+# make a thumbnail image.
+#
+# Thumbnail will have the same filename, except "_thumb" will be added right
+# before the dot preceding the extension. so foo.png yields foo_thumb.png
+#
+# Thumbnail will retain aspect ratio, and be either $max_width wide or
+# $max_height tall (or, if the aspect is just right, both)
+function make_thumbnail($filename, $max_width = '70', $max_height = '70') {
+ $last_dot = strrpos($filename, '.');
+ if($last_dot === false) {
+ die("couldn't make thumbnail because filename has no extension.");
+ }
+
+ $thumb = substr($filename, 0, $last_dot);
+ $thumb .= '_thumb';
+ $thumb .= substr($filename, $last_dot);
+
+ $convert = path_to('convert');
+
+ # can't be too careful
+ $max_width = ereg_replace('[^0-9]', '', $max_width);
+ if($max_width == '') {
+ $max_width = '70';
+ }
+ $max_height = ereg_replace('[^0-9]', '', $max_height);
+ if($max_height == '') {
+ $max_height = '70';
+ }
+
+ $command = "$convert -geometry ${max_width}x$max_height " . escapeshellarg($filename) . ' ' . escapeshellarg($thumb);
+
+ exec($command, $dummy, $ret);
+ if($ret != 0) {
+ die("Thumbnail creation failed. Convert called exit($ret)");
+ }
+
+ return $thumb;
+}
+
+# Argument: path to image file
+#
+# Return: string in the format WIDTHxHEIGHT, or boolean false
+#
+# Example: image_dimensions('uploads/foo.png'); ==> "124x58"
+function image_dimensions($image) {
+ $identify = path_to('identify');
+ $command = "$identify -format '%wx%h' " . escapeshellarg($image);
+ $dimensions = substr(`$command`, 0, -1); # substr() to remove newline
+ if($dimensions == '') {
+ return false;
+ } else {
+ return $dimensions;
+ }
+}
+