Transform .jpg, .jpeg or .gif to .png without saving them on machine

Question

Is it possible to transform a .jpg, .jpeg or .gif image to .png in php without saving the image in your computer? Something like:

function read_image($filename, $extension) {
    switch($extension) {
        case '.png':
            $image = imagecreatefrompng($filename);
            break;
        case '.jpg': case '.jpeg':
            $unTransformed = imagecreatefromjpeg($filename);
            $image = transform($unTransformed);
            break;
        case '.gif':
            $unTransformed = imagecreatefromgif($filename);
            $image = transform($unTransformed);
            break;
        return $image;
    }
}
function transform($unTransformed) {

    // Some magic here without actually saving the image to your machine when transforming

    return $transformed;
}

I honestly couldn't find an answer for this. Also note that GD is mandatory.

Have you seen this... http://stackoverflow.com/questions/14431363/converting-during-upload-before-saving-on-server-png-gif-to-jpg — Hiren Pandya, Apr 10 '13 at 12:25
Just in case.. Dont store it and just return it as you are doing in your program.. — Hiren Pandya, Apr 10 '13 at 12:26

score 4 · Accepted Answer · answered Apr 10 '13 at 12:29

4

Using output buffering and capturing the output of imagepng should work, like this:

function transform($unTransformed) {
    ob_start();
    imagepng($unTransformed);
    $transformed = ob_get_clean();
    return $transformed;
}

Of course, this is assuming you actually want a variable containing a png bytestream of your image file. If the only purpose is to output it anyways, don't bother and do as Marty McVry suggests.

answered Apr 10 '13 at 12:29

fvu

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This seems to bug :S Anyway, I need to do some colorizing on it. – Dragos Rizescu Apr 10 '13 at 13:12

score 2 · Answer 2 · answered Apr 10 '13 at 12:28

Directly from the PHP manual: (imagepng()-function, which outputs a PNG image to either the browser or a file)

header('Content-Type: image/png');
$transformed = imagepng($untransformed);

You might encounter a problem sending the headers along, so it's possibly necessary to output the headers somewhere else or transform the stream created by imagepng to a base64-string and display the image like that, depending on the rest of your code.

Transform .jpg, .jpeg or .gif to .png without saving them on machine

2 Answers2