public static Image Evaluate(MercatorUi.MovableControls.MovablePictureBox currentPictureBox)
{
    // enter your customized code here
    MercatorUi.Forms.Billing.BillingForm billingForm = (MercatorUi.Forms.Billing.BillingForm)currentPictureBox.Form;
    if (billingForm.BillingEngine.IsNew)
        return null;
    else
        return MercatorController.xFunctions.xQrCode(
            billingForm.BillingEngine.PiedsVRecord.JOURNAL.PadRight(5) + billingForm.BillingEngine.PiedsVRecord.PIECE.ToString().PadLeft(10),
            Api.Min(currentPictureBox.Width, currentPictureBox.Height),
            false);
}