C#圖片加水印實例與代碼

本文要提供的類可以為圖片加文字水印，以及判斷是否是圖片文件。經過測試可運行，例子請下載：http://hovertree.com/h/bjaf/5qc5eh6y.htm

例子效果圖：

以下是HovercWarter類的代碼：

 1 using System.Drawing;
 2 using System.Drawing.Imaging;
 3 using System.IO;
 4 
 5 namespace HoverTreeBatch.HovercFrame
 6 {
 7 public class HovercWarter
 8 {
 9 public static Image AddTextToImg(Image image, string text)
10 {
11 Bitmap bitmap = new Bitmap(image, image.Width, image.Height);
12 Graphics g = Graphics.FromImage(bitmap);
13 
14 float fontSize = 12.0f; //字體大小
15 float textWidth = text.Length * fontSize; //文本的長度
16 //下麵定義一個矩形區域，以後在這個矩形里畫上白底黑字
17 float rectX = 0;
18 float rectY = 0;
19 float rectWidth = text.Length * (fontSize + 8);
20 float rectHeight = fontSize + 8;
21 //聲明矩形域
22 RectangleF textArea = new RectangleF(rectX, rectY, rectWidth, rectHeight);
23 
24 Font font = new Font("宋體", fontSize); //定義字體
25 Brush whiteBrush = new SolidBrush(Color.White); //白筆刷，畫文字用
26 Brush blackBrush = new SolidBrush(Color.Black); //黑筆刷，畫背景用
27 
28 g.FillRectangle(blackBrush, rectX, rectY, rectWidth, rectHeight);
29 
30 g.DrawString(text, font, whiteBrush, textArea);
31 MemoryStream ms = new MemoryStream();
32 //保存為Jpg類型
33 bitmap.Save(ms, ImageFormat.Jpeg);
34 
35 Image h_hovercImg = Image.FromStream(ms);
36 
37 g.Dispose();
38 bitmap.Dispose();
39 
40 
41 return h_hovercImg;
42 }
43 
44 
45 /// <summary>
46 /// 根據文件頭判斷上傳的文件類型
47 /// </summary>
48 /// <param name="filePath">filePath是文件的完整路徑 </param>
49 /// <returns>返回true或false</returns>
50 public static bool IsPicture(string filePath)
51 {
52 try
53 {
54 FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);
55 BinaryReader reader = new BinaryReader(fs);
56 string fileClass;
57 byte buffer;
58 buffer = reader.ReadByte();
59 fileClass = buffer.ToString();
60 buffer = reader.ReadByte();
61 fileClass += buffer.ToString();
62 reader.Close();
63 fs.Close();
64 if (fileClass == "255216" || fileClass == "7173" || fileClass == "13780" || fileClass == "6677")
65 //何問起 hovertree.com
66 //255216是jpg;7173是gif;6677是BMP,13780是PNG;7790是exe,8297是rar 
67 {
68 return true;
69 }
70 else
71 {
72 return false;
73 }
74 }
75 catch
76 {
77 return false;
78 }
79 }
80 }
81 }

另外出一道.NET的題目：http://hovertree.com/shortanswer/bjaf/9vqxwuda.htm

開發技術文章收集: http://www.cnblogs.com/sosoft/p/kaifajishu.html