code: private void txtBorderWidthFocusLost(java.awt.event.FocusEvent evt) {//GEN-FIRST:event_txtBorderWidthFocusLost
          // TODO: the name (and label?) of this text box no longer matches its purpose
          if (txtBorderWidth.getText().matches("[0-9]+")) {
              quietZoneHorizontal = Integer.parseInt(txtBorderWidth.getText());
              encodeData();
          } else {
              txtBorderWidth.setText(String.valueOf(quietZoneHorizontal));
          }
      }
docs: GEN-LAST:event_chkReaderInitActionPerformed