使用GD庫操作的一般步驟：
- 創建畫布
- 創建顏色
- 用GD庫的函數去畫畫
- 告訴瀏覽器你的mime類型
- 輸出到瀏覽器或者保存到本地
- 銷毀
<?php
//width,height畫布的寬和高，num是顯示字符的數量，type是顯現字符的類型，有3種
function verify($width=100,$height=40,$num=5,$type=3){
//1.創建畫布
$image = imagecreatetruecolor($width, $height);
//給矩形填充淺色
imagefilledrectangle($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,$num);
break;
}
//4.開始寫字
for($i=0;$i<$num;$i++){
$x=floor($width/$num)*$i;
$y=mt_rand(10,$height-20);
imagechar($image, 5, $x, $y, $string[$i], deepColor($image));
}
//5.干擾線(點)
for($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.指定輸出類型
header("Content-type:image/png");
//7.準備輸出
imagepng($image);
//8.銷毀
imagedestroy($image);
}
//2.生成淺色
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));
}
封裝驗證碼類
class Code{
//驗證碼個數
protected $number;
//驗證碼類型
protected $codeType;
//圖像寬度
protected $width;
//圖像高度
protected $height;
//圖像資源
protected $image;
//驗證碼字符串
protected $code;
public function __construct($number=4,$codeType=2,$width=100,$height=50){
//初始化自己的成員屬性
$this->number = $number;
$this->codeType = $codeType;
$this->width = $width;
$this->height = $height;
//生成驗證碼
$this->code = $this->createCode();
}
public function __destruct(){
imagedestroy($this->image);
}
public function __get($name){
if($name == 'code'){
echo $this->code;
}else{
return false;
}
}
protected function createCode(){
//通過你的驗證碼類型生成不同的驗證碼
switch($this->codeType){
case 0: //純數字
$code = $this->getNumberCode();
break;
case 1: //純字母
$code = $this->getCharCode();
break;
case 2: //數字和字母組合
$code = $this->getNumCharCode();
break;
default:
die('不支持這種驗證碼類型');
}
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(){
//創建畫布
$this->createImage();
//填充背景色
$this->fillBack();
//將驗證碼畫到畫布
$this->drawChar();
//添加干擾項
$this->drawDisturb();
//輸出并顯示
$this->show();
}
}
