Unable to create thumb, image is black

Question

Am uploading Multiple image from single input and create thumb form all uploaded image on fly But when i run code i get only black image but orginal image is same as upl

Answer 1

I think it's better to go for the mime type than the extension.

You'll do this:

function check_supported_type($type)
{
    switch($type)
    {
        case "image/jpeg":
        case "image/gif":
        case "image/png":
            return true;
        default:
            return false;
    }
}

function GetMimeType($file)
{
    //$type = mime_content_type($file); //deprecated

    /* //file info -> normal method, but returns wrong values for ics files..
    $finfo = finfo_open(FILEINFO_MIME_TYPE); // return mime type ala mimetype extension
    $type = $filename.":".finfo_file($finfo, $filename);
    finfo_close($finfo);
    */

    $forbiddenChars = array('?', '*', ':', '|', ';', '<', '>');

    if(strlen(str_replace($forbiddenChars, '', $file)) < strlen($file))
        throw new \ArgumentException("Forbidden characters!");

    $file = escapeshellarg($file);

    ob_start();
    $type = system("file --mime-type -b ".$file);
    ob_clean();

    return $type;
}

use it like this:

$file = "someimage.jpg";
$mime = GetMimeType($file);
if(check_supported_type($mime))
{
   //do your image processing
}

hope this helps

EDIT:

Maybe you can take a look at my other answer: https://stackoverflow.com/a/26981319/3641016 there you'll see how to generate thumbs.

EDIT:

added the answer to your editet question:

replace:

$wm = $w/$nw;
$hm = $h/$nw;
$h_height = $nh/2;
$w_height = $nw/2;

if($w> $h) {
    $adjusted_width = $w / $hm;
    $half_width = $adjusted_width / 2;
    $int_width = $w / $hm;
    imagecopyresampled($dimg,$simg,-$int_width,0,0,0,$adjusted_width,$nh,$w,$h);
} else {
    imagecopyresampled($dimg,$simg,0,0,0,0,$nw,$nh,$w,$h);
}

with:

if($w > $h)
{
    imagecopyresampled($dimg, $simg, 0,0, ($nw / $h * $w / 2 - $nw / 2),0, $nw,$nw, $h,$h);
}
else
{
    imagecopyresampled($dimg, $simg, 0,0, 0,($nw / $w * $h / 2 - $nw / 2), $nw,$nw, $w,$w);
}

and everything should be ok. (if the thumb is quadratic)