QwtPlotCurve shift by 1 pixel

[carhun]

Hello!

How can I shift curve by 1 pixel?

I try to do in this way, but this doesn't help: I have QVector<QPointF> and than I do smth like:

for (int i = 0; i < sample.size(); i++) {
    tmp = samples.at(i);
 
    newVector.append(tmp.x, tmp.y - 1);
}
setSamples(newVector);

for (int i = 0; i < sample.size(); i++) {
    tmp = samples.at(i);

    newVector.append(tmp.x, tmp.y - 1);
}
setSamples(newVector);

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tmp there is struct like:
struct {
double x;
double y;
}

Problem is that scale is to big: 0 - 8*10^8
and when curves have same value i need some value shift down by 1 pixel...