php实现图片压缩

本文实例为大家分享了PHP实现图片压缩的具体代码，供大家参考，具体内容如下

<?php
  $files =[];
  ini_set('memory_limit','500M');
  function getDir($dir){
    global $files;
    $hd=scandir($dir);
    foreach ($hd as $val) {
      $sub_dir = $dir."/".$val;
      if($val=="." || $val== ".."){
        continue;
      }elseif(is_dir($sub_dir)){
        getDir($sub_dir);
      }else{
        array_push($files, $sub_dir);
      }
    }
    return $files;
  }
  $dir = "D:/php/2021_city";
  $info = getDir($dir);
  foreach($info as $file){
    $tmpPath="D:/img/";
    $arr = pathinfo($file);
    $subDir = explode("/",$arr['dirname'])[3];
    $tmpPath = $tmpPath.$subDir;
    if(!is_dir($tmpPath)){
      mkdir($tmpPath,0777,true);
    }
    sleep(1);
    getNewFile($file,$tmpPath);
    echo "file[$file] is finish".PHP_EOL;
  }

  function getNewFile($filepath,$tmpPath){
    $imgInfo = getimagesize($filepath);
    $width = $imgInfo[0];//width
    $height = $imgInfo[1];//height
    $fileName = pathinfo($filepath)['basename'];
    $tmpFilePath = $tmpPath."/".$fileName;
    getThumb($filepath,$width,$height,$tmpFilePath);
  }
function resizeImage($im, $dest, $maxwidth, $maxheight) {
  $img = getimagesize($im);
  switch ($img[2]) {
     case 1:
      $im = @imagecreatefromgif($im);
      break;
     case 2:
      $im = @imagecreatefromjpeg($im);
      break;
     case 3:
      $im = @imagecreatefrompng($im);
      break;
  }
  
  $pic_width = imagesx($im);
  $pic_height = imagesy($im);
  $resizewidth_tag = false;
  $resizeheight_tag = false;
  if (($maxwidth && $pic_width > $maxwidth) || ($maxheight && $pic_height > $maxheight)) {
  if ($maxwidth && $pic_width > $maxwidth) {
    $widthratio = $maxwidth / $pic_width;
    $resizewidth_tag = true;
   }
  
  if ($maxheight && $pic_height > $maxheight) {
    $heightratio = $maxheight / $pic_height;
    $resizeheight_tag = true;
  }
  
  if ($resizewidth_tag && $resizeheight_tag) {
    if ($widthratio < $heightratio)
    $ratio = $widthratio;
    else
    $ratio = $heightratio;
  }
   if ($resizewidth_tag && !$resizeheight_tag)
    $ratio = $widthratio;
   if ($resizeheight_tag && !$resizewidth_tag)
    $ratio = $heightratio;
   $newwidth = $pic_width * $ratio;
   $newheight = $pic_height * $ratio;
  
   if (function_exists("imagecopyresampled")) {
    $newim = imagecreatetruecolor($newwidth, $newheight);
    imagecopyresampled($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $pic_width, $pic_height);
   } else {
    $newim = imagecreate($newwidth, $newheight);
    imagecopyresized($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $pic_width, $pic_height);
   }
  
  imagejpeg($newim, $dest);
  imagedestroy($newim);
  } else {
    imagejpeg($im, $dest);
  }
}
/**
 * 图片压缩处理
 * @param string $sFile 源图片路径
 * @param int $iWidth 自定义图片宽度
 * @param int $iHeight 自定义图片高度
 * @return string 压缩后的图片路径
 */
function getThumb($sFile,$iWidth,$iHeight,$tmpFilePath){
 //图片公共路径
 $public_path = '';
 //判断该图片是否存在
 if(!file_exists($public_path.$sFile)) return $sFile;
 //判断图片格式(图片文件后缀)
 $extend = explode("." , $sFile);
 $attach_fileext = strtolower($extend[count($extend) - 1]);
 if (!in_array($attach_fileext, array('jpg','png','jpeg'))){
 return '';
 }
 //压缩图片文件名称
 $sFileNameS = str_replace(".".$attach_fileext, "_".$iWidth.'_'.$iHeight.'.'.$attach_fileext, $sFile);
 //判断是否已压缩图片，若是则返回压缩图片路径
 if(file_exists($public_path.$sFileNameS)){
 return $sFileNameS;
 }
 //生成压缩图片，并存储到原图同路径下
 // resizeImage($public_path.$sFile, $public_path.$sFileNameS, $iWidth, $iHeight);
 resizeImage($public_path.$sFile,$tmpFilePath, $iWidth, $iHeight);
 if(!file_exists($public_path.$sFileNameS)){
 return $sFile;
 }
 return $sFileNameS;
}
?>