Steps to reproduce

Create an empty model with a range-constrained axis but no data, like so:

var pm = new PlotModel();
pm.Axes.Add(new LinearAxis
{
    Position = AxisPosition.Bottom,
    AbsoluteMinimum = -200.0,
    AbsoluteMaximum = -100.0,
    MinimumRange = 10.0,
});
plot1.Model = pm;

I used the WindowsFormsDemo but many of the examples should be usable as well.

Platform: OxyPlot.WinForms on Windows 10 64 bit
.NET version: 4.8

Expected behaviour

I would expect the axis to honour the absolute limits and the minimum range, so any of these visible ranges would be fine:

• [-200.0, -100.0]
• [-200.0, -190.0]
• [-155.0, -145.0]
• [-110.0, -100.0]

Actual behaviour

Instead I get the range [-100.0, -99.0] which violates both the AbsoluteMaximum and the MinimumRange properties:

Cause and proposed fix

The problem is the following code in Axis.cs:

protected virtual void CoerceActualMaxMin()
{
    // Coerce actual minimum
    if (double.IsNaN(this.ActualMinimum) || double.IsInfinity(this.ActualMinimum))
    {
        this.ActualMinimum = 0;
    }

    // Coerce actual maximum
    if (double.IsNaN(this.ActualMaximum) || double.IsInfinity(this.ActualMaximum))
    {
        this.ActualMaximum = 100;
    }

which uses values outside the allowed range. A possible fix would be to change this to:

        this.ActualMinimum = Math.Max(0, this.AbsoluteMinimum);

and

        this.ActualMaximum = Math.Min(100, this.AbsoluteMaximum);

respectively. With these changes I get the initial display range [-110.0, -100.0] which is valid.