asp .net 为图片添加图片水印 .
首先写好一个写入图片水印的类，先创建一个ImageWriter类库 (该类中有包含枚举类型和方法)
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 ImageWriter
{
/// <summary>
/// 图片处理类
/// </summary>
public class ImageManager
{
#region 变量声明开始
/// <summary>
/// 枚举: 水印位置
/// </summary>
public enum WatermarkPosition
{
/// <summary>
/// 左上
/// </summary>
LeftTop,
/// <summary>
/// 左中
/// </summary>
Left,
/// <summary>
/// 左下
/// </summary>
LeftBottom,
/// <summary>
/// 正上
/// </summary>
Top,
/// <summary>
/// 正中
/// </summary>
Center,
/// <summary>
/// 正下
/// </summary>
Bottom,
/// <summary>
/// 右上
/// </summary>
RightTop,
/// <summary>
/// 右中
/// </summary>
RightCenter,
/// <summary>
/// 右下
/// </summary>
RigthBottom
}
#endregion 变量声明结束
#region 构造函数开始
/// <summary>
/// 构造函数: 默认
/// </summary>
public ImageManager()
{ }
#endregion 构造函数结束
#region 私有函数开始
/// <summary>
/// 获取: 图片去扩展名(包含完整路径及其文件名)小写字符串
/// </summary>
/// <param name="path">图片路径(包含完整路径,文件名及其扩展名): string</param>
/// <returns>返回: 图片去扩展名(包含完整路径及其文件名)小写字符串: string</returns>
private string GetFileName(string path)
{
return path.Remove(path.LastIndexOf('.')).ToLower();
}
/// <summary>
/// 获取: 图片以'.'开头的小写字符串扩展名
/// </summary>
/// <param name="path">图片路径(包含完整路径,文件名及其扩展名): string</param>
/// <returns>返回: 图片以'.'开头的小写字符串扩展名: string</returns>
private string GetExtension(string path)
{
return path.Remove(0, path.LastIndexOf('.')).ToLower();
}
/// <summary>
/// 获取: 图片以 '.' 开头的小写字符串扩展名对应的 System.Drawing.Imaging.ImageFormat 对象
/// </summary>
/// <param name="format">以 '. '开头的小写字符串扩展名: string</param>
/// <returns>返回: 图片以 '.' 开头的小写字符串扩展名对应的 System.Drawing.Imaging.ImageFormat 对象: System.Drawing.Imaging.ImageFormat</returns>
private ImageFormat GetImageFormat(string format)
{
switch (format)
{
case ".bmp":
return ImageFormat.Bmp;
case ".emf":
return ImageFormat.Emf;
case ".exif":
return ImageFormat.Exif;
case ".gif":
return ImageFormat.Gif;
case ".ico":
return ImageFormat.Icon;
case ".png":
return ImageFormat.Png;
case ".tif":
return ImageFormat.Tiff;
case ".tiff":
return ImageFormat.Tiff;
case ".wmf":
return ImageFormat.Wmf;
default:
return ImageFormat.Jpeg;
}
}
/// <summary>
/// 获取: 枚举 Uinatlex.ToolBox.ImageManager.WatermarkPosition 对应的 System.Drawing.Rectangle 对象
/// </summary>
/// <param name="positon">枚举 Uinatlex.ToolBox.ImageManager.WatermarkPosition: Uinatlex.ToolBox.ImageManager.WatermarkPosition</param>
/// <param name="X">原图宽度: int</param>
/// <param name="Y">原图高度: int</param>
/// <param name="x">水印宽度: int</param>
/// <param name="y">水印高度: int</param>
/// <param name="i">边距: int</param>
/// <returns>返回: 枚举 Uinatlex.ToolBox.ImageManager.WatermarkPosition 对应的 System.Drawing.Rectangle 对象: System.Drawing.Rectangle</returns>
private Rectangle GetWatermarkRectangle(WatermarkPosition positon, int X, int Y, int x, int y, int i)
{
switch (positon)
{
case WatermarkPosition.LeftTop:
return new Rectangle(i, i, x, y);
case WatermarkPosition.Left:
return new Rectangle(i, (Y - y) / 2, x, y);
case WatermarkPosition.LeftBottom:
return new Rectangle(i, Y - y - i, x, y);
case WatermarkPosition.Top:
return new Rectangle((X - x) / 2, i, x, y);
case WatermarkPosition.Center:
return new Rectangle((X - x) / 2, (Y - y) / 2, x, y);
case WatermarkPosition.Bottom:
return new Rectangle((X - x) / 2, Y - y - i, x, y);
case WatermarkPosition.RightTop:
return new Rectangle(X - x - i, i, x, y);
case WatermarkPosition.RightCenter:
return new Rectangle(X - x - i, (Y - y) / 2, x, y);
default:
return new Rectangle(X - x - i, Y - y - i, x, y);
}
}
#endregion 私有函数结束
#region 文字生成开始
#endregion 文字生成结束
#region 设置透明度开始
/// <summary>
/// 设置: 图片 System.Drawing.Bitmap 对象透明度
/// </summary>
/// <param name="sBitmap">图片 System.Drawing.Bitmap 对象: System.Drawing.Bitmap</param>
/// <param name="transparence">水印透明度(值越高透明度越低,范围在0.0f~1.0f之间): float</param>
/// <returns>图片 System.Drawing.Bitmap: System.Drawing.Bitmap</returns>
public Bitmap SetTransparence(Bitmap bm, float transparence)
{
if (transparence == 0.0f || transparence == 1.0f)
throw new ArgumentException("透明度值只能在0.0f~1.0f之间");
float[][] floatArray =
{
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, transparence, 0.0f },
new float[] { 0.0f, 0.0f, 0.0f, 0.0f, 1.0f }
};
ImageAttributes imageAttributes = new ImageAttributes();
imageAttributes.SetColorMatrix(new ColorMatrix(floatArray), ColorMatrixFlag.Default, ColorAdjustType.Bitmap);
Bitmap bitmap = new Bitmap(bm.Width, bm.Height);
Graphics graphics = Graphics.FromImage(bitmap);
graphics.DrawImage(bm, new Rectangle(0, 0, bm.Width, bm.Height), 0, 0, bm.Width, bm.Height, GraphicsUnit.Pixel, imageAttributes);
graphics.Dispose();
imageAttributes.Dispose();
bm.Dispose();
return bitmap;
}
/// <summary>
/// 设置: 图片 System.Drawing.Bitmap 对象透明度
/// </summary>
/// <param name="readpath">图片路径(包含完整路径,文件名及其扩展名): string</param>
/// <param name="transparence">水印透明度(值越高透明度越低,范围在0.0f~1.0f之间): float</param>
/// <returns>图片 System.Drawing.Bitmap: System.Drawing.Bitmap</returns>
public Bitmap SetTransparence(string readpath, float transparence)
{
return SetTransparence(new Bitmap(readpath), transparence);
}
#endregion 设置透明度结束
#region 添加水印开始
/// <summary>
/// 生成: 原图绘制水印的 System.Drawing.Bitmap 对象
/// </summary>
/// <param name="sBitmap">原图 System.Drawing.Bitmap 对象: System.Drawing.Bitmap</param>
/// <param name="wBitmap">水印 System.Drawing.Bitmap 对象: System.Drawing.Bitmap</param>
/// <param name="position">枚举 Uinatlex.ToolBox.ImageManager.WatermarkPosition : Uinatlex.ToolBox.ImageManager.WatermarkPosition</param>
/// <param name="margin">水印边距: int</param>
/// <returns>返回: 原图绘制水印的 System.Drawing.Bitmap 对象 System.Drawing.Bitmap</returns>
public Bitmap CreateWatermark(Bitmap sBitmap, Bitmap wBitmap, WatermarkPosition position, int margin)
{
Graphics graphics = Graphics.FromImage(sBitmap);
graphics.DrawImage(wBitmap, GetWatermarkRectangle(position, sBitmap.Width, sBitmap.Height, wBitmap.Width, wBitmap.Height, margin));
graphics.Dispose();
wBitmap.Dispose();
return sBitmap;
}
#endregion 添加水印结束
#region 图片切割开始
#endregion 图片切割结束
#region 图片缩放开始
#endregion 图片缩放结束
#region 保存图片到文件开始
#region 普通保存开始
/// <summary>
/// 保存: System.Drawing.Bitmap 对象到图片文件
/// </summary>
/// <param name="bitmap">System.Drawing.Bitmap 对象: System.Drawing.Bitmap</param>
/// <param name="writepath">保存路径(包含完整路径,文件名及其扩展名): string</param>
public void Save(Bitmap bitmap, string writepath)
{
try
{
bitmap.Save(writepath, GetImageFormat(GetExtension(writepath)));
bitmap.Dispose();
}
catch
{
throw new ArgumentException("图片保存错误");
}
}
/// <summary>
/// 保存: 对象到图片文件
/// </summary>
/// <param name="readpath">原图路径(包含完整路径,文件名及其扩展名): string</param>
/// <param name="writepath">保存路径(包含完整路径,文件名及其扩展名): string</param>
public void Save(string readpath, string writepath)
{
if (string.Compare(readpath, writepath) == 0)
throw new ArgumentException("源图片与目标图片地址相同");
try
{
Save(new Bitmap(readpath), writepath);
}
catch
{
throw new ArgumentException("图片读取错误");
}
}
#endregion 普通保存结束
#region 文字绘图保存开始
#endregion 文字绘图保存结束
#region 透明度调整保存开始
/// <summary>
/// 保存: 设置透明度的对象到图片文件
/// </summary>
/// <param name="sBitmap">图片 System.Drawing.Bitmap 对象: System.Drawing.Bitmap</param>
/// <param name="transparence">水印透明度(值越高透明度越低,范围在0.0f~1.0f之间): float</param>
/// <param name="writepath">保存路径(包含完整路径,文件名及其扩展名): string</param>
public void SaveTransparence(Bitmap bitmap, float transparence, string writepath)
{
Save(SetTransparence(bitmap, transparence), writepath);
}
/// <summary>
/// 保存: 设置透明度的象到图片文件
/// </summary>
/// <param name="readpath">原图路径(包含完整路径,文件名及其扩展名): string</param>
/// <param name="transparence">水印透明度(值越高透明度越低,范围在0.0f~1.0f之间): float</param>
/// <param name="writepath">保存路径(包含完整路径,文件名及其扩展名): string</param>
public void SaveTransparence(string readpath, float transparence, string writepath)
{
Save(SetTransparence(readpath, transparence), writepath);
}
#endregion 透明度调整保存结束
#region 水印图片保存开始
/// <summary>
/// 保存: 绘制水印的对象到图片文件
/// </summary>
/// <param name="sBitmap">原图 System.Drawing.Bitmap 对象: System.Drawing.Bitmap</param>
/// <param name="wBitmap">水印 System.Drawing.Bitmap 对象: System.Drawing.Bitmap</param>
/// <param name="position">枚举 Uinatlex.ToolBox.ImageManager.WatermarkPosition : Uinatlex.ToolBox.ImageManager.WatermarkPosition</param>
/// <param name="margin">水印边距: int</param>
/// <param name="writepath">保存路径(包含完整路径,文件名及其扩展名): string</param>
public void SaveWatermark(Bitmap sBitmap, Bitmap wBitmap, WatermarkPosition position, int margin, string writepath)
{
Save(CreateWatermark(sBitmap, wBitmap, position, margin), writepath);
}
/// <summary>
/// 保存: 绘制水印的对象到图片文件
/// </summary>
/// <param name="readpath">图片路径(包含完整路径,文件名及其扩展名): string</param>
/// <param name="watermarkpath">水印图片路径(包含完整路径,文件名及其扩展名): string</param>
/// <param name="transparence">水印透明度(值越高透明度越低,范围在0.0f~1.0f之间): float</param>
/// <param name="position">枚举 Uinatlex.ToolBox.ImageManager.WatermarkPosition : Uinatlex.ToolBox.ImageManager.WatermarkPosition</param>
/// <param name="margin">水印边距: int</param>
/// <param name="writepath">保存路径(包含完整路径,文件名及其扩展名): string</param>
public void SaveWatermark(string readpath, string watermarkpath, float transparence, WatermarkPosition position, int margin, string writepath)
{
if (string.Compare(readpath, writepath) == 0)
throw new ArgumentException("源图片与目标图片地址相同");
if (transparence == 0.0f)
Save(readpath, writepath);
else if (transparence == 1.0f)
SaveWatermark(new Bitmap(readpath), new Bitmap(watermarkpath), position, margin, writepath);
else
SaveWatermark(new Bitmap(readpath), SetTransparence(watermarkpath, transparence), position, margin, writepath);
}
#endregion 水印图片保存结束
#region 图片切割保存开始
#endregion 图片切割保存结束
#region 图片缩放保存开始
#endregion 图片缩放保存开始
#endregion 保存图片到文件结束
}
}
/*
调用很简单 im.SaveWatermark(原图地址, 水印地址, 透明度, 水印位置, 边距,保存位置);
Uinatlex.ToolBox.ImageManager im = new Uinatlex.ToolBox.ImageManager();
im.SaveWatermark(Server.MapPath("/原图.jpg"), Server.MapPath("/水印.jpg"), 0.5f, Uinatlex.ToolBox.ImageManager.WatermarkPosition.RigthBottom, 10, Server.MapPath("/原图.jpg"));
*/
在客户端页面中调用上面这个类
protected void Page_Load(object sender, EventArgs e)
{
string newfileName = Server.MapPath("img/") + DateTime.Now.Millisecond + "" + DateTime.Now.Second + ".jpg";
ImageManager im = new ImageManager();
//调用很简单 im.SaveWatermark(原图地址, 水印地址, 透明度, 水印位置, 边距,保存到的位置);
im.SaveWatermark(Server.MapPath("img/Chrysanthemum.jpg"), Server.MapPath("img/woshi.jpg"), 0.9f, ImageManager.WatermarkPosition.RigthBottom, 10, newfileName);
}