title: Custom SVG-Font Icon not centered in Icon Widget
body: <p>I am using the material design icons for floating action buttons.
  Now I wanted to use a custom icon. From a SVG file I generated a font with the Flutter-Icon-Generator (<a href="http://fluttericon.com/" rel="nofollow noreferrer">http://fluttericon.com/</a>). Everything worked out nicely but the icon is not centered.</p>
  
  <p>Here the minimized screenshot, the €-Icon is centered, the other one (custom one) is not:</p>
  
  <p><a href="https://i.stack.imgur.com/cvTNQ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/cvTNQ.png" alt="enter image description here"></a> </p>
  
  <p>The corresponding code of the FloatingActionButton's is:</p>
  
  <pre><code>  Widget money() {
      return Container(
        child: FloatingActionButton(
          backgroundColor: widget.openColor,
          elevation: 0,
          heroTag: "btn_money",
          onPressed: () {
            widget.onPressed(DashboardFabAction.AddMoney);
            animate();
          },
          tooltip: 'Money',
          child: Icon(Icons.euro_symbol, color: widget.iconColorOpen,),
        ),
      );
    }
  
    Widget eggs() {
      return Container(
        child: FloatingActionButton(
          backgroundColor: widget.openColor,
          elevation: 0,
          heroTag: "btn_eggs",
          onPressed: () {
            widget.onPressed(DashboardFabAction.AddEggs);
            animate();
          },
          tooltip: 'Eggs',
          child: Icon(CustomIcons.egg, color: widget.iconColorOpen,),
        ),
      );
    }
  </code></pre>
  
  <p>The CustomIcons' code is:</p>
  
  <pre><code>import 'package:flutter/widgets.dart';
  
  class CustomIcons {
    CustomIcons._();
  
    static const _kFontFam = 'CustomIcons';
  
    static const IconData egg = const IconData(0xe800, fontFamily: _kFontFam);
  }
  </code></pre>
  
  <p>The pubspec.yaml is not interesting here since i get the correct icon there.</p>
  
  <p>Thanks in advance for your answers!</p>