force waterfall to throttle by client dc paint from appframe idle

- Attempting to improve waterfall jitter between platforms

src/visual/WaterfallCanvas.cpp

@@ -88,7 +88,12 @@ void WaterfallCanvas::processInputQueue() {
 }
 
 void WaterfallCanvas::OnPaint(wxPaintEvent& WXUNUSED(event)) {
-    wxPaintDC dc(this);
+//    event.Skip();
+}
+
+void WaterfallCanvas::DoPaint() {
+    wxClientDC dc(this);
+    //    wxPaintDC dc(this);
 
     const wxSize ClientSize = GetClientSize();
     long double currentZoom = zoom;
@@ -354,8 +359,9 @@ void WaterfallCanvas::OnKeyDown(wxKeyEvent& event) {
     }
 }
 void WaterfallCanvas::OnIdle(wxIdleEvent &event) {
-    Refresh();
-    event.RequestMore();
+//    Refresh();
+//    event.RequestMore();
+    event.Skip();
 }
 
 void WaterfallCanvas::OnMouseMoved(wxMouseEvent& event) {

src/visual/WaterfallCanvas.h

@@ -28,6 +28,7 @@ public:
     void attachSpectrumCanvas(SpectrumCanvas *canvas_in);
     void processInputQueue();
     SpectrumVisualDataQueue *getVisualDataQueue();
+    void DoPaint();
 
 private:
     void OnPaint(wxPaintEvent& event);