title: Flutter: Creating the ruler in millimetre
body: <p>I am creating a ruler app where I can measure anything in millimetre.</p>
  <p>Something similar to this app <a href="https://play.google.com/store/apps/details?id=org.nixgame.ruler&amp;hl=en_IN" rel="noreferrer">https://play.google.com/store/apps/details?id=org.nixgame.ruler&amp;hl=en_IN</a> but very basic.</p>
  <p>I am repeating the <strong>Divider</strong> widget into a <strong>Column</strong> widget and keeping a gap of <strong>6.299</strong> as given.</p>
  <pre><code>class Ruler extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      return Container(
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.end,
          children: rulerPin(350),
        ),
      );
    }
  
    List&lt;Divider&gt; rulerPin(int count) {
      return List.generate(count, (i) {
        return Divider(
          height: 6.299,
          thickness: 1,
        );
      }).toList();
    }
  }
  </code></pre>
  <p>But the problem is when I measure with the physical ruler on my mobile phone the values do not match. Check the given screenshots.</p>
  <p><a href="https://i.stack.imgur.com/F0olf.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/F0olf.jpg" alt="enter image description here" /></a></p>
  <p>I am using this reference <a href="https://stackoverflow.com/questions/49636370/calculate-logical-pixels-from-millimeters">Calculate logical pixels from millimeters</a></p>
  <p>Kindly suggest if I am following the correct approach.</p>