From 1cca53ad6e53745c9b0a6d5945f1fafe958096c1 Mon Sep 17 00:00:00 2001
From: David Freese <w1hkj@w1hkj.com>
Date: Wed, 30 Oct 2013 07:21:19 -0500
Subject: [PATCH] WF latency

  * Restore latency adjustment for WF display
---
 src/dialogs/confdialog.cxx  | 27 +++++++++++++++++++++++++++
 src/dialogs/confdialog.fl   | 11 +++++++++++
 src/include/confdialog.h    |  1 +
 src/include/configuration.h |  3 +++
 src/waterfall/waterfall.cxx | 11 ++++++++---
 5 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/src/dialogs/confdialog.cxx b/src/dialogs/confdialog.cxx
index ce363334..138892f0 100644
--- a/src/dialogs/confdialog.cxx
+++ b/src/dialogs/confdialog.cxx
@@ -2036,6 +2036,13 @@ progdefaults.changed = true;
 setwfrange();
 }
 
+Fl_Counter2 *wf_latency=(Fl_Counter2 *)0;
+
+static void cb_wf_latency(Fl_Counter2* o, void*) {
+  progdefaults.wf_latency = (int)o->value();
+progdefaults.changed = true;
+}
+
 Fl_Counter2 *cntrWfheight=(Fl_Counter2 *)0;
 
 static void cb_cntrWfheight(Fl_Counter2* o, void*) {
@@ -6308,6 +6315,26 @@ ab and newline are automatically included."));
                 o->value(progdefaults.HighFreqCutoff);
                 o->labelsize(FL_NORMAL_SIZE);
               } // Fl_Counter2* cntrWfwidth
+              { Fl_Counter2* o = wf_latency = new Fl_Counter2(295, 124, 95, 22, _("Latency"));
+                wf_latency->tooltip(_("Signal averaging over time\n0 - least\n4 - greatest"));
+                wf_latency->type(1);
+                wf_latency->box(FL_UP_BOX);
+                wf_latency->color(FL_BACKGROUND_COLOR);
+                wf_latency->selection_color(FL_INACTIVE_COLOR);
+                wf_latency->labeltype(FL_NORMAL_LABEL);
+                wf_latency->labelfont(0);
+                wf_latency->labelsize(14);
+                wf_latency->labelcolor(FL_FOREGROUND_COLOR);
+                wf_latency->minimum(1);
+                wf_latency->maximum(16);
+                wf_latency->step(1);
+                wf_latency->value(8);
+                wf_latency->callback((Fl_Callback*)cb_wf_latency);
+                wf_latency->align(Fl_Align(FL_ALIGN_RIGHT));
+                wf_latency->when(FL_WHEN_CHANGED);
+                o->value(progdefaults.wf_latency);
+                o->labelsize(FL_NORMAL_SIZE);
+              } // Fl_Counter2* wf_latency
               o->end();
             } // Fl_Group* o
             { Fl_Group* o = new Fl_Group(27, 221, 490, 80, _("Changes take effect on next program startup"));
diff --git a/src/dialogs/confdialog.fl b/src/dialogs/confdialog.fl
index 8b50e478..d3ccfca8 100644
--- a/src/dialogs/confdialog.fl
+++ b/src/dialogs/confdialog.fl
@@ -2438,6 +2438,17 @@ setwfrange();}
                 code1 {o->labelsize(FL_NORMAL_SIZE);}
                 class Fl_Counter2
               }
+              Fl_Counter wf_latency {
+                label Latency
+                callback {progdefaults.wf_latency = (int)o->value();
+progdefaults.changed = true;}
+                tooltip {Signal averaging over time
+0 - least
+4 - greatest} xywh {295 124 95 22} type Simple align 8 minimum 1 maximum 16 step 1 value 8
+                code0 {o->value(progdefaults.wf_latency);}
+                code1 {o->labelsize(FL_NORMAL_SIZE);}
+                class Fl_Counter2
+              }
             }
             Fl_Group {} {
               label {Changes take effect on next program startup} open
diff --git a/src/include/confdialog.h b/src/include/confdialog.h
index a3d18949..05c48f1a 100644
--- a/src/include/confdialog.h
+++ b/src/include/confdialog.h
@@ -229,6 +229,7 @@ extern Fl_Counter2 *cntLowFreqCutoff;
 extern Fl_Check_Button *btnWFaveraging;
 extern Fl_Choice *mnuFFTPrefilter;
 extern Fl_Counter2 *cntrWfwidth;
+extern Fl_Counter2 *wf_latency;
 extern Fl_Counter2 *cntrWfheight;
 extern Fl_Check_Button *btnWaterfallHistoryDefault;
 extern Fl_Check_Button *btnWaterfallQSY;
diff --git a/src/include/configuration.h b/src/include/configuration.h
index 11cd4d26..4b4f38b5 100644
--- a/src/include/configuration.h
+++ b/src/include/configuration.h
@@ -639,6 +639,9 @@
         ELEM_(bool, WFaveraging, "WFAVERAGING",                                         \
               "Use FFT averaging to decrease waterfall noise",                          \
               false)                                                                    \
+        ELEM_(int, wf_latency, "WF_LATENCY",                                            \
+              "Waterfal latency, 1...16",                                               \
+              8)                                                                        \
         ELEM_(bool, UseCursorLines, "USECURSORLINES",                                   \
               "Draw cursor with vertical lines",                                        \
               true)                                                                     \
diff --git a/src/waterfall/waterfall.cxx b/src/waterfall/waterfall.cxx
index 7a083c4d..dabecd31 100644
--- a/src/waterfall/waterfall.cxx
+++ b/src/waterfall/waterfall.cxx
@@ -503,14 +503,19 @@ void WFdisp::processFFT() {
 
 	if (--dispcnt == 0) {
 		static const int log2disp100 = log2disp(-100);
-		static const double vscale = 2.0 / FFT_LEN;
+		double vscale = 2.0 / FFT_LEN;
 
 		memset(wfbuf, 0, FFT_LEN * sizeof(*wfbuf));
 		void *pv = static_cast<void*>(wfbuf);
 		wf_fft_type *pbuf = static_cast<wf_fft_type*>(pv);
 
-		for (int i = 0; i < FFT_LEN; i++)
-			pbuf[i] = fftwindow[i] * circbuff[i] * vscale;
+		int latency = progdefaults.wf_latency;
+		if (latency < 1) latency = 1;
+		if (latency > 16) latency = 16;
+		int nsamples = FFT_LEN * latency / 16;
+		vscale *= sqrt(16.0 / latency);
+		for (int i = 0; i < nsamples; i++)
+			pbuf[i] = fftwindow[i * 16 / latency] * circbuff[i] * vscale;
 
 		wfft->RealFFT(wfbuf);