// define the bounds in points
Bounds bo = BoundsImpl.create(0, 0, 800, 600); // in points
// build the rendered chart structure
Generator gr = Generator.instance();
GeneratedChartState gcs = null;
try {
gcs = gr.build(idr.getDisplayServer(), cm, bo, null);
} catch (ChartException gex) {
gex.printStackTrace();