<?php
$im = imagecreatetruecolor(80,23);//創(chuàng)建畫布
$bgcolor = imagecolorallocate($im,220,230,230);//調(diào)制背景色
$bordercolor = imagecolorallocate($im,0,0,255);//調(diào)制邊框顏色
$tcolor = imagecolorallocate($im,255,0,0);
$green = imagecolorallocate($im,0,255,0);
imagefill($im,10,10,$bgcolor);//填充背景色
imagerectangle($im,1,1,79,22,$bordercolor);//繪制邊框
for($i = 0;$i < 4; $i++){
$num_case = rand(0,2);//產(chǎn)生隨機數(shù)0-2，根據(jù)數(shù)值的不同決定產(chǎn)生的是數(shù)字|小寫|大寫
switch($num_case){
case 0:$num = rand(48,57);break;//數(shù)字
case 1:$num = rand(65,90);break;//大寫
default:$num = rand(97,122);//小寫
}
$text[$i] = sprintf("%c",$num);//將隨機產(chǎn)生的ASCII碼轉(zhuǎn)換為相應(yīng)的字符
imagettftext($im,rand(10,20),rand(0,30),15*$i+5,20,$tcolor,"simkai.ttf",$text[$i]);//顯示字符
}
for($i=0;$i<100;$i++){
imagesetpixel($im,rand(1,79),rand(1,22),$green);
}
session_start();
$_SESSION["ckcode"]=implode($text);
header("Content-type:image/png");//設(shè)置輸出類型
imagepng($im);//輸出圖像
imagedestroy($im);