La transparence des PNG est supporté et aucun fond noir ne sera généré. La classe nécessite la compilation de la librairie gd et libexif.
Désolé pour les anglophobes, je code toujours en anglais.
<?php
class thumbnail {
private $types = array(
IMAGETYPE_JPEG => 'jpeg',
IMAGETYPE_GIF => 'gif',
IMAGETYPE_PNG => 'png'
);
private $thumbnaildir = './';
public $maxWidth = 0;
public $maxHeight = 0;
public function __construct($thumbnaildir=NULL) {
if (FALSE === extension_loaded('gd')) {
throw new exception('gd must be compiled to use this class.');
}
if (FALSE === extension_loaded('exif')) {
throw new exception('libexif must be compiled to use this class.');
}
$this->thumbnaildir = $thumbnaildir;
}
public function execute($filename) {
if (FALSE === file_exists($filename)) {
throw new exception('No such file.');
}
if (FALSE === $type = exif_imagetype($filename)) {
throw new exception('File is not an image.');
}
if (FALSE === array_key_exists($type, $this->types)) {
throw new exception('Image type is not supported by this class.');
} else {
$type = $this->types[$type];
}
try {
$this->validation();
$result = $this->resize($filename, $type);
} catch ( exception $e ) {
throw $e;
}
return $result;
}
private function resize($filename, $type) {
if (0 === $this->maxHeight && 0 === $this->maxWidth) {
return TRUE;
}
list($width, $height) = getimagesize($filename);
if ($width <= $this->maxWidth && $height <= $this->maxHeight) {
return TRUE;
}
if ($width > $height) {
$thumbnail_width = $this->maxWidth;
$thumbnail_height = (int) ($this->maxWidth * $height / $width);
} else {
$thumbnail_width = (int) ($this->maxHeight * $width / $height);
$thumbnail_height = $this->maxHeight;
}
$read = 'imagecreatefrom' . $type;
$write = 'image' . $type;
if (FALSE === function_exists($write) ) {
throw new exception('Image type is not supported by your GD library.');
}
if (FALSE === $img = $read($filename) ) {
throw new exception('An exception occured while opening original file.');
}
if ('gif' === $type) {
$des = imagecreate($thumbnail_width, $thumbnail_height);
$resize = 'imagecopyresized';
} else {
$des = imagecreatetruecolor($thumbnail_width, $thumbnail_height);
$resize = 'imagecopyresampled';
}
if ('png' === $type) {
if (FALSE === imagealphablending($des, FALSE) ) {
throw new exception('Enable to activate full alpha information.');
}
if (FALSE === imagesavealpha($des, TRUE)) {
throw new exception('Enable to activate full alpha information.');
}
}
if (FALSE === $resize($des, $img, 0, 0, 0, 0, $thumbnail_width, $thumbnail_height, $width, $height)) {
throw new exception('An exception occured while resizing the original file.');
}
if (FALSE === $write($des, $this->thumbnaildir . '/' . $filename)) {
throw new exception('An exception occured while writing thumbnail file.');
}
return TRUE;
}
private function validation() {
if (FALSE === is_writable($this->thumbnaildir)) {
throw new exception('Thumbnails directory is not writable.');
}
if (FALSE === is_int($this->maxWidth) || FALSE === is_int($this->maxHeight)) {
throw new exception('Maximum dimensions must be integer.');
}
if (0 > $this->maxWidth || 0 > $this->maxHeight) {
throw new exception('Maximum dimensions must be positive integer.');
}
}
}
// Exemple d'utilisation
try {
$thumb = new thumbnail('./thumbs/');
$thumb->maxWidth = 80;
$thumb->maxHeight = 60;
$thumb->execute('image.png');
} catch (exception $e) {
echo '<br />';
echo 'Error message: ' , $e->getMessage() , '<br />';
echo 'Error code: ' , $e->getCode() , '<br />';
echo 'Script Name: ' , $e->getFile() , '<br />';
echo 'Line Number: ' , $e->getLine() , '<br />';
}
?>
