网页中的*生成图片

<%

 
Call Com_CreatValidCode(Request.QueryString("tel"))
Public Sub Com_CreatValidCode(pTel)
'----------禁止缓存
Response.Expires = 0
Response.AddHeader "Pragma","no-cache"
Response.AddHeader "cache-ctrol","no-cache"
Response.ContentType = "Image/BMP"
Randomize
Dim i, ii, iii ,rndColor,strLen,sql,rs
Const cOdds = 5 '------------杂点出现的机率
Const str="0123456789-"
strLen = len(pTel)
rndColor = ChrB(cint(rnd*255)) & ChrB(cint(rnd*255)) & ChrB(cint(rnd*255))
'-----------颜色的数据(字符，背景)
Dim vColorData(1)
'vColorData(0) = ChrB(0) & ChrB(0) & ChrB(0) '----蓝0，绿0，红0（黑色）
'vColorData(1) = ChrB(255) & ChrB(255) & ChrB(255) '----蓝250，绿236，红211（浅蓝色）
'vColorData(0) = ChrB(197) & ChrB(106) & ChrB(49) '---- 蓝0，绿0，红0（黑色）
'vColorData(1) = ChrB(238) & ChrB(210) & ChrB(193) '-----蓝250，绿236，红211（浅蓝色）
vColorData(0) = ChrB(0) & ChrB(0) & ChrB(0) '---------蓝0，绿0，红0（黑色）
vColorData(1) = ChrB(205) & ChrB(237) & ChrB(245) '------------蓝250，绿236，红211（浅蓝色）

'--------------------随机产生字符
Randomize
Dim vCode()
redim vCode(strLen-1)
For i = 0 To strLen-1
vCode(i) =instr(1,str,mid(pTel,i+1,1),1)-1
Next

'-----------字符的数据
Dim vNumberData(11)
'Verdana Font
vNumberData(0) = "11111111111000111101110111011101110111011101110111011101110111011110001111111111"
vNumberData(1) = "11111111111101111110011111110111111101111111011111110111111101111110001111111111"
vNumberData(2) = "11111111111000111101110111011101111110111111011111101111110111111100000111111111"
vNumberData(3) = "11111111111000111101110111111101111100111111110111111101110111011110001111111111"
vNumberData(4) = "11111111111110111111001111101011111010111101101111100001111110111111100111111111"
vNumberData(5) = "11111111110000011101111111011111110000111111110111111101110111011110001111111111"
vNumberData(6) = "11111111111000111101101111011111110000111101110111011101110111011110001111111111"
vNumberData(7) = "11111111110000011101101111111011111101111111011111110111111101111111011111111111"
vNumberData(8) = "11111111111000111101110111011101111000111101110111011101110111011110001111111111"
vNumberData(9) = "11111111111000111101110111011101110111011110000111111101111011011110000111111111"
vNumberData(10) = "11111111111111111111111111111111111111111100000111111111111111111111111111111111"
vNumberData(11) = "11111111111111111111111111111111111111111111111111111111111111111111111111111111"
'-----------------输出图像文件头 <br>
Response.BinaryWrite ChrB(66) & ChrB(77) &chrb(((strLen*8*10*3+54) mod 256)) & chrb(((strLen*8*10*3+54)/ 256)mod 256) & ChrB((((strLen*8*10*3+54)/ 256)/256)mod 256) & ChrB(((((strLen*8*10*3+54)/ 256)/256)/256)mod 256) & ChrB(0) & ChrB(0) &_
ChrB(0) & ChrB(0) & ChrB(54) & ChrB(0) & ChrB(0) & ChrB(0) & ChrB(40) & ChrB(0) &_
ChrB(0) & ChrB(0) & ChrB(strLen*8) & ChrB(0) & ChrB(0) & ChrB(0) & ChrB(10) & ChrB(0) &_
ChrB(0) & ChrB(0) & ChrB(1) & ChrB(0)
'------------------输出图像信息头
Response.BinaryWrite ChrB(24) & ChrB(0) & ChrB(0) & ChrB(0) & ChrB(0) & ChrB(0)&_
ChrB((strLen*8*10*3)mod 256)&ChrB(((strLen*8*10*3)/256)mod 256)&ChrB((((strLen*8*10*3)/256)/256)mod 256)&ChrB(((((strLen*8*10*3)/256)/256)/256)mod 256)&_
ChrB(196) & ChrB(14) & ChrB(0) & ChrB(0) & ChrB(196) & ChrB(14)&ChrB(0) & ChrB(0) &_
ChrB(0) & ChrB(0) & ChrB(0) & ChrB(0) & ChrB(0) & ChrB(0) & ChrB(0) & ChrB(0)
For i = 9 To 0 Step -1 '----------历经所有行
For ii = 0 To strLen-1 '-------历经所有字
For iii = 1 To 8 '--------历经所有像素
'---------逐行、逐字、逐像素地输出图像数据
If Rnd * 99 + 1 < cOdds Then '---------随机生成杂点
Response.BinaryWrite rndColor
Else
Response.BinaryWrite vColorData(Mid(vNumberData(vCode(ii)), i * 8 + iii, 1))
End If
Next
Next
Next
End Sub
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本文转自http://www.corange.cn/archives/2008/11/2229.html