comparison layer/SpectrogramLayer.cpp @ 162:f32212631b9c

* Handle generator transforms (plugins whose channel count isn't dependent on
  number of audio inputs, as they have none)
* Be less keen to suspend writing FFT data in spectrogram repaint -- only do it
  if we find we actually need to query the FFT data (i.e. we aren't repainting
  an area that hasn't been generated at all yet)

     }
 
     MagnitudeRange overallMag = m_viewMags[v];
     bool overallMagChanged = false;
 
-    fft->suspendWrites();
+    bool fftSuspended = false;
 
 #ifdef DEBUG_SPECTROGRAM_REPAINT
     std::cerr << (float(v->getFrameForX(1) - v->getFrameForX(0)) / increment) << " bins per pixel" << std::endl;
 #endif
 

 	}
 
         for (int s = s0i; s <= s1i; ++s) {
 
             if (!fft->isColumnAvailable(s)) continue;
+            
+            if (!fftSuspended) {
+                fft->suspendWrites();
+                fftSuspended = true;
+            }
+
             MagnitudeRange mag;
 
             for (size_t q = minbin; q < bins; ++q) {
 
                 float y0 = yval[q + 1];

 
 #ifdef DEBUG_SPECTROGRAM_REPAINT
     std::cerr << "SpectrogramLayer::paint() returning" << std::endl;
 #endif
 
-    fft->resume();
+    if (fftSuspended) fft->resume();
 }
 
 void
 SpectrogramLayer::illuminateLocalFeatures(View *v, QPainter &paint) const
 {