php如何实现等比例压缩图片的代码

<?php
/**
 * desription 压缩图片
 * @param sting $imgsrc 图片路径
 * @param string $imgdst 压缩后保存路径
 */
function compressedImage($imgsrc, $imgdst) {
    list($width, $height, $type) = getimagesize($imgsrc);
    
    $new_width = $width;//压缩后的图片宽
    $new_height = $height;//压缩后的图片高
            
    if($width >= 600){
        $per = 600 / $width;//计算比例
        $new_width = $width * $per;
        $new_height = $height * $per;
    }
    
    switch ($type) {
        case 1:
            $giftype = check_gifcartoon($imgsrc);
            if ($giftype) {
                header('Content-Type:image/gif');
                $image_wp = imagecreatetruecolor($new_width, $new_height);
                $image = imagecreatefromgif($imgsrc);
                imagecopyresampled($image_wp, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);
                //90代表的是质量、压缩图片容量大小
                imagejpeg($image_wp, $imgdst, 90);
                imagedestroy($image_wp);
                imagedestroy($image);
            }
            break;
        case 2:
            header('Content-Type:image/jpeg');
            $image_wp = imagecreatetruecolor($new_width, $new_height);
            $image = imagecreatefromjpeg($imgsrc);
            imagecopyresampled($image_wp, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);
            //90代表的是质量、压缩图片容量大小
            imagejpeg($image_wp, $imgdst, 90);
            imagedestroy($image_wp);
            imagedestroy($image);
            break;
        case 3:
            header('Content-Type:image/png');
            $image_wp = imagecreatetruecolor($new_width, $new_height);
            $image = imagecreatefrompng($imgsrc);
            imagecopyresampled($image_wp, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);
            //90代表的是质量、压缩图片容量大小
            imagejpeg($image_wp, $imgdst, 90);
            imagedestroy($image_wp);
            imagedestroy($image);
            break;
    }
}
$dir = "./avators";//根目录
$dir_one = scandir($dir);
foreach ($dir_one as $key => $value) {
    if (in_array($value,['.','..'])) {
        continue;
    }
    $dir_two = scandir($dir."/".$value);
    foreach ($dir_two as $k2 => $v2) {
        if (in_array($value,['.','..'])) {
            continue;
        }
        $file = $dir."/".$value."/".$v2;
        if (file_exists($file)) {
            compressedImage($file,$file);
            echo $file.'==';
        }
    }
}
echo 'success';
?>