Question

Once again, here I am with a simple issue that I cannot solve because the search terms I use apparently don’t match the ones that have been used before. What I want to create is just a tiny piece of script making it possible to change the image width using the URL.

An example can be found on http://waarneming.nl/fotonew/0/2639780.jpg. If you add the variables ?w=100&h=100, the image is resized. Important to mention is that I need no cropping (which doesn’t happen in the example too, even though 100×100 is of course not the right ratio). The only thing to happen is what can be done with CSS and HTML too: change height and width of a larger picture. But because I need the resized image in another script, I want to use URL variables.

Hope you can help!

Answer 1

Use the SimpleImage library:

<?php

/*
* File: SimpleImage.php
* Author: Simon Jarvis
* Copyright: 2006 Simon Jarvis
* Date: 08/11/06
* Link: http://www.white-hat-web-design.co.uk/articles/php-image-resizing.php
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details:
* http://www.gnu.org/licenses/gpl.html
*
*/

class SimpleImage {

   var $image;
   var $image_type;

   function load($filename) {

      $image_info = getimagesize($filename);
      $this->image_type = $image_info[2];
      if( $this->image_type == IMAGETYPE_JPEG ) {

         $this->image = imagecreatefromjpeg($filename);
      } elseif( $this->image_type == IMAGETYPE_GIF ) {

         $this->image = imagecreatefromgif($filename);
      } elseif( $this->image_type == IMAGETYPE_PNG ) {

         $this->image = imagecreatefrompng($filename);
      }
   }
   function save($filename, $image_type=IMAGETYPE_JPEG, $compression=75, $permissions=null) {

      if( $image_type == IMAGETYPE_JPEG ) {
         imagejpeg($this->image,$filename,$compression);
      } elseif( $image_type == IMAGETYPE_GIF ) {

         imagegif($this->image,$filename);
      } elseif( $image_type == IMAGETYPE_PNG ) {

         imagepng($this->image,$filename);
      }
      if( $permissions != null) {

         chmod($filename,$permissions);
      }
   }
   function output($image_type=IMAGETYPE_JPEG) {

      if( $image_type == IMAGETYPE_JPEG ) {
         imagejpeg($this->image);
      } elseif( $image_type == IMAGETYPE_GIF ) {

         imagegif($this->image);
      } elseif( $image_type == IMAGETYPE_PNG ) {

         imagepng($this->image);
      }
   }
   function getWidth() {

      return imagesx($this->image);
   }
   function getHeight() {

      return imagesy($this->image);
   }
   function resizeToHeight($height) {

      $ratio = $height / $this->getHeight();
      $width = $this->getWidth() * $ratio;
      $this->resize($width,$height);
   }

   function resizeToWidth($width) {
      $ratio = $width / $this->getWidth();
      $height = $this->getheight() * $ratio;
      $this->resize($width,$height);
   }

   function scale($scale) {
      $width = $this->getWidth() * $scale/100;
      $height = $this->getheight() * $scale/100;
      $this->resize($width,$height);
   }

   function resize($width,$height) {
      $new_image = imagecreatetruecolor($width, $height);
      imagecopyresampled($new_image, $this->image, 0, 0, 0, 0, $width, $height, $this->getWidth(), $this->getHeight());
      $this->image = $new_image;
   }      

}
?>

Then, try this:

<?php
   include('SimpleImage.php');
   $image = new SimpleImage();
   $image->load($_GET['file']);
   $image->resize($_GET['width'], $_GET['height']);
   $image->output();
?>

In order to call the script, you would pass the filename, width and height through your URL. Assuming the script is named foo.php:

http://www.example.com/foo.php?file=picture_name.jpg&width=100&height=100