From 703865214133371fcb0fdb67870e0816db5171e4 Mon Sep 17 00:00:00 2001
From: "Charles J. Cliffe" <cj@cubicproductions.com>
Date: Fri, 11 Dec 2015 19:57:40 -0500
Subject: [PATCH] Fix some waterfall zoom navigation mistakes

---
 src/visual/InteractiveCanvas.cpp |  6 ++++++
 src/visual/InteractiveCanvas.h   |  3 ++-
 src/visual/WaterfallCanvas.cpp   | 21 +++++++++++----------
 3 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/src/visual/InteractiveCanvas.cpp b/src/visual/InteractiveCanvas.cpp
index 9015de9..228277f 100644
--- a/src/visual/InteractiveCanvas.cpp
+++ b/src/visual/InteractiveCanvas.cpp
@@ -53,6 +53,12 @@ long long InteractiveCanvas::getFrequencyAt(float x) {
     return freq;
 }
 
+long long InteractiveCanvas::getFrequencyAt(float x, long long iqCenterFreq, long long iqBandwidth) {
+    long long freq = iqCenterFreq - (long long)(0.5 * (long double) iqBandwidth) + ((long double) x * (long double) iqBandwidth);
+    
+    return freq;
+}
+
 void InteractiveCanvas::setCenterFrequency(long long center_freq_in) {
     centerFreq = center_freq_in;
 }
diff --git a/src/visual/InteractiveCanvas.h b/src/visual/InteractiveCanvas.h
index 28072cf..f310918 100644
--- a/src/visual/InteractiveCanvas.h
+++ b/src/visual/InteractiveCanvas.h
@@ -12,7 +12,8 @@ public:
     ~InteractiveCanvas();
 
     long long getFrequencyAt(float x);
-
+    long long getFrequencyAt(float x, long long iqCenterFreq, long long iqBandwidth);
+    
     virtual void setView(long long center_freq_in, int bandwidth_in);
     virtual void disableView();
     bool getViewState();
diff --git a/src/visual/WaterfallCanvas.cpp b/src/visual/WaterfallCanvas.cpp
index 6f4ed05..da8302c 100644
--- a/src/visual/WaterfallCanvas.cpp
+++ b/src/visual/WaterfallCanvas.cpp
@@ -182,9 +182,8 @@ void WaterfallCanvas::OnPaint(wxPaintEvent& WXUNUSED(event)) {
                 bw = minBandwidth;
             }
             if (mouseInView) {
-                long long mfreqA = getFrequencyAt(mpos);
-                setBandwidth(bw);
-                long long mfreqB = getFrequencyAt(mpos);
+                long long mfreqA = getFrequencyAt(mpos, centerFreq, getBandwidth());
+                long long mfreqB = getFrequencyAt(mpos, centerFreq, bw);
                 centerFreq += mfreqA - mfreqB;
             }
             
@@ -198,12 +197,14 @@ void WaterfallCanvas::OnPaint(wxPaintEvent& WXUNUSED(event)) {
                     if (spectrumCanvas) {
                         spectrumCanvas->disableView();
                     }
+                    bw = wxGetApp().getSampleRate();
+                    centerFreq = wxGetApp().getFrequency();
                 } else {
                     if (mouseInView) {
-                        long long mfreqA = getFrequencyAt(mpos);
-                        setBandwidth(bw);
-                        long long mfreqB = getFrequencyAt(mpos);
+                        long long mfreqA = getFrequencyAt(mpos, centerFreq, getBandwidth());
+                        long long mfreqB = getFrequencyAt(mpos, centerFreq, bw);
                         centerFreq += mfreqA - mfreqB;
+                        setBandwidth(bw);
                     } else {
                         setBandwidth(bw);
                     }
@@ -822,11 +823,11 @@ void WaterfallCanvas::updateCenterFrequency(long long freq) {
         long long minFreq = wxGetApp().getFrequency()-(wxGetApp().getSampleRate()/2);
         long long maxFreq = wxGetApp().getFrequency()+(wxGetApp().getSampleRate()/2);
         
-        if (freq < minFreq) {
-            wxGetApp().setFrequency(freq+(wxGetApp().getSampleRate()/2));
+        if (freq - bandwidth / 2 < minFreq) {
+            wxGetApp().setFrequency(wxGetApp().getFrequency() - (minFreq - (freq - bandwidth/2)));
         }
-        if (freq > maxFreq) {
-            wxGetApp().setFrequency(freq-(wxGetApp().getSampleRate()/2));
+        if (freq + bandwidth / 2 > maxFreq) {
+            wxGetApp().setFrequency(wxGetApp().getFrequency() + ((freq + bandwidth/2) - maxFreq));
         }
     } else {
         if (spectrumCanvas) {