QCustomPlot Discussion and Comments

Fixing the Scale in y axis(disable zoom)Return to overview

how to fix the scale in the y-axis.but should be movable in x direction

If I got you right, try something like this:
plot->axisRect(0)->setRangeZoomFactor(.5,1);

This is more straightforward

  plot->axisRect(0)->setRangeZoom(Qt::Horizontal;

connect(ui->customPlot, SIGNAL(mouseWheel(QWheelEvent*)), this, SLOT(mouseWheel())); 

///....

void MainWindow::mouseWheel() 
{
    zoomed = true;
    if( QApplication::keyboardModifiers() == Qt::ControlModifier ) {
            ui->customPlot->axisRect()->setRangeZoom(Qt::Horizontal);
            qDebug() << "----------x Axis changed by wheel-----------";
        } else {
            ui->customPlot->axisRect()->setRangeZoom(Qt::Horizontal | Qt::Vertical);
            qDebug() << "----------xy Axis changed by wheel-----------";
    }

    qDebug() << "----------zoomed by wheel-----------";
}

it's worked for me