text cover using textpadding don't work

[rozrabiak]

Hi, I trying to cover text on TFT, but this code doesn't work for me.
Can anyone help me?

void hmi::printRpm(int rpm)
{
    int _rpm = rpm;
    String rpmString = String(_rpm);
    tft.setCursor(38, 110);
    tft.setTextFont(7);
    tft.setTextSize(1);

    tft.setTextColor(TXT_COLOR, BG_COLOR);
    int16_t w = tft.textWidth("888", 7); // Width of maximum length string)

    tft.setTextPadding(w); // Set blanking width to string length
    tft.setTextDatum(TL_DATUM); // Set datum to top left

    tft.print(rpmString);
    tft.setTextPadding(0);
}