如何优化此功能？

Question

I created a function for generating and saving multiple image sizes when a user uploads an image via a web form. I was wondering, how can I better optimize my code (reduce the number of lines while still being easily readable)

save_image($_FILES['image'], $_GET['member_id'], 250, 300, large) //usage example

The Function

function save_image($file, $id, $sizex, $sizey, $pre){
$image=$_FILES['image']['name'];
$tmpName = $_FILES['image']['tmp_name'];
if ($image){
    //get the original name of the file from the clients machine
        $filename = stripslashes($_FILES['image']['name']);
    //get the extension of the file in a lower case format
        $extension = getExtension($filename);
        $extension = strtolower($extension);
    if (($extension == "jpg") || ($extension == "jpeg")){
        $size = getimagesize($tmpName);
        $max_x = 180;
        $max_y = 300;
        $img = imagecreatefromjpeg($file['tmp_name']);
        $imagex = imagesx($img);
        $imagey = imagesy($img);
        $dim = max($imagex/$max_x, $imagey/$max_y);
        $nx = $imagex/$dim;
        $ny = $imagey/$dim;
        $image = imagecreatetruecolor($nx, $ny);
        imagecopyresampled($image, $img, 0, 0, 0, 0, $nx, $ny, $imagex, $imagey);
        imagejpeg($image, '../images/uploads/'.$id.'-large.jpg');
        //Make the thumb
        $size = getimagesize($tmpName);
        $max_x = 120;
        $max_y = 230;
        $img = imagecreatefromjpeg($file['tmp_name']);
        $imagex = imagesx($img);
        $imagey = imagesy($img);
        $dim = max($imagex/$max_x, $imagey/$max_y);
        $nx = $imagex/$dim;
        $ny = $imagey/$dim;
        $image = imagecreatetruecolor($nx, $ny);
        imagecopyresampled($image, $img, 0, 0, 0, 0, $nx, $ny, $imagex, $imagey);
        imagejpeg($image, '../images/uploads/'.$id.'-med.jpg');
        $size = getimagesize($tmpName);
        $max_x = 60;
        $max_y = 115;
        $img = imagecreatefromjpeg($file['tmp_name']);
        $imagex = imagesx($img);
        $imagey = imagesy($img);
        $dim = max($imagex/$max_x, $imagey/$max_y);
        $nx = $imagex/$dim;
        $ny = $imagey/$dim;
        $image = imagecreatetruecolor($nx, $ny);
        imagecopyresampled($image, $img, 0, 0, 0, 0, $nx, $ny, $imagex, $imagey);
        imagejpeg($image, '../images/uploads/'.$id.'-thumb.jpg');
    }else{
        return false;
    }
}else{
    return false;
}
return true;
}

Answer 1

First of all I noticed you create a variable and it has not been used.

$size = getimagesize($tmpName);

So why call a function and assign its value when it is not being used.

Secondly to get the width and height you don't have to do

$imagex = imagesx($img);

$imagey = imagesy($img);

So I would suggest you replace the 3 lines mentioned in this code with a single one

list($width, $height, $type, $attr) = getimagesize($tmpName);

Finally instead of duplicating the code create a function with parameters passed and call the function as it is shown in the comments above.

Also noticed that you send "large" ie image size as the parameter then why are you running through the thumb and med cases. Would suggest use switch cases like change the save function to

function save_image($_FILES['image'], $_GET['member_id'], 250, 300, $type = "large")

and then use a switch on $type.

Answer 2

You have 3 times almost the same code

    $size = getimagesize($tmpName);
    $max_x = 60;
    $max_y = 115;
    $img = imagecreatefromjpeg($file['tmp_name']);
    $imagex = imagesx($img);
    $imagey = imagesy($img);
    $dim = max($imagex/$max_x, $imagey/$max_y);
    $nx = $imagex/$dim;
    $ny = $imagey/$dim;
    $image = imagecreatetruecolor($nx, $ny);
    imagecopyresampled($image, $img, 0, 0, 0, 0, $nx, $ny, $imagex, $imagey);
    imagejpeg($image, '../images/uploads/'.$id.'-thumb.jpg');

You should easily be able to make a function for that, that's a good start.

Answer 3

A lot of your code is redundant.

You could make a little function :

function repetitiveFunctionForPicture($image, $max_x, $max_y,$tmpName, $file){
    $size = getimagesize($tmpName);
    $img = imagecreatefromjpeg($file['tmp_name']);
    $imagex = imagesx($img);
    $imagey = imagesy($img);
    $dim = max($imagex/$max_x, $imagey/$max_y);
    $nx = $imagex/$dim;
    $ny = $imagey/$dim;
    $image = imagecreatetruecolor($nx, $ny);
    imagecopyresampled($image, $img, 0, 0, 0, 0, $nx, $ny, $imagex, $imagey);
    imagejpeg($image, '../images/uploads/'.$id.'-large.jpg');
}

which can be called like this :

repetitiveFunctionForPicture($image, 180, 300,$tmpName, $file);