asp .net 为图片添加文字水印(内包含有加图片水印的方法，但尚未完善暂不能使用)

在项目中先创建一个Imag_writer


类库

在该类库下分别创建两个枚举类型WaterMarkType

(水印的类型)、WaterMarkPosition

(水印的位置)。代码如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Imag_writer
{
/// <summary>
/// 水印的类型
/// </summary>
public enum WaterMarkType
{
/// <summary>
/// 文字水印
/// </summary>
TextMark,
/// <summary>
/// 图片水印
/// </summary>
ImageMark // 暂时只能添加文字水印
}
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Imag_writer
{
/// <summary>
/// 水印的位置
/// </summary>
public enum WaterMarkPosition
{
/// <summary>
/// 左上角
/// </summary>
WMP_Left_Top,
/// <summary>
/// 左下角
/// </summary>
WMP_Left_Bottom,
/// <summary>
/// 右上角
/// </summary>
WMP_Right_Top,
/// <summary>
/// 右下角
/// </summary>
WMP_Right_Bottom
}
}

再创建一个ImageWaterMark

类(用来处理图片添加水印的类)，代码如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Collections;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
namespace Imag_writer
{
//// <summary>
/// 处理图片的类（包括加水印，生成缩略图）
/// </summary>
public class ImageWaterMark
{
public ImageWaterMark()
{
//
// TODO: 在此处添加构造函数逻辑
//
}
/// <summary>
/// 添加水印(分图片水印与文字水印两种)
/// </summary>
/// <param name="oldpath">原图片绝对地址</param>
/// <param name="newpath">新图片放置的绝对地址(不可与原图片名相同)</param>
/// <param name="wmtType">要添加的水印的类型</param>
/// <param name="sWaterMarkContent">水印内容，此即为要添加的文字</param>
public void AddWaterMarkText(string oldpath, string newpath,WaterMarkType wmtType, string sWaterMarkContent)
{
try
{
Image image = Image.FromFile(oldpath);
Bitmap b = new Bitmap(image.Width, image.Height,PixelFormat.Format24bppRgb);
Graphics g = Graphics.FromImage(b);
g.Clear(Color.White);
g.SmoothingMode = SmoothingMode.HighQuality;
g.InterpolationMode = InterpolationMode.High;
g.DrawImage(image, 0, 0, image.Width, image.Height);
switch (wmtType)
{
/**/
/*case WaterMarkType.ImageMark:
//图片水印
this.addWatermarkImage(g,
Page.Server.MapPath(Watermarkimgpath),
WatermarkPosition,image.Width,image.Height);
break;*/
case WaterMarkType.TextMark:
//文字水印
this.addWatermarkText(g, sWaterMarkContent, "WM_BOTTOM_RIGHT",
image.Width, image.Height);
break;
}
b.Save(newpath);
b.Dispose();
image.Dispose();
}
catch
{
if (File.Exists(oldpath))
{
//File.Delete(oldpath);
}
}
finally
{
if (File.Exists(oldpath))
{
// File.Delete(oldpath);
}
}
}

//--------------------------------------------------------------------------------------
///  <summary>
/// 在图片上生成图片水印
///  </summary>
///  <param name="Path">原服务器图片路径 </param>
///  <param name="Path_syp">生成的带图片水印的图片路径 </param>
///  <param name="Path_sypf">水印图片路径 </param>
public void AddWaterPic(string Path, string Path_syp, string Path_sypf)
{
Image image = Image.FromFile(Path);
Image copyImage = Image.FromFile(Path_sypf);
Graphics g = Graphics.FromImage(image);
Rectangle rect = new Rectangle(image.Width - copyImage.Width, image.Height - copyImage.Height, copyImage.Width, copyImage.Height);
g.DrawImage(copyImage, rect, 0, 0, copyImage.Width, copyImage.Height, GraphicsUnit.Pixel);
g.Dispose();
image.Save(Path_syp);
image.Dispose();
}

// 给图片加水印#region 给图片加水印
/// <summary>
/// 添加水印(分图片水印与文字水印两种)
/// </summary>
/// <param name="oldpath">原图片绝对地址</param>
/// <param name="newpath">新图片放置的绝对地址(不可与原图片名相同)</param>
/// <param name="wmtType">要添加的水印的类型</param>
/// <param name="sWaterMarkContent">水印内容，若添加文字水印，此即为要添加的文字；
/// 若要添加图片水印，此为图片的路径(图片水印暂不可用)</param>
public void addWaterMark(string oldpath, string newpath,
WaterMarkType wmtType, string sWaterMarkContent)
{
try
{
Image image = Image.FromFile(oldpath);
Bitmap b = new Bitmap(image.Width, image.Height,
PixelFormat.Format24bppRgb);
Graphics g = Graphics.FromImage(b);
g.Clear(Color.White);
g.SmoothingMode = SmoothingMode.HighQuality;
g.InterpolationMode = InterpolationMode.High;
g.DrawImage(image, 0, 0, image.Width, image.Height);
switch (wmtType)
{
/**//*case WaterMarkType.ImageMark:
//图片水印
this.addWatermarkImage(g,
Page.Server.MapPath(Watermarkimgpath),
WatermarkPosition,image.Width,image.Height);
break;*/
case WaterMarkType.TextMark:
//文字水印
this.addWatermarkText(g, sWaterMarkContent, "WM_BOTTOM_RIGHT",
image.Width, image.Height);
break;
}
b.Save(newpath);
b.Dispose();
image.Dispose();
}
catch
{
if(File.Exists(oldpath))
{
//File.Delete(oldpath);
}
}
finally
{
if(File.Exists(oldpath))
{
// File.Delete(oldpath);
}
}
}
/**//// <summary>
///  加水印文字
/// </summary>
/// <param name="picture">imge 对象</param>
/// <param name="_watermarkText">水印文字内容</param>
/// <param name="_watermarkPosition">水印位置</param>
/// <param name="_width">被加水印图片的宽</param>
/// <param name="_height">被加水印图片的高</param>
private void addWatermarkText(Graphics picture, string _watermarkText,
string _watermarkPosition, int _width, int _height)
{
// 确定水印文字的字体大小
int[] sizes = new int[]{32, 30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, 8, 6, 4};
Font crFont = null;
SizeF crSize = new SizeF();
for (int i = 0;i < sizes.Length; i++)
{
crFont = new Font("Arial Black", sizes[i], FontStyle.Bold);
crSize = picture.MeasureString(_watermarkText, crFont);
if((ushort)crSize.Width < (ushort)_width)
{
break;
}
}
// 生成水印图片（将文字写到图片中）
Bitmap floatBmp = new Bitmap((int)crSize.Width + 3,
(int)crSize.Height + 3, PixelFormat.Format32bppArgb);
Graphics fg=Graphics.FromImage(floatBmp);
PointF pt=new PointF(0,0);
// 画阴影文字
Brush TransparentBrush0 = new SolidBrush(Color.FromArgb(255, Color.Black));
Brush TransparentBrush1 = new SolidBrush(Color.FromArgb(255, Color.Black));
fg.DrawString(_watermarkText,crFont,TransparentBrush0, pt.X, pt.Y + 1);
fg.DrawString(_watermarkText,crFont,TransparentBrush0, pt.X + 1, pt.Y);
fg.DrawString(_watermarkText,crFont,TransparentBrush1, pt.X + 1, pt.Y + 1);
fg.DrawString(_watermarkText,crFont,TransparentBrush1, pt.X, pt.Y + 2);
fg.DrawString(_watermarkText,crFont,TransparentBrush1, pt.X + 2, pt.Y);
TransparentBrush0.Dispose();
TransparentBrush1.Dispose();
// 画文字
fg.SmoothingMode=System.Drawing.Drawing2D.SmoothingMode.HighQuality;
fg.DrawString(_watermarkText,
crFont, new SolidBrush(Color.White),
pt.X, pt.Y, StringFormat.GenericDefault);
// 保存刚才的操作
fg.Save();
fg.Dispose();
// floatBmp.Save("d://WebSite//DIGITALKM//ttt.jpg");
// 将水印图片加到原图中
this.addWatermarkImage(
picture,
new Bitmap(floatBmp),
"WM_BOTTOM_RIGHT",
_width,
_height);
}
/**//// <summary>
///  加水印图片
/// </summary>
/// <param name="picture">imge 对象</param>
/// <param name="iTheImage">Image对象（以此图片为水印）</param>
/// <param name="_watermarkPosition">水印位置</param>
/// <param name="_width">被加水印图片的宽</param>
/// <param name="_height">被加水印图片的高</param>
private void addWatermarkImage( Graphics picture,Image iTheImage,
string _watermarkPosition,int _width,int _height)
{
Image watermark = new Bitmap(iTheImage);

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, 0.3f, 0.0f},
new float[] {0.0f, 0.0f, 0.0f, 0.0f, 1.0f}
};

ColorMatrix colorMatrix = new ColorMatrix(colorMatrixElements);

imageAttributes.SetColorMatrix(colorMatrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap);
int xpos = 0;
int ypos = 0;
int WatermarkWidth = 0;
int WatermarkHeight = 0;
double bl = 1d;
//计算水印图片的比率
//取背景的1/4宽度来比较
if ((_width > watermark.Width * 4) && (_height > watermark.Height * 4))
{
bl = 1;
}
else if ((_width > watermark.Width * 4) && (_height<watermark.Height * 4))
{
bl = Convert.ToDouble(_height / 4) / Convert.ToDouble(watermark.Height);

}
else if ((_width < watermark.Width * 4) && (_height > watermark.Height * 4))
{
bl = Convert.ToDouble(_width / 4) / Convert.ToDouble(watermark.Width);
}
else
{
if ((_width * watermark.Height) > (_height * watermark.Width))
{
bl = Convert.ToDouble(_height / 4) / Convert.ToDouble(watermark.Height);

}
else
{
bl = Convert.ToDouble(_width / 4) / Convert.ToDouble(watermark.Width);

}

}
WatermarkWidth = Convert.ToInt32(watermark.Width * bl);
WatermarkHeight = Convert.ToInt32(watermark.Height * bl);
switch (_watermarkPosition)
{
case "WM_TOP_LEFT":
xpos = 10;
ypos = 10;
break;
case "WM_TOP_RIGHT":
xpos = _width - WatermarkWidth - 10;
ypos = 10;
break;
case "WM_BOTTOM_RIGHT":
xpos = _width - WatermarkWidth - 10;
ypos = _height -WatermarkHeight - 10;
break;
case "WM_BOTTOM_LEFT":
xpos = 10;
ypos = _height - WatermarkHeight - 10;
break;
}
picture.DrawImage(
watermark,
new Rectangle(xpos, ypos, WatermarkWidth, WatermarkHeight),
0,
0,
watermark.Width,
watermark.Height,
GraphicsUnit.Pixel,
imageAttributes);
watermark.Dispose();
imageAttributes.Dispose();
}
/**//// <summary>
///  加水印图片
/// </summary>
/// <param name="picture">imge 对象</param>
/// <param name="WaterMarkPicPath">水印图片的地址</param>
/// <param name="_watermarkPosition">水印位置</param>
/// <param name="_width">被加水印图片的宽</param>
/// <param name="_height">被加水印图片的高</param>
private void addWatermarkImage( Graphics picture,string WaterMarkPicPath,
string _watermarkPosition,int _width,int _height)
{
Image watermark = new Bitmap(WaterMarkPicPath);

this.addWatermarkImage(picture, watermark, _watermarkPosition, _width,
_height);
}
//生成缩略图#region 生成缩略图
/**//// <summary>
/// 保存图片
/// </summary>
/// <param name="image">Image 对象</param>
/// <param name="savePath">保存路径</param>
/// <param name="ici">指定格式的编解码参数</param>
private void SaveImage(Image image, string savePath, ImageCodecInfo ici)
{
//设置 原图片 对象的 EncoderParameters 对象
EncoderParameters parameters = new EncoderParameters(1);
parameters.Param[0] = new EncoderParameter(
System.Drawing.Imaging.Encoder.Quality, ((long) 90));
image.Save(savePath, ici, parameters);
parameters.Dispose();
}
/**//// <summary>
/// 获取图像编码解码器的所有相关信息
/// </summary>
/// <param name="mimeType">包含编码解码器的多用途网际邮件扩充协议 (MIME) 类型的字符串</param>
/// <returns>返回图像编码解码器的所有相关信息</returns>
private ImageCodecInfo GetCodecInfo(string mimeType)
{
ImageCodecInfo[] CodecInfo = ImageCodecInfo.GetImageEncoders();
foreach(ImageCodecInfo ici in CodecInfo)
{
if(ici.MimeType == mimeType)
return ici;
}
return null;
}
/**//// <summary>
/// 生成缩略图
/// </summary>
/// <param name="sourceImagePath">原图片路径(相对路径)</param>
/// <param name="thumbnailImagePath">生成的缩略图路径,如果为空则保存为原图片路径(相对路径)</param>
/// <param name="thumbnailImageWidth">缩略图的宽度（高度与按源图片比例自动生成）</param>
public void ToThumbnailImages(
string SourceImagePath,
string ThumbnailImagePath,
int ThumbnailImageWidth)
{
Hashtable htmimes = new Hashtable();
htmimes[".jpeg"] = "image/jpeg";
htmimes[".jpg"] = "image/jpeg";
htmimes[".png"] = "image/png";
htmimes[".tif"] = "image/tiff";
htmimes[".tiff"] = "image/tiff";
htmimes[".bmp"] = "image/bmp";
htmimes[".gif"] = "image/gif";
// 取得原图片的后缀
string sExt = SourceImagePath.Substring(
SourceImagePath.LastIndexOf(".")).ToLower();
//从 原图片 创建 Image 对象
Image image = Image.FromFile(SourceImagePath);
int num = ((ThumbnailImageWidth / 4) * 3);
int width = image.Width;
int height = image.Height;
//计算图片的比例
if ((((double) width) / ((double) height)) >= 1.3333333333333333f)
{
num = ((height * ThumbnailImageWidth) / width);
}
else
{
ThumbnailImageWidth = ((width * num) / height);
}
if ((ThumbnailImageWidth < 1) || (num < 1))
{
return;
}
//用指定的大小和格式初始化 Bitmap 类的新实例
Bitmap bitmap = new Bitmap(ThumbnailImageWidth, num,
PixelFormat.Format32bppArgb);
//从指定的 Image 对象创建新 Graphics 对象
Graphics graphics = Graphics.FromImage(bitmap);
//清除整个绘图面并以透明背景色填充
graphics.Clear(Color.Transparent);
graphics.SmoothingMode = SmoothingMode.HighQuality;
graphics.InterpolationMode = InterpolationMode.High;
//在指定位置并且按指定大小绘制 原图片 对象
graphics.DrawImage(image, new Rectangle(0, 0, ThumbnailImageWidth, num));
image.Dispose();

try
{
//将此 原图片 以指定格式并用指定的编解码参数保存到指定文件
SaveImage(bitmap, ThumbnailImagePath,
GetCodecInfo((string)htmimes[sExt]));
}
catch(System.Exception e)
{
throw e;
}
}
}
}

最后在客户端调用时的代码如下(
在页面加载时去处理添加图片水印，也可以根据自己的需要去写要某个事件中)：

protected void Page_Load(object sender, EventArgs e)
{
//新的文件名称
string newfileName = Server.MapPath("img/") + DateTime.Now.Millisecond + "" + DateTime.Now.Second + ".jpg";
ImageWaterMark iwm = new ImageWaterMark();
//原图片路径，新图片路径，要添加的水印类型，要添加的文字内容或是水印图片的路径(加图片水印时用到的)
iwm.addWaterMark(Server.MapPath("img/Chrysanthemum.jpg"), newfileName, WaterMarkType.TextMark, "shiqiang");
}