这一段公司有个项目，客户要求上传的图片要带上自定义的水印。以前也经常和朋友讨论C#图片水印方面的问题，但是从来没有实际操作过。所以，借这次项目的机会也研究了一下C#图片水印的功能！本人参考的是discuz论坛中的代码。这种方法是直接把要上传的图片先转化成System.Drawing.Image，而不用保存到服务器端的磁盘上，然后加上水印重新绘制，再保存到服务器端的磁盘上，下面就拿出来晒晒：
1/// <summary> 2 /// 加图片水印 3 /// </summary> 4 /// <param name="img">要加水印的原图(System.Drawing)</param> 5 /// <param name="filename">文件名</param> 6 /// <param name="watermarkFilename">水印文件名</param> 7 /// <param name="watermarkStatus">图片水印位置1=左上 2=中上 3=右上 4=左中 5=中中 6=右中 7=左下 8=右中 9=右下</param> 8 /// <param name="quality">加水印后的质量0~100,数字越大质量越高</param> 9 /// <param name="watermarkTransparency">水印图片的透明度1~10,数字越小越透明,10为不透明</param> 10 public static void ImageWaterMarkPic(Image img, string filename, string watermarkFilename, int watermarkStatus, int quality, int watermarkTransparency) 11 { 12 Graphics g = Graphics.FromImage(img); 13 //设置高质量插值法 14 //g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High; 15 //设置高质量,低速度呈现平滑程度 16 //g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality; 17 Image watermark = new Bitmap(watermarkFilename); 18 19 if (watermark.Height >= img.Height || watermark.Width >= img.Width) 20 return; 21 22 ImageAttributes imageAttributes = new ImageAttributes(); 23 ColorMap colorMap = new ColorMap(); 24 25 colorMap.OldColor = Color.FromArgb(25502550); 26 colorMap.NewColor = Color.FromArgb(0000); 27 ColorMap[] remapTable = { colorMap }; 28 29 imageAttributes.SetRemapTable(remapTable, ColorAdjustType.Bitmap); 30 31 float transparency = 0.5F; 32 if (watermarkTransparency >= 1 && watermarkTransparency <= 10) 33 transparency = (watermarkTransparency / 10.0F); 34 35 36 float[][] colorMatrixElements = { 37 new float[] {1.0f0.0f0.0f0.0f0.0f}, 38 new float[] {0.0f1.0f0.0f0.0f0.0f}, 39 new float[] {0.0f0.0f1.0f0.0f0.0f}, 40 new float[] {0.0f0.0f0.0f, transparency, 0.0f}, 41 new float[] {0.0f0.0f0.0f0.0f1.0f} 42 }; 43 44 ColorMatrix colorMatrix = new ColorMatrix(colorMatrixElements); 45 46 imageAttributes.SetColorMatrix(colorMatrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap); 47 48 int xpos = 0; 49 int ypos = 0; 50 51 switch (watermarkStatus) 52 { 53 case 1: 54 xpos = (int)(img.Width * (float).01); 55 ypos = (int)(img.Height * (float).01); 56 break; 57 case 2: 58 xpos = (int)((img.Width * (float).50- (watermark.Width / 2)); 59 ypos = (int)(img.Height * (float).01); 60 break; 61 case 3: 62 xpos = (int)((img.Width * (float).99- (watermark.Width)); 63 ypos = (int)(img.Height * (float).01); 64 break; 65 case 4: 66 xpos = (int)(img.Width * (float).01); 67 ypos = (int)((img.Height * (float).50- (watermark.Height / 2)); 68 break; 69 case 5: 70 xpos = (int)((img.Width * (float).50- (watermark.Width / 2)); 71 ypos = (int)((img.Height * (float).50- (watermark.Height / 2)); 72 break; 73 case 6: 74 xpos = (int)((img.Width * (float).99- (watermark.Width)); 75 ypos = (int)((img.Height * (float).50- (watermark.Height / 2)); 76 break; 77 case 7: 78 xpos = (int)(img.Width * (float).01); 79 ypos = (int)((img.Height * (float).99- watermark.Height); 80 break; 81 case 8: 82 xpos = (int)((img.Width * (float).50- (watermark.Width / 2)); 83 ypos = (int)((img.Height * (float).99- watermark.Height); 84 break; 85 case 9: 86 xpos = (int)((img.Width * (float).99- (watermark.Width)); 87 ypos = (int)((img.Height * (float).99- watermark.Height); 88 break; 89 } 90 91 g.DrawImage(watermark, new Rectangle(xpos, ypos, watermark.Width, watermark.Height), 00, watermark.Width, watermark.Height, GraphicsUnit.Pixel, imageAttributes); 92 93 ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders(); 94 ImageCodecInfo ici = null; 95 foreach (ImageCodecInfo codec in codecs) 96 { 97 if (codec.MimeType.IndexOf("jpeg"> -1) 98 ici = codec; 99 }100 EncoderParameters encoderParams = new EncoderParameters();101 long[] qualityParam = new long[1];102 if (quality < 0 || quality > 100)103 quality = 80;104 105 qualityParam[0= quality;106 107 EncoderParameter encoderParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qualityParam);108 encoderParams.Param[0= encoderParam;109 110 if (ici != null)111 img.Save(filename, ici, encoderParams);112 else113 img.Save(filename);114 115 g.Dispose();116 img.Dispose();117 watermark.Dispose();118 imageAttributes.Dispose();119 }120 121 /// <summary>122 /// 增加图片文字水印123 /// </summary>124 /// <param name="img">要加水印的原图(System.Drawing)</param>125 /// <param name="filename">文件名</param>126 /// <param name="watermarkText">水印文字</param>127 /// <param name="watermarkStatus">图片水印位置1=左上 2=中上 3=右上 4=左中 5=中中 6=右中 7=左下 8=右中 9=右下</param>128 /// <param name="quality">加水印后的质量0~100,数字越大质量越高</param>129 /// <param name="fontname">水印的字体</param>130 /// <param name="fontsize">水印的字号</param>131 public static void ImageWaterMarkText(Image img, string filename, string watermarkText, int watermarkStatus, int quality, string fontname, int fontsize)132 {133 Graphics g = Graphics.FromImage(img);134 Font drawFont = new Font(fontname, fontsize, FontStyle.Regular, GraphicsUnit.Pixel);135 SizeF crSize;136 crSize = g.MeasureString(watermarkText, drawFont);137 138 float xpos = 0;139 float ypos = 0;140 141 switch (watermarkStatus)142 {143 case 1:144 xpos = (float)img.Width * (float).01;145 ypos = (float)img.Height * (float).01;146 break;147 case 2:148 xpos = ((float)img.Width * (float).50- (crSize.Width / 2);149 ypos = (float)img.Height * (float).01;150 break;151 case 3:152 xpos = ((float)img.Width * (float).99- crSize.Width;153 ypos = (float)img.Height * (float).01;154 break;155 case 4:156 xpos = (float)img.Width * (float).01;157 ypos = ((float)img.Height * (float).50- (crSize.Height / 2);158 break;159 case 5:160 xpos = ((float)img.Width * (float).50- (crSize.Width / 2);161 ypos = ((float)img.Height * (float).50- (crSize.Height / 2);162 break;163 case 6:164 xpos = ((float)img.Width * (float).99- crSize.Width;165 ypos = ((float)img.Height * (float).50- (crSize.Height / 2);166 break;167 case 7:168 xpos = (float)img.Width * (float).01;169 ypos = ((float)img.Height * (float).99- crSize.Height;170 break;171 case 8:172 xpos = ((float)img.Width * (float).50- (crSize.Width / 2);173 ypos = ((float)img.Height * (float).99- crSize.Height;174 break;175 case 9:176 xpos = ((float)img.Width * (float).99- crSize.Width;177 ypos = ((float)img.Height * (float).99- crSize.Height;178 break;179 }180 181 //g.DrawString(watermarkText, drawFont, new SolidBrush(Color.White), xpos + 1, ypos + 1);文字阴影182 g.DrawString(watermarkText, drawFont, new SolidBrush(Color.Black), xpos, ypos);183 184 ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();185 ImageCodecInfo ici = null;186 foreach (ImageCodecInfo codec in codecs)187 {188 if (codec.MimeType.IndexOf("jpeg"> -1)189 ici = codec;190 }191 EncoderParameters encoderParams = new EncoderParameters();192 long[] qualityParam = new long[1];193 if (quality < 0 || quality > 100)194 quality = 80;195 196 qualityParam[0= quality;197 198 EncoderParameter encoderParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qualityParam);199 encoderParams.Param[0= encoderParam;200 201 if (ici != null)202 img.Save(filename, ici, encoderParams);203 else204 img.Save(filename);205 206 g.Dispose();207 img.Dispose();208 }209