public void Draw(Graphics g, PhysicalAxis xAxis, PhysicalAxis yAxis)
{
int yMin = yAxis.PhysicalMin.Y;
int yMax = yAxis.PhysicalMax.Y;
yMin -= pixelIndent_;
yMax += pixelIndent_;
float length = Math.Abs(yMax - yMin);
float lengthDiff = length - length * scale_;
float indentAmount = lengthDiff / 2;
yMin -= (int)indentAmount;
yMax += (int)indentAmount;
int xPos = (int)xAxis.WorldToPhysical(value_, false).X;
g.DrawLine(pen_, new Point(xPos, yMin), new Point(xPos, yMax));
// todo: clip and proper logic for flipped axis min max.
}