效果:
myvcode.class.php:封装创建验证码的类
/*<br>* file:myvcode.class.php<br>* 验证码类,类名Vcode<br>*/<br>class Vcode<br>{<br>private $width; /*验证码宽度*/<br>private $height; /*验证码高度*/<br>private $codeNum; /*验证码字符个数*/<br>private $checkCode; /*验证码字符*/<br>private $image; /*验证码资源*/<br>private $pixNum; /*绘制干扰点的个数*/<br>private $lineNum; /*绘制干扰线的条数*/
/*<br>*构造方法实例化验证码对象,并初始化数据<br><a href="mailto:*@param">*@param</a> int $width 设置默认宽度<br><a href="mailto:*@param">*@param</a> int $height 设置默认高度<br><a href="mailto:*@param">*@param</a> int $codeNum 设置验证码中的字符个数<br><a href="mailto:*@param">*@param</a> int $pixNum 设置干扰点的个数<br><a href="mailto:*@param">*@param</a> int $lineNum 设置干扰线的数量<br>*/<br>function __construct($width=80,$height=40,$codeNum=4,$pixNum=40,$lineNum=5)<br>{<br>$this->width = $width;<br>$this->height = $height;<br>$this->codeNum = $codeNum;<br>$this->pixNum = $pixNum;<br>$this->lineNum = $lineNum;<br>}<br>/*内部私有方法,创建图像资源*/<br>private function getCreateImage()<br>{<br>$this->image = imagecreatetruecolor($this->width, $this->height);<br>$white = imagecolorallocate($this->image,0xff,0xff,0xff);<br>imagefill($this->image, 0, 0, $white);<br>$black = imagecolorallocate($this->image,0,0,0);<br>imagerectangle($this->image, 0, 0, $this->width-1, $this->height-1, $black);<br>}<br>/*内部私有方法,绘制字符,去掉o0Llz和012*/<br>private function createCheckCode()<br>{<br>$code = '3456789abcdefghijkmnpqrstuvwxyABCDEFGHIJKMNPQRSTUVWXY';<br>$this->checkCode = "";<br>for($i=0; $icodeNum;$i++)<br>{<br>$char = $code{rand(0,strlen($code) - 1)};<br>$this->checkCode .= $char;<br>$fontColor = imagecolorallocate($this->image, rand(0,128), rand(0,128),rand(0,128));<br>$fontSize = rand(3,5);<br>$x = rand(0,$this->width-imagefontwidth($fontSize));<br>$y = rand(0,$this->height-imagefontheight($fontSize));<br>imagechar($this->image, $fontSize, $x, $y, $char, $fontColor);<br>}<br>}<br>/*内部私有方法设置干扰元素*/<br>private function setDisturbColor()<br>{<br>/*绘制干扰点*/<br>for($i=0; $ipixNum; $i++)<br>{<br>$color = imagecolorallocate($this->image, rand(0,255), rand(0,255), rand(0,255));<br>imagesetpixel($this->image, rand(1,$this->width-2), rand(1,$this->height-2), $color);<br>}<br>/*绘制干扰线*/<br>for($i=0; $ilineNum; $i++)<br>{<br>$color = imagecolorallocate($this->image, rand(0,255), rand(0,255), rand(0,255));<br>imageline($this->image, rand(1,$this->width / 2), rand(1,$this->height / 2),<br>rand($this->width / 2,$this->width – 2), rand($this->height / 2,$this->height – 2), $color);
}<br>}<br>/*开启session保存 利用echo 输出图像*/<br>function __toString()<br>{<br>$_SESSION['code'] = strtoupper($this->checkCode);<br>$this->getCreateImage();<br>$this->createCheckCode();<br>$this->setDisturbColor();<br>$this->outputImg();<br>}<br>/*内部私有方法输出图像*/<br>private function outputImg()<br>{<br>header("content-type:image/png");<br>imagepng($this->image);<br>}<br>/*析构方法,释放对象*/<br>function __destruct()<br>{<br>imagedestroy($this->image);<br>}<br>}<br>?>
imgcode.php输出图像
<?php session_start(); require_once('myvcode.class.php'); echo new Vcode(); ?>
test.html:同过img标签引用
<img src="/static/imghwm/default1.png" data-src="imgcode.php" class="lazy" alt="PHP制作图形验证码代码分享_php实例" >
可以加一个a标签,用js实现换一张效果:
/*局部刷新换验证码*/
function changeCode()
{
var imgcode = document.getElementById(‘code');
var change = document.getElementById(‘change');
change.onclick = function()
{
/*必须加后面的参数才能刷新*/
imgcode.src='code.php?tm'+Math.random();
}
}
code和change分别是img和a的id

php把负数转为正整数的方法:1、使用abs()函数将负数转为正数,使用intval()函数对正数取整,转为正整数,语法“intval(abs($number))”;2、利用“~”位运算符将负数取反加一,语法“~$number + 1”。

实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。

方法:1、用“str_replace(" ","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\ \;||\xc2\xa0)/","其他字符",$str)”语句。

php判断有没有小数点的方法:1、使用“strpos(数字字符串,'.')”语法,如果返回小数点在字符串中第一次出现的位置,则有小数点;2、使用“strrpos(数字字符串,'.')”语句,如果返回小数点在字符串中最后一次出现的位置,则有。

在php中,可以使用substr()函数来读取字符串后几个字符,只需要将该函数的第二个参数设置为负值,第三个参数省略即可;语法为“substr(字符串,-n)”,表示读取从字符串结尾处向前数第n个字符开始,直到字符串结尾的全部字符。


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