Image thumbnail creator

create-thumb.php

<?php
/*
JPEG / GIF / PNG Resizer / Image Viewer

Parameters (passed via URL):
src = path / url of jpeg or png image file
percent = if this is defined, image is resized by it's
          value in percent (i.e. 50 to divide by 50 percent)
w = image width
h = image height
thumb: set = displays thumbnail.
        not set = displays original image.
force: by default this script will constrain the image proportions. If you wish to
        force with width/height settings, set &force in the URL
        width and height and thumb MUST be set.

Requires the PHP GD Extension

Originally By: Michael John G. Lopez - www.sydel.net
Modified By: Brian DiChiara - www.briandichiara.com

Modifications:
Supports Transparent PNG and GIF
Does not resize images smaller than specified w/h
Supports Remote files (http://www.notyoursite.com/image.jpg)

Usage Example:
<img src="image.php?src=myimage.jpg&thumb&w=200&h=200" border="0" alt="my image" />
*/

function getExtension($f){
    $pos = strrpos($f, '.');
    if(!$pos) {
        return '';
    }
    $str = substr($f, $pos + 1, strlen($f));
    return strtolower($str);
}

$img = $_GET['src'];
$ext = strtolower(getExtension($_GET['src']));
$percent = (isset($_GET['percent']) && !empty($_GET['percent'])) ? $_GET['percent'] : false;
//$constrain = (isset($_GET['constrain'])) ? ($_GET['constrain'] == 0 || $_GET['constrain'] == "false" || $_GET['constrain'] == "0") ? false : true : true;
$force = (isset($_GET['force']) && isset($_GET['w']) && isset($_GET['h']) && !empty($_GET['w']) && !empty($_GET['h'])) ? true : false;

$remote = @file ($img);
if($remote){
    $fp = @fopen ($img, 'rb');
    $data = '';
    while (!feof ($fp)){
        $data .= fgets($fp, 4096);
    }
    $src = @imagecreatefromstring($data);
    $sw = @imagesx($src);
    $sh = @imagesy($src);
} else {
    $dims = @getimagesize($img); // get width/height of original image
   
    $sw = $dims[0]; //returns width
    $sh = $dims[1]; //returns height
}

$w = (isset($_GET['w']) && !empty($_GET['w'])) ? $_GET['w'] : 0; //desired maximum width
$h = (isset($_GET['h']) && !empty($_GET['h'])) ? $_GET['h'] : 0; //desired maximum height

$resize = false; //assume no resize is needed

if ($percent> 0) {
    // calculate resized height and width if percent is defined
    $percent = $percent * 0.01;
    $w = $sw * $percent;
    $h = $sh * $percent;
} else {
    $resize = (($sh> $h && isset($h) && $h != 0) || ($sw> $w && isset($w) && $w != 0)) ? true : $resize;
    $resize = ($force) ? true : $resize;
    if(($resize && isset($_GET['thumb']))){
        if (isset ($w) && (!isset ($h) || $h == 0)) {
            // autocompute height if only width is set
            $h = (100 / ($sw / $w)) * .01;
            $h = @round ($sh * $h);
        } elseif (isset ($h) && (!isset ($w) || $w == 0)) {
            // autocompute width if only height is set
            $w = (100 / ($sh / $h)) * .01;
            $w = @round ($sw * $w);
        } elseif (isset ($h) && isset ($w) && !$force) {
            // get the smaller resulting image dimension if both height
            // and width are set and $constrain is also set
            $hx = (100 / ($sw / $w)) * .01;
            $hx = @round ($sh * $hx);
   
            $wx = (100 / ($sh / $h)) * .01;
            $wx = @round ($sw * $wx);
   
            if ($hx <$h) {
                $h = (100 / ($sw / $w)) * .01;
                $h = @round ($sh * $h);
            } else {
                $w = (100 / ($sh / $h)) * .01;
                $w = @round ($sw * $w);
            }
        }
    } else {
        $w = $sw;
        $h = $sh;
    }
}

switch ($ext){
    case "jpg"  : $type = "jpeg";    break;
    case "bmp"  : $type = "x-ms-bmp";  break;
    case "png"  : $type = "x-png"; break;
    case "tif"  : $type = "x-tiff";    break;
    case "ico"  : $type = "x-icon";    break;
    default  :    $type = $ext;      break;
}

 
if((!$resize || !isset($_GET['thumb'])) && !remote){
    //display contents
    header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
    header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
    header("Cache-Control: no-store, no-cache, must-revalidate");
    header("Cache-Control: post-check=0, pre-check=0", false);
    header("Pragma: no-cache");
    header('Content-Length: '.filesize($img));
    header('Content-type: image/' . $type);
    readfile($img);
} else {
    $im = ($remote) ? $src : false;
    switch ($ext){
        case "jpg"  :
        case "jpeg" :    $im = @imagecreatefromjpeg($img);   break;
        case "wbmp" :    $im = @imagecreatefromwbmp($img);   break;
        case "png"  : $im = @imagecreatefrompng($img); break;
        case "gif"  : $im = @imagecreatefromgif($img); break;
        default  :    $im = false; break;
    }
   
    header('Content-type: image/' . $type);
   
    if (!$im) {
        // just return the contents of the actual image.
        readfile ($img);
    } else {
        // Create the resized image destination
        $thumb = @imagecreatetruecolor ($w, $h);
       
        //preserve alpha opacity - thanks to Martin Schmidt
        $colorcount = @imagecolorstotal($im);
        @imagetruecolortopalette($thumb,true,$colorcount);
        @imagepalettecopy($thumb,$im);
        $transparentcolor = @imagecolortransparent($im);
        @imagefill($thumb,0,0,$transparentcolor);
        @imagecolortransparent($thumb,$transparentcolor);
       
        // Copy from image source, resize it, and paste to image destination
        @imagecopyresampled ($thumb, $im, 0, 0, 0, 0, $w, $h, $sw, $sh);
       
        // Output resized image
        switch ($ext){
            case "wbmp" :    @imagewbmp ($thumb);    break;
            case "png"  : @imagepng ($thumb);    break;
            case "gif"  : @imagegif ($thumb);    break;
            default  :    @imagejpeg ($thumb);    break;
        }
       
        imagedestroy($thumb);
        imagedestroy($im);
    }
}