PHP生成图像验证码

1、生成加法运算验证码图片

session_start ();

/*定义头文件为图片*/

header("Content-type: image/png");

/*生成验证码*/

/*创建图片设置字体颜色*/

$im = imagecreate($w, $h);

$red = imagecolorallocate($im, 255, 255, 255);

$white = imagecolorallocate($im, 255, 255, 255);

/*随机生成两个数字*/

$num1 = rand(1, 20);

$num2 = rand(1, 20);

$_SESSION ["administratorConfirmCode"] = $num1+$num2;

/*设置图片背景颜色*/

$gray = imagecolorallocate($im, 118, 151, 199);

$black = imagecolorallocate($im, mt_rand(0, 100), mt_rand(0, 100), mt_rand(0, 100));

/*创建图片背景*/

imagefilledrectangle($im, 0, 0, 100, 24, $black);

/*在画布上随机生成大量点*/

for ($i = 0; $i < 80; $i++) {

imagesetpixel($im, rand(0, $w), rand(0, $h), $gray);

}

/*将计算验证码写入到图片中*/

imagestring($im, 5, 5, 4, $num1, $red);

imagestring($im, 5, 30, 3, "+", $red);

imagestring($im, 5, 45, 4, $num2, $red);

imagestring($im, 5, 70, 3, "=", $red);

imagestring($im, 5, 80, 2, "?", $white);

/*输出图片*/

imagepng($im);

imagedestroy($im);

2、生成字符验证码图片【值得注意的是在字体哪里，需要引入实际的字体路径，否则，可能出现图像显示不了验证码】

session_start ();

/*设置文件头为图片输出*/

Header("Content-type: image/JPEG");

/*调用生成验证码函数*/

$str="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz01234565789";

$result="";

for($i=0;$i<$length;$i++){

$num[$i]=rand(0,61);

$result.=$str[$num[$i]];

}

$text = $result;

$_SESSION ["administratorConfirmCode"] = $text;

/*设置图片的宽度和高度*/

$im_x = $w;

$im_y = $y;

/*创建图片*/

$im = imagecreatetruecolor($im_x,$im_y);

$text_c = ImageColorAllocate($im, mt_rand(0,100),mt_rand(0,100),mt_rand(0,100));

$tmpC0=mt_rand(100,255);

$tmpC1=mt_rand(100,255);

$tmpC2=mt_rand(100,255);

$buttum_c = ImageColorAllocate($im,$tmpC0,$tmpC1,$tmpC2);

imagefill($im, 16, 13, $buttum_c);

/*字体文件*/

$font = _WEB_DIR_.'/font/comic.ttf';

for ($i=0;$i<strlen($text);$i++){

$tmp =substr($text,$i,1);

$array = array(-1,1);

$p = array_rand($array);

$an = $array[$p]*mt_rand(1,10);//角度

$size = 28;

imagettftext($im, $size, $an, 15+$i*$size, 35, $text_c, $font, $tmp);

}

/*将字符写入文件中*/

$distortion_im = imagecreatetruecolor ($im_x, $im_y);

imagefill($distortion_im, 16, 13, $buttum_c);

for ( $i=0; $i<$im_x; $i++) {

for ( $j=0; $j<$im_y; $j++) {

$rgb = imagecolorat($im, $i , $j);

if( (int)($i+20+sin($j/$im_y*2*M_PI)*10) <= imagesx($distortion_im)&& (int)($i+20+sin($j/$im_y*2*M_PI)*10) >=0 ) {

imagesetpixel ($distortion_im, (int)($i+10+sin($j/$im_y*2*M_PI-M_PI*0.1)*4) , $j , $rgb);

}

}

}

/*干扰元素点的数量*/

$count = 160;

/*创建干扰元素点*/

for($i=0; $i<$count; $i++){

$randcolor = ImageColorallocate($distortion_im,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255));

imagesetpixel($distortion_im, mt_rand()%$im_x , mt_rand()%$im_y , $randcolor);

}

/*创建干扰线条*/

$rand = mt_rand(5,30);

$rand1 = mt_rand(15,25);

$rand2 = mt_rand(5,10);

for ($yy=$rand; $yy<=+$rand+2; $yy++){

for ($px=-80;$px<=80;$px=$px+0.1){

$x=$px/$rand1;

if ($x!=0){

$y=sin($x);

}

$py=$y*$rand2;

imagesetpixel($distortion_im, $px+80, $py+$yy, $text_c);

}

}

/*以PNG格式将图像输出到浏览器*/

ImagePNG($distortion_im);

/*销毁图像*/

ImageDestroy($distortion_im);

ImageDestroy($im);