Thursday, July 14, 2011

Resizing images with PHP

class SimpleImage {

var $image;

var $image_type;

function load($filename) {



load('picture.jpg');
$image->resizeToWidth(250);
$image->save('picture2.jpg');
?>
$image_info = getimagesize($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;
}

}
?>







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

}
?>


Further Inf

No comments: