Generating thumbnails

[Jmz]

I'm using the function from this tutorial to generate image thumbnails.

My function looks like this:

/*
    Function createthumb($name,$filename,$new_w,$new_h)
    creates a resized image
    variables:
    $name        Original filename
    $filename    Filename of the resized image
    $new_w        width of resized image
    $new_h        height of resized image
*/    
function createthumb($name,$filename,$new_w,$new_h)
{
    $system=explode(".",$name);
    if (preg_match("/jpg|jpeg/",$system[1])){$src_img=imagecreatefromjpeg($name);}
    if (preg_match("/png/",$system[1])){$src_img=imagecreatefrompng($name);}
    $old_x=imageSX($src_img);
    $old_y=imageSY($src_img);
    if ($old_x > $old_y) 
    {
        $thumb_w=$new_w;
        $thumb_h=$old_y*($new_h/$old_x);
    }
    if ($old_x < $old_y) 
    {
        $thumb_w=$old_x*($new_w/$old_y);
        $thumb_h=$new_h;
    }
    if ($old_x == $old_y) 
    {
        $thumb_w=$new_w;
        $thumb_h=$new_h;
    }
    $dst_img=ImageCreateTrueColor($thumb_w,$thumb_h);
    imagecopyresampled($dst_img,$src_img,0,0,0,0,$thumb_w,$thumb_h,$old_x,$old_y); 
    if (preg_match("/png/",$system[1]))
    {
        imagepng($dst_img,$filename); 
    } else {
        imagejpeg($dst_img,$filename); 
    }
    imagedestroy($dst_img); 
    imagedestroy($src_img); 
} 

This works fine if the image is located inside the same folder as the page. So if $name is 'apple.jpg' or 'images/apple.jpg' then there is no problem generating the thumbnail.

However, if the image is located in another folder the thumbnail just comes out black. So I can't use '../images/apple.jpg' and I cant use '/var/myserver/mysite/images/apple.jpg'.

Is there any way I can get round this?

I thought it could be something to do with there being more than one '.' in the image location that is killing it but I cant get it to work still.

Also, it does seem to work if I use the absolute path (/var/myserver/mysite/images/apple.jpg) when saving the image.

[Jmz]

I managed to fix this

It was just because of the way the script got the file extension. It got confused if there was more than one '.'

I used this to get the file extension instead:

$system = substr($name, strrpos($name, '.') + 1); 

[unwrittenphp]

In case you're interested...

<?php
class Image {
    
    private $resource = false;
    
    public $mime = "";
    
    public $width = 0;
    
    public $height = 0;
    
    public function __construct($image, $raw = false, $mime = null) {
        if ($raw) {
            if (is_null($mime)) {
                $this->error("Please specify a mime type.");
            }
            $this->resource = imagecreatefromstring($image);
            $this->mime = $mime;
        } else {
            $this->mime_type($image);
            $this->resource = $this->load_image($image);
        }
        $this->dimensions();
    }
    
    public function draw($w = null, $h = null, $raw = false) {
        if ($this->resource) {
            if (is_null($w) && is_null($h)) {
                $out = $this->resource;
            } else {
                $w = (is_null($w)) ? $this->width : $w;
                $h = (is_null($h)) ? $this->height : $h;
                $out = imagecreatetruecolor($w, $h);
                imagecopyresampled($out, $this->resource, 0, 0, 0, 0, $w, $h, $this->width, $this->height);
            }
            if (!$raw) {
                header("Content-Type: ".$this->mime);
                switch ($this->mime) {
                    case "image/jpeg" : imagejpeg($out); break;
                    case "image/png" : imagepng($out); break;
                    case "image/gif" : imagegif($out); break;
                }
            } else {
                return $out;
            }
        }
    }
    
    private function mime_type($image) {
        $p = explode(".", $image);
        $ext = strtolower(end($p));
        $ext = ($ext == "jpg") ? "jpeg" : $ext;
        $this->mime = "image/".$ext;
    }
    
    private function dimensions() {
        if ($this->img == "") {
            $this->width = imagesx($this->resource);
            $this->height = imagesy($this->resouce);
        } else {
            list($w, $h) = getimagesize($this->img);
            $this->width = $w;
            $this->height = $h;
        }
    }
    
    private function load_image($image) {
        $fp = fopen($image, "r");
        $data = "";
        while (!feof($fp)) {
            $data = fread($fp, 1024);
        }
        fclose($fp);
        return $data;
    }
    
    private function error($str) {
        trigger_error($str, E_USER_ERROR);
    }
}
?>

And to use...

require_once("Image.php");

function thumb($image, $max) {
    $img = new Image($image);
    if ($img->width > $img->height) {
        $p = ($max / $img->width);
    } else {
        $p = ($max / $img->height);
    }
    $nw = ceil($img->width * $p);
    $nh = ceil($img->height * $p);
    return array("res" => $img->draw($nw, $nh, true), "mime" => $img->mime);
}

$image = thumb("/path/to/image.ext", 200);
$thumb_path = "/path/to/saved/thumb.ext";
switch ($image['mime']) {
    case "image/jpeg" : imagejpeg($image['res'], $thumb_path); break;
    case "image/png" : imagepng($image['res'], $thumb_path); break;
    case "image/gif" : imagegif($image['res'], $thumb_path); break;
}
imagedestroy($image['res']);