Use QTeXEngine to easily export graphics.
EditBy: QTeXEngine enables Qt based applications to easily export graphics created using the QPainter class to TeX. It is built on top of QPaintEngine and uses the TikZ/Pgf graphic systems for TeX.

QTeXEngine was written as an add-on to QtiPlot, in order to enable the export of 2D plots to TeX. All drawing capabilities of the QPainter class used in QtiPlot are supported by QTeXEngine. you can free download QTeXEngine 0.2 now.