I developed a function which creates a thumbnail for a given image in a predefined size. Please note that this function was created to be used within a WordPress plugin so it uses paths related to WordPress but these paths can be easily adapted to be used without WordPress.
Preamble
PHP file:
/var/www/wordpress/wp-content/plugins/thumbnail_generator/thumbnail_generator.php
Sample image:
/var/www/wordpress/wp-content/plugins/thumbnail_generator/pictures/album1/picture1.jpeg
Sample image size:
1600×1066 pixels
My function will create a thumbnail called picture1.jpeg.png with a width of 100px and an appropriate height in a directory called:
/var/www/wordpress/wp-content/plugins/thumbnail_generator/thumbnails/pictures/album1/.
thumbnail_generator.php
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 | createThumbnail('pictures/album1/picture1.jpeg', 100); function createThumbnail($relativePath, $resizedWidth) { $thumbnailDirectory = plugin_dir_path(__FILE__) . 'thumbnails/'; $imageFile = plugin_dir_path(__FILE__) . $relativePath; // Determine image type if (preg_match('/[.](jpe?g?|jfif|tiff)$/', $imageFile)) $image = imagecreatefromjpeg($imageFile); else if (preg_match('/[.](gif)$/', $imageFile)) $image = imagecreatefromgif($imageFile); else if (preg_match('/[.](png)$/', $imageFile)) $image = imagecreatefrompng($imageFile); // Calculate the thumbnail size (depending on the image aspect ratio) if (isset($image)) { $width = imagesx($image); $height = imagesy($image); $resizedHeight = round(($height * ($resizedWidth / $width)), 0); $thumbnail = imagecreatetruecolor($resizedWidth, $resizedHeight); imagecopyresized($thumbnail, $image, 0, 0, 0, 0, $resizedWidth, $resizedHeight, $width, $height); // Save thumbnail to subdirectory $slashPosition = strrpos($relativePath, '/'); $thumbnailName = substr($relativePath, $slashPosition); $thumbnailDirectory = $thumbnailDirectory . substr($relativePath, 0, $slashPosition); if (!file_exists($thumbnailDirectory)) mkdir($thumbnailDirectory, 0755, true); imagepng($thumbnail, $thumbnailDirectory . $thumbnailName . '.png', 0); } } |