模拟网站验证码

function TfrmLabelPages.PwdImg(img: Timage): string;
var
  I,j,k:   Integer;
  vPoint:   TPoint;
  vLeft:   Integer;
  arrStr:array [1..36]of string ;
  strResult: string;
begin
  strResult := '';
  arrStr[1] := '0';  arrStr[2]:='1';  arrStr[3]:='2';  arrStr[4]:='3';
  arrStr[5] := '4';  arrStr[6]:='5';  arrStr[7]:='6';  arrStr[8]:='7';
  arrStr[9] := '8';  arrStr[10]:='9'; arrStr[11]:='A'; arrStr[12]:='B';
  arrStr[13] := 'C'; arrStr[14]:='D'; arrStr[15]:='E'; arrStr[16]:='F';
  arrStr[17] := 'G'; arrStr[18]:='H'; arrStr[19]:='I'; arrStr[20]:='J';
  arrStr[21] := 'K'; arrStr[22]:='L'; arrStr[23]:='M'; arrStr[24]:='N';
  arrStr[25] := 'O'; arrStr[26]:='P'; arrStr[27]:='Q'; arrStr[28]:='R';
  arrStr[29] := 'S'; arrStr[30]:='T'; arrStr[31]:='U'; arrStr[32]:='V';
  arrStr[33] := 'W'; arrStr[34]:='X'; arrStr[35]:='Y'; arrStr[36]:='Z';
  For j:=1 to 4  do
  begin //www.delphitop.com
   Randomize;
   k := strtoint(Format('%.1d',[Random(36)]));
   strResult := strResult + trim(arrStr[k])
  end;
  vLeft := 10;
  img.picture := nil;
  for I := 1 to Length(strResult) do
  begin
   with Img do
   begin
   Canvas.Font.Size := Random(10)+ 9;
   Canvas.Font.Color := RGB(Random(256) and $C0,
   Random(256) and $C0, Random(256) and $C0);
   if Random(2)=1 then
   Canvas.Font.Style := [fsBold]
   else Canvas.Font.Style := [];
   begin
   Canvas.Font.Name := Screen.Fonts[10];
   vPoint.X := Random(4)+ vLeft;
   vPoint.Y := Random(5);
   Canvas.TextOut(vPoint.X, vPoint.Y,strResult[I]);
   vLeft := vPoint.X + Canvas.TextWidth(strResult[I]);
   end;
   end;
  end;
end;