viewer: added default parameter

Minor code enhancement

app/widget/viewer/viewer.cpp

@@ -249,7 +249,7 @@ void ViewerWidget::DisconnectNodeEvent(ViewerOutput *n)
   disconnect(n->audio_playback_cache(), &AudioPlaybackCache::Validated, this, &ViewerWidget::AudioCacheValidated);
   disconnect(n, &ViewerOutput::TextureInputChanged, this, &ViewerWidget::UpdateStack);
 
-  SetDisplayImage(nullptr, false);
+  SetDisplayImage(nullptr);
 
   ruler()->SetPlaybackCache(nullptr);
 
@@ -434,7 +434,7 @@ void ViewerWidget::SetEmptyImage()
     }
   }
 
-  SetDisplayImage(frame, false);
+  SetDisplayImage(frame);
 
   if (frame) {
     last_loaded_buffer_is_empty_ = true;
@@ -872,7 +872,7 @@ void ViewerWidget::RendererGeneratedFrame()
         }
       }
 
-      SetDisplayImage(frame, false);
+      SetDisplayImage(frame);
     }
   }
 

app/widget/viewer/viewer.h

@@ -185,7 +185,7 @@ private:
 
   bool ViewerMightBeAStill();
 
-  void SetDisplayImage(FramePtr frame, bool main_only);
+  void SetDisplayImage(FramePtr frame, bool main_only = false);
 
   void RequestNextFrameForQueue(bool prioritize = false, bool increment = true);