从上传的多个图像调整大小相同的比例PHP

Question

我一直在砸我的头几个小时，我不能为我的生活弄清楚如何调整一个简单的形式上传相同比例的图像。如果有人上传比2048px水平或垂直更大的图像，我想将其大小调整为2048px的大小，然后将其保存在文件夹中。

由于我基本恢复，只有我的形式我没有什么给你看，但遗憾的是大多已被搜索和阅读GD但对我不起作用划伤......

任何提示都非常不胜感激！

编辑：

if(isset($con, $_POST['save_button'])){ 
    // IMAGE PROCESSING 
    $name = $_FILES['file_upload']['name']; 
    $tmp_name = $_FILES['file_upload']['tmp_name']; 
    $type = $_FILES['file_upload']['type']; 
    $size = $_FILES['file_upload']['size']; 
    $error = $_FILES['file_upload']['error']; 

    move_uploaded_file($tmp_name, "social_images/$name.jpg"); 

    function resize_image($img, $w, $h, $crop=FALSE) { 
     list($width, $height) = getimagesize($img); 
     $r = $width/$height; 
     if ($crop) { 
      if ($width > $height) { 
       $width = ceil($width-($width*abs($r-$w/$h))); 
      } else { 
       $height = ceil($height-($height*abs($r-$w/$h))); 
      } 
      $newwidth = $w; 
      $newheight = $h; 
     } else { 
      if ($w/$h > $r) { 
       $newwidth = $h*$r; 
       $newheight = $h; 
      } else { 
       $newheight = $w/$r; 
       $newwidth = $w; 
      } 
     } 
     $src = imagecreatefromjpeg($img); 
     $dst = imagecreatetruecolor($newwidth, $newheight); 
     imagecopyresampled($dst, $src, 0, 0, 0, 0, $newwidth, $newheight, $width, $height); 
     return $dst; 
    } 

    $img = resize_image("social_images/$name.jpg", 780, 780); 

    header("location: index.php"); 
    exit(); 
} 

Answer 1

新鲜重试并重新测试：

<?php 
function shazam($file, $w, $h) { 
    list($width, $height) = getimagesize($file); 

    if ($width > $height) { 
     $r = ($w/$width); 
     $newwidth = $w; 
     $newheight = ceil($height * $r); 
    } 

    if ($width < $height) { 
     $r = ($h/$height); 
     $newheight = $h; 
     $newwidth = ceil($width * $r); 
    } 

    if ($width == $height) { 
     $newheight = $h; 
     $newwidth = $w; 
    } 

    $src = imagecreatefromjpeg($file); 
    $tgt = imagecreatetruecolor($newwidth, $newheight); 
    imagecopyresampled($tgt, $src, 0, 0, 0, 0, $newwidth, $newheight, $width, $height); 

    return $tgt; 
} 

$img = shazam("thepicwithpath.jpg", 850, 850); 
imagejpeg($img, "theresizedpicwithpath.jpg", 75); 
?> 

注意，imagejpeg（）的到底是什么东西实际上产生新的文件。