本文主要给大家介绍的是asp .net实现给图片添加图片水印的方法，注意是图片水印，需要的朋友们可以参考学习，下面话不多说来看看详细的介绍吧。
方法如下
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>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>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>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>枚举 Uinatlex.ToolBox.ImageManager.WatermarkPosition: Uinatlex.ToolBox.ImageManager.WatermarkPosition</param> /// <param>原图宽度: int</param> /// <param>原图高度: int</param> /// <param>水印宽度: int</param> /// <param>水印高度: int</param> /// <param>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>图片 System.Drawing.Bitmap 对象: System.Drawing.Bitmap</param> /// <param>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>图片路径(包含完整路径,文件名及其扩展名): string</param> /// <param>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>原图 System.Drawing.Bitmap 对象: System.Drawing.Bitmap</param> /// <param>水印 System.Drawing.Bitmap 对象: System.Drawing.Bitmap</param> /// <param>枚举 Uinatlex.ToolBox.ImageManager.WatermarkPosition : Uinatlex.ToolBox.ImageManager.WatermarkPosition</param> /// <param>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>System.Drawing.Bitmap 对象: System.Drawing.Bitmap</param> /// <param>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>原图路径(包含完整路径,文件名及其扩展名): string</param> /// <param>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>图片 System.Drawing.Bitmap 对象: System.Drawing.Bitmap</param> /// <param>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>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>原图路径(包含完整路径,文件名及其扩展名): string</param> /// <param>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>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>原图 System.Drawing.Bitmap 对象: System.Drawing.Bitmap</param> /// <param>水印 System.Drawing.Bitmap 对象: System.Drawing.Bitmap</param> /// <param>枚举 Uinatlex.ToolBox.ImageManager.WatermarkPosition : Uinatlex.ToolBox.ImageManager.WatermarkPosition</param> /// <param>水印边距: int</param> /// <param>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>图片路径(包含完整路径,文件名及其扩展名): string</param> /// <param>水印图片路径(包含完整路径,文件名及其扩展名): string</param> /// <param>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>枚举 Uinatlex.ToolBox.ImageManager.WatermarkPosition : Uinatlex.ToolBox.ImageManager.WatermarkPosition</param> /// <param>水印边距: int</param> /// <param>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