chrtoimages.aspx

本系统分两个子功能： 一：学生事务 统计学生的入学

sub page_load(byval sender As Object,byval E As EventArgs) 
'Font_Size'字体大小 intrger 
'Char_Number'验证码的位数 intrger 
'BackgroundColor'背景颜色 十六进制数的字符串 
dim My_Stream as MemoryStream=Get_Images(20,50,"#000000") 
Show_image(My_Stream)'显示内存图像 
My_Stream.Close()'关闭打开的流文件 
end sub 

'Font_Size'字体大小 intrger 
'Char_Number'验证码的位数 intrger 
'BackgroundColor'背景颜色 十六进制数的字符串 
function Get_Images(Font_Size as integer,Char_Number as integer,BackgroundColor as string) as MemoryStream'把字符转换为图像，并且保存到内存流 
dim image_w as integer=int(Font_Size*1.5)+Font_Size*Char_Number'这个数字在调用页面需要,你要自己算出明确的数值 注意注意注意注意！！！！！ 
dim image_h as integer=int(2.5*Font_Size)'这个数字在调用页面需要,你要自己算出明确的数值 注意注意注意注意！！！！！ 

dim Temp_Bitmap as Bitmap'封装GDI+位图 
dim Temp_Graphics as Graphics'封装GDI+绘图面 
dim Color_Back as Color=ColorTranslator.FromHtml(BackgroundColor)'背景颜色 

Temp_Bitmap = new Bitmap(image_w, 5*image_h, PixelFormat.Format32bppRgb)'注意注 确定背景大小 

Temp_Graphics = Graphics.FromImage(Temp_Bitmap) 
Temp_Graphics.FillRectangle(new SolidBrush(Color_Back),new Rectangle(0, 0,image_w, 5*image_h))'注意注 绘制背景 

DIM Sesson_Company AS String=""'为了进行验证比较 
dim n as integer 
for n= 0 to Char_Number-1 
dim Show_Str as string=getChar()'要显示为图像的字符 
Sesson_Company=Sesson_Company & Show_Str 
dim Show_Str_Font_Size as integer=Int(3 * Rnd()+(Font_Size-2))'字体随机大小 下波动2 
dim Color_Font as Color= ColorTranslator.FromHtml(getColor())'字体随机颜色 
dim Show_Font_Name as string=getFont()'字体 
dim Show_Str_Font as Font=new Font(Show_Font_Name,Show_Str_Font_Size,FontStyle.Bold)'定义文本格式（字体，字号,粗体） 
Temp_Graphics.DrawString(Show_Str, Show_Str_Font, new SolidBrush(Color_Font), int(Font_Size/2)+n*Font_Size, Int(image_h*0.125 * Rnd()+image_h*0.08))'绘出字符 '绘字符的Y方向下波动＋4 
next 
session("imagenumber")=LCase(trim(Sesson_Company))'保存到session便于调用的页面比较 '不区分大小写 

Font_Size=Font_Size*4 
image_h=int(2.5*Font_Size) 
Temp_Graphics.DrawString("欢", new Font(getFont1(),Int(3 * Rnd()+(Font_Size-2)),FontStyle.Bold), new SolidBrush(ColorTranslator.FromHtml(getColor())), int(Font_Size/5+0*1.3*Font_Size), int(image_h/4)+Int(image_h*0.125 * Rnd()+image_h*0.08))'绘出字符 '绘字符的Y方向下波动＋4 
Temp_Graphics.DrawString("迎", new Font(getFont1(),Int(3 * Rnd()+(Font_Size-2)),FontStyle.Bold), new SolidBrush(ColorTranslator.FromHtml(getColor())), int(Font_Size/5+1*1.3*Font_Size), int(image_h/4)+Int(image_h*0.125 * Rnd()+image_h*0.08))'绘出字符 '绘字符的Y方向下波动＋4 
Temp_Graphics.DrawString("使", new Font(getFont1(),Int(3 * Rnd()+(Font_Size-2)),FontStyle.Bold), new SolidBrush(ColorTranslator.FromHtml(getColor())), int(Font_Size/5+2*1.3*Font_Size), int(image_h/4)+Int(image_h*0.125 * Rnd()+image_h*0.08))'绘出字符 '绘字符的Y方向下波动＋4 
Temp_Graphics.DrawString("用", new Font(getFont1(),Int(3 * Rnd()+(Font_Size-2)),FontStyle.Bold), new SolidBrush(ColorTranslator.FromHtml(getColor())), int(Font_Size/5+3*1.3*Font_Size), int(image_h/4)+Int(image_h*0.125 * Rnd()+image_h*0.08))'绘出字符 '绘字符的Y方向下波动＋4 
Temp_Graphics.DrawString("！ ", new Font(getFont1(),Int(3 * Rnd()+(Font_Size-2)),FontStyle.Bold), new SolidBrush(ColorTranslator.FromHtml(getColor())), int(Font_Size/5+4*1.3*Font_Size), int(image_h/4)+Int(image_h*0.125 * Rnd()+image_h*0.08))'绘出字符 '绘字符的Y方向下波动＋4 
Temp_Graphics.DrawString("请", new Font(getFont1(),Int(3 * Rnd()+(Font_Size-2)),FontStyle.Bold), new SolidBrush(ColorTranslator.FromHtml(getColor())), int(Font_Size/5+5*1.3*Font_Size), int(image_h/4)+Int(image_h*0.125 * Rnd()+image_h*0.08))'绘出字符 '绘字符的Y方向下波动＋4 
Temp_Graphics.DrawString("按", new Font(getFont1(),Int(3 * Rnd()+(Font_Size-2)),FontStyle.Bold), new SolidBrush(ColorTranslator.FromHtml(getColor())), int(Font_Size/5+6*1.3*Font_Size), int(image_h/4)+Int(image_h*0.125 * Rnd()+image_h*0.08))'绘出字符 '绘字符的Y方向下波动＋4 
Temp_Graphics.DrawString("F5", new Font(getFont1(),Int(3 * Rnd()+(Font_Size-2)),FontStyle.Bold), new SolidBrush(ColorTranslator.FromHtml(getColor())), int(Font_Size/5+7*1.3*Font_Size), int(image_h/4)+Int(image_h*0.125 * Rnd()+image_h*0.08))'绘出字符 '绘字符的Y方向下波动＋4 
Temp_Graphics.DrawString("键", new Font(getFont1(),Int(3 * Rnd()+(Font_Size-2)),FontStyle.Bold), new SolidBrush(ColorTranslator.FromHtml(getColor())), int(Font_Size/5+8*1.3*Font_Size), int(image_h/4)+Int(image_h*0.125 * Rnd()+image_h*0.08))'绘出字符 '绘字符的Y方向下波动＋4 
Temp_Graphics.DrawString("！", new Font(getFont1(),Int(3 * Rnd()+(Font_Size-2)),FontStyle.Bold), new SolidBrush(ColorTranslator.FromHtml(getColor())), int(Font_Size/5+9*1.3*Font_Size), int(image_h/4)+Int(image_h*0.125 * Rnd()+image_h*0.08))'绘出字符 '绘字符的Y方向下波动＋4 

dim Temp_Stream as MemoryStream=new MemoryStream() 
Temp_Bitmap.Save(Temp_Stream, ImageFormat.jpeg) 
Temp_Graphics.Dispose()'释放资源 
Temp_Bitmap.Dispose()'释放资源 
Temp_Stream.Close()'关闭打开的流文件 
return Temp_Stream'返回流 
end function 

function Show_image(Show_Stream as MemoryStream)'显示内存图像 
Response.ClearContent() 
Response.ContentType = "Image/Jpeg" 
Response.BinaryWrite(Show_Stream.ToArray()) 
Response.End() 
end function 

function getChar() as string'获得随机字符 0-9 a-z A-Z 
Dim Char_array(5) 
Char_array(0) = chr(Int(10 * Rnd()+48)) 
Char_array(1) = chr(Int(26 * Rnd()+65)) 
Char_array(2) = chr(Int(26 * Rnd()+65)) 
Char_array(3) = chr(Int(26 * Rnd()+97)) 
Char_array(4) = chr(Int(26 * Rnd()+97)) 
return Char_array(Int(5 * Rnd())) 
end function 

function getColor() as string'获得随机颜色 
Dim int_a As integer 
Dim int_b As integer 
Dim int_c As integer 
int_a=Int(180 * Rnd()+20) 
int_b=Int(180 * Rnd()+20) 
int_c=Int(180 * Rnd()+20) 
if int_a>150 and int_b>150 and int_c>150 then int_a=Int(150 * Rnd()+20) 
return "#" & Hex(int_a) & Hex(int_b) & Hex(int_c) 
end function 

function getFont() as string'获得随机字体 
Dim font_array(7) 
font_array(0) = "Book Antiqua" 
font_array(1) = "Microsoft Sans Serif" 
font_array(2) = "Comic Sans MS" 
font_array(3) = "Comic Sans MS" 
font_array(4) = "Comic Sans MS" 
font_array(5) = "Comic Sans MS" 
font_array(6) = "Comic Sans MS" 
return font_array(Int(7 * Rnd())) 
end function 

function getFont1() as string'获得随机字体 
Dim font_array(10) 
font_array(0) = "华文行楷" 
font_array(1) = "隶书" 
font_array(2) = "华文彩云" 
font_array(3) = "方正舒体" 
font_array(4) = "华文彩云" 
font_array(5) = "方正舒体" 
font_array(6) = "华文彩云" 
font_array(7) = "方正舒体" 
font_array(8) = "楷体_GB2312" 
font_array(9) = "华文行楷" 
return font_array(Int(10 * Rnd())) 
end function 
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' 注 意 ' 
' ' ' 
'把所有的代码保存为：ChrToImages.aspx --------->可以直接运行看效果 ' 
'在其它页面的调用方法：<img width=image_w height=image_h src="ChrToImages.aspx" align="absmiddle"> ' 
'image_w、image_h,你要自己算出明确的数值,并注意session("imagenumber") ' 
' ' 
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