title: How to have a background colour for each letter except for the ' . '(dot) or ' , '(coma) in flutter
body: <p>I want to have a background colour for each letter except for the <strong>'.'(dot)</strong>, <strong>','(coma)</strong> or the <strong>'-'(minus)</strong>, when I try to use the <strong>backgroundColor</strong> parameter in the <strong>TextStyle()</strong> it gives a background the colour to the  <strong>'.'(dot)</strong>, <strong>','(coma)</strong> and <strong>'-'(minus)</strong> as well and I don't want that.</p>
  <p>I'm using the <a href="https://pub.dev/packages/animated_flip_counter" rel="nofollow noreferrer">animated_flip_counter</a> for the animation.</p>
  <p>My code:</p>
  <pre><code>            Container(
                height: 200,
                width: 300,
                padding: const EdgeInsets.all(10.0),
                decoration: BoxDecoration(
                  color: Colors.black54,
                  borderRadius: BorderRadius.circular(3.0),
                ),
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    Container(
                      padding: const EdgeInsets.all(10.0),
                      decoration: BoxDecoration(
                        color: Colors.redAccent.withOpacity(0.32),
                        borderRadius: BorderRadius.circular(3.0),
                      ),
                      child: Container(
                        // height: 50,
                        // // width: 500,
                        padding: const EdgeInsets.all(10),
                        // alignment: Alignment.center,
                        decoration: BoxDecoration(
                          borderRadius: BorderRadius.circular(3.0),
                          border: Border.all(color: Colors.redAccent, width: 2),
                          color: Colors.black.withOpacity(0.32),
                        ),
  
                        child: AnimatedFlipCounter(
                          value: _counter,
                          fractionDigits: 2, // decimal precision
                          decimalSeparator: '.',
                          thousandSeparator: ',',
                          prefix: '-',
                          curve: Curves.bounceOut,
                          textStyle: const TextStyle(
                            fontSize: 20,
                            letterSpacing: 5,
                            backgroundColor: Colors.black26,
                            color: Colors.white,
                          ),
                        ),
                      ),
                    ),
                  ],
                ),
              ),
  </code></pre>
  <p>What i want:</p>
  <p><a href="https://i.stack.imgur.com/SqfQkm.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/SqfQkm.png" alt="enter image description here" /></a></p>
  <p>What I have:</p>
  <p><a href="https://i.stack.imgur.com/sfwD2m.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/sfwD2m.png" alt="enter image description here" /></a></p>