PHP驗證碼效能的實現

PHP驗證碼功能的實現

/** *產生驗證碼圖片 */public function actionVerfiycode() {Header ( "Content-type: image/gif" );$border = 0; //是否要邊框 1要:0不要$how = 4; //驗證碼位元$w = $how * 15; //圖片寬度$h = 20; //圖片高度$fontsize = 5; //字型大小$alpha = "abcdefghijkmnopqrstuvwxyz"; //驗證碼內容1:字母$number = "0123456789"; //驗證碼內容2:數字$randcode = ""; //驗證碼字串初始化srand ( ( double ) microtime () * 1000000 ); //初始化隨機數種子$im = ImageCreate ( $w, $h ); //建立驗證圖片$bgcolor = ImageColorAllocate ( $im, 255, 255, 255 ); //設定背景顏色ImageFill ( $im, 0, 0, $bgcolor ); //填充背景色if ($border) {$black = ImageColorAllocate ( $im, 0, 0, 0 ); //設定邊框顏色ImageRectangle ( $im, 0, 0, $w - 1, $h - 1, $black ); //繪製邊框}for($i = 0; $i < $how; $i ++) {$alpha_or_number = mt_rand ( 0, 1 ); //字母還是數字$str = $alpha_or_number ? $alpha : $number;$which = mt_rand ( 0, strlen ( $str ) - 1 ); //取哪個字元$code = substr ( $str, $which, 1 ); //取字元$j = ! $i ? 4 : $j + 15; //繪字元位置$color3 = ImageColorAllocate ( $im, mt_rand ( 0, 100 ), mt_rand ( 0, 100 ), mt_rand ( 0, 100 ) ); //字元隨即顏色ImageChar ( $im, $fontsize, $j, 3, $code, $color3 ); //繪字元$randcode .= $code; //逐位加入驗證碼字串}for($i = 0; $i < 5; $i ++) //繪背景幹擾線{$color1 = ImageColorAllocate ( $im, mt_rand ( 0, 255 ), mt_rand ( 0, 255 ), mt_rand ( 0, 255 ) ); //幹擾線顏色ImageArc ( $im, mt_rand ( - 5, $w ), mt_rand ( - 5, $h ), mt_rand ( 20, 300 ), mt_rand ( 20, 200 ), 55, 44, $color1 ); //幹擾線}for($i = 0; $i < $how * 40; $i ++) //繪背景幹擾點{$color2 = ImageColorAllocate ( $im, mt_rand ( 0, 255 ), mt_rand ( 0, 255 ), mt_rand ( 0, 255 ) ); //幹擾點顏色 ImageSetPixel ( $im, mt_rand ( 0, $w ), mt_rand ( 0, $h ), $color2 ); //幹擾點}$session=new CHttpSession;$session->open();Yii::app()->session->add('randcode',$randcode);/*繪圖結束*/Imagegif ( $im );ImageDestroy ( $im );/*繪圖結束*/}

引自：http://www.admin5.com/article/20080314/75984.shtml

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