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) {
  if (xPosition == null) return;

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

  // 如果是预览状态，绘制虚线效果
  if (state == DrawingToolState.drawing) {
    _drawDashedLine(canvas, Offset(xPosition!, 0),
        Offset(xPosition!, size.height), paint);
  } else {
    canvas.drawLine(
      Offset(xPosition!, 0),
      Offset(xPosition!, size.height),
      paint,
    );
  }
}