Created CircularRevealClipper

+import 'dart:math' show sqrt, max;
+import 'dart:ui' show lerpDouble;
+
+import 'package:flutter/material.dart';
+
+class CircularRevealClipper extends CustomClipper<Path> {
+  final double fraction;
+  final Alignment? centerAlignment;
+  final Offset? centerOffset;
+  final double? minRadius;
+  final double? maxRadius;
+
+  CircularRevealClipper({
+    required this.fraction,
+    this.centerAlignment,
+    this.centerOffset,
+    this.minRadius,
+    this.maxRadius,
+  });
+
+  @override
+  Path getClip(Size size) {
+    final Offset center = this.centerAlignment?.alongSize(size) ??
+        this.centerOffset ??
+        Offset(size.width / 2, size.height / 2);
+    final minRadius = this.minRadius ?? 0;
+    final maxRadius = this.maxRadius ?? calcMaxRadius(size, center);
+
+    return Path()
+      ..addOval(
+        Rect.fromCircle(
+          center: center,
+          radius: lerpDouble(minRadius, maxRadius, fraction)!,
+        ),
+      );
+  }
+
+  @override
+  bool shouldReclip(CustomClipper<Path> oldClipper) => true;
+
+  static double calcMaxRadius(Size size, Offset center) {
+    final w = max(center.dx, size.width - center.dx);
+    final h = max(center.dy, size.height - center.dy);
+    return sqrt(w * w + h * h);
+  }
+}
+