Image類封裝之生成縮略圖

<?php
/**
 * GDBasic.php
 * author: F.X
 * date: 2017
 * description GD基礎類
 */

namespace Imooc\Lib;


class GDBasic
{
    protected static $_check =false;

    //檢查服務器環境中gd庫
    public static function check()
    {
        //當靜態變量不爲false
        if(static::$_check)
        {
            return true;
        }

        //檢查gd庫是否加載
        if(!function_exists("gd_info"))
        {
            throw new \Exception('GD is not exists');
        }

        //檢查gd庫版本
        $version = '';
        $info = gd_info();
        if(preg_match("/\\d+\\.\\d+(?:\\.\\d+)?/", $info["GD Version"], $matches))
        {
            $version = $matches[0];
        }

        //當gd庫版本小於2.0.1
        if(!version_compare($version,'2.0.1','>='))
        {
            throw new \Exception("GD requires GD version '2.0.1' or greater, you have " . $version);
        }

        self::$_check = true;
        return self::$_check;
    }
}

GDBasic.php

 

 

Image.php

<?php
/*
 * @Description: 圖像類
 * @Author: your name
 * @Date: 2019-07-02 09:19:45
 * @LastEditTime: 2019-07-02 10:13:06
 * @LastEditors: Please set LastEditors
 */

namespace Imooc\Lib;
require_once 'GDBasic.php';

class Image extends GDBasic
{
    protected $_width;
    protected $_height;
    protected $_type;
    protected $_im;
    protected $_mime;
    protected $_real_path;

    public function __construct($file)
    {
        //檢查GD庫
        self::check();
        $imageInfo = $this->createImageByFile($file);
        $this->_width = $imageInfo['width'];
        $this->_height = $imageInfo['height'];
        $this->_type = $imageInfo['type'];
        $this->_im = $imageInfo['im'];
        $this->_mime = $imageInfo['mime'];
        $this->_real_path = $imageInfo['real_path'];


    }



    /**
     * @根據文件創建圖像: 
     * @param $file
     * @return array
     * @throws \Exception
     */
    public function createImageByFile($file)
    {
        //檢查文件是否存在
        if(!file_exists($file))
        {
            throw new \Exception('file is not exists');
        }
        //獲取圖像信息
        $imageInfo = getimagesize($file);
        $realpath = realpath($file);
        if(!$imageInfo)
        {
            throw new \Exception('file is not image file');
        }

        switch($imageInfo[2])
        {
            case IMAGETYPE_GIF:
                $im = imagecreatefromgif($file);
                break;
            case IMAGETYPE_JPEG:
                $im = imagecreatefromjpeg($file);
                break;
            case IMAGETYPE_PNG:
                $im = imagecreatefrompng($file);
                break;
            default:
                throw new \Exception('image file is not gif,png,jpeg');
        }

        return array(
            'width'=>$imageInfo[0],
            'height'=>$imageInfo[1],
            'type'=>$imageInfo[2],
            'mime'=>$imageInfo['mime'],
            'im'=>$im,
            'real_path'=>$realpath
        );


    }


    /**
     * @縮略圖: 
     * @param int $width 縮略圖寬度
     * @param int $height 縮略圖高度 
     * @return: $this
     * @throws \Exception
     */
    public function resize($width,$height)
    {
        if(!is_numeric($width) || !is_numeric($height))
        {
            throw new \Exception('width and height is not number');
        }

        //根據傳參的寬高獲取最終的寬高
        $srcW = $this->_width;
        $srcH = $this->_height;

        if($width<=0 ||$height<=0)
        {
            $desW = $srcW;
            $desH = $srcH;            
        }
        else
        {
            $srcP = $srcW/$srcH;
            $desP = $width/$height;

            if($width > $srcW)
            {
                if($height > $srcH)
                {
                    $desW = $srcW;
                    $desH = $srcH;
                }
                else
                {
                    $desH = $height;
                    $desW = round($desH * $srcp);
                }
            }
            else
            {
                if($desP > $srcP)
                {
                    $desW = $width;
                    $desH = round($desW/$srcP);                    
                }
                else
                {
                    $desH = $height;
                    $desw = round($desH * $srcP);
                }
            }

        }


        //檢測php版本是否小於php5.5
        if(version_compare(PHP_VERSION,'5.5.0','<'))
        {
            $desIm = imagecreatetruecolor($desW,$desH);
            if(imagecopyresampled($desIm,$this->_im,0,0,0,0,$desW,$desH,$srcW,$srcH))
            {
                imagedestory($this->_im);
                $this->_im = $desIm;
                $this->_width = imagesx($this->_im);
                $this->_height = imagesy($this->_im);
                
            }
        }
        else
        {
            if($desIm = imagescale($this->_im,$desW,$desH))
            {
                $this->_im = $desIm;
                $this->_width = imagesx($this->_im);
                $this->_height = imagesy($this->_im);
            }
        }
        return $this;

    }


    /**
     * @圖像輸出: 
     * @param {type} 
     * @return: bool
     */
    public function show()
    {
        header('Content-Type:'.$this->_mime);
        if($this->_type == 1)
        {
            imagegif($this->_im);
            return true;
        }
        if($this->_type ==2)
        {
            imagejpeg($this->_im);
            return true;
        }
        if($this->_type == 3)
        {
            imagepng($this->_im);
            return true;
        }
    }
}



?>

show.php

 

<?php
require_once './lib/Image.php';
$image = new \Imooc\Lib\Image('./images/b.png');
$image->resize(200,100)->show();





?>