ceil/floor/truncate/round return integers.

samples/swarm/swarm_ui_lib/layout/GridTracks.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of layout;
 
 // This file has classes representing the grid tracks and grid template
 
 /**
  * The data structure representing the grid-rows or grid-columns
@@ skipping 73 matching lines @@
   _GridLocation align(_GridLocation span, int size) {
     switch (value) {
       case 'start':
         return new _GridLocation(span.start, size);
       case 'end':
         return new _GridLocation(span.end - size, size);
       case 'center':
         size = Math.min(size, span.length);
         num center = span.start + span.length / 2;
         num left = center - size / 2;
-        return new _GridLocation(left.round().toInt(), size);
+        return new _GridLocation(left.round(), size);
       case 'stretch':
         return span;
     }
   }
 }
 
 
 /**
  * Represents a grid-template. Used in conjunction with a grid-cell to
  * place cells in the grid, without needing to specify the exact row/column.
@@ skipping 75 matching lines @@
 /**
  * Used to return a row/column and span during parsing of grid-row and
  * grid-column during parsing.
  */
 class _GridLocation {
   final int start, length;
   _GridLocation(this.start, this.length) {}
 
   int get end => start + length;
 }