58 lines
1.9 KiB
Dart
58 lines
1.9 KiB
Dart
import 'dart:math';
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import 'package:flutter/material.dart';
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class HeadingMarkerPainter extends CustomPainter {
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final double headingAngle; // 航向角（度）
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HeadingMarkerPainter({required this.headingAngle});
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@override
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void paint(Canvas canvas, Size size) {
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// 中心点坐标（对应SVG的cx=20, cy=20）
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final center = Offset(size.width / 2, size.height / 2);
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// 圆圈半径（对应SVG的r=10）
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final circleRadius = 10.0;
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// ========== 1. 绘制绿色半透明圆圈（SVG的circle） ==========
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final circlePaint = Paint()
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..color = const Color(0xFF1AFA29)
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.withOpacity(0.7) // #1afa29 70%透明度
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..style = PaintingStyle.fill;
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canvas.drawCircle(center, circleRadius, circlePaint);
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// 绘制白色描边（SVG的stroke="#fff" stroke-width="2"）
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final strokePaint = Paint()
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..color = Colors.white
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..style = PaintingStyle.stroke
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..strokeWidth = 2.0;
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canvas.drawCircle(center, circleRadius, strokePaint);
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// ========== 2. 绘制航向箭头（SVG的path） ==========
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// 保存画布状态（旋转后恢复）
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canvas.save();
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// 平移+旋转：以圆心为旋转中心，根据航向角旋转（对应SVG的transform）
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canvas.translate(center.dx, center.dy);
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canvas.rotate(headingAngle * pi / 180); // 角度转弧度
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// 箭头路径（对应SVG的d="M0,-8 L4,4 L0,1 L-4,4 Z"）
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final arrowPath = Path()
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..moveTo(0, -8) // 顶部顶点
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..lineTo(4, 4) // 右侧点
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..lineTo(0, 1) // 中下点
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..lineTo(-4, 4) // 左侧点
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..close(); // 闭合路径
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final arrowPaint = Paint()..color = Colors.white;
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canvas.drawPath(arrowPath, arrowPaint);
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// 恢复画布状态
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canvas.restore();
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}
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@override
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bool shouldRepaint(covariant HeadingMarkerPainter oldDelegate) {
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// 航向角变化时重新绘制
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return oldDelegate.headingAngle != headingAngle;
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}
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}
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