php 上传图片并生成缩略图

<?php
    // clearDir('upload/images/');

    if ($_FILES['file']['error'] == 0) {
        $MAX_FILE_SIZE = 300000;
        if ($_FILES['file']['size'] > $MAX_FILE_SIZE) {
            exit('文件超出指定大小');
        }
        
        $allowSuffix = ['jpg', 'png', 'jpeg'];
        
        $myImg = explode('.', $_FILES['file']['name']);
        
        $mySuffix = array_pop($myImg);
        
        if (!in_array($mySuffix, $allowSuffix)) {
            exit('文件类型不对');
        }
        
        $allowMine = [
            'image/jpg',
            'image/jpeg',
            'image/pjpeg',
            'image/gif'
        ];
        
        if (!in_array($_FILES['file']['type'], $allowMine)) {
            exit('文件mime类型不对');
        }
        
        $path = "upload/images/";
        $name = date('Ymdhis').mt_rand(0, 9). '.' .$mySuffix;
        
        if(is_uploaded_file($_FILES['file']['tmp_name'])) {
            if (move_uploaded_file($_FILES['file']['tmp_name'], $path.$name)) {
                $thumb_url = create_thumb($path.$name);
                $thumb_url2 = create_thumb($path.$name, 200, true);
                echo '上传成功, 缩略图路径为: '.$thumb_url;
                echo '方缩略图路径为: '.$thumb_url2;
            } else {
                echo '上传失败';
            }
        } else {
            exit('不是上传文件');
        }
    } else {
        exit('上传失败');
    }
    
    /**
     * 给图片生成缩略图
     */
    function create_thumb($url, $max_width = 200, $is_square = false) {
        $image = imagecreatefromjpeg($url);
        
        list($ow, $oh) = getimagesize($url);
        $path_arr = explode('.', $url);
        
        //如果要求生成正方形的缩略图
        if ($is_square) {
            if ($ow > $max_width) {
                $nw = $max_width;
                $new_image = imagecreatetruecolor($nw, $nw);
                $white = imagecolorallocate($new_image, 255, 255, 255);
                imagefilledrectangle($new_image, 0, 0, $nw, $nw, $white);
                
                $o_wh = $ow > $oh ? $oh : $ow;
                imagecopyresampled($new_image, $image, 0, 0, 0, 0, $nw, $nw, $o_wh, $o_wh);
                imagejpeg($new_image, $path_arr[0].'_thumbf.jpg');
                
                $result = $path_arr[0].'_thumbf.jpg';
            } else {
                $new_image = imagecreatetruecolor($ow, $ow);
                $white = imagecolorallocate($new_image, 255, 255, 255);
                imagefilledrectangle($new_image, 0, 0, $ow, $ow, $white);
                
                if ($ow > $oh) {
                    imagecopyresampled($new_image, $image, 0, ($ow -  $oh)/ 2, 0, 0, $ow, $oh, $ow, $oh);
                } else {
                    imagecopyresampled($new_image, $image, 0, 0, 0, 0, $ow, $ow, $ow, $ow);
                }
                
                imagejpeg($new_image, $path_arr[0].'_thumbf.jpg');
                $result = $path_arr[0].'_thumbf.jpg';
            }
        } else {
            if ($ow > $max_width) {
                $percent = $max_width / $ow;
                $nw = $max_width;
                $nh = $oh * $percent;
                $new_image = imagecreatetruecolor($nw, $nh);
                imagecopyresampled($new_image, $image, 0, 0, 0, 0, $nw, $nh, $ow, $oh);
                
                imagejpeg($new_image, $path_arr[0].'_thumb.jpg');
                $result = $path_arr[0].'_thumb.jpg';
            } else {
                $new_image = imagecreatetruecolor($ow, $oh);
                $white = imagecolorallocate($new_image, 255, 255, 255);
                imagefilledrectangle($new_image, 0, 0, $ow, $oh, $white);
                imagecopyresampled($new_image, $image, 0, 0, 0, 0, $ow, $oh, $ow, $oh);
                imagejpeg($new_image, $path_arr[0].'_thumb.jpg');
                $result = $path_arr[0].'_thumb.jpg';
            }
        }
        
        imagedestroy($image);
        return $result;
    }
    
    //清空文件夹
    function clearDir($dir) {
        if (is_dir($dir)) {
            if ($dh = opendir($dir)) {
                while ($file=readdir($dh)) {
                    if (is_file($dir.$file)) {
                        unlink($dir.$file);
                    }
                }
                
                closedir($dh);
            }
        }
    }
?>