摘要:[C#]簡單實做Captcha (完全用.Net內建函式)
看到保哥的這篇實做Captcha，所以我手癢的也自己try了一下，當然主要還是參考保哥的那篇。
01 
using (Bitmap bmp = new Bitmap(90, 30))
02{
03
int x1 = 0;
04 int y1 = 0;
05 int x2 = 0;
06 int y2 = 0;
07 int x3 = 0;
08 int y3 = 0;
09 int intNoiseWidth = 25;
10 int intNoiseHeight = 15;
11 Random rdn = new Random();
12 Graphics g = Graphics.FromImage(bmp);
13
14 //設定字型
15 Font font = new Font("Courier New", 12, FontStyle.Bold);
16
17 //設定圖片背景
18 g.Clear(Color.Cornsilk);
19
20 //產生雜點
21 for (int i = 0; i < 80; i++)
22
{
23 x1 = rdn.Next(0, bmp.Width);
24 y1 = rdn.Next(0, bmp.Height);
25 bmp.SetPixel(x1, y1, Color.Brown);
26
}
27
28 //產生擾亂弧線
29 for (int i = 0; i < 15; i++)
30 {
31 x1 = rdn.Next(bmp.Width - intNoiseWidth);
32 y1 = rdn.Next(bmp.Height - intNoiseHeight);
33 x2 = rdn.Next(1, intNoiseWidth);
34 y2 = rdn.Next(1, intNoiseHeight);
35 x3 = rdn.Next(0, 45);
36 y3 = rdn.Next(-270, 270);
37 g.DrawArc(new Pen(Brushes.Gray), x1, y1, x2, y2, x3, y3);
38 }
39
40 //把GenPassword()方法換成你自己的密碼產生器，記得把產生出來的密碼存起來日後才能與user的輸入做比較。
41 g.DrawString(GenPassword(6), font, Brushes.Black, 3, 3);
42
43 //你可以直接輸出到web page像保哥一樣，我這邊選擇儲存成GIF檔案。
44 bmp.Save(@"C:\Temp\Captcha.gif", ImageFormat.Gif);
45}
using (Bitmap bmp = new Bitmap(90, 30))
using 02
{03
int x1 = 0;04
int y1 = 0;05
int x2 = 0;06
int y2 = 0;07
int x3 = 0;08
int y3 = 0;09
int intNoiseWidth = 25;10
int intNoiseHeight = 15;11
Random rdn = new Random();12
Graphics g = Graphics.FromImage(bmp);13
14
//設定字型15
Font font = new Font("Courier New", 12, FontStyle.Bold);16
17
//設定圖片背景18
g.Clear(Color.Cornsilk);19
20
//產生雜點21
for (int i = 0; i < 80; i++)22
{
23
x1 = rdn.Next(0, bmp.Width);24
y1 = rdn.Next(0, bmp.Height);25
bmp.SetPixel(x1, y1, Color.Brown);26
}27
28
//產生擾亂弧線29
for (int i = 0; i < 15; i++)30
{31
x1 = rdn.Next(bmp.Width - intNoiseWidth);32
y1 = rdn.Next(bmp.Height - intNoiseHeight);33
x2 = rdn.Next(1, intNoiseWidth);34
y2 = rdn.Next(1, intNoiseHeight);35
x3 = rdn.Next(0, 45);36
y3 = rdn.Next(-270, 270);37
g.DrawArc(new Pen(Brushes.Gray), x1, y1, x2, y2, x3, y3);38
}39
40
//把GenPassword()方法換成你自己的密碼產生器，記得把產生出來的密碼存起來日後才能與user的輸入做比較。41
g.DrawString(GenPassword(6), font, Brushes.Black, 3, 3);42
43
//你可以直接輸出到web page像保哥一樣，我這邊選擇儲存成GIF檔案。44
bmp.Save(@"C:\Temp\Captcha.gif", ImageFormat.Gif);45
}下面是輸出的結果
