PHP生成图像验证码的方法小结(2种方法)

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);

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);