Flutter绘制拖尾效果

演示:

代码:

Dart 复制代码
import 'dart:ui';

import 'package:flutter/material.dart';
import 'package:kq_flutter_widgets/widgets/chart/ex/extension.dart';

class TrailingView extends StatelessWidget {
  const TrailingView({super.key});

  @override
  Widget build(BuildContext context) {
    return LayoutBuilder(builder: (v1, v2) {
      Path path = Path();
      path.moveTo(50, 50);
      path.cubicTo(50, 50, 100, 300, 300, 400);

      return CustomPaint(
        size: Size(v2.maxWidth, v2.maxHeight),
        painter: Trailing(path: path, r: 8),
      );
    });
  }
}

///拖尾效果
class Trailing extends CustomPainter {
  ///路径
  final Path path;

  ///起始值大小半径
  final double r;

  Trailing({
    required this.path,
    required this.r,
  });

  @override
  void paint(Canvas canvas, Size size) {
    PathMetric? pathMetric1 = path.computeMetric();
    if (pathMetric1 != null) {
      int length1 = pathMetric1.length.toInt();
      for (int i = 0; i < length1.toInt(); i++) {
        Tangent? tangent1 = pathMetric1.getTangentForOffset(i.toDouble());
        double mix = i / length1.toInt();
        if (tangent1 != null) {
          Offset cur = tangent1.position;
          canvas.drawCircle(
              cur,
              r * mix,
              Paint()
                ..color = Colors.redAccent
                ..maskFilter = const MaskFilter.blur(BlurStyle.normal, 8));
        }
      }
    }
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) {
    return true;
  }
}

主要思路:

根据路径获取路径上的点,并从路径的起始点到终点绘制从大变小的圆点,且设置画笔为外发光模式,就可以达到一个可以根据路径显示的拖尾效果了。

相关推荐
孤鸿玉15 小时前
Fluter InteractiveViewer 与ScrollView滑动冲突问题解决
flutter
叽哥1 天前
Flutter Riverpod上手指南
android·flutter·ios
BG2 天前
Flutter 简仿Excel表格组件介绍
flutter
zhangmeng2 天前
FlutterBoost在iOS26真机运行崩溃问题
flutter·app·swift
恋猫de小郭2 天前
对于普通程序员来说 AI 是什么?AI 究竟用的是什么?
前端·flutter·ai编程
卡尔特斯2 天前
Flutter A GlobalKey was used multipletimes inside one widget'schild list.The ...
flutter
w_y_fan2 天前
Flutter 滚动组件总结
前端·flutter
醉过才知酒浓2 天前
Flutter Getx 的页面传参
flutter
火柴就是我3 天前
flutter 之真手势冲突处理
android·flutter
Speed1233 天前
`mockito` 的核心“打桩”规则
flutter·dart