// step 4: we grab the ContentByte and do some stuff with it
PdfContentByte cb = writer.getDirectContent();
cb.circle(250.0f, 500.0f, 200.0f);
cb.circle(250.0f, 500.0f, 150.0f);
cb.stroke();
cb.setRGBColorFill(0xFF, 0x00, 0x00);
cb.circle(250.0f, 500.0f, 100.0f);
cb.fillStroke();
cb.setRGBColorFill(0xFF, 0xFF, 0xFF);