使用GD库操作的一般步骤：
- 创建画布
- 创建颜色
- 用GD库的函数去画画
- 告诉浏览器你的mime类型
- 输出到浏览器或者保存到本地
- 销毁
<?php
//width,height画布的宽和高，num是显示字符的数量，type是显现字符的类型，有3种
function verify($width=100,$height=40,$num=5,$type=3){
//1.创建画布
$image = imagecreatetruecolor($width, $height);
//给矩形填充浅色
imagefilledrectangle($image,0,0,$width,$height,lightColor($image)) ;
//3.生成字符
$string="";
switch ($type) {
case 1:
$str= "0123456789";
$string=substr(str_shuffle($str),0,$num);
break;
case 2:
$arr=range("a", "z");
shuffle($arr);
$string=substr(implode("",$arr),0,$num);
break;
case 3:
$str="0123456789qwertyuioplkjhgfdsazxcvbnmQWERTYUIOPLKJHGFGDSAZXCVBNM";
$string=substr(str_shuffle($str), 0,$num);
break;
}
//4.开始写字
for($i=0;$i<$num;$i++){
$x=floor($width/$num)*$i;
$y=mt_rand(10,$height-20);
imagechar($image, 5, $x, $y, $string[$i], deepColor($image));
}
//5.干扰线(点)
for($i=0;$i<$num;$i++){
imagearc($image,mt_rand(10,$width),mt_rand(10,$height),mt_rand(10,$width),mt_rand(10,$height),mt_rand(0,10),mt_rand(0,270),deepColor($image));
}
for($i=0;$i<50;$i++){
imagesetpixel($image,mt_rand(0,$width),mt_rand(0,$height),deepColor($image));
}
//6.指定输出类型
header("Content-type:image/png");
//7.准备输出
imagepng($image);
//8.销毁
imagedestroy($image);
}
//2.生成浅色
function lightColor($image){
return imagecolorallocate($image, mt_rand(130,250), mt_rand(130,250), mt_rand(130,250));
}
//生成深色
function deepColor($image){
return imagecolorallocate($image, mt_rand(0,125), mt_rand(0,125), mt_rand(0,125));
}
封装验证码类
class Code{
//验证码个数
protected $number;
//验证码类型
protected $codeType;
//图像宽度
protected $width;
//图像高度
protected $height;
//图像资源
protected $image;
//验证码字符串
protected $code;
public function __construct($number=4,$codeType=2,$width=100,$height=50){
//初始化自己的成员属性
$this->number = $number;
$this->codeType = $codeType;
$this->width = $width;
$this->height = $height;
//生成验证码
$this->code = $this->createCode();
}
public function __destruct(){
imagedestroy($this->image);
}
public function __get($name){
if($name == 'code'){
echo $this->code;
}else{
return false;
}
}
protected function createCode(){
//通过你的验证码类型生成不同的验证码
switch($this->codeType){
case 0: //纯数字
$code = $this->getNumberCode();
break;
case 1: //纯字母
$code = $this->getCharCode();
break;
case 2: //数字和字母组合
$code = $this->getNumCharCode();
break;
default:
die('不支持这种验证码类型');
}
return $code;
}
protected function getNumberCode(){
$str = join('',range(0,9));
return substr(str_shuffle($str), 0,$this->number);
}
protected function getCharCode(){
$str = join('',range('a', 'z'));
$str = $str.strtoupper($str);
return substr(str_shuffle($str), 0,$this->number);
}
protected function getNumCharCode(){
$numStr =join('',range(0, 9));
$str = join('',range('a', 'z'));
$str = $numStr.$str.strtoupper($str);
return substr(str_shuffle($str), 0,$this->number);
}
protected function createImage(){
$this->image = imagecreatetruecolor($this->width, $this->height);
}
protected function fillBack(){
imagefill($this->image,0,0,$this->lightColor());
}
protected function lightColor(){
return imagecolorallocate($this->image, mt_rand(130,250), mt_rand(130,250), mt_rand(130,250));
}
protected function darkColor(){
return imagecolorallocate($this->image, mt_rand(0,120), mt_rand(0,120), mt_rand(0,120));
}
protected function drawChar(){
$width = ceil($this->width/$this->number);
for($i= 0;$i<$this->number;$i++){
$x = mt_rand($i*$width+10,($i+1)*$width-10);
$y= mt_rand(0,$this->height-15);
imagechar($this->image, 5, $x, $y, $this->code[$i], $this->darkColor());
}
}
protected function drawDisturb(){
for($i=0;$i<100;$i++){
$x= mt_rand(0,$this->width);
$y = mt_rand(0,$this->height);
imagesetpixel($this->image, $x, $y, $this->lightColor());
}
}
protected function show(){
header("Content-type:image/png");
imagepng($this->image);
}
public function outImage(){
//创建画布
$this->createImage();
//填充背景色
$this->fillBack();
//将验证码画到画布
$this->drawChar();
//添加干扰项
$this->drawDisturb();
//输出并显示
$this->show();
}
}
