PHP实现将上传图片自动缩放到指定分辨率，并保持清晰度封装类示例_php技巧_

 class AutoImage{ private $image; public function resize($src, $width, $height){ //$src 就是 $_FILES['upload_image_file']['tmp_name'] //$width和$height是指定的分辨率 //如果想按指定比例放缩，可以将$width和$height改为$src的指定比例 $this->image = $src; $info = getimagesize($src);//获取图片的真实宽、高、类型 if($info[0] == $width && $info[1] == $height){ //如果分辨率一样，直接返回原图 return $src; } switch ($info['mime']){ case 'image/jpeg': header('Content-Type:image/jpeg'); $image_wp = imagecreatetruecolor($width, $height); $image_src = imagecreatefromjpeg($src); imagecopyresampled($image_wp, $image_src, 0, 0, 0, 0, $width, $height, $info[0], $info[1]); imagedestroy($image_src); imagejpeg($image_wp,$this->image); break; case 'image/png': header('Content-Type:image/png'); $image_wp = imagecreatetruecolor($width, $height); $image_src = imagecreatefrompng($src); imagecopyresampled($image_wp, $image_src, 0, 0, 0, 0, $width, $height, $info[0], $info[1]); imagedestroy($image_src); imagejpeg($image_wp,$this->image); break; case 'image/gif': header('Content-Type:image/gif'); $image_wp = imagecreatetruecolor($width, $height); $image_src = imagecreatefromgif($src); imagecopyresampled($image_wp, $image_src, 0, 0, 0, 0, $width, $height, $info[0], $info[1]); imagedestroy($image_src); imagejpeg($image_wp,$this->image); break; } return $this->image; } }