Method StepTuner

src/visual/TuningCanvas.cpp:173–270

* Perform tuner step * * @param state Current hover state * @param digit Digit position * @param tuningDir Tuning direction, true for up * @param preventCarry Prevent carry operation on digit overflow * @param zeroOut Zero out 'digit' and lower digits */

 * @param zeroOut   Zero out 'digit' and lower digits
 */
void TuningCanvas::StepTuner(ActiveState state, TuningDirection tuningDir, int digit, bool preventCarry, bool zeroOut) {
    double exp = pow(10, digit);
    long long amount = tuningDir ? exp : -exp;

    if (halfBand && state == TUNING_HOVER_BW) {
        amount *= 2;
    }
    
    auto activeDemod = wxGetApp().getDemodMgr().getCurrentModem();
    if (state == TUNING_HOVER_FREQ && activeDemod) {
        long long demod_freq = activeDemod->getFrequency();
        long long diff = abs(wxGetApp().getFrequency() - demod_freq);

        if (zeroOut) { // Zero digits to right
            double intpart;
            modf(demod_freq / (exp * 10), &intpart);
            demod_freq = intpart * exp * 10;
        } else if (preventCarry) { // Prevent digit from carrying
            bool carried = (long long)((demod_freq) / (exp * 10)) != (long long)((demod_freq + amount) / (exp * 10)) || (bottom && demod_freq < exp);
            demod_freq += carried ? (9 * -amount) : amount;
        } else {
            demod_freq += amount;
        }

        if (wxGetApp().getSampleRate() / 2 < diff) {
            wxGetApp().setFrequency(demod_freq);
        }

        activeDemod->setTracking(true);
        activeDemod->setFollow(true);
        activeDemod->setFrequency(demod_freq);
        if (activeDemod->isDeltaLock()) {
            activeDemod->setDeltaLockOfs(activeDemod->getFrequency() - wxGetApp().getFrequency());
        }
        activeDemod->updateLabel(demod_freq);
    }

    if (state == TUNING_HOVER_BW) {
        long nbw = wxGetApp().getDemodMgr().getLastBandwidth();

        if (zeroOut) { // Zero digits to right
            double intpart;
            modf(nbw / (exp * 10), &intpart);
            nbw = intpart * exp * 10;
        } else if (preventCarry) { // Prevent digit from carrying
            bool carried = (long)((nbw) / (exp * 10)) != (long)((nbw + amount) / (exp * 10)) || (bottom && nbw < exp);
            nbw += carried ? (9 * -amount) : amount;
        } else {
            nbw += amount;
        }

        if (nbw > CHANNELIZER_RATE_MAX) {
            nbw = CHANNELIZER_RATE_MAX;
        }

        wxGetApp().getDemodMgr().setLastBandwidth(nbw);

        if (activeDemod) {