comparison layer/ScrollableImageCache.cpp @ 1079:7ebfb61b1701 spectrogram-minor-refactor

More filling in render & cache code

 
 void
 ScrollableImageCache::scrollTo(sv_frame_t newStartFrame)
 {
     if (!m_v) throw std::logic_error("ScrollableImageCache: not associated with a LayerGeometryProvider");
+
+    if (m_startFrame == newStartFrame) {
+	// haven't moved
+        return;
+    }
 	
     int dx = (m_v->getXForFrame(m_startFrame) -
 	      m_v->getXForFrame(newStartFrame));
 
 #ifdef DEBUG_SCROLLABLE_IMAGE_CACHE

     }
 
     int w = m_image.width();
 
     if (dx == 0) {
-	// haven't moved
+	// haven't moved visibly
 	return;
     }
 
     if (dx <= -w || dx >= w) {
 	// scrolled entirely off