Flutter, Star Path for clipping, N-pointed star clipper for Flutter

star_clipping_Dartpad.dart

//Based on the blog article by "The Plumber" https://www.kindacode.com/article/flutter-drawing-an-n-pointed-star-with-customclipper/


// main.dart
import 'package:flutter/material.dart';
import 'dart:math' as math;

// This custom clipper help us achieve n-pointed star shape
class StarClipper extends CustomClipper<Path> {
  /// The number of points of the star
  final int points;
  StarClipper(this.points);

  // Degrees to radians conversion
  double _degreeToRadian(double deg) => deg * (math.pi / 180.0);

  @override
  Path getClip(Size size) {
    Path path = Path();
    double max = 2 * math.pi;

    double width = size.width;
    double halfWidth = width / 2;

    double wingRadius = halfWidth;
    double radius = halfWidth / 2;

    double degreesPerStep = _degreeToRadian(360 / points);
    double halfDegreesPerStep = degreesPerStep / 2;

    path.moveTo(width, halfWidth);

    for (double step = 0; step < max; step += degreesPerStep) {
      path.lineTo(halfWidth + wingRadius * math.cos(step),
          halfWidth + wingRadius * math.sin(step));
      path.lineTo(halfWidth + radius * math.cos(step + halfDegreesPerStep),
          halfWidth + radius * math.sin(step + halfDegreesPerStep));
    }

    path.close();
    return path;
  }

  // If the new instance represents different information than the old instance, this method will return true, otherwise it should return false.
  @override
  bool shouldReclip(CustomClipper<Path> oldClipper) {
    StarClipper starClipper = oldClipper as StarClipper;
    return points != starClipper.points;
  }
}

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'KindaCode.com',
      theme: ThemeData(
        primarySwatch: Colors.indigo,
      ),
      home: const MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key}) : super(key: key);

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Kindacode.com'),
      ),
      body: ListView(
        //  child: Center(
        //    child: Column(
        children: [
          // 5-pointed star
          Column(children: [
            SizedBox(
              height: 180,
              width: 180,
              child: ClipPath(
                clipper: StarClipper(5),
                child: Container(
                  height: 20,
                  color: Colors.green,
                ),
              ),
            ),
          ]),

          // 5-pointed star Image
          Column(children: [
            SizedBox(
              height: 180,
              width: 180,
              child: ClipPath(
                  clipper: StarClipper(5),
                  child: const Image(
                    image: NetworkImage(
                        'https://flutter.github.io/assets-for-api-docs/assets/widgets/owl.jpg'),
                  )),
            ),
          ]),

          // 6-pointed star
          Column(children: [
            SizedBox(
              height: 180,
              width: 180,
              child: ClipPath(
                clipper: StarClipper(6),
                child: Container(
                  height: 300,
                  color: Colors.amber,
                ),
              ),
            ),
          ]),
          // 10-pointed star
          Column(children: [
            SizedBox(
              height: 180,
              width: 180,
              child: ClipPath(
                clipper: StarClipper(10),
                child: Container(
                  height: 150,
                  color: Colors.indigo,
                ),
              ),
            ),
          ]),
          // 20-pointed star
          Column(children: [
            SizedBox(
              height: 180,
              width: 180,
              child: ClipPath(
                clipper: StarClipper(20),
                child: Container(
                  height: 150,
                  color: Colors.cyan,
                ),
              ),
            ),
          ]),

          //red box, for comparison
          Column(children: [
            SizedBox(
              height: 180,
              width: 180,
              child: Container(
                height: 300,
                color: Colors.red,
              ),
            )
          ]),

          // Comparison image, copied from https://api.flutter.dev/flutter/painting/BoxDecoration-class.html NOV 2021
          Column(children: [
            SizedBox(
              height: 180,
              width: 180,
              child: Container(
                decoration: BoxDecoration(
                  color: const Color(0xff7c94b6),
                  image: const DecorationImage(
                    image: NetworkImage(
                        'https://flutter.github.io/assets-for-api-docs/assets/widgets/owl-2.jpg'),
                    fit: BoxFit.cover,
                  ),
                  border: Border.all(
                    color: Colors.black,
                    width: 8,
                  ),
                  borderRadius: BorderRadius.circular(12),
                ),
              ),
            ),
          ]),
        ],
      ),
      //  ),
      //),
    );
  }
}