php驗證碼和不能正常顯示解決方法

效果如圖：

php驗證碼和不能正常顯示解決方法

檔案都放到了同一檔案夾下。

************************************容易出現的問題*************

1.未開啟php_gd2.dll 去php.ini将其前面的“ ;”去掉

2.上面的checks.php中<?前面有空格或者内容

3.字元編碼改為統一的

4.最容易忽略的一點：

5.如果copy代碼到你的項目中圖檔顯示為×，檢查你的checks.php放置路徑

你本機上的環境是将報錯提示全部打開的,是以在輸出時有系統的未定義提示資訊也跟着一起輸出了,這樣生成的圖檔肯定就不正常了,方法有兩,在ValidationCode.php和checks.php檔案開頭加上ini_set('display_errors', 'Off'); 就ok了

**********************************************************

CreateImage.class.php

<?php
class ValidationCode
{


	private $width,$height,$codenum;
	public $checkcode;     //産生的驗證碼
	private $checkimage;    //驗證碼圖檔
	private $disturbColor = ''; //幹擾像素
	
	function __construct($width='80',$height='20',$codenum='4')
	{
	   $this->width=$width;
	   $this->height=$height;
	   $this->codenum=$codenum;
	}
	
	function outImg()
	{
	   //輸出頭
	   $this->outFileHeader();
	   //産生驗證碼
	   $this->createCode();
	
	   //産生圖檔
	   $this->createImage();
	   //設定幹擾像素
	   $this->setDisturbColor();
	   //往圖檔上寫驗證碼
	   $this->writeCheckCodeToImage();
	   imagepng($this->checkimage);
	   imagedestroy($this->checkimage);
	}
	
	private function outFileHeader()
	{
	   header ('Content-type: image/png');
	}
	
	private function createCode()
	{
	   $this->checkcode = strtoupper(substr(md5(rand()),0,$this->codenum));
	}
	
	private function createImage()
	{
	   $this->checkimage = @imagecreate($this->width,$this->height);
	   $back = imagecolorallocate($this->checkimage,255,255,255);
	   $border = imagecolorallocate($this->checkimage,0,0,0);  
	   imagefilledrectangle($this->checkimage,0,0,$this->width - 1,$this->height - 1,$back); // 白色底
	   imagerectangle($this->checkimage,0,0,$this->width - 1,$this->height - 1,$border);   // 黑色邊框
	}
	
	private function setDisturbColor()
	{
	   for ($i=0;$i<=200;$i++)
	   {
		$this->disturbColor = imagecolorallocate($this->checkimage, rand(0,255), rand(0,255), rand(0,255));
		imagesetpixel($this->checkimage,rand(2,128),rand(2,38),$this->disturbColor);
	   }
	}
	
	private function writeCheckCodeToImage()
	{
	   for ($i=0;$i<=$this->codenum;$i++)
	   {
		$bg_color = imagecolorallocate ($this->checkimage, rand(0,255), rand(0,128), rand(0,255));
		$x = floor($this->width/$this->codenum)*$i;
		$y = rand(0,$this->height-15);
		imagechar ($this->checkimage, rand(5,8), $x, $y, $this->checkcode[$i], $bg_color);
	   }
	}
	
	function __destruct()
	{
	   unset($this->width,$this->height,$this->codenum);
	}
}

checks.php

<?php
ini_set('display_errors','off');
session_start();
header("content-type:image/png");  	  //設定建立圖像的格式
$image_width=70;                      //設定圖像寬度
$image_height=18;                     //設定圖像高度
srand(microtime()*100000);         	  //設定随機數的種子
for($i=0;$i<4;$i++){                  //循環輸出一個4位的随機數
   $new_number.=dechex(rand(0,15));
}
$_SESSION[check_checks]=$new_number;    //将擷取的随機數驗證碼寫入到SESSION變量中     

$num_image=imagecreate($image_width,$image_height);  //建立一個畫布
imagecolorallocate($num_image,255,255,255);     	 //設定畫布的顔色
for($i=0;$i<strlen($_SESSION[check_checks]);$i++){  //循環讀取SESSION變量中的驗證碼
   $font=mt_rand(3,5);                            	//設定随機的字型
   $x=mt_rand(1,8)+$image_width*$i/4;               //設定随機字元所在位置的X坐标
   $y=mt_rand(1,$image_height/4);                   //設定随機字元所在位置的Y坐标
   $color=imagecolorallocate($num_image,mt_rand(0,100),mt_rand(0,150),mt_rand(0,200));  	 //設定字元的顔色
   imagestring($num_image,$font,$x,$y,$_SESSION[check_checks][$i],$color);				     //水準輸出字元
}
imagepng($num_image);      			//生成PNG格式的圖像
imagedestroy($num_image);  			//釋放圖像資源
?>

index.php

<?php
header("content-type:text/html; charset=utf-8");
session_start();
if(!empty($_POST["Submit"])){
$checks=$_POST["checks"];
if($checks==""){
echo "<script> alert('驗證碼不能為空');window.location.href='index.php';</script>";
}
if($checks==$_SESSION[check_checks]){
	echo "<script> alert('使用者登入成功!');window.location.href='index.php';</script>";
}else{
	echo "<script> alert('您輸入的驗證碼不正确!');window.location.href='index.php';</script>";
}
}
?>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>rand函數的應用</title>
<style type="text/css">
<!--
.STYLE1 {
	font-size: 12px;
	color: #FFFFFF;
	font-weight: bold;
}
.style2 {font-weight: bold; font-size: 12px;}
-->
</style>
</head>
<body>
<form name="form" method="post" action="">
<input type="hidden" name="Submit" id="Submit" value="1" />
  <table width="1003"  cellspacing="0" cellpadding="0">
    <tr>
      <td width="168" height="169" background="images/index_01.gif">&nbsp;</td>
      <td width="685" background="images/index_02.gif">&nbsp;</td>
      <td width="150" background="images/index_03.gif">&nbsp;</td>
    </tr>
    <tr>
      <td width="168" height="311" background="images/index_04.gif">&nbsp;</td>
      <td background="images/index_05.gif"><table width="675" height="169"   cellpadding="0" cellspacing="0">
        <tr>
          <td height="43" align="center" valign="baseline">&nbsp;</td>
          <td align="center" valign="middle">&nbsp;</td>
          <td align="center" valign="baseline">&nbsp;</td>
        </tr>
        <tr>
          <td width="382" height="24" align="center" valign="baseline">&nbsp;</td>
          <td width="207" height="24" valign="middle"><span class="style2">使用者名</span><span class="STYLE1">
            <input  name="txt_user" id="txt_user" style="height:20px " size="10">
              </span></td>
          <td width="86" height="24" align="center" valign="baseline">&nbsp;</td>
        </tr>
        <tr>
          <td height="24" align="center" valign="baseline">&nbsp;</td>
          <td height="24" valign="middle"><span class="style2">密碼</span><span class="STYLE1">
          <input  name="txt_pwd" type="password" id="txt_pwd" style="FONT-SIZE: 9pt; height:20px" size="10">
          </span></td>
          <td height="24" align="center" valign="baseline">&nbsp;</td>
        </tr>
        <tr>
          <td height="24" align="center" valign="baseline">&nbsp;</td>
          <td height="24" valign="middle"><span class="style2">驗證碼</span><span class="STYLE1">
          <input name="checks" size="6" style="height:20px ">
          <img src="./checks.php" width="70" height="18"  align="bottom"></span>&nbsp;&nbsp;</td>
          <td height="24" align="center" valign="baseline">&nbsp;</td>
        </tr>
        <tr>
          <td height="40" align="center" valign="baseline">&nbsp;</td>
          <td align="center" valign="baseline">&nbsp;&nbsp;&nbsp;&nbsp;<input type="submit" id="Submit" name="Submit" value="登入" /></td>
          <td align="center" valign="baseline">&nbsp;</td>
        </tr>
      </table></td>
      <td background="images/index_06.gif">&nbsp;</td>
    </tr>
    <tr>
      <td height="100">&nbsp;</td>
      <td>&nbsp;</td>
      <td>&nbsp;</td>
    </tr>
  </table>
</form>
</body>
</html>

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