float width = outputDevice.getDeviceLength(fieldElem.getWidth());
float height = outputDevice.getDeviceLength(fieldElem.getHeight());
PdfFormField field = PdfFormField.createEmpty(writer);
FSColor color = box.getStyle().getColor();
FSColor darker = box.getEffBackgroundColor(c).darkenColor();
createAppearances(cb, field, onValue, width, height, true, color, darker);
createAppearances(cb, field, onValue, width, height, false, color, darker);
field.setWidget(
outputDevice.createTargetArea(c, box),