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(
      'HorizontalLineTool.draw: yPosition=$yPosition, priceLevel=$priceLevel');

  if (yPosition == null) {
    debugPrint('HorizontalLineTool.draw: yPosition为null，跳过绘制');
    return;
  }

  final paint = Paint()
    ..color = color
    ..strokeWidth = strokeWidth
    ..style = PaintingStyle.stroke;

  // 绘制横跨整个图表的水平线
  debugPrint('绘制水平线: y=$yPosition, 宽度=${size.width}');
  canvas.drawLine(
    Offset(0, yPosition!),
    Offset(size.width, yPosition!),
    paint,
  );

  // 绘制价格标签
  if (priceLevel != null) {
    final textPainter = TextPainter(
      text: TextSpan(
        text: priceLevel!.toStringAsFixed(2),
        style: TextStyle(color: color, fontSize: 12),
      ),
      textDirection: TextDirection.ltr,
    );
    textPainter.layout();
    textPainter.paint(
        canvas,
        Offset(size.width - textPainter.width - 5,
            yPosition! - textPainter.height / 2));
  }
}