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