Added clearing to the plasma underlay display.

wfmain.cpp

@@ -3903,10 +3903,12 @@ void wfmain::receiveSpectrumData(QByteArray spectrum, double startFreq, double e
             // TODO: create non-button function to do this
             // This will break if the button is ever moved or renamed.
             on_clearPeakBtn_clicked();
+        } else {
+            plasmaPrepared = false;
+            preparePlasma();
         }
         // Inform other threads (cluster) that the frequency range has changed.
         emit setFrequencyRange(startFreq, endFreq);
-        // TODO: Add clear-out for the buffer
     }
 
     oldLowerFreq = startFreq;
@@ -3949,8 +3951,10 @@ void wfmain::receiveSpectrumData(QByteArray spectrum, double startFreq, double e
     }
     plasmaMutex.lock();
     spectrumPlasma.push_front(spectrum);
-    spectrumPlasma.pop_back();
-    //spectrumPlasma.resize(spectrumPlasmaSize);
+    if(spectrumPlasma.size() > (int)spectrumPlasmaSize)
+    {
+        spectrumPlasma.pop_back();
+    }
     plasmaMutex.unlock();
 
 
@@ -4065,10 +4069,13 @@ void wfmain::preparePlasma()
     plasmaMutex.lock();
     spectrumPlasma.clear();
 
-    for(unsigned int p=0; p < spectrumPlasmaSize; p++)
-    {
-        spectrumPlasma.append(empty);
-    }
+//    spectrumPlasma.append(empty);
+
+//    It may be possible to skip this.
+//    for(unsigned int p=0; p < spectrumPlasmaSize; p++)
+//    {
+//        spectrumPlasma.append(empty);
+//    }
 
     spectrumPlasma.squeeze();
     plasmaMutex.unlock();