How to implement the code of compressing images in equal proportions in php

/** * desription 压缩图片 * @param sting $imgsrc 图片路径 * @param string $imgdst 压缩后保存路径 */ public function compressedImage($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; } }