PHP生成可視性相對不錯的驗證碼

經常上一些論壇，填驗證碼，好多論壇的驗證碼看我都頭暈，老填不對，看起來比較難受，難道不能弄的大點嗎？看了下php manaul我自己即興寫了一下還待改進,但看起來舒服多了。代碼如下：

 

<? function getRandomStr(){ $seedStr="abstuv456TUVWwxyzABCcderDEFGHIfghijklmnopqJKLMNS3OPQRXYZ012789"; mt_srand(); $ranStr=""; for($i=0;$i<4;$i++){ $ranStr.=$seedStr[mt_rand(0,61)]."|"; } return $ranStr; } //get from php manaul function imagelinethick($image, $x1, $y1, $x2, $y2, $color, $thick = 1) { if ($thick == 1) { return imageline($image, $x1, $y1, $x2, $y2, $color); } $t = $thick / 2 - 0.5; if ($x1 == $x2 || $y1 == $y2) { return imagefilledrectangle($image, round(min($x1, $x2) - $t), round(min($y1, $y2) - $t), round(max($x1, $x2) + $t), round(max($y1, $y2) + $t), $color); } $k = ($y2 - $y1) / ($x2 - $x1); //y = kx + q $a = $t / sqrt(1 + pow($k, 2)); $points = array( round($x1 - (1+$k)*$a), round($y1 + (1-$k)*$a), round($x1 - (1-$k)*$a), round($y1 - (1+$k)*$a), round($x2 + (1+$k)*$a), round($y2 - (1-$k)*$a), round($x2 + (1-$k)*$a), round($y2 + (1+$k)*$a), ); imagefilledpolygon($image, $points, 4, $color); return imagepolygon($image, $points, 4, $color); } $ranStr=getRandomStr(); //produce random str $strArray = explode('|',$ranStr); //get the code array $width = 130; //imgwidth $height = 53; //imgheight $font_file = 'ariali.ttf';//font file you can get from c:/windows/fonts $img=imagecreate($width,$height); $black=imagecolorallocate($img,0xFF,0xFF,0xFF); $blurPix=imagecolorallocate($img,100,230,247);//blur point color $fontColor=imagecolorallocate($img,41,160,238);//font color $lineColor=imagecolorallocate($img,0,160,200);//line color //draw blur point mt_srand(); for($i=0;$i<800;$i++){ imagesetpixel($img,mt_rand(0,$width),mt_rand(0,$height),$blurPix); } $result="";//final code string $position=array(12,40,70,100);//the position of the four cod character for($i=0;$i<count($strArray)-1;++$i){ $result.=$strarray[$i]; imagefttext($img, mt_rand(20,35), mt_rand(0,40), $position[$i], mt_rand(38,40), $fontColor, $font_file, $strArray[$i]);//draw every code } //draw curve $points = array(); for ($i=1; $i<mt_rand(100,200); $i=$i+1) { $x = $i; //define x-value, which is $i itself $y = mt_rand(10,12)*sin($x/60)*sin($x/5);//define y-value //append a point's x-value and y-value $points[] = $x; //x-value $points[] = 20-$y; //y-value } //count points $totalPoints = count($points)/2; for ($i=0; $i<$totalPoints-1; $i++){ imagelinethick($img, $points[2*$i], $points[1+2*$i], $points[2+2*$i], $points[3+2*$i], $lineColor,2); } imagerectangle($img,0,0,$width-1,$height-1,$fontColor); session_start(); $_SESSION["code"] = $result;//save into session for validate //procuce valiate code picture @header("Content-Type:image/png"); imagepng($img); imagedestroy($img); ?>

 

使用時：<img src="code.php" border="0">就行了。

 

效果如下：