Three PHP Chinese verification code generation and calling methods_PHP tutorial

Three PHP Chinese verification code generation and calling methods To generate a Chinese verification code in PHP, you must do a different operation than generating a verification code. Because the GD function only accepts text encoded in UTF8 format, when using PHP to generate a Chinese verification code, you must first perform encoding conversion. The iconv of operating php can be instantiated.

Three PHP tutorials Chinese verification code generation and calling methods
To generate a Chinese verification code in PHP, you must do a different operation than generating a verification code. Because the gd function only accepts text encoded in UTF8 format, when using PHP to generate a Chinese verification code, you must first perform encoding conversion. The iconv of operating php can be instantiated.
*/

$ch_str="You want to generate Chinese verification code with Chinese characters";
$str=array();
for ($i=0;$i {
$str[]=$ch_str[$i].$ch_str[$i+1].$ch_str[$i+2];
}
//The length and height of the picture
$image_x=200;
$image_y=100;
$im = imagecreate($image_x,$image_y);
//The background color of the picture here is white
$bkg = imagecolorallocate($im,255,255,255);
//Displayed font style, this requires placing the file in the corresponding directory. If you don't have a file, go find one in the window's font file.
$fnt = "simfang.ttf";
//Assign some color to the image
$white=imagecolorallocate($im,234,185,95);
//Draw an elliptical arc on the picture and specify the lower coordinate point
imagearc($im, 150, 8, 20, 20, 75, 170, $white);
imagearc($im, 180, 7,50, 30, 75, 175, $white);
//Draw a line segment on the picture and specify the lower coordinate point
imageline($im,20,20,180,30,$white);
imageline($im,20,18,170,50,$white);
imageline($im,25,50,80,50,$white);
//The number of random points
$noise_num=3000;
$line_num=80;
//Color of various confusing characters
$rectangle_color=imagecolorallocate($im,0xaa,0xaa,0xaa);
$noise_color=imagecolorallocate($im,0x00,0x00,0x00);
$font_color=imagecolorallocate($im,0x00,0x00,0x00);
for($i=0;$i<$noise_num;$i++)
{
//Draw a single pixel on a coordinate point. This point is defined above and is black.
imagesetpixel($im,mt_rand(0,$image_x),mt_rand(0,$image_y),$noise_color);
}

for($i=0;$i<$line_num;$i++)
{
$line_color=imagecolorallocate($im,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255));
//Draw a line between two coordinate points, the color is defined above
Imageline($im,mt_rand(0,$image_x),mt_rand(0,$image_y),mt_rand(0,$image_x),mt_rand(0,$image_y),$line_color);
}
$randnum=rand(0,count($str)-4);
//Keep it an even number
if ($randnum%2)
{
$randnum+=1;
}
$str1=$str[$randnum].$str[$randnum+1];
for ($i=0;$i<2;$i++)
{
imagettftext($im, rand(28,32), rand(0,70), rand(($image_x/4)*$i+$image_x/10,($image_x/4)*$i+$image_x/8), rand($image_y/2+$image_y/10,$image_y/2+$image_y/5), $font_color, $fnt, $str[$randnum+$i]);
}
imagepng($im);
imagedestroy($im);

//Generate Chinese verification code 2
$str="Chinese characters";
$image_x=110;
$image_y=110;
$im = imagecreate($image_x,$image_y);
$bkg = imagecolorallocate($im,255,255,255);
$fnt = "hb.ttf"; //Displayed font style
$white=imagecolorallocate($im,234,185,95);
imagearc($im, 150, 8, 20, 20, 75, 170, $white);
imagearc($im, 180, 7,50, 30, 75, 175, $white);
imageline($im,20,20,180,30,$white);
imageline($im,20,18,170,50,$white);
imageline($im,25,50,80,50,$white);
$noise_num=3000;
$line_num=80;
imagecolorallocate($im,0xff,0xff,0xff);
$rectangle_color=imagecolorallocate($im,0xaa,0xaa,0xaa);
$noise_color=imagecolorallocate($im,0x00,0x00,0x00);
$font_color=imagecolorallocate($im,0x00,0x00,0x00);
$line_color=imagecolorallocate($im,0x00,0x00,0x00);
for($i=0;$i<$noise_num;$i++)
imagesetpixel($im,mt_rand(0,$image_x),mt_rand(0,$image_y),$noise_color);
for($i=0;$i<$line_num;$i++)
imageline($im,mt_rand(0,$image_x),mt_rand(0,$image_y),mt_rand(0,$image_x),mt_rand(0,$image_y),$line_color);
$randnum=rand(0,strlen($str)-4);
if ($randnum%2)$randnum+=1;
$str1=substr($str,$randnum,4);
$str2 = iconv("gb2312","utf-8",$str1);//Verify that the Chinese characters are in $str1

imagettftext($im, rand(28,32), rand(0,70), rand(25,27), rand(70,100), $font_color, $fnt, $str2);
imagepng($im);
imagedestroy($im);

//Put Chinese characters in the array
/*
The gd function only accepts text encoded in utf8 format, so encoding conversion must be performed first before writing text. Both the iconv and mbstring libraries that come with PHP can complete this work
*/

$randcode=array('宠');
$codetable=array();
$fp=fopen("gb2312.txt","r");
while($line=fgets($fp))
    $codetable[hexdec(substr($line,0,6))]=substr($line,7,6);
fclose($fp); 

//gb2312转utf8
function gb2utf8($gbstr)
{
    global $codetable;
    if(trim($gbstr)=="")
        return $gbstr;
    $ret="";
    $utf8="";
    while($gbstr)
    {
        if(ord(substr($gbstr,0,1))>127)
        {
            $thisw=substr($gbstr,0,2);
            $gbstr=substr($gbstr,2,strlen($gbstr));
            $utf8="";
            @$utf8=u2utf8(hexdec($codetable[hexdec(bin2hex($thisw))-0x8080]));

 

            if($utf8!="")
            for($i=0;$i                 $ret.=chr(substr($utf8,$i,3));
        }
        else
        {
            $ret.=substr($gbstr,0,1);
            $gbstr=substr($gbstr,1,strlen($gbstr));
        }
    }
    return $ret;
} 
 

//unicode转utf8
function u2utf8($c)
{
    $str="";
    if($c<0x80)
        $str.=$c;
    elseif($c<0x800)
    {
        $str.=(0xc0|$c>>6);
        $str.=(0x80|$c&0x3f);
    }
    elseif($c<0x10000)
    {
        $str.=(0xe0|$c>>12);
        $str.=(0x80|$c>>6&0x3f);
        $str.=(0x80|$c&0x3f);
    }
    elseif($c<0x200000)
    {
        $str.=(0xf0|$c>>18);
        $str.=(0x80|$c>>12&0x3f);

 

        $str.=(0x80|$c>>6&0x3f);
        $str.=(0x80|$c&0x3f);
    }
    return $str;
} 

//生成附加码
function create_excode($length)
{
 global $randcode;
    header("content-type: image/png");
 $image_x=$length*30;    //图片宽度
 $image_y=40;            //图片高度
    $noise_num=80*$length;   //杂点数量
    $line_num=$length-2;      //干扰线数量
 $image=imagecreate($image_x,$image_y);
 imagecolorallocate($image,0xff,0xff,0xff);                  //设定背景颜色
 $rectangle_color=imagecolorallocate($image,0xaa,0xaa,0xaa); //边框颜色
 $noise_color=imagecolorallocate($image,0x00,0x00,0x00);     //杂点颜色
 $font_color=imagecolorallocate($image,0x00,0x00,0x00);      //字体颜色
 $line_color=imagecolorallocate($image,0x33,0x33,0x33);      //干扰线颜色

 //加入杂点
    for($i=0;$i<$noise_num;$i++)
  imagesetpixel($image,mt_rand(0,$image_x),mt_rand(0,$image_y),$noise_color);

$font_face="simkai.ttf"; //Font
$x=2;
$session_code='';
for($i=0;$i<$length;$i++)
{
          $code=$randcode[mt_rand(0,count($randcode)-1)];
Imagettftext($image,18,mt_rand(-6,6),$x,29,$font_color,$font_face,gb2utf8($code));
         $x+=30;
          $session_code.=$code;
}
@session_start();
$_session['excode']=$session_code; //Put the value of the additional code in the session

//Add interference line
for($i=0;$i<$line_num;$i++)
Imageline($image,mt_rand(0,$image_x),mt_rand(0,$image_y),
                         mt_rand(0,$image_x),mt_rand(0,$image_y),$line_color);
imagerectangle($image,0,0,$image_x-1,$image_y-1,$rectangle_color); //Add a border
imagepng($image);
imagedestroy($image);
}
create_excode(6);

// When using it, use html syntax directly: Just call it. When doing verification on the server side, compare the verification characters stored in the session with the characters submitted by the user. If they are the same, the verification is passed