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| import 'package:flutter/material.dart';
class GradientBorderPainter extends CustomPainter {
final double strokeWidth;
final BorderRadiusGeometry radius;
final Gradient gradient;
GradientBorderPainter({
required this.strokeWidth,
required this.radius,
required this.gradient,
});
@override
void paint(Canvas canvas, Size size) {
final rect = Rect.fromLTWH(0, 0, size.width, size.height);
final paint = Paint()
..shader = gradient.createShader(rect)
..strokeWidth = strokeWidth
..style = PaintingStyle.stroke;
final path = Path.combine(
PathOperation.difference,
Path()..addRRect(radius.resolve(TextDirection.ltr).toRRect(rect)),
Path()..addRRect(radius.resolve(TextDirection.ltr).toRRect(rect.deflate(strokeWidth / 2)))
);
canvas.drawPath(path, paint);
}
@override
bool shouldRepaint(CustomPainter oldDelegate) => false;
}
class _HomePageState extends State<HomePage> {
@override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: ClipRRect(
borderRadius: BorderRadius.circular(16),
child: Container(
width: 200,
height: 200,
decoration: BoxDecoration(
border: Border.all(
width: 4,
color: Colors.transparent,
),
),
child: SizedBox.expand(
child: CustomPaint(
painter: GradientBorderPainter(
strokeWidth: 4,
radius: BorderRadius.circular(16),
gradient: LinearGradient(
begin: Alignment.centerLeft,
end: Alignment.centerRight,
colors: [
Colors.red,
Colors.blue,
],
),
),
),
),
),
),
),
);
}
}
|