Total axis scale remodelation

Hi!! Quite a question here, I think...

I need the Y axis of a plot to have a continuous scale that fits 0, 20, 40, 100, 120, 140, 200... That is, labels every +20, +20, +60. Another requisite is that the space between ticks is always the same (say, one label every 20 pixels).

Question is... how can I accomplish this? I'm currently trying to subclass QwtScaleDiv, QwtScaleDraw and QwtScaleEngine, but I don't seem to have enough knowledge of Qwt to do it properly. I'm also looking at friedberg and oscilloscope examples...

Any help would be greatly appreciated!! :)


PS: truly great component, this one!!
PPS: just to get the big picture, I'm plotting seconds into the Y-axis. I need the aforementioned nonlinear scale (+20, +20, +60), while I will be plotting continuous values into the graph. The X-axis contains GPS' heading values, so it's a time-heading graph.

PPPS: sorry for changing the whole post!! XD situation here changed so quickly...
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