resize picture without imagemagick or GD

[Anon]

How can this be done?

Resizing an image without imagemagick and GD library?

Thanx,
Niels

[[deleted]]

You can't resize an image without some sort of image software.

You can fake it by giving the wrong (smaller) size in your html code, but you should only do that if you don't care about the quality of your pages.

[geo115fr]

I had recently the same problem trying to create thumbnails from the images yuploaded by the users.

The webmaster hosting my site did not want to recompile php with jpeg support. Also I did not want to install a full-fledged software such as ImageMagick.

The turnaround was to install the IJG jpeg library as standalone (instead of as a module compiled in php). Then you can use it with a system() call. See script below.

The only significant problem is that you can't really choose the thumbnail size because only 3 scale factore are available.

script:

creates thumbnails for each jpeg image within a folder

$repertoire is the folder name

$largeur : required width (approx.) in pixels

$qualite : quality of the jpeg compression (5 to 95, default 75)

function traitement_miniatures($repertoire,$largeur,$qualite=75) {
global $SCRIPT_FILENAME;
$rep_complet = dirname($SCRIPT_FILENAME)."/".$repertoire;
$repertoire = "./".$repertoire;
if ( (!is_int($largeur)) or ($largeur<=0) )
return array(False,"Width($largeur) must be grater than zero");
if ( (!is_int($qualite)) or ($qualite<5) or ($qualite>95) )
return array(False,"Quality ($qualite) must be between 5 and 95");

test permissions to the folder

$perms = fileperms($repertoire);
$perms = $perms & 07;
if (!(($perms & 01) and ($perms & 02) and ($perms & 04)))
return array(False,"Folder $rep_complet must be with access Read Write List Execute");

$retour = "";
$rep = opendir($repertoire);
$log = fopen($repertoire."/miniatures.log","a"); # audit trail
while($photo = readdir($rep)) {
$ext=strrchr($photo,".");

select files with .jp* extension except existing thumbnails

if ( ($ext) and (strpos($ext,1,2)=="jp") and (!strpos($photo,"mini.jpg")) ) {
if ( ($detail_photo = getimagesize("$repertoire/$photo"))
and ($detail_photo[2]==2) ) { # it is a jpeg format image
$mini_photo = substr($photo,0,strrpos($photo,"."))."mini.jpg"; # name of thumbnail file

     # Do not process an image if thumbnail already present
     if (!file_exists("$repertoire/$mini_photo")) {
        # compute scaling factor
        # only valid : 1/2 1/4 1/8 , find closest value
        $rapport = $detail_photo[0] / $largeur ; # $detail_photo[0] : width of source image
        if ($rapport > 6) $rapport=8;
           elseif ($rapport > 3) $rapport=4;
              elseif ($rapport > 1.5) $rapport=2;
        # don't create a thumbnail if no reduction
        if ($rapport >= 2) {

           # create a thumbnail with  pnm format then compress to jpeg
           $empl="/usr/local/bin"; # full path of jpeg library commands
           system("$empl/djpeg -scale 1/$rapport -pnm $rep_complet/$photo | $empl/cjpeg -quality $qualite -outfile $rep_complet/$mini_photo",$rc);
       if (!$rc) $rc="Ok"; # return code 0
       else      $rc="Error $rc";
       if ($rc=="Ok")
           fwrite($log,"on ".date("d/n/y").", scale 1/".$rapport."°, creation of $mini_photo\n");
       else
           fwrite($log,"on ".date("d/n/y").", $rc when creating  $mini_photo\n");
       $retour .= "$mini_photo($rc) ";
       }
    }
  }

}
}
fclose($log);
return array(True,$retour);
}