<?
# http://www.newhouse.nl/imagescaler/scaler.php?img=lissabon2.jpg
# max_width,max_height,jpeg_quality
$resolutions=array(
  200,200,60,
  250,250,70
);

$imagefile=fetchVar("img",false);
if(preg_match("/^[^\/]+\.jpg$/i",$imagefile))
{
  $res_num=fetchVar("res",true);
  if($res_num*3+2 < count($resolutions))
  {
    $max_width=$resolutions[$res_num*3];
    $max_height=$resolutions[$res_num*3+1];
    $quality=$resolutions[$res_num*3+2];
    
    $sourcedir=preg_replace("/\/[^\/]+$/","/",$_SERVER["SCRIPT_FILENAME"]);
    $sourcefile=$sourcedir.$imagefile;
    $scaleddir="/tmp/scaler/";
    if(! file_exists($scaleddir))
    {
      mkdir($scaleddir,0755);
    }
    $hashsource=$sourcefile."/".$max_width."/".$max_height."/".$quality;
    $hashed=crypt($hashsource,"\$1\$4j9ch3jk2");
    $hashed=preg_replace("/[\$\/\.]/","_",$hashed);
    $hashed=preg_replace("/^_1_/","",$hashed);
    $scaledfile=$scaleddir.$hashed.".jpg";
# echo "[$sourcefile] [$scaledfile]";
    if(! file_exists($sourcefile))
    {
      die("File not found: $imagefile");
    }
    if(!file_exists($scaledfile) || (filectime($scaledfile) < filectime($sourcefile)) )
    {
      resize($sourcefile,$scaledfile,$max_width,$max_height,$quality);
    }
    header("Content-type: image/jpeg");
    readfile($scaledfile);
  }
}

function resize($sourcefile,$scaledfile,$max_width,$max_height,$quality)
{
  if(file_exists($scaledfile)) unlink($scaledfile);
  $srcimg=imagecreatefromjpeg($sourcefile);
  if(!$srcimg) die("failed to create source img");
  $srcwidth=imagesx($srcimg);
  $srcheight=imagesy($srcimg);
  $destwidth=$srcwidth;
  $destheight=$srcheight;
  if( ($srcwidth > 0) && ($srcheight > 0) && (($srcwidth > $max_width) || ($srcheight > $max_height)) )
  {
    $srcaspect=$srcwidth / $srcheight;
    $maxaspect=$max_width / $max_height;
    if($srcaspect > $maxaspect)
    {
      # limit by width:
      $destwidth=$max_width;
      $destheight=$destwidth / $srcaspect;
    }
    else
    {
      # limit by height:
      $destheight=$max_height;
      $destwidth=$destheight * $srcaspect;
    }
    $destimg=imagecreatetruecolor($destwidth,$destheight);
    imagecopyresampled($destimg, $srcimg, 0, 0, 0, 0, $destwidth, $destheight, $srcwidth, $srcheight);
    
  }
  else
  {
    $destimg=$srcimg;
  }
  imagejpeg($destimg,$scaledfile,$quality);
}


# fetch a POST or GET variabele, removing possible slashes
# $forcenumber=true? Then interpret the value as an integer
function fetchVar($varname, $forcenumber)
{
    if (isset($_POST[$varname])) {
        $value = $_POST[$varname];
    } elseif (isset($_GET[$varname])) {
        $value = $_GET[$varname];
    }
    if (isset($value)) {
        if (get_magic_quotes_gpc()) {
            $value = stripslashes($value);
        }
        if ($forcenumber) {
          $value=intval($value);
        }
    }
    return $value;
}
?>