asp .net 为图片添加文字水印(内包含有加图片水印的方法) .
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"); }
