Support reversed segarc where painting is from max to min scale

[AmoebeLabs]

The Problem To Be Solved

The segmented arc draws its arc using a scale where min < max: if not, nothing is drawn.

In some cases it would be nice to be able to draw the arc from max to min: ie reversed.

I would use that for instance for a thermostat to show both actual temperature and on another - reversed - segmented arc the setpoint. That segmented arc also has reversed start/stop angles.

So temperature is drawn from left to right, and setpoint from right to left on the same scale!

(Optional): Suggested Solution

The implementation must handle both min<max (default) and min>max. As min and max have a standard meaning, maybe a reversed flag orso could be better than support of min>max, which is weird, as we actually want to implement a reversed draw of the arc.