Add a shift+click waterfall option to set Tx DF

Thanks to Mike W9MDB for contributing this patch.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6512 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

doc/user_guide/en/tutorial-example1.adoc

@@ -84,6 +84,8 @@ call CQ again.)
 - Click somewhere on the waterfall to set Rx frequency (green marker
 on waterfall scale).
 
+- Shift-click on the waterfall to set Tx frequency (red marker).
+
 - Ctrl-click on the waterfall to set both Rx and Tx frequencies.
 
 - Double-click on a signal in the waterfall to set Rx frequency and

mouse_commands.txt

@@ -5,9 +5,11 @@
   </tr>
   <tr>
     <td align="right">Waterfall:</td>
-    <td>Set Rx frequency.<br/>
-        Double-click to set Rx frequency and decode there.<br/>
-        Ctrl-click to set Rx and Tx frequencies and decode.
+    <td>Click to set the Rx frequency.<br/>
+        Shift-click to set Tx frequency.<br/>
+        Ctrl-click to set Rx and Tx frequencies.<br/>
+	Double-clicks decode at the resulting Rx frequency.<br/>
+        If Lock Tx=Rx is checked all actions set Tx/Rx.
     </td>
   </tr>
   <tr>

plotter.cpp

@@ -520,11 +520,20 @@ void CPlotter::mousePressEvent(QMouseEvent *event)             //mousePressEvent
   if(x<0) x=0;
   if(x>m_Size.width()) x=m_Size.width();
   bool ctrl = (event->modifiers() & Qt::ControlModifier);
-  int freq = int(FreqfromX(x)+0.5);
-  int tx_freq = m_txFreq;
-  if (ctrl or m_lockTxFreq) tx_freq = freq;
+  bool shift = (event->modifiers() & Qt::ShiftModifier);
+  int newFreq = int(FreqfromX(x)+0.5);
+  int oldTxFreq = m_txFreq;
+  int oldRxFreq = m_rxFreq;
 
-  emit setFreq1 (freq, tx_freq);
+  if (ctrl or m_lockTxFreq) {
+    emit setFreq1 (newFreq, newFreq);
+  }
+  else if (shift) {
+    emit setFreq1 (oldRxFreq, newFreq);
+  }
+  else {
+    emit setFreq1(newFreq,oldTxFreq);
+  }
 
   int n=1;
   if(ctrl) n+=100;