KPlotWidget is used for easily creating 2-D plots of data sets,
complete with plot axes that include labeled tickmarks and
optional axis labels. Data sets can be represented as any
combination of: discrete points (using a variety of point
shapes), connected line segments (using any QPen), or bar-graph
rectangles (using any QPen/QBrush). In addition, any data point
can have a label string attached to it. This example
demonstrates most of the commonly-used features of KPlotWidget.
It is included in KDE, under kdelibs/kdeui/tests. The first part
of this tutorial will explain how to produce this plot using
KPlotWidget.