gistfile1.php

<?php
  public function resize($new_w, $new_h, $preserve=false){
    $name = $this->image;
    $e = $this->getExtension();
    $filename = dirname($this->image) .'/'. $e['file'] .'_'. $new_w .'x'. $new_h . $e['extension'];
    
    // this function only works if the imagecreatefromjpeg function exists
    if(!function_exists('imagecreatefromjpeg')){ return false; }
    
    // adapted from http://icant.co.uk/articles/phpthumbnails/
    $system=explode(".",$name);
    $len = count($system) - 1;
    if (preg_match("/jpg|jpeg/",$system[$len])){$src_img=imagecreatefromjpeg($name);}
    if (preg_match("/png/",$system[$len])){$src_img=imagecreatefrompng($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);
    // end adapted code
    
    if(!$preserve){
      // we should replace the current image
      if(file_exists($this->image)){
        unlink($this->image);
      }
      $this->image = $filename;
    }
    
    if(!file_exists($filename)){
      throw new Exception("Image::resize() failed to create the file `$filename`");
    }
    return $filename;
  }
?>