The following script will easily allow you to resize images using PHP and the GD library. If you’re looking to resize uploaded images or easily generate thumbnails give it a try
Update: Looking to resize transparent PNG’s and GIF’s? We’ve updated our original code, take a look at http://www.white-hat-web-design.co.uk/blog/retaining-transparency-with-php-image-resizing/
The code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 |
<?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;
}
}
?>
|
Usage
Save the above file as SimpleImage.php and take a look at the following examples of how to use the script.
The first example below will load a file named picture.jpg resize it to 250 pixels wide and 400 pixels high and resave it as picture2.jpg
1 2 3 4 5 6 7 |
<?php
include('SimpleImage.php');
$image = new SimpleImage();
$image->load('picture.jpg');
$image->resize(250,400);
$image->save('picture2.jpg');
?>
|
If you want to resize to a specifed width but keep the dimensions ratio the same then the script can work out the required height for you, just use the resizeToWidth function.
1 2 3 4 5 6 7 |
<?php
include('SimpleImage.php');
$image = new SimpleImage();
$image->load('picture.jpg');
$image->resizeToWidth(250);
$image->save('picture2.jpg');
?>
|
You may wish to scale an image to a specified percentage like the following which will resize the image to 50% of its original width and height
1 2 3 4 5 6 7 |
<?php
include('SimpleImage.php');
$image = new SimpleImage();
$image->load('picture.jpg');
$image->scale(50);
$image->save('picture2.jpg');
?>
|
You can of course do more than one thing at once. The following example will create two new images with heights of 200 pixels and 500 pixels
1 2 3 4 5 6 7 8 9 |
<?php
include('SimpleImage.php');
$image = new SimpleImage();
$image->load('picture.jpg');
$image->resizeToHeight(500);
$image->save('picture2.jpg');
$image->resizeToHeight(200);
$image->save('picture3.jpg');
?>
|
The output function lets you output the image straight to the browser without having to save the file. Its useful for on the fly thumbnail generation
1 2 3 4 5 6 7 8 |
<?php
header('Content-Type: image/jpeg');
include('SimpleImage.php');
$image = new SimpleImage();
$image->load('picture.jpg');
$image->resizeToWidth(150);
$image->output();
?>
|
The following example will resize and save an image which has been uploaded via a form
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 |
<?php
if( isset($_POST['submit']) ) {
include('SimpleImage.php');
$image = new SimpleImage();
$image->load($_FILES['uploaded_image']['tmp_name']);
$image->resizeToWidth(150);
$image->output();
} else {
?>
<form action="upload.php" method="post" enctype="multipart/form-data">
<input type="file" name="uploaded_image" />
<input type="submit" name="submit" value="Upload" />
</form>
<?php
}
?>
|
Rz Rasel 