary>
 public string drawedimagepath
 {
 get{return this.drawedimagepath;}
 set{this.drawedimagepath=value;}
 }
 /// <summary>
 /// 获取或设置水印在修改图片中的右边距
 /// </summary>
 public int rightspace
 {
 get{return this.rightspace;}
 set{this.rightspace=value;}
 }
 /// <summary>
  /// 获取或设置水印在修改图片中距底部的高度
 /// </summary>
 public int bottoamspace
 {
 get{return this.bottoamspace;}
 set{this.bottoamspace=value;}
 }
 /// <summary>
 /// 获取或设置要绘制水印的透明度,注意是原来图片透明度的百分比
 /// </summary>
 public int lucencypercent
 {
 get{return this.lucencypercent;}
 set { if(value>=0&&value<=100) this.lucencypercent=value; }
 }
 /// <summary>
 /// 获取或设置要输出图像的路径
 /// </summary>
 public string outpath
 {
 get{return this.outpath;}
 set{this.outpath=value;}
  }
  #endregion

  #region 开始绘制水印 drawimage
  /// <summary>
 /// 开始绘制水印
 /// </summary>
  /// <example>
  /// <code>
  ///  watermark wm = new watermark();
  ///  wm.drawedimagepath= server.mappath("") + "/upfile/" + "backlogo.gif";
  ///  wm.modifyimagepath=path; 
  ///  wm.rightspace=184;
  ///  wm.bottoamspace=81;
  ///  wm.lucencypercent=50;
  ///  wm.outpath=server.mappath("") + "/upfile/" + filename + "_new" + extension;
  ///  wm.drawimage();
  ///  
  ///  //保存加水印过后的图片,删除原始图片 
  ///  mfilename=filename + "_new" + extension;
  ///  if(file.exists(path)) { file.delete(path); } 
  /// </code>
  /// </example>
 public void drawimage()
 {
 image modifyimage=null;
 image drawedimage=null;
 graphics g=null;
 try { 
 modifyimage=image.fromfile(this.modifyimagepath);//建立图形对象
 drawedimage=image.fromfile(this.drawedimagepath);
 g=graphics.fromimage(modifyimage);
 
 int x=modifyimage.width-this.rightspace;//获取要绘制图形坐标
 int y=modifyimage.height-this.bottoamspace;
 
 float[][] matrixitems ={//设置颜色矩阵
   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)this.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);
 
 g.drawimage(//绘制阴影图像
  drawedimage,
  new rectangle(x,y,drawedimage.width,drawedimage.height),
  0,0,drawedimage.width,drawedimage.height,
  graphicsunit.pixel,imgattr);
 
 string[] allowimagetype={".jpg",".gif",".png",".bmp",".tiff",".wmf",".ico"};//保存文件
 fileinfo file=new fileinfo(this.modifyimagepath);
 imageformat imagetype=imageformat.gif;
 switch(file.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;
 if(this.outpath==null || this.outpath=="") {
  file.delete(this.modifyimagepath);
  fs=new filestream(this.modifyimagepath,filemode.create,fileaccess.write);
 } else {
  fs=new filestream(this.outpath,filemode.create,fileaccess.write);
 }
 if(fs!=null) {
  fs.write(imgdata,0,imgdata.length);
  fs.close();
 }
 } finally {
 try {
  drawedimage.dispose();
  modifyimage.dispose();
  g.dispose();
 } catch{}
 }
 }
  #endregion
 }
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。