dockfft: zoom slider uses log scale with max 100000x

Signed-off-by: Jeff Long <[email protected]>

src/qtgui/dockfft.cpp

@@ -541,7 +541,8 @@ void DockFft::setWaterfallRange(float min, float max)
 void DockFft::setZoomLevel(float level)
 {
     ui->fftZoomSlider->blockSignals(true);
-    ui->fftZoomSlider->setValue((int) level);
+    float logZoom = 100.0f / 5.0f * log10f(level);
+    ui->fftZoomSlider->setValue(qRound(logZoom));
     ui->zoomLevelLabel->setText(QString("%1x").arg((int) level));
     ui->fftZoomSlider->blockSignals(false);
 }
@@ -628,8 +629,9 @@ void DockFft::on_fftAvgSlider_valueChanged(int value)
 /** FFT zoom level changed */
 void DockFft::on_fftZoomSlider_valueChanged(int level)
 {
-    ui->zoomLevelLabel->setText(QString("%1x").arg(level));
-    emit fftZoomChanged((float)level);
+    float linearZoom = powf(10.0f, (float)level * 5.0f / 100.0f);
+    ui->zoomLevelLabel->setText(QString("%1x").arg(qRound(linearZoom)));
+    emit fftZoomChanged(linearZoom);
 }
 
 void DockFft::on_wfModeBox_currentIndexChanged(int index)

src/qtgui/dockfft.ui

@@ -298,7 +298,7 @@
                <string>Zoom level for frequency axis</string>
               </property>
               <property name="minimum">
-               <number>1</number>
+               <number>0</number>
               </property>
               <property name="maximum">
                <number>100</number>

src/qtgui/plotter.cpp

@@ -907,48 +907,25 @@ void CPlotter::zoomStepX(float step, int x)
     }
 
     // calculate new range shown on FFT
-    double new_range = qBound(10.0, m_Span * (double)step, (double)m_SampleFreq * 10.0);
+    double new_range = m_Span * (double)step;
 
     // Frequency where event occurred is kept fixed under mouse
     double ratio = (double)x / (qreal)m_Size.width() / m_DPR;
     qint64 fixed_hz = freqFromX(x);
     double f_max = (double)fixed_hz + (1.0 - ratio) * new_range;
     double f_min = f_max - new_range;
 
-    // ensure we don't go beyond the rangelimits
-    bool limit_hit = false;
-    double lolim = (double)(m_CenterFreq) - (double)m_SampleFreq / 2.0;
-    double hilim = (double)m_CenterFreq + (double)m_SampleFreq / 2.0;
-    if (f_min < lolim)
-    {
-        f_min = lolim;
-        limit_hit = true;
-    }
-    if (f_max > hilim)
-    {
-        f_max = hilim;
-        limit_hit = true;
-    }
-
     // the new span
     quint32 new_span = qRound(f_max - f_min);
     if( new_span & 1 )
     {
         new_span++; // keep span even to avoid rounding in span/2
     }
 
-    // find new FFT center frequency
-    qint64 new_FftCenter;
-    if( limit_hit ) // cannot keep fixed_hz fixed
-    {
-    	new_FftCenter = qRound64((f_min + f_max) / 2.0) - m_CenterFreq;
-    }
-    else // calculate new FFT center frequency that really keeps fixed_hz fixed
-    {
-    	qint64 wouldbe_hz = (m_CenterFreq + m_FftCenter - new_span / 2) + ratio * new_span;
-    	new_FftCenter = m_FftCenter + (fixed_hz - wouldbe_hz);
-    }
+    qint64 wouldbe_hz = (m_CenterFreq + m_FftCenter - new_span / 2) + ratio * new_span;
+    qint64 new_FftCenter = m_FftCenter + (fixed_hz - wouldbe_hz);
     setFftCenterFreq(new_FftCenter);
+
     setSpanFreq(new_span);
 
     double factor = (double)m_SampleFreq / (double)m_Span;
@@ -964,7 +941,7 @@ void CPlotter::zoomStepX(float step, int x)
 void CPlotter::zoomOnXAxis(float level)
 {
     double current_level = (double)m_SampleFreq / (double)m_Span;
-    zoomStepX(current_level / level, xFromFreq(m_DemodCenterFreq));
+    zoomStepX(current_level / level, qRound((qreal)m_Size.width() * m_DPR / 2.0));
     updateOverlay();
 }
 
@@ -1525,6 +1502,7 @@ void CPlotter::draw(bool newData)
     {
         m_2DPixmap.fill(PLOTTER_BGD_COLOR);
         QPainter painter2(&m_2DPixmap);
+        painter2.translate(QPointF(0.5, 0.5));
 
         // Update histogram IIR
         const double frameTime = 1.0 / (double)fft_rate;
@@ -1882,7 +1860,7 @@ void CPlotter::setNewFftData(const float *fftData, int size)
         double currentZoom = (double)m_SampleFreq / (double)m_Span;
         double maxZoom = (double)m_fftDataSize / 4.0;
         if (currentZoom > maxZoom)
-            zoomStepX(currentZoom / maxZoom, xFromFreq(m_CenterFreq + m_FftCenter));
+            zoomStepX(currentZoom / maxZoom, qRound((qreal)m_Size.width() * m_DPR / 2.0));
     }
 
     // For dBFS, define full scale as peak (not RMS). A 1.0 FS peak sine wave
@@ -1996,6 +1974,7 @@ void CPlotter::drawOverlay()
 
     m_OverlayPixmap.fill(Qt::transparent);
     QPainter painter(&m_OverlayPixmap);
+    painter.translate(QPointF(-0.5, -0.5));
     // painter.setRenderHint(QPainter::Antialiasing);
     painter.setFont(m_Font);
 
@@ -2343,10 +2322,6 @@ int CPlotter::xFromFreq(qint64 freq)
                        + (double)m_FftCenter
                        - (double)m_Span / 2.0;
     int x = qRound(w * ((double)freq - startFreq) / (double)m_Span);
-    if (x < 0)
-        return 0;
-    if (x > (int)w)
-        return w;
     return x;
 }