PHP学习笔记（5）GD库画验证码

<?php 
   header("content-type:image/png");
   $width = 500;
   $height = 500;
   $img = imagecreatetruecolor($width, $height);
   $string = "hello";
   //7种颜色，存入数组
   $red = imagecolorallocate($img, 255, 0, 0);
   $white = imagecolorallocate($img, 255, 255, 255);
   $green = imagecolorallocate($img, 0, 255, 0);
   $blue = imagecolorallocate($img, 0, 0, 255);
   $aaa = imagecolorallocate($img, 255, 255, 0);
   $bbb = imagecolorallocate($img, 0, 255, 255);
   $ccc = imagecolorallocate($img, 255, 0, 255);
   $colors = array($white,$red,$green,$blue,$aaa,$bbb,$ccc);
   //画点
   for ($i=0; $i < 1000; $i++) { 
      imagesetpixel($img, mt_rand(0,$width), mt_rand(0,$height), $colors[mt_rand(0,6)]);
   }
   //划线
   for ($i=0; $i < 200; $i++) { 
      imageline($img, mt_rand(0,$width), mt_rand(0,$height), mt_rand(0,$width), mt_rand(0,$height), $colors[mt_rand(0,6)]);
   }
   //生成4位验证码
   $a1 = range(0, 9);
   $a2 = range(a, z);
   $a3 = range(A, Z);
   $a4 = array_merge($a1,$a2,$a3);
   $num = 4;
   $fontsize = 60;
   for ($i=0; $i < 4; $i++) { 
      imagettftext($img, $fontsize, mt_rand(-45,45), $width/$num*$i+$fontsize, $height/2, $colors[mt_rand(0,6)], "Fonts/msyh.ttf", $a4[mt_rand(0,61)]);
   }

   imagepng($img);
 ?>

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下面的小一点：

<?php 
   header("content-type:image/png");
   $width = 110;
   $height = 40;
   $img = imagecreatetruecolor($width, $height);
   $string = "hello";
   //7种颜色，存入数组
   $red = imagecolorallocate($img, 255, 0, 0);
   $white = imagecolorallocate($img, 255, 255, 255);
   $green = imagecolorallocate($img, 0, 255, 0);
   $blue = imagecolorallocate($img, 0, 0, 255);
   $aaa = imagecolorallocate($img, 255, 255, 0);
   $bbb = imagecolorallocate($img, 0, 255, 255);
   $ccc = imagecolorallocate($img, 255, 0, 255);
   $colors = array($white,$red,$green,$blue,$aaa,$bbb,$ccc);
   //画点
   for ($i=0; $i < 10; $i++) { 
      imagesetpixel($img, mt_rand(0,$width), mt_rand(0,$height), $colors[mt_rand(0,6)]);
   }
   //划线
   for ($i=0; $i < 4; $i++) { 
      imageline($img, mt_rand(0,$width), mt_rand(0,$height), mt_rand(0,$width), mt_rand(0,$height), $colors[mt_rand(0,6)]);
   }
   //生成4位验证码
   $a1 = range(0, 9);
   $a2 = range(a, z);
   $a3 = range(A, Z);
   $a4 = array_merge($a1,$a2,$a3);
   $num = 4;
   $fontsize = 20;
   for ($i=0; $i < 4; $i++) { 
      imagettftext($img, $fontsize, mt_rand(-45,45), $width/$num*$i+5, 30, $colors[mt_rand(0,6)], "Fonts/msyh.ttf", $a4[mt_rand(0,61)]);
   }
   imagepng($img);
 ?>