89 lines
2.6 KiB
Dart
89 lines
2.6 KiB
Dart
// Author: fruit.com.cn
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// 职责：绘制收藏点赞周围的紧凑双向短线，无圆环或阴影，不参与手势。
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import 'dart:math' as math;
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import 'package:flutter/material.dart';
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const int _rayCount = 8;
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const double _startProgress = 0.1;
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const double _radiusStart = 0.34;
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const double _radiusTravel = 0.14;
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const double _rayLength = 0.07;
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const double _strokeFraction = 0.025;
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const double _rayAlpha = 0.65;
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const double _fullCircle = math.pi * 2;
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const double _rayRotation = math.pi / _rayCount;
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/// 收藏/点赞的装饰反馈：选中外扩，取消收束。
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class RailTapBurst extends StatelessWidget {
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/// [progress] 来自按钮的点击动画，不创建独立计时器。
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const RailTapBurst({
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super.key,
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required this.progress,
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required this.color,
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required this.contracting,
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});
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final double progress;
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final Color color;
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final bool contracting;
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@override
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Widget build(BuildContext context) => IgnorePointer(
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child: CustomPaint(
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painter: _RailBurstPainter(
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progress: progress,
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color: color,
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contracting: contracting,
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),
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),
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);
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}
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class _RailBurstPainter extends CustomPainter {
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const _RailBurstPainter({
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required this.progress,
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required this.color,
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required this.contracting,
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});
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final double progress;
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final Color color;
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final bool contracting;
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@override
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void paint(Canvas canvas, Size size) {
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final phase = ((progress - _startProgress) / (1 - _startProgress)).clamp(
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0.0,
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1.0,
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);
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if (phase == 0 || phase == 1) return;
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final eased = Curves.easeOutCubic.transform(phase);
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final travel = contracting ? 1 - eased : eased;
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final base = size.shortestSide;
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final radius = base * (_radiusStart + _radiusTravel * travel);
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final alpha = math.sin(math.pi * phase);
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final paint = Paint()
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..style = PaintingStyle.stroke
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..strokeCap = StrokeCap.round
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..strokeWidth = base * _strokeFraction
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..color = color.withValues(alpha: alpha * _rayAlpha);
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final center = size.center(Offset.zero);
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final length = base * _rayLength * (1 - phase);
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for (var index = 0; index < _rayCount; index++) {
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final angle = _fullCircle * index / _rayCount + _rayRotation;
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canvas.drawLine(
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center + Offset.fromDirection(angle, radius),
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center + Offset.fromDirection(angle, radius + length),
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paint,
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);
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}
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}
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@override
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bool shouldRepaint(covariant _RailBurstPainter oldDelegate) =>
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oldDelegate.progress != progress ||
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oldDelegate.color != color ||
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oldDelegate.contracting != contracting;
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}
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