Deal in integers when doing aspect ratio operations. Fixes #1470.

modules/gallery/models/item.php

@@ -628,7 +628,7 @@ public function thumb_img($extra_attrs=array(), $max=null, $center_vertically=fa
     list ($height, $width) = $this->scale_dimensions($max);
     if ($center_vertically && $max) {
       // The constant is divide by 2 to calculate the file and 10 to convert to em
-      $margin_top = ($max - $height) / 20;
+      $margin_top = (int)(($max - $height) / 20);
       $extra_attrs["style"] = "margin-top: {$margin_top}em";
       $extra_attrs["title"] = $this->title;
     }
@@ -656,10 +656,10 @@ public function scale_dimensions($max) {
     if ($height) {
       if (isset($max)) {
         if ($width > $height) {
-          $height = (int)($max * ($height / $width));
+          $height = (int)($max * $height / $width);
           $width = $max;
         } else {
-          $width = (int)($max * ($width / $height));
+          $width = (int)($max * $width / $height);
           $height = $max;
         }
       }
@@ -700,10 +700,10 @@ public function movie_img($extra_attrs) {
     $height = $this->height;
     if ($width > $max_size || $height > $max_size) {
       if ($width > $height) {
-        $height *= $max_size / $width;
+        $height = (int)($height * $max_size / $width);
         $width = $max_size;
       } else {
-        $width *= $max_size / $height;
+        $width = (int)($width * $max_size / $height);
         $height = $max_size;
       }
     }