Change title of x-axis of QwtPlotMultiBarChart

[tham]

How could I change the title of the x-axis of QwtPlotMultiBarChart? Following the codes of the example, I could draw multi bar chart like this

But how could I change the label of x-axis from 0,1,2,3,4 to text(ex : worst, bad, average, good, great)? Thanks

[tham]

@tham I find the answer, you can do that by override the class "QwtScaleDraw"(check the example distrowatch).