PHP驗證碼類實現(xiàn)驗證碼功能，有兩個方法，分別是用內(nèi)置字體和自定義字體生成驗證碼。具體代碼如下：
<?php
/**
* 驗證碼生成類
* @example
* $pic = new uImage();
* $code = $pic->getVerifyCode();
* header("Content-type:image/png");
* $pic->captchaFromFont($font='RAVIE.TTF'); or $pic->captcha();
*/
class uImage {
/**
* 驗證碼字符
* @access protected
*/
protected $code;
/**
* 生成圖片驗證碼,直接輸出的是圖片,字體大小是內(nèi)置字體，最大是5
* @access public
* @param int $width 驗證碼圖片寬度
* @param int $height 驗證碼圖片的高度
* @param int $snow 背景雪花的數(shù)量
* @param int $line 干擾線的條數(shù)
*/
public function captcha($width=100, $height=30, $snow=80, $line=3) {
$pic = imagecreatetruecolor($width, $height);
$backageColor = imagecolorallocate($pic, 0xFF, 0xFF, 0xFF);
imagefill($pic, 0, 0, $backageColor);
//打雪花
for($i=0; $i<=$snow;$i++) {
$color = imagecolorallocate($pic, mt_rand(150, 230), mt_rand(150, 230), mt_rand(150, 230));
imagechar($pic, 1, mt_rand(0, $width), mt_rand(0, $height), "*", $color);
imagecolordeallocate ($pic, $color);
}
//畫干擾線
for($i=0; $i<=$line; $i++) {
$x1 = mt_rand(2, $width * 0.2);
$x2 = mt_rand($width * 0.8, $width - 2);
$y1 = mt_rand(2, $height - 2);
$y2 = mt_rand(2, $height - 2);
$color = imagecolorallocate($pic, mt_rand(130, 250), mt_rand(130, 250), mt_rand(130, 250));
imageline($pic, $x1, $y1, $x2, $y2, $color);
imagecolordeallocate ($pic, $color);
}
//畫字符
$code = $this->code;
$eachW = $width / strlen($code); //圖片依據(jù)字符個數(shù)分配等份數(shù)
$fontWidth = imagefontwidth(5); //取得字體寬度
$fontHeight = imagefontheight(5); //取得字體高度
for($i=0; $i<strlen($code);$i++) {
$color = imagecolorallocate($pic, mt_rand(30, 155), mt_rand(30, 155), mt_rand(30, 150));
$x = mt_rand($eachW * $i, $eachW * ($i+1)-$fontWidth);
$y = mt_rand(3, $height-$fontHeight);
imagechar($pic, 5, $x, $y, $code{$i}, $color); //水平畫字符
imagecolordeallocate ($pic, $color);
}
//輸出
ob_start();
ob_clean();
imagepng($pic);
imagedestroy($pic);
}
/**
* 根據(jù)自定義字體生成驗證碼
* @access public
* @param string $font 字符文件， TrueType 字體文件，.ttf字體
* @param int $fontWeight 字符大小
* @param int $width 圖片寬
* @param int $height 圖片高
* @param int $snow 背景雪花個數(shù)
* @param int $line 干擾線條數(shù)
* @param int $padding 圖片內(nèi)邊距
*/
public function captchaFromFont($font, $fontWeight=16, $width=100, $height=30, $snow=80, $line=3, $padding=3){
if(!isset($font)){
return false;
}
$pic = imagecreatetruecolor($width, $height);
$backageColor = imagecolorallocate($pic, 0xFF, 0xFF, 0xFF);
imagefill($pic, 0, 0, $backageColor);
imagecolordeallocate ($pic, $backageColor);
//打雪花
for($i=0; $i<=$snow;$i++) {
$color = imagecolorallocate($pic, mt_rand(150, 230), mt_rand(150, 230), mt_rand(150, 230));
imagechar($pic, 1, mt_rand(0, $width), mt_rand(0, $height), "*", $color);
imagecolordeallocate ($pic, $color);
}
//畫干擾線
for($i=0; $i<=$line; $i++) {
$x1 = mt_rand(2, $width * 0.2);
$x2 = mt_rand($width * 0.8, $width - 2);
$y1 = mt_rand(2, $height - 2);
$y2 = mt_rand(2, $height - 2);
$color = imagecolorallocate($pic, mt_rand(130, 250), mt_rand(130, 250), mt_rand(130, 250));
imageline($pic, $x1, $y1, $x2, $y2, $color);
imagecolordeallocate ($pic, $color);
}
//畫字符
$code = $this->code;
$eachW = $width / strlen($code); //圖片依據(jù)字符個數(shù)分配等份數(shù)
$codeArray = str_split($code);
for($i=0; $i<count($codeArray); $i++){
//取得字符寬高
$fontbox = imagettfbbox($fontWeight, 0, $font, $codeArray[$i]);
$fontWidth = $fontbox[2] - $fontbox[0];
$fontHeight = $fontbox[1] - $fontbox[7];
$color = imagecolorallocate($pic, mt_rand(30, 155), mt_rand(30, 155), mt_rand(30, 150)); //字符顏色
$angle = mt_rand(-20, 20); //字符角度
if($i==0){
$start = $eachW * $i+$padding;
$end = $eachW * ($i+1)-$fontWidth;
}
elseif($i == count($codeArray)){
$start = $eachW * $i;
$end = $eachW * ($i+1)-$fontWidth-$padding;
}
else{
$start = $eachW * $i;
$end = $eachW * ($i+1)-$fontWidth-$padding;
}
$x = $start < $end ? mt_rand($start, $end) : $start;
$y = ($fontHeight+$padding) > $height ? $padding : mt_rand($fontHeight+$padding, $height-$padding);
imagettftext($pic, $fontWeight, $angle, $x, $y, $color, $font, $codeArray[$i]); //用 TrueType 字體向圖像寫入文本
imagecolordeallocate ($pic, $color);
}
//輸出
ob_start();
ob_clean();
imagepng($pic);
imagedestroy($pic);
}
/**
* 獲取驗證碼
* @access public
* @param int $len 驗證碼字符的長度
* @return strint 生成的驗證碼字符
*/
public function getVerifyCode($len=4){
if(!isset($this->code)){
$this->code = $this->getCode($len);
}
return $this->code;
}
/**
* 生成驗證碼
* @access protected
* @param int $len 驗證碼字符的長度
* @return strint 生成的驗證碼字符
*/
protected function getCode($len) {
$str = "23456789abcdefghijklmnqrstuvwxyz";
$code = "";
for($i=0; $i<$len; $i++) {
$code .= $str{mt_rand(0, strlen($str)-1)};
}
$this->code = $code;
return $code;
}
}