php制作驗(yàn)證碼的過程

本篇文章給大家分享的是有關(guān)php制作驗(yàn)證碼的過程，小編覺得挺實(shí)用的，因此分享給大家學(xué)習(xí)，希望大家閱讀完這篇文章后可以有所收獲，話不多說，跟著小編一起來看看吧。

php使用GD庫生成驗(yàn)證碼

一、繪圖步驟:

1.創(chuàng)建畫布，分配顏色,使用以下兩個(gè)函數(shù)(可以在php手冊GD庫函數(shù)中找到)：

imagecreatetruecolor()

imagecolorallocate()

2.繪畫過程：

imagefill()

imagettftext()

imagesetpixel()

imageline()

3.輸出圖像：

header(“Content-Type:image/png”);

imagepng();

imagejpeg();

4.銷毀圖片（釋放內(nèi)存）

imagedestroy();

二、繪圖具體步驟

生成驗(yàn)證碼字符串

private function getCode(){
        $str="0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
        $t='';
        for($i=0;$i<$this->m;$i++){
            $t.=$str[rand(0,$this->type['letter'])];
        }
        return $t;
    }

畫出驗(yàn)證碼

function drawCode(){
        $code=$this->getCode();//獲取驗(yàn)證碼字符串
        imagefill($this->im, 0, 0, $this->bg);
        for ($i=0; $i <200 ; $i++) { 
            imagesetpixel($this->im, rand(0,$this->width), rand(0,$this->height), rand(0,255));
        }
        imageline($this->im, rand(0,$this->width), rand(0,$this->height), rand(0,$this->width), rand(0,$this->height), rand(0,255));
        $c=imagecolorallocate($this->im, rand(0,200), rand(0,200), rand(0,200));
        for($i=0;$i<$this->m;$i++){
            imagettftext($this->im, 18, rand(-40,40), 8+(18*$i), 24, $c, "georgia.ttf",$code[$i] );
        }
    }

輸出圖像

function printImage(){
        $this->drawCode();
        header("Content-Type:image/jpeg");
        imagepng($this->im);
        $this->destroy();
    }
    function destroy(){
        imagedestroy($this->im);
    }

三、代碼演示

<?php
/**
* 驗(yàn)證碼畫圖類
*/
class Image 
{
    private $width;
    private $height;
    private $im;
    private $bg;
    private $m;
    private $type=array('num' => 9,'letter' => 61 );
    function __construct($width,$height,$m)
    {
        $this->width=$width;
        $this->height=$height;
        $this->m=$m;
        $this->im=imagecreatetruecolor($this->width, $this->height);
        $this->bg=imagecolorallocate($this->im, 220, 220, 220);
    }
    private function getCode(){
        $str="0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
        $t='';
        for($i=0;$i<$this->m;$i++){
            $t.=$str[rand(0,$this->type['letter'])];
        }
        return $t;
    }
    function drawCode(){
        $code=$this->getCode();//獲取驗(yàn)證碼字符串
        imagefill($this->im, 0, 0, $this->bg);
        //加干擾點(diǎn)
        for ($i=0; $i <200 ; $i++) { 
            imagesetpixel($this->im, rand(0,$this->width), rand(0,$this->height), rand(0,255));
        }
        //加干擾線
        imageline($this->im, rand(0,$this->width), rand(0,$this->height), rand(0,$this->width), rand(0,$this->height), rand(0,255));
        $c=imagecolorallocate($this->im, rand(0,200), rand(0,200), rand(0,200));
        for($i=0;$i<$this->m;$i++){
            imagettftext($this->im, 18, rand(-40,40), 8+(18*$i), 24, $c, "georgia.ttf",$code[$i] );
        }
    }
    function printImage(){
        $this->drawCode();
        header("Content-Type:image/jpeg");
        imagepng($this->im);
        $this->destroy();
    }
    function destroy(){
        imagedestroy($this->im);
    }
}
function unit_test(){
    $obj=new Image(20*4,30,4);
    $obj->printImage();
}
unit_test();
?>

以上就是php制作驗(yàn)證碼的過程，小編相信有部分知識(shí)點(diǎn)可能是我們?nèi)粘９ぷ鲿?huì)見到或用到的。希望你能通過這篇文章學(xué)到更多知識(shí)。更多詳情敬請(qǐng)關(guān)注億速云行業(yè)資訊頻道。