draw method

@override void draw(Canvas canvas, Size size, double scaleX, double scrollX, double getX(double), double getY(double),)

Implementation

@override
void draw(Canvas canvas, Size size, double scaleX, double scrollX,
    double Function(double) getX, double Function(double) getY) {
  debugPrint(
      'ArrowTool.draw: startPoint=$startPoint, endPoint=$endPoint, 状态=$state');

  final paint = Paint()
    ..color = color.withOpacity(state == DrawingToolState.drawing ? 0.6 : 1.0)
    ..strokeWidth = strokeWidth
    ..style = PaintingStyle.stroke;

  if (startPoint != null && endPoint != null) {
    debugPrint('绘制完整箭头: 从 $startPoint 到 $endPoint');

    // 如果是预览状态，绘制虚线
    if (state == DrawingToolState.drawing) {
      _drawDashedLine(canvas, startPoint!, endPoint!, paint);
    } else {
      // 绘制箭头主体
      canvas.drawLine(startPoint!, endPoint!, paint);
    }

    // 计算箭头头部
    final direction = (endPoint! - startPoint!).direction;
    final arrowHead1 =
        endPoint! + Offset.fromDirection(direction + 2.5, arrowHeadSize);
    final arrowHead2 =
        endPoint! + Offset.fromDirection(direction - 2.5, arrowHeadSize);

    // 绘制箭头头部
    if (state == DrawingToolState.drawing) {
      _drawDashedLine(canvas, endPoint!, arrowHead1, paint);
      _drawDashedLine(canvas, endPoint!, arrowHead2, paint);
    } else {
      canvas.drawLine(endPoint!, arrowHead1, paint);
      canvas.drawLine(endPoint!, arrowHead2, paint);
    }
  } else if (startPoint != null) {
    debugPrint('绘制箭头起点: $startPoint');
    // 绘制起点标记
    canvas.drawCircle(startPoint!, 4.0, paint..style = PaintingStyle.fill);

    // 绘制起点周围的小圆圈指示器
    canvas.drawCircle(startPoint!, 6.0, paint..style = PaintingStyle.stroke);
  }
}