return true;
}
+/**
+ * Generates a thumbnail for the given image
+ *
+ * If the GD library has at least version 2 and PNG support is available, the returned data
+ * is the content of a transparent PNG file containing the thumbnail. Otherwise, the function
+ * returns contents of a JPEG file with black background containing the thumbnail.
+ *
+ * @param string $filepath the full path to the original image file
+ * @param int $width the width of the requested thumbnail
+ * @param int $height the height of the requested thumbnail
+ * @return string|bool false if a problem occurs, the thumbnail image data otherwise
+ */
+function generate_image_thumbnail($filepath, $width, $height) {
+ global $CFG;
+
+ if (empty($CFG->gdversion) or empty($filepath) or empty($width) or empty($height)) {
+ return false;
+ }
+
+ $imageinfo = getimagesize($filepath);
+
+ if (empty($imageinfo)) {
+ return false;
+ }
+
+ $originalwidth = $imageinfo[0];
+ $originalheight = $imageinfo[1];
+
+ if (empty($originalwidth) or empty($originalheight)) {
+ return false;
+ }
+
+ $original = imagecreatefromstring(file_get_contents($filepath));
+
+ if (function_exists('imagepng')) {
+ $imagefnc = 'imagepng';
+ $filters = PNG_NO_FILTER;
+ $quality = 1;
+ } else if (function_exists('imagejpeg')) {
+ $imagefnc = 'imagejpeg';
+ $filters = null;
+ $quality = 90;
+ } else {
+ debugging('Neither JPEG nor PNG are supported at this server, please fix the system configuration.');
+ return false;
+ }
+
+ if (function_exists('imagecreatetruecolor') and $CFG->gdversion >= 2) {
+ $thumbnail = imagecreatetruecolor($width, $height);
+ if ($imagefnc === 'imagepng') {
+ imagealphablending($thumbnail, false);
+ imagefill($thumbnail, 0, 0, imagecolorallocatealpha($thumbnail, 0, 0, 0, 127));
+ imagesavealpha($thumbnail, true);
+ }
+ } else {
+ $thumbnail = imagecreate($width, $height);
+ }
+
+ $ratio = min($width / $originalwidth, $height / $originalheight);
+
+ if ($ratio < 1) {
+ $targetwidth = floor($originalwidth * $ratio);
+ $targetheight = floor($originalheight * $ratio);
+ } else {
+ // do not enlarge the original file if it is smaller than the requested thumbnail size
+ $targetwidth = $originalwidth;
+ $targetheight = $originalheight;
+ }
+
+ $dstx = floor(($width - $targetwidth) / 2);
+ $dsty = floor(($height - $targetheight) / 2);
+
+ imagecopybicubic($thumbnail, $original, $dstx, $dsty, 0, 0, $targetwidth, $targetheight, $originalwidth, $originalheight);
+
+ ob_start();
+ if (!$imagefnc($thumbnail, null, $quality, $filters)) {
+ ob_end_clean();
+ return false;
+ }
+ $data = ob_get_clean();
+ imagedestroy($original);
+ imagedestroy($thumbnail);
+
+ return $data;
+}
