ai_chat_assistant/lib/widgets/_hole_overlay.dart

import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';

// 一个带洞的遮罩层，点击洞外区域触发onTap事件
class HoleOverlay extends StatelessWidget {
  final Offset iconPosition;
  final double iconSize;
  final VoidCallback? onTap;
  final Widget? child;

  const HoleOverlay({
    super.key,
    required this.iconPosition,
    required this.iconSize,
    this.onTap,
    this.child,
  });

  @override
  Widget build(BuildContext context) {
    debugPrint('🔧 HoleOverlay build: iconPosition=$iconPosition, iconSize=$iconSize');
    
    final holeRect = Rect.fromLTWH(
      iconPosition.dx,
      iconPosition.dy,
      iconSize,
      iconSize,
    );
    
    return CustomPaint(
      painter: _HolePainter(
        iconPosition: iconPosition,
        iconSize: iconSize,
      ),
      child: GestureDetector(
        onTapDown: (details) {
          final tapPosition = details.localPosition;
          final isInHole = holeRect.contains(tapPosition);
          debugPrint('🎯 HoleOverlay onTapDown: position=$tapPosition, holeRect=$holeRect, isInHole=$isInHole');
          
          if (!isInHole) {
            debugPrint('🔥 HoleOverlay: 点击洞外，触发onTap');
            onTap?.call();
          } else {
            debugPrint('🚫 HoleOverlay: 点击洞内，不触发onTap');
          }
        },
        child: child,
        behavior: HitTestBehavior.translucent,
      ),
    );
  }
}

class _HolePainter extends CustomPainter {
  final Offset iconPosition;
  final double iconSize;

  _HolePainter({
    required this.iconPosition,
    required this.iconSize,
  });

  @override
  void paint(Canvas canvas, Size size) {
    final holeRect = Rect.fromLTWH(
      iconPosition.dx,
      iconPosition.dy,
      iconSize,
      iconSize,
    );
    
    debugPrint('🎨 HolePainter paint: size=$size, holeRect=$holeRect');
    
    // 使用 saveLayer 确保混合模式正确
    canvas.saveLayer(Offset.zero & size, Paint());
    
    // 画半透明背景
    final backgroundPaint = Paint()
      ..color = Colors.black.withOpacity(0.3);
    canvas.drawRect(Offset.zero & size, backgroundPaint);
    debugPrint('🔲 HolePainter paint: 绘制背景完成');
    
    // 挖洞：使用 BlendMode.clear
    final holePaint = Paint()
      ..blendMode = BlendMode.clear;
    canvas.drawOval(holeRect, holePaint);
    debugPrint('⭕ HolePainter paint: 挖洞完成，holeRect=$holeRect');
    
    canvas.restore();
    
    // 调试：画红色边框显示洞的位置
    final debugPaint = Paint()
      ..color = Colors.red
      ..style = PaintingStyle.stroke
      ..strokeWidth = 2.0;
    canvas.drawOval(holeRect, debugPaint);
    debugPrint('🔴 HolePainter paint: 绘制调试边框完成');
  }

  @override
  bool shouldRepaint(covariant _HolePainter oldDelegate) {
    return oldDelegate.iconPosition != iconPosition || 
           oldDelegate.iconSize != iconSize;
  }
}