diff --git a/src/ui/GLPanel.cpp b/src/ui/GLPanel.cpp
index 010fbbc..9b3d78b 100644
--- a/src/ui/GLPanel.cpp
+++ b/src/ui/GLPanel.cpp
@@ -27,7 +27,7 @@ GLPanel::GLPanel() : fillType(GLPANEL_FILL_SOLID), contentsVisible(true), visibl
 }
 
 void GLPanel::genArrays() {
-    float min = -1.0, mid = 0, max = 1.0;
+    float gmin = -1.0, gmid = 0, gmax = 1.0;
     
     if (fillType == GLPANEL_FILL_SOLID || fillType == GLPANEL_FILL_GRAD_X || fillType == GLPANEL_FILL_GRAD_Y) {
         glPoints.reserve(2 * 4);
@@ -36,10 +36,10 @@ void GLPanel::genArrays() {
         glColors.resize(4 * 4);
         
         float pts[2 * 4] = {
-            min, min,
-            min, max,
-            max, max,
-            max, min
+                gmin, gmin,
+                gmin, gmax,
+                gmax, gmax,
+                gmax, gmin
         };
         
         RGBA4f c[4];
@@ -73,15 +73,15 @@ void GLPanel::genArrays() {
         
         if (fillType == GLPANEL_FILL_GRAD_BAR_X) {
             float pts[2 * 8] = {
-                min, min,
-                min, max,
-                mid, max,
-                mid, min,
-                
-                mid, min,
-                mid, max,
-                max, max,
-                max, min
+                    gmin, gmin,
+                    gmin, gmax,
+                    gmid, gmax,
+                    gmid, gmin,
+
+                    gmid, gmin,
+                    gmid, gmax,
+                    gmax, gmax,
+                    gmax, gmin
             };
             glPoints.assign(pts, pts + (2 * 8));
 
@@ -93,15 +93,15 @@ void GLPanel::genArrays() {
 
         } else if (fillType == GLPANEL_FILL_GRAD_BAR_Y) {
             float pts[2 * 8] = {
-                min, min,
-                min, mid,
-                max, mid,
-                max, min,
-                
-                min, mid,
-                min, max,
-                max, max,
-                max, mid
+                    gmin, gmin,
+                    gmin, gmid,
+                    gmax, gmid,
+                    gmax, gmin,
+
+                    gmin, gmid,
+                    gmin, gmax,
+                    gmax, gmax,
+                    gmax, gmid
             };
             glPoints.assign(pts, pts + (2 * 8));
 
@@ -154,11 +154,11 @@ float GLPanel::getHeight() {
     return size[1];
 }
 
-float GLPanel::getWidthPx() {
+float GLPanel::getWidthPx() const {
     return pdim.x;
 }
 
-float GLPanel::getHeightPx() {
+float GLPanel::getHeightPx() const {
     return pdim.y;
 }
 
@@ -179,8 +179,8 @@ void GLPanel::setCoordinateSystem(GLPanelCoordinateSystem coord_in) {
     genArrays();
 }
 
-bool GLPanel::hitTest(CubicVR::vec2 pos, CubicVR::vec2 &result) {
-    CubicVR::vec4 hitPos = CubicVR::mat4::vec4_multiply(CubicVR::vec4(pos.x, pos.y, 0.0, 1.0), transformInverse);
+bool GLPanel::hitTest(CubicVR::vec2 pos_in, CubicVR::vec2 &result) const {
+    CubicVR::vec4 hitPos = CubicVR::mat4::vec4_multiply(CubicVR::vec4(pos_in.x, pos_in.y, 0.0, 1.0), transformInverse);
     
     if (hitPos.x >= -1.0 && hitPos.x <= 1.0 && hitPos.y >= -1.0 && hitPos.y <= 1.0) {
         result.x = hitPos.x;
@@ -197,12 +197,12 @@ void GLPanel::setFill(GLPanelFillType fill_mode) {
     genArrays();
 }
 
-void GLPanel::setFillColor(RGBA4f color1) {
+void GLPanel::setFillColor(const RGBA4f& color1) {
     fill[0] = color1;
     genArrays();
 }
 
-void GLPanel::setFillColor(RGBA4f color1, RGBA4f color2) {
+void GLPanel::setFillColor(const RGBA4f& color1, const RGBA4f& color2) {
     fill[0] = color1;
     fill[1] = color2;
     genArrays();
@@ -213,7 +213,7 @@ void GLPanel::setMarginPx(float marg) {
 }
 
 
-void GLPanel::setBorderColor(RGBA4f clr) {
+void GLPanel::setBorderColor(const RGBA4f& clr) {
     borderColor = clr;
 }
 
@@ -234,7 +234,7 @@ void GLPanel::setBlend(GLuint src, GLuint dst) {
 }
 
 void GLPanel::addChild(GLPanel *childPanel) {
-    std::vector<GLPanel *>::iterator i = std::find(children.begin(), children.end(), childPanel);
+    auto i = std::find(children.begin(), children.end(), childPanel);
 
     if (i == children.end()) {
         children.push_back(childPanel);
@@ -242,7 +242,7 @@ void GLPanel::addChild(GLPanel *childPanel) {
 }
 
 void GLPanel::removeChild(GLPanel *childPanel) {
-    std::vector<GLPanel *>::iterator i = std::find(children.begin(), children.end(), childPanel);
+    auto i = std::find(children.begin(), children.end(), childPanel);
 
     if (i != children.end()) {
         children.erase(i);
@@ -250,7 +250,7 @@ void GLPanel::removeChild(GLPanel *childPanel) {
 }
 
 void GLPanel::drawChildren() {
-    if (children.size()) {
+    if (!children.empty()) {
         std::vector<GLPanel *>::iterator panel_i;
         
         for (panel_i = children.begin(); panel_i != children.end(); panel_i++) {
@@ -306,7 +306,7 @@ void GLPanel::calcTransform(mat4 transform_in) {
 }
 
 void GLPanel::draw() {
-    float min = -1.0, max = 1.0;
+    float gmin = -1.0, gmax = 1.0;
 
     glLoadMatrixf(transform.to_ptr());
     
@@ -330,32 +330,32 @@ void GLPanel::draw() {
             if (borderPx.left) {
                 glLineWidth(borderPx.left);
                 glBegin(GL_LINES);
-                glVertex2f(min, min);
-                glVertex2f(min, max);
+                glVertex2f(gmin, gmin);
+                glVertex2f(gmin, gmax);
                 glEnd();
             }
         
             if (borderPx.right) {
                 glLineWidth(borderPx.right);
                 glBegin(GL_LINES);
-                glVertex2f(max, min);
-                glVertex2f(max, max);
+                glVertex2f(gmax, gmin);
+                glVertex2f(gmax, gmax);
                 glEnd();
             }
 
             if (borderPx.top) {
                 glLineWidth(borderPx.top);
                 glBegin(GL_LINES);
-                glVertex2f(min, min);
-                glVertex2f(max, min);
+                glVertex2f(gmin, gmin);
+                glVertex2f(gmax, gmin);
                 glEnd();
             }
 
             if (borderPx.bottom) {
                 glLineWidth(borderPx.bottom);
                 glBegin(GL_LINES);
-                glVertex2f(min, max);
-                glVertex2f(max, max);
+                glVertex2f(gmin, gmax);
+                glVertex2f(gmax, gmax);
                 glEnd();
             }
 
diff --git a/src/ui/GLPanel.h b/src/ui/GLPanel.h
index 1ab5152..f32fd2e 100644
--- a/src/ui/GLPanel.h
+++ b/src/ui/GLPanel.h
@@ -63,7 +63,7 @@ public:
     std::vector<GLPanel *> children;
     
     GLPanel();
-    virtual ~GLPanel() {};
+    virtual ~GLPanel() = default;;
     
     void setPosition(float x, float y);
 
@@ -71,18 +71,18 @@ public:
     void setSize(float w, float h);
     float getWidth();
     float getHeight();
-    float getWidthPx();
-    float getHeightPx();
+    float getWidthPx() const;
+    float getHeightPx() const;
     void setCoordinateSystem(GLPanelCoordinateSystem coord);
     
-    bool hitTest(CubicVR::vec2 pos, CubicVR::vec2 &result);
+    bool hitTest(CubicVR::vec2 pos_in, CubicVR::vec2 &result) const;
     
     void setFill(GLPanelFillType fill_mode);
-    void setFillColor(RGBA4f color1);
-    void setFillColor(RGBA4f color1, RGBA4f color2);
+    void setFillColor(const RGBA4f& color1);
+    void setFillColor(const RGBA4f& color1, const RGBA4f& color2);
     void setMarginPx(float marg);
 
-    void setBorderColor(RGBA4f clr);
+    void setBorderColor(const RGBA4f& clr);
     void setBorderPx(float bord);
     void setBorderPx(float bordl, float bordr, float bordt, float bordb);
     
@@ -107,7 +107,7 @@ private:
 public:
     GLTextPanel();
     
-    void drawPanelContents();
+    void drawPanelContents() override;
     
     void setText(std::string text, GLFont::Align hAlign = GLFont::GLFONT_ALIGN_CENTER, GLFont::Align vAlign = GLFont::GLFONT_ALIGN_CENTER , bool useNativeFont = false);
     std::string getText();
@@ -119,5 +119,5 @@ public:
         
     }
     
-    void drawPanelContents();
+    void drawPanelContents() override;
 };
diff --git a/src/ui/UITestCanvas.cpp b/src/ui/UITestCanvas.cpp
index 037258e..822d95a 100644
--- a/src/ui/UITestCanvas.cpp
+++ b/src/ui/UITestCanvas.cpp
@@ -15,7 +15,6 @@
 
 #include "CubicSDR.h"
 #include "CubicSDRDefs.h"
-#include "AppFrame.h"
 #include <algorithm>
 
 wxBEGIN_EVENT_TABLE(UITestCanvas, wxGLCanvas) EVT_PAINT(UITestCanvas::OnPaint)
@@ -33,9 +32,7 @@ InteractiveCanvas(parent, dispAttrs) {
     glContext = new UITestContext(this, &wxGetApp().GetContext(this), wxGetApp().GetContextAttributes());
 }
 
-UITestCanvas::~UITestCanvas() {
-    
-}
+UITestCanvas::~UITestCanvas() = default;
 
 void UITestCanvas::OnPaint(wxPaintEvent& WXUNUSED(event)) {
   //  wxPaintDC dc(this);
@@ -61,7 +58,7 @@ void UITestCanvas::OnIdle(wxIdleEvent& /* event */) {
 
 void UITestCanvas::OnMouseMoved(wxMouseEvent& event) {
     InteractiveCanvas::OnMouseMoved(event);
-    
+
 }
 
 void UITestCanvas::OnMouseDown(wxMouseEvent& event) {
diff --git a/src/ui/UITestCanvas.h b/src/ui/UITestCanvas.h
index 27c341e..702cd29 100644
--- a/src/ui/UITestCanvas.h
+++ b/src/ui/UITestCanvas.h
@@ -18,19 +18,19 @@
 class UITestCanvas: public InteractiveCanvas {
 public:
     UITestCanvas(wxWindow *parent, const wxGLAttributes& dispAttrs);
-    ~UITestCanvas();
+    ~UITestCanvas() override;
     
 private:
     void OnPaint(wxPaintEvent& event);
     void OnIdle(wxIdleEvent &event);
-    
+
     void OnMouseMoved(wxMouseEvent& event);
     void OnMouseDown(wxMouseEvent& event);
     void OnMouseWheelMoved(wxMouseEvent& event);
     void OnMouseReleased(wxMouseEvent& event);
     void OnMouseEnterWindow(wxMouseEvent& event);
     void OnMouseLeftWindow(wxMouseEvent& event);
-    
+
     UITestContext *glContext;
     
     wxDECLARE_EVENT_TABLE();
diff --git a/src/visual/ColorTheme.cpp b/src/visual/ColorTheme.cpp
index 8cf73bc..c52aa37 100644
--- a/src/visual/ColorTheme.cpp
+++ b/src/visual/ColorTheme.cpp
@@ -4,17 +4,15 @@
 // SPDX-License-Identifier: GPL-2.0+
 
 #include "ColorTheme.h"
-#include "CubicSDR.h"
-#include "CubicSDRDefs.h"
 
 ThemeMgr ThemeMgr::mgr;
 
-void ThemeMgr::setTheme(int themeId) {
-    currentTheme = themes[themeId];
-    this->themeId = themeId;
+void ThemeMgr::setTheme(int themeId_in) {
+    currentTheme = themes[themeId_in];
+    themeId = themeId_in;
 }
 
-int ThemeMgr::getTheme() {
+int ThemeMgr::getTheme() const {
     return themeId;
 }
 
diff --git a/src/visual/ColorTheme.h b/src/visual/ColorTheme.h
index bb5bce7..6fe88cd 100644
--- a/src/visual/ColorTheme.h
+++ b/src/visual/ColorTheme.h
@@ -27,24 +27,24 @@ public:
             r(r), g(g), b(b), a(a) {
     }
 
-    RGBA4f() :
-            RGBA4f(0, 0, 0) {
-    }
-
-    ~RGBA4f() {
-    }
-
-    RGBA4f & operator=(const RGBA4f &other) {
+    RGBA4f(const RGBA4f &other) {
         r = other.r;
         g = other.g;
         b = other.b;
         a = other.a;
-        return *this;
     }
+
+    RGBA4f() :
+            RGBA4f(0, 0, 0) {
+    }
+
+    ~RGBA4f() = default;
+
+    RGBA4f & operator=(const RGBA4f &other) = default;
     
-    RGBA4f operator*(float v) { return RGBA4f(r*v, g*v, b*v); }
+    RGBA4f operator*(float v) const { return RGBA4f(r*v, g*v, b*v); }
     
-    operator wxColour() {
+    explicit operator wxColour() const {
         return wxColour(
                         (unsigned char) std::min((r * 255.0), 255.0),
                        (unsigned char) std::min((g * 255.0), 255.0),
@@ -90,8 +90,8 @@ public:
     ~ThemeMgr();
     ColorTheme *currentTheme;
     std::map<int, ColorTheme *> themes;
-    void setTheme(int themeId);
-    int getTheme();
+    void setTheme(int themeId_in);
+    int getTheme() const;
     int themeId;
 
     static ThemeMgr mgr;
diff --git a/src/visual/GainCanvas.cpp b/src/visual/GainCanvas.cpp
index f0477a6..9888f8e 100644
--- a/src/visual/GainCanvas.cpp
+++ b/src/visual/GainCanvas.cpp
@@ -14,8 +14,6 @@
 #endif
 
 #include "CubicSDR.h"
-#include "CubicSDRDefs.h"
-#include "AppFrame.h"
 #include <algorithm>
 #include <cmath>
 
@@ -46,9 +44,7 @@ GainCanvas::GainCanvas(wxWindow *parent, const wxGLAttributes& dispAttrs) :
 	userGainAsChanged = false;
 }
 
-GainCanvas::~GainCanvas() {
-
-}
+GainCanvas::~GainCanvas() = default;
 
 void GainCanvas::OnPaint(wxPaintEvent& WXUNUSED(event)) {
   //  wxPaintDC dc(this);
@@ -157,8 +153,6 @@ void GainCanvas::OnMouseDown(wxMouseEvent& event) {
 void GainCanvas::OnMouseWheelMoved(wxMouseEvent& event) {
     InteractiveCanvas::OnMouseWheelMoved(event);
     
-    CubicVR::vec2 hitResult;
-    
     CubicVR::vec2 mpos = mouseTracker.getGLXY();
     
     for (auto gi : gainPanels) {
@@ -217,9 +211,6 @@ void GainCanvas::updateGainUI() {
 	//to take into account a user gain change. Doesn't matter,
 	//UpdateGainValues() takes cares of updating the true value realtime.
     gains = devInfo->getGains(SOAPY_SDR_RX, 0);
-    
-	SDRRangeMap::iterator gi;
-    
     numGains = gains.size();
     float i = 0;
     
@@ -232,15 +223,15 @@ void GainCanvas::updateGainUI() {
     startPos = spacing/2.0;
     barHeight = 1.0f;
     
-    while (gainPanels.size()) {
+    while (!gainPanels.empty()) {
         MeterPanel *mDel = gainPanels.back();
         gainPanels.pop_back();
         bgPanel.removeChild(mDel);
         delete mDel;
     }
 
-    for (auto gi : gains) {
-        MeterPanel *mPanel = new MeterPanel(gi.first, gi.second.minimum(), gi.second.maximum(), devConfig->getGain(gi.first,wxGetApp().getGain(gi.first)));
+    for (const auto& gi : gains) {
+        auto *mPanel = new MeterPanel(gi.first, gi.second.minimum(), gi.second.maximum(), devConfig->getGain(gi.first,wxGetApp().getGain(gi.first)));
 
         float midPos = -1.0+startPos+spacing*i;
         mPanel->setPosition(midPos, 0);
@@ -271,14 +262,13 @@ bool GainCanvas::updateGainValues() {
 	DeviceConfig *devConfig = wxGetApp().getConfig()->getDevice(devInfo->getDeviceId());
 
 	gains = devInfo->getGains(SOAPY_SDR_RX, 0);
-	SDRRangeMap::iterator gi;
 
 	size_t numGainsToRefresh = std::min(gains.size(), gainPanels.size());
 	size_t panelIndex = 0;
 
 	//actually the order of gains iteration should be constant because map of string,
 	//and gainPanels were built in that order in updateGainUI()
-	for (auto gi : gains) {
+	for (const auto& gi : gains) {
 
 		if (panelIndex >= numGainsToRefresh) {
 			break;
diff --git a/src/visual/GainCanvas.h b/src/visual/GainCanvas.h
index 251c8a2..e91d0c9 100644
--- a/src/visual/GainCanvas.h
+++ b/src/visual/GainCanvas.h
@@ -22,7 +22,7 @@
 class GainCanvas: public InteractiveCanvas {
 public:
     GainCanvas(wxWindow *parent, const wxGLAttributes& dispAttrs);
-    ~GainCanvas();
+    ~GainCanvas() override;
 
     void setHelpTip(std::string tip);
     void updateGainUI();
diff --git a/src/visual/ImagePanel.cpp b/src/visual/ImagePanel.cpp
index 041220c..be37ab1 100644
--- a/src/visual/ImagePanel.cpp
+++ b/src/visual/ImagePanel.cpp
@@ -32,7 +32,7 @@ void ImagePanel::render(wxDC&  dc) {
 	double destw = destSize.GetWidth();
 	double desth = destSize.GetHeight();
 
-	double sf = 1.0, wf, hf;
+	double sf, wf, hf;
 
 	wf = destw / imagew;
 	hf = desth / imageh;
diff --git a/src/visual/InteractiveCanvas.cpp b/src/visual/InteractiveCanvas.cpp
index b33ea18..e0fa95a 100644
--- a/src/visual/InteractiveCanvas.cpp
+++ b/src/visual/InteractiveCanvas.cpp
@@ -14,9 +14,6 @@
 #endif
 
 #include "CubicSDR.h"
-#include "CubicSDRDefs.h"
-#include "AppFrame.h"
-#include <algorithm>
 
 #include <wx/numformatter.h>
 
@@ -27,8 +24,7 @@ InteractiveCanvas::InteractiveCanvas(wxWindow *parent, const wxGLAttributes& dis
     mouseTracker.setTarget(this);
 }
 
-InteractiveCanvas::~InteractiveCanvas() {
-}
+InteractiveCanvas::~InteractiveCanvas() = default;
 
 void InteractiveCanvas::setView(long long center_freq_in, long long bandwidth_in) {
     isView = true;
@@ -44,7 +40,7 @@ void InteractiveCanvas::disableView() {
     lastBandwidth = 0;
 }
 
-bool InteractiveCanvas::getViewState() {
+bool InteractiveCanvas::getViewState() const {
     return isView;
 }
 
@@ -66,7 +62,7 @@ void InteractiveCanvas::setCenterFrequency(long long center_freq_in) {
     centerFreq = center_freq_in;
 }
 
-long long InteractiveCanvas::getCenterFrequency() {
+long long InteractiveCanvas::getCenterFrequency() const {
     if (isView) {
         return centerFreq;
     } else {
@@ -78,7 +74,7 @@ void InteractiveCanvas::setBandwidth(long long bandwidth_in) {
     bandwidth = bandwidth_in;
 }
 
-long long InteractiveCanvas::getBandwidth() {
+long long InteractiveCanvas::getBandwidth() const {
     if (isView) {
         return bandwidth;
     } else {
@@ -90,15 +86,15 @@ MouseTracker *InteractiveCanvas::getMouseTracker() {
     return &mouseTracker;
 }
 
-bool InteractiveCanvas::isAltDown() {
+bool InteractiveCanvas::isAltDown() const {
     return altDown;
 }
 
-bool InteractiveCanvas::isCtrlDown() {
+bool InteractiveCanvas::isCtrlDown() const {
     return ctrlDown;
 }
 
-bool InteractiveCanvas::isShiftDown() {
+bool InteractiveCanvas::isShiftDown() const {
     return shiftDown;
 }
 
diff --git a/src/visual/InteractiveCanvas.h b/src/visual/InteractiveCanvas.h
index 14bd1e7..9561fdf 100644
--- a/src/visual/InteractiveCanvas.h
+++ b/src/visual/InteractiveCanvas.h
@@ -13,28 +13,28 @@
 class InteractiveCanvas: public wxGLCanvas {
 public:
     InteractiveCanvas(wxWindow *parent, const wxGLAttributes& dispAttrs);
-    virtual ~InteractiveCanvas();
+    ~InteractiveCanvas() override;
 
     long long getFrequencyAt(float x);
     long long getFrequencyAt(float x, long long iqCenterFreq, long long iqBandwidth);
     
     virtual void setView(long long center_freq_in, long long bandwidth_in);
     virtual void disableView();
-    bool getViewState();
+    bool getViewState() const;
 
     void setCenterFrequency(long long center_freq_in);
-    long long getCenterFrequency();
+    long long getCenterFrequency() const;
 
     void setBandwidth(long long bandwidth_in);
-    long long getBandwidth();
+    long long getBandwidth() const;
 
     MouseTracker *getMouseTracker();
     bool isMouseInView();
     bool isMouseDown();
     
-    bool isAltDown();
-    bool isCtrlDown();
-    bool isShiftDown();
+    bool isAltDown() const;
+    bool isCtrlDown() const;
+    bool isShiftDown() const;
 
 protected:
     void OnKeyDown(wxKeyEvent& event);
diff --git a/src/visual/MeterCanvas.cpp b/src/visual/MeterCanvas.cpp
index 63d67fc..bbc196d 100644
--- a/src/visual/MeterCanvas.cpp
+++ b/src/visual/MeterCanvas.cpp
@@ -36,15 +36,13 @@ MeterCanvas::MeterCanvas(wxWindow *parent, const wxGLAttributes& dispAttrs) :
     glContext = new MeterContext(this, &wxGetApp().GetContext(this), wxGetApp().GetContextAttributes());
 }
 
-MeterCanvas::~MeterCanvas() {
-
-}
+MeterCanvas::~MeterCanvas() = default;
 
 void MeterCanvas::setLevel(float level_in) {
     level = level_in;
     Refresh();
 }
-float MeterCanvas::getLevel() {
+float MeterCanvas::getLevel() const {
     return level;
 }
 
@@ -68,7 +66,7 @@ void MeterCanvas::setInputValue(float slider_in) {
     Refresh();
 }
 
-bool MeterCanvas::inputChanged() {
+bool MeterCanvas::inputChanged() const {
     return (inputValue != userInputValue);
 }
 
@@ -77,8 +75,8 @@ float MeterCanvas::getInputValue() {
     return userInputValue;
 }
 
-void MeterCanvas::setShowUserInput(bool showUserInput) {
-    this->showUserInput = showUserInput;
+void MeterCanvas::setShowUserInput(bool showUserInput_in) {
+    showUserInput = showUserInput_in;
 }
 
 void MeterCanvas::OnPaint(wxPaintEvent& WXUNUSED(event)) {
@@ -151,7 +149,7 @@ void MeterCanvas::OnMouseWheelMoved(wxMouseEvent& event) {
     InteractiveCanvas::OnMouseWheelMoved(event);
     float movement = 3.0 * (float)event.GetWheelRotation();
 
-	float currentValue = 0;
+	float currentValue;
 	if (showUserInput) {
 		currentValue = userInputValue;
 	} else {
diff --git a/src/visual/MeterCanvas.h b/src/visual/MeterCanvas.h
index 1246d7d..2b5094d 100644
--- a/src/visual/MeterCanvas.h
+++ b/src/visual/MeterCanvas.h
@@ -18,19 +18,19 @@
 class MeterCanvas: public InteractiveCanvas {
 public:
     MeterCanvas(wxWindow *parent, const wxGLAttributes& dispAttrs);
-    ~MeterCanvas();
+    ~MeterCanvas() override;
 
     void setLevel(float level_in);
-    float getLevel();
+    float getLevel() const;
 
     void setMax(float max_in);
     void setMin(float max_in);
 
     void setUserInputValue(float slider_in);
     void setInputValue(float slider_in);
-    bool inputChanged();
+    bool inputChanged() const;
     float getInputValue();
-    void setShowUserInput(bool showUserInput);
+    void setShowUserInput(bool showUserInput_in);
 
     void setHelpTip(std::string tip);
 
diff --git a/src/visual/MeterContext.h b/src/visual/MeterContext.h
index e154135..a6373d0 100644
--- a/src/visual/MeterContext.h
+++ b/src/visual/MeterContext.h
@@ -6,8 +6,6 @@
 #include "PrimaryGLContext.h"
 #include "Gradient.h"
 
-#define NUM_WATERFALL_LINES 512
-
 class MeterCanvas;
 
 class MeterContext: public PrimaryGLContext {
diff --git a/src/visual/ModeSelectorCanvas.cpp b/src/visual/ModeSelectorCanvas.cpp
index 16e4ff0..d8b8341 100644
--- a/src/visual/ModeSelectorCanvas.cpp
+++ b/src/visual/ModeSelectorCanvas.cpp
@@ -35,9 +35,7 @@ InteractiveCanvas(parent, dispAttrs), numChoices(0), currentSelection(-1), toggl
     highlightColor = RGBA4f(1.0,1.0,1.0,1.0);
 }
 
-ModeSelectorCanvas::~ModeSelectorCanvas() {
-
-}
+ModeSelectorCanvas::~ModeSelectorCanvas() = default;
 
 int ModeSelectorCanvas::getHoveredSelection() {
     if (!mouseTracker.mouseInView()) {
@@ -163,7 +161,7 @@ void ModeSelectorCanvas::addChoice(std::string label) {
     numChoices = selections.size();
 }
 
-void ModeSelectorCanvas::setSelection(std::string label) {
+void ModeSelectorCanvas::setSelection(const std::string& label) {
     for (int i = 0; i < numChoices; i++) {
         if (selections[i].label == label) {
             currentSelection = i;
@@ -201,11 +199,11 @@ int ModeSelectorCanvas::getSelection() {
     return selections[currentSelection].value;
 }
 
-void ModeSelectorCanvas::setToggleMode(bool toggleMode) {
-    this->toggleMode = toggleMode;
+void ModeSelectorCanvas::setToggleMode(bool toggleMode_in) {
+    toggleMode = toggleMode_in;
 }
 
-bool ModeSelectorCanvas::modeChanged() {
+bool ModeSelectorCanvas::modeChanged() const {
     return inputChanged;
 }
 
@@ -213,12 +211,12 @@ void ModeSelectorCanvas::clearModeChanged() {
     inputChanged = false;
 }
 
-void ModeSelectorCanvas::setPadding(float padX, float padY) {
-    this->padX = padX;
-    this->padY = padY;
+void ModeSelectorCanvas::setPadding(float padX_in, float padY_in) {
+    padX = padX_in;
+    padY = padY_in;
 }
 
-void ModeSelectorCanvas::setHighlightColor(RGBA4f hc) {
-    this->highlightColor = hc;
-    this->highlightOverride = true;
+void ModeSelectorCanvas::setHighlightColor(const RGBA4f& hc) {
+    highlightColor = hc;
+    highlightOverride = true;
 }
diff --git a/src/visual/ModeSelectorCanvas.h b/src/visual/ModeSelectorCanvas.h
index 4fa0abd..fe88f78 100644
--- a/src/visual/ModeSelectorCanvas.h
+++ b/src/visual/ModeSelectorCanvas.h
@@ -28,25 +28,25 @@ public:
 class ModeSelectorCanvas: public InteractiveCanvas {
 public:
     ModeSelectorCanvas(wxWindow *parent, const wxGLAttributes& dispAttrs);
-    ~ModeSelectorCanvas();
+    ~ModeSelectorCanvas() override;
 
     int getHoveredSelection();
     void setHelpTip(std::string tip);
 
     void addChoice(int value, std::string label);
     void addChoice(std::string label);
-    void setSelection(std::string label);
+    void setSelection(const std::string& label);
     std::string getSelectionLabel();
     void setSelection(int value);
     int getSelection();
 
-    void setToggleMode(bool toggleMode);
+    void setToggleMode(bool toggleMode_in);
 
-    bool modeChanged();
+    bool modeChanged() const;
     void clearModeChanged();
     
-    void setPadding(float padX, float padY);
-    void setHighlightColor(RGBA4f hc);
+    void setPadding(float padX_in, float padY_in);
+    void setHighlightColor(const RGBA4f& hc);
     
 private:
     void setNumChoices(int numChoices_in);
diff --git a/src/visual/ModeSelectorContext.cpp b/src/visual/ModeSelectorContext.cpp
index 8eb0005..1b84750 100644
--- a/src/visual/ModeSelectorContext.cpp
+++ b/src/visual/ModeSelectorContext.cpp
@@ -25,7 +25,7 @@ void ModeSelectorContext::DrawBegin() {
     glDisable(GL_TEXTURE_2D);
 }
 
-void ModeSelectorContext::DrawSelector(std::string label, int c, int cMax, bool on, float r, float g, float b, float a, float px, float py) {
+void ModeSelectorContext::DrawSelector(const std::string& label, int c, int cMax, bool on, float r, float g, float b, float a, float px, float py) {
     GLint vp[4];
     glGetIntegerv( GL_VIEWPORT, vp);
 
diff --git a/src/visual/ModeSelectorContext.h b/src/visual/ModeSelectorContext.h
index 7576853..13464bd 100644
--- a/src/visual/ModeSelectorContext.h
+++ b/src/visual/ModeSelectorContext.h
@@ -6,8 +6,6 @@
 #include "PrimaryGLContext.h"
 #include "Gradient.h"
 
-#define NUM_WATERFALL_LINES 512
-
 class ModeSelectorCanvas;
 
 class ModeSelectorContext: public PrimaryGLContext {
@@ -15,6 +13,6 @@ public:
     ModeSelectorContext(ModeSelectorCanvas *canvas, wxGLContext *sharedContext, wxGLContextAttrs *ctxAttrs);
 
     void DrawBegin();
-    void DrawSelector(std::string label, int c, int cMax, bool on, float r, float g, float b, float a, float padx, float pady);
+    void DrawSelector(const std::string& label, int c, int cMax, bool on, float r, float g, float b, float a, float padx, float pady);
     void DrawEnd();
 };
diff --git a/src/visual/PrimaryGLContext.cpp b/src/visual/PrimaryGLContext.cpp
index 5cf3c5d..502caa3 100644
--- a/src/visual/PrimaryGLContext.cpp
+++ b/src/visual/PrimaryGLContext.cpp
@@ -14,13 +14,10 @@
 #endif
 
 #include "CubicSDR.h"
-#include "CubicSDRDefs.h"
-#include "AppFrame.h"
-#include <algorithm>
 
 wxString PrimaryGLContext::glGetwxString(GLenum name) {
     const GLubyte *v = glGetString(name);
-    if (v == 0) {
+    if (v == nullptr) {
         // The error is not important. It is GL_INVALID_ENUM.
         // We just want to clear the error stack.
         glGetError();
@@ -65,7 +62,7 @@ PrimaryGLContext::PrimaryGLContext(wxGLCanvas *canvas, wxGLContext *sharedContex
 //#endif
 }
 
-void PrimaryGLContext::DrawDemodInfo(DemodulatorInstancePtr demod, RGBA4f color, long long center_freq, long long srate, bool centerline) {
+void PrimaryGLContext::DrawDemodInfo(const DemodulatorInstancePtr& demod, const RGBA4f& color, long long center_freq, long long srate, bool centerline) {
     if (!demod) {
         return;
     }
@@ -203,7 +200,7 @@ void PrimaryGLContext::DrawDemodInfo(DemodulatorInstancePtr demod, RGBA4f color,
 
 }
 
-void PrimaryGLContext::DrawFreqBwInfo(long long freq, int bw, RGBA4f color, long long center_freq, long long srate, bool stack, bool centerline) {
+void PrimaryGLContext::DrawFreqBwInfo(long long freq, int bw, const RGBA4f& color, long long center_freq, long long srate, bool stack, bool centerline) {
     if (!srate) {
         srate = wxGetApp().getSampleRate();
     }
@@ -310,7 +307,7 @@ void PrimaryGLContext::DrawFreqBwInfo(long long freq, int bw, RGBA4f color, long
     glDisable(GL_BLEND);
 }
 
-void PrimaryGLContext::DrawDemod(DemodulatorInstancePtr demod, RGBA4f color, long long center_freq, long long srate) {
+void PrimaryGLContext::DrawDemod(const DemodulatorInstancePtr& demod, const RGBA4f& color, long long center_freq, long long srate) {
     if (!demod) {
         return;
     }
@@ -431,7 +428,7 @@ void PrimaryGLContext::drawSingleDemodLabel(const std::wstring& demodStr, float
     refDrawingFont.drawString(demodStr, 2.0 * (uxPos - 0.5), -1.0 + hPos, demodAlign, GLFont::GLFONT_ALIGN_CENTER, 0, 0, true);
 }
 
-void PrimaryGLContext::DrawFreqSelector(float uxPos, RGBA4f color, float w, long long /* center_freq */, long long srate) {
+void PrimaryGLContext::DrawFreqSelector(float uxPos, const RGBA4f& color, float w, long long /* center_freq */, long long srate) {
     
     DemodulatorInstancePtr demod = wxGetApp().getDemodMgr().getCurrentModem();
 
@@ -483,7 +480,7 @@ void PrimaryGLContext::DrawFreqSelector(float uxPos, RGBA4f color, float w, long
 
 }
 
-void PrimaryGLContext::DrawRangeSelector(float uxPos1, float uxPos2, RGBA4f color) {
+void PrimaryGLContext::DrawRangeSelector(float uxPos1, float uxPos2, const RGBA4f& color) {
     if (uxPos2 < uxPos1) {
         float temp = uxPos2;
         uxPos2=uxPos1;
@@ -531,6 +528,6 @@ void PrimaryGLContext::EndDraw() {
 //    CheckGLError();
 }
 
-void PrimaryGLContext::setHoverAlpha(float hoverAlpha) {
-    this->hoverAlpha = hoverAlpha;
+void PrimaryGLContext::setHoverAlpha(float hoverAlpha_in) {
+    hoverAlpha = hoverAlpha_in;
 }
diff --git a/src/visual/PrimaryGLContext.h b/src/visual/PrimaryGLContext.h
index fe3ae13..d87b39c 100644
--- a/src/visual/PrimaryGLContext.h
+++ b/src/visual/PrimaryGLContext.h
@@ -24,14 +24,14 @@ public:
     void BeginDraw(float r, float g, float b);
     void EndDraw();
 
-    void DrawFreqSelector(float uxPos, RGBA4f color, float w = 0, long long center_freq = -1, long long srate = 0);
-    void DrawRangeSelector(float uxPos1, float uxPos2, RGBA4f color);
-    void DrawDemod(DemodulatorInstancePtr demod, RGBA4f color, long long center_freq = -1, long long srate = 0);
+    void DrawFreqSelector(float uxPos, const RGBA4f& color, float w = 0, long long center_freq = -1, long long srate = 0);
+    void DrawRangeSelector(float uxPos1, float uxPos2, const RGBA4f& color);
+    void DrawDemod(const DemodulatorInstancePtr& demod, const RGBA4f& color, long long center_freq = -1, long long srate = 0);
     
-    void DrawDemodInfo(DemodulatorInstancePtr demod, RGBA4f color, long long center_freq = -1, long long srate = 0, bool centerline = false);
-    void DrawFreqBwInfo(long long freq, int bw, RGBA4f color, long long center_freq = - 1, long long srate = 0, bool stack = false, bool centerline = false);
+    void DrawDemodInfo(const DemodulatorInstancePtr& demod, const RGBA4f& color, long long center_freq = -1, long long srate = 0, bool centerline = false);
+    void DrawFreqBwInfo(long long freq, int bw, const RGBA4f& color, long long center_freq = - 1, long long srate = 0, bool stack = false, bool centerline = false);
 
-    void setHoverAlpha(float hoverAlpha);
+    void setHoverAlpha(float hoverAlpha_in);
 
 private:
     float hoverAlpha;
diff --git a/src/visual/ScopeCanvas.cpp b/src/visual/ScopeCanvas.cpp
index 805cc9d..11d2b71 100644
--- a/src/visual/ScopeCanvas.cpp
+++ b/src/visual/ScopeCanvas.cpp
@@ -14,8 +14,6 @@
 #endif
 
 #include "CubicSDR.h"
-#include "CubicSDRDefs.h"
-#include "AppFrame.h"
 #include <algorithm>
 #include <cmath>
 
@@ -31,7 +29,7 @@ EVT_LEAVE_WINDOW(ScopeCanvas::OnMouseLeftWindow)
 EVT_ENTER_WINDOW(ScopeCanvas::OnMouseEnterWindow)
 wxEND_EVENT_TABLE()
 
-ScopeCanvas::ScopeCanvas(wxWindow *parent, const wxGLAttributes& dispAttrs) : InteractiveCanvas(parent, dispAttrs), ppmMode(false), ctr(0), ctrTarget(0), dragAccel(0), helpTip("") {
+ScopeCanvas::ScopeCanvas(wxWindow *parent, const wxGLAttributes& dispAttrs) : InteractiveCanvas(parent, dispAttrs), ppmMode(false), ctr(0), ctrTarget(0), dragAccel(0) {
 
     glContext = new ScopeContext(this, &wxGetApp().GetContext(this), wxGetApp().GetContextAttributes());
     inputData->set_max_num_items(2);
@@ -51,9 +49,7 @@ ScopeCanvas::ScopeCanvas(wxWindow *parent, const wxGLAttributes& dispAttrs) : In
     spectrumPanel.setUseDBOffset(false);
 }
 
-ScopeCanvas::~ScopeCanvas() {
-
-}
+ScopeCanvas::~ScopeCanvas() = default;
 
 bool ScopeCanvas::scopeVisible() {
     float panelInterval = (2.0 + panelSpacing);
@@ -84,11 +80,11 @@ void ScopeCanvas::setDeviceName(std::string device_name) {
     deviceName.append(" ");
 }
 
-void ScopeCanvas::setPPMMode(bool ppmMode) {
-    this->ppmMode = ppmMode;
+void ScopeCanvas::setPPMMode(bool ppmMode_in) {
+    ppmMode = ppmMode_in;
 }
 
-bool ScopeCanvas::getPPMMode() {
+bool ScopeCanvas::getPPMMode() const {
     return ppmMode;
 }
 
@@ -96,7 +92,7 @@ void ScopeCanvas::setShowDb(bool show) {
     this->showDb = show;
 }
 
-bool ScopeCanvas::getShowDb() {
+bool ScopeCanvas::getShowDb() const {
     return showDb;
 }
 
@@ -110,12 +106,12 @@ void ScopeCanvas::OnPaint(wxPaintEvent& WXUNUSED(event)) {
         
         if (!avData->spectrum) {
             scopePanel.setMode(avData->mode);
-            if (avData->waveform_points.size()) {
+            if (!avData->waveform_points.empty()) {
                 scopePanel.setPoints(avData->waveform_points);
             }
 
         } else {
-            if (avData->waveform_points.size()) {
+            if (!avData->waveform_points.empty()) {
                 spectrumPanel.setPoints(avData->waveform_points);
                 spectrumPanel.setFloorValue(avData->fft_floor);
                 spectrumPanel.setCeilValue(avData->fft_ceil);
diff --git a/src/visual/ScopeCanvas.h b/src/visual/ScopeCanvas.h
index 395f808..2a4ca01 100644
--- a/src/visual/ScopeCanvas.h
+++ b/src/visual/ScopeCanvas.h
@@ -32,11 +32,11 @@ public:
     void OnKeyUp(wxKeyEvent& event);
 
     void setDeviceName(std::string device_name);
-    void setPPMMode(bool ppmMode);
-    bool getPPMMode();
+    void setPPMMode(bool ppmMode_in);
+    bool getPPMMode() const;
 
     void setShowDb(bool showDb);
-    bool getShowDb();
+    bool getShowDb() const;
 
     bool scopeVisible();
     bool spectrumVisible();
diff --git a/src/visual/ScopeContext.cpp b/src/visual/ScopeContext.cpp
index 309fa48..c3eb0da 100644
--- a/src/visual/ScopeContext.cpp
+++ b/src/visual/ScopeContext.cpp
@@ -48,7 +48,7 @@ void ScopeContext::DrawTunerTitles(bool ppmMode) {
     refDrawingFont.drawString("Center Frequency", 0.66f, -1.0  +hPos*shiftFactor, GLFont::GLFONT_ALIGN_CENTER, GLFont::GLFONT_ALIGN_CENTER, 0, 0, true);
 }
 
-void ScopeContext::DrawDeviceName(std::string deviceName) {
+void ScopeContext::DrawDeviceName(const std::string& deviceName) {
     GLint vp[4];
     glGetIntegerv(GL_VIEWPORT, vp);
     float viewHeight = (float) vp[3];
@@ -56,7 +56,7 @@ void ScopeContext::DrawDeviceName(std::string deviceName) {
 
     glColor3f(0.65f, 0.65f, 0.65f);
 
-    GLFont::getFont(12, GLFont::getScaleFactor()).drawString(deviceName.c_str(), 1.0, hPos, GLFont::GLFONT_ALIGN_RIGHT, GLFont::GLFONT_ALIGN_CENTER, 0, 0, true);
+    GLFont::getFont(12, GLFont::getScaleFactor()).drawString(deviceName, 1.0, hPos, GLFont::GLFONT_ALIGN_RIGHT, GLFont::GLFONT_ALIGN_CENTER, 0, 0, true);
 }
 
 void ScopeContext::DrawEnd() {
diff --git a/src/visual/ScopeContext.h b/src/visual/ScopeContext.h
index 1b0030c..cacdd07 100644
--- a/src/visual/ScopeContext.h
+++ b/src/visual/ScopeContext.h
@@ -6,8 +6,6 @@
 #include "PrimaryGLContext.h"
 #include "Gradient.h"
 
-#define NUM_WATERFALL_LINES 512
-
 class ScopeCanvas;
 
 class ScopeContext: public PrimaryGLContext {
@@ -16,7 +14,7 @@ public:
 
     void DrawBegin(bool clear=true);
     void DrawTunerTitles(bool ppmMode=false);
-    void DrawDeviceName(std::string deviceName);
+    void DrawDeviceName(const std::string& deviceName);
     void DrawDivider();
     void DrawEnd();
 
diff --git a/src/visual/SpectrumCanvas.cpp b/src/visual/SpectrumCanvas.cpp
index 2427408..c36da4d 100644
--- a/src/visual/SpectrumCanvas.cpp
+++ b/src/visual/SpectrumCanvas.cpp
@@ -17,7 +17,6 @@
 #include "CubicSDRDefs.h"
 #include "AppFrame.h"
 #include <algorithm>
-#include <wx/numformatter.h>
 #include "WaterfallCanvas.h"
 
 wxBEGIN_EVENT_TABLE(SpectrumCanvas, wxGLCanvas) EVT_PAINT(SpectrumCanvas::OnPaint)
@@ -33,7 +32,7 @@ EVT_RIGHT_UP(SpectrumCanvas::OnMouseRightReleased)
 wxEND_EVENT_TABLE()
 
 SpectrumCanvas::SpectrumCanvas(wxWindow *parent, const wxGLAttributes& dispAttrs) :
-        InteractiveCanvas(parent, dispAttrs), waterfallCanvas(NULL) {
+        InteractiveCanvas(parent, dispAttrs), waterfallCanvas(nullptr) {
 
     glContext = new PrimaryGLContext(this, &wxGetApp().GetContext(this), wxGetApp().GetContextAttributes());
 
@@ -46,9 +45,7 @@ SpectrumCanvas::SpectrumCanvas(wxWindow *parent, const wxGLAttributes& dispAttrs
     bwChange = 0.0;
 }
 
-SpectrumCanvas::~SpectrumCanvas() {
-
-}
+SpectrumCanvas::~SpectrumCanvas() = default;
 
 void SpectrumCanvas::OnPaint(wxPaintEvent& WXUNUSED(event)) {
   //  wxPaintDC dc(this);
@@ -93,11 +90,11 @@ void SpectrumCanvas::OnPaint(wxPaintEvent& WXUNUSED(event)) {
     auto demods = wxGetApp().getDemodMgr().getDemodulators();
     auto activeDemodulator = wxGetApp().getDemodMgr().getActiveContextModem();
 
-    for (int i = 0, iMax = demods.size(); i < iMax; i++) {
-        if (!demods[i]->isActive()) {
+    for (auto & demod : demods) {
+        if (!demod->isActive()) {
             continue;
         }
-        glContext->DrawDemodInfo(demods[i], ThemeMgr::mgr.currentTheme->fftHighlight, getCenterFrequency(), getBandwidth(), activeDemodulator==demods[i]);
+        glContext->DrawDemodInfo(demod, ThemeMgr::mgr.currentTheme->fftHighlight, getCenterFrequency(), getBandwidth(), activeDemodulator==demod);
     }
 
     if (waterfallCanvas && !activeDemodulator) {
diff --git a/src/visual/SpectrumCanvas.h b/src/visual/SpectrumCanvas.h
index 2d63591..bbe7586 100644
--- a/src/visual/SpectrumCanvas.h
+++ b/src/visual/SpectrumCanvas.h
@@ -18,7 +18,7 @@ class WaterfallCanvas;
 class SpectrumCanvas: public InteractiveCanvas {
 public:
     SpectrumCanvas(wxWindow *parent, const wxGLAttributes& dispAttrs);
-    ~SpectrumCanvas();
+    ~SpectrumCanvas() override;
 
     //This is public because it is indeed forwarded from
     //AppFrame::OnGlobalKeyDown, because global key handler intercepts 
@@ -40,7 +40,7 @@ public:
     bool getUseDBOfs();
     
     void setView(long long center_freq_in, int bandwidth_in);
-    void disableView();
+    void disableView() override;
 
     void setScaleFactorEnabled(bool en);
     void setFFTSize(int fftSize);
diff --git a/src/visual/TuningCanvas.cpp b/src/visual/TuningCanvas.cpp
index 476f04f..bbc5385 100644
--- a/src/visual/TuningCanvas.cpp
+++ b/src/visual/TuningCanvas.cpp
@@ -56,9 +56,7 @@ TuningCanvas::TuningCanvas(wxWindow *parent, const wxGLAttributes& dispAttrs) :
     currentPPM = lastPPM = 0;
 }
 
-TuningCanvas::~TuningCanvas() {
-
-}
+TuningCanvas::~TuningCanvas() = default;
 
 bool TuningCanvas::changed() {
 
@@ -182,52 +180,52 @@ void TuningCanvas::StepTuner(ActiveState state, TuningDirection tuningDir, int d
     
     auto activeDemod = wxGetApp().getDemodMgr().getCurrentModem();
     if (state == TUNING_HOVER_FREQ && activeDemod) {
-        long long freq = activeDemod->getFrequency();
-        long long diff = abs(wxGetApp().getFrequency() - freq);
+        long long demod_freq = activeDemod->getFrequency();
+        long long diff = abs(wxGetApp().getFrequency() - demod_freq);
 
         if (zeroOut) { // Zero digits to right
             double intpart;
-            modf(freq / (exp * 10), &intpart);
-            freq = intpart * exp * 10;
+            modf(demod_freq / (exp * 10), &intpart);
+            demod_freq = intpart * exp * 10;
         } else if (preventCarry) { // Prevent digit from carrying
-            bool carried = (long long)((freq) / (exp * 10)) != (long long)((freq + amount) / (exp * 10)) || (bottom && freq < exp);
-            freq += carried?(9*-amount):amount;
+            bool carried = (long long)((demod_freq) / (exp * 10)) != (long long)((demod_freq + amount) / (exp * 10)) || (bottom && demod_freq < exp);
+            demod_freq += carried ? (9 * -amount) : amount;
         } else {
-            freq += amount;
+            demod_freq += amount;
         }
 
         if (wxGetApp().getSampleRate() / 2 < diff) {
-            wxGetApp().setFrequency(freq);
+            wxGetApp().setFrequency(demod_freq);
         }
 
         activeDemod->setTracking(true);
         activeDemod->setFollow(true);
-        activeDemod->setFrequency(freq);
+        activeDemod->setFrequency(demod_freq);
         if (activeDemod->isDeltaLock()) {
             activeDemod->setDeltaLockOfs(activeDemod->getFrequency() - wxGetApp().getFrequency());
         }
-        activeDemod->updateLabel(freq);
+        activeDemod->updateLabel(demod_freq);
     }
 
     if (state == TUNING_HOVER_BW) {
-        long bw = wxGetApp().getDemodMgr().getLastBandwidth();
+        long nbw = wxGetApp().getDemodMgr().getLastBandwidth();
 
         if (zeroOut) { // Zero digits to right
             double intpart;
-            modf(bw / (exp * 10), &intpart);
-            bw = intpart * exp * 10;
+            modf(nbw / (exp * 10), &intpart);
+            nbw = intpart * exp * 10;
         } else if (preventCarry) { // Prevent digit from carrying
-            bool carried = (long)((bw) / (exp * 10)) != (long)((bw + amount) / (exp * 10)) || (bottom && bw < exp);
-            bw += carried?(9*-amount):amount;
+            bool carried = (long)((nbw) / (exp * 10)) != (long)((nbw + amount) / (exp * 10)) || (bottom && nbw < exp);
+            nbw += carried ? (9 * -amount) : amount;
         } else {
-            bw += amount;
+            nbw += amount;
         }
 
-        if (bw > CHANNELIZER_RATE_MAX) {
-            bw = CHANNELIZER_RATE_MAX;
+        if (nbw > CHANNELIZER_RATE_MAX) {
+            nbw = CHANNELIZER_RATE_MAX;
         }
 
-        wxGetApp().getDemodMgr().setLastBandwidth(bw);
+        wxGetApp().getDemodMgr().setLastBandwidth(nbw);
 
         if (activeDemod) {
             activeDemod->setBandwidth(wxGetApp().getDemodMgr().getLastBandwidth());
@@ -298,12 +296,10 @@ void TuningCanvas::OnIdle(wxIdleEvent & /* event */) {
 void TuningCanvas::OnMouseMoved(wxMouseEvent& event) {
     InteractiveCanvas::OnMouseMoved(event);
 
-    int index = 0;
-
     top = mouseTracker.getMouseY() >= 0.5;
     bottom = mouseTracker.getMouseY() <= 0.5;
 
-    index = glContext->GetTunerDigitIndex(mouseTracker.getMouseX(), 11, freqDP, freqW); // freq
+    int index = glContext->GetTunerDigitIndex(mouseTracker.getMouseX(), 11, freqDP, freqW); // freq
     if (index > 0) {
         hoverIndex = index;
         hoverState = altDown?TUNING_HOVER_PPM:TUNING_HOVER_FREQ;
diff --git a/src/visual/TuningCanvas.h b/src/visual/TuningCanvas.h
index dad6665..1f1193b 100644
--- a/src/visual/TuningCanvas.h
+++ b/src/visual/TuningCanvas.h
@@ -24,7 +24,7 @@ public:
         TUNING_DIRECTION_DOWN, TUNING_DIRECTION_UP
     };
     TuningCanvas(wxWindow *parent, const wxGLAttributes& dispAttrs);
-    ~TuningCanvas();
+    ~TuningCanvas() override;
 
     void setHelpTip(std::string tip);
     bool changed();
diff --git a/src/visual/TuningContext.cpp b/src/visual/TuningContext.cpp
index 5575c4e..c3742ab 100644
--- a/src/visual/TuningContext.cpp
+++ b/src/visual/TuningContext.cpp
@@ -9,11 +9,11 @@
 // http://stackoverflow.com/questions/7276826/c-format-number-with-commas
 class comma_numpunct: public std::numpunct<char> {
 protected:
-    virtual char do_thousands_sep() const {
+    char do_thousands_sep() const override {
         return ',';
     }
 
-    virtual std::string do_grouping() const {
+    std::string do_grouping() const override {
         return "\03";
     }
 };
@@ -120,7 +120,7 @@ void TuningContext::DrawTuner(long long freq, int count, float displayPos, float
 }
 
 
-void TuningContext::DrawTunerDigitBox(int index, int count, float displayPos, float displayWidth, RGBA4f /* c */) {
+void TuningContext::DrawTunerDigitBox(int index, int count, float displayPos, float displayWidth, const RGBA4f& /* c */) {
     GLint vp[4];
     glGetIntegerv( GL_VIEWPORT, vp);
 
@@ -160,7 +160,7 @@ int TuningContext::GetTunerDigitIndex(float mPos, int count, float displayPos, f
     return count - index;
 }
 
-void TuningContext::DrawTunerBarIndexed(int start, int end, int count, float displayPos, float displayWidth, RGBA4f color, float /* alpha */, bool top,
+void TuningContext::DrawTunerBarIndexed(int start, int end, int count, float displayPos, float displayWidth, const RGBA4f& color, float /* alpha */, bool top,
 bool bottom) {
     float ofs = (displayWidth / (float) count);
     float p2 = displayPos + ofs * (float) (count - start + 1);
diff --git a/src/visual/TuningContext.h b/src/visual/TuningContext.h
index 13b8eef..2e1347c 100644
--- a/src/visual/TuningContext.h
+++ b/src/visual/TuningContext.h
@@ -6,8 +6,6 @@
 #include "PrimaryGLContext.h"
 #include "Gradient.h"
 
-#define NUM_WATERFALL_LINES 512
-
 class TuningCanvas;
 
 class TuningContext: public PrimaryGLContext {
@@ -17,9 +15,9 @@ public:
     void DrawBegin();
     void Draw(float r, float g, float b, float a, float p1, float p2);
     void DrawTuner(long long freq, int count, float displayPos, float displayWidth);
-    void DrawTunerDigitBox(int index, int count, float displayPos, float displayWidth, RGBA4f c);
+    static void DrawTunerDigitBox(int index, int count, float displayPos, float displayWidth, const RGBA4f& c);
     int GetTunerDigitIndex(float mPos, int count, float displayPos, float displayWidth);
-    void DrawTunerBarIndexed(int start, int end, int count, float displayPos, float displayWidth, RGBA4f color, float alpha, bool top, bool bottom);
+    void DrawTunerBarIndexed(int start, int end, int count, float displayPos, float displayWidth, const RGBA4f& color, float alpha, bool top, bool bottom);
 
     void DrawDemodFreqBw(long long freq, unsigned int bw, long long center);
     void DrawEnd();
diff --git a/src/visual/WaterfallCanvas.cpp b/src/visual/WaterfallCanvas.cpp
index a77ecb0..0280c1a 100644
--- a/src/visual/WaterfallCanvas.cpp
+++ b/src/visual/WaterfallCanvas.cpp
@@ -53,8 +53,7 @@ WaterfallCanvas::WaterfallCanvas(wxWindow *parent, const wxGLAttributes& dispAtt
     fft_size_changed.store(false);
 }
 
-WaterfallCanvas::~WaterfallCanvas() {
-}
+WaterfallCanvas::~WaterfallCanvas() = default;
 
 void WaterfallCanvas::setup(unsigned int fft_size_in, int waterfall_lines_in) {
     if (fft_size == fft_size_in && waterfall_lines_in == waterfall_lines) {
@@ -333,23 +332,23 @@ void WaterfallCanvas::OnPaint(wxPaintEvent& WXUNUSED(event)) {
 
     glContext->setHoverAlpha(0);
 
-    for (int i = 0, iMax = demods.size(); i < iMax; i++) {
-        if (!demods[i]->isActive()) {
+    for (auto & demod : demods) {
+        if (!demod->isActive()) {
             continue;
         }
-        if (activeDemodulator == demods[i] || lastActiveDemodulator == demods[i]) {
+        if (activeDemodulator == demod || lastActiveDemodulator == demod) {
             continue;
         }
-        glContext->DrawDemod(demods[i], currentTheme->waterfallHighlight, currentCenterFreq, currentBandwidth);
+        glContext->DrawDemod(demod, currentTheme->waterfallHighlight, currentCenterFreq, currentBandwidth);
     }
 
-    for (int i = 0, iMax = demods.size(); i < iMax; i++) {
-        demods[i]->getVisualCue()->step();
+    for (auto & demod : demods) {
+        demod->getVisualCue()->step();
 
-        int squelchBreak = demods[i]->getVisualCue()->getSquelchBreak();
+        int squelchBreak = demod->getVisualCue()->getSquelchBreak();
         if (squelchBreak) {
             glContext->setHoverAlpha((float(squelchBreak) / 60.0));
-            glContext->DrawDemod(demods[i], currentTheme->waterfallHover, currentCenterFreq, currentBandwidth);
+            glContext->DrawDemod(demod, currentTheme->waterfallHover, currentCenterFreq, currentBandwidth);
         }
     }
     
@@ -452,15 +451,15 @@ void WaterfallCanvas::OnKeyDown(wxKeyEvent& event) {
         if (wxGetApp().getDemodMgr().getActiveContextModem()) {
             wxGetApp().setFrequency(wxGetApp().getDemodMgr().getActiveContextModem()->getFrequency());
         } else if (mouseTracker.mouseInView()) {
-            long long freq = getFrequencyAt(mouseTracker.getMouseX());
+            long long nfreq = getFrequencyAt(mouseTracker.getMouseX());
             
             int snap = wxGetApp().getFrequencySnap();
             
             if (snap > 1) {
-                freq = roundf((float)freq/(float)snap)*snap;
+                nfreq = roundf((float)nfreq / (float)snap) * snap;
             }
             
-            wxGetApp().setFrequency(freq);
+            wxGetApp().setFrequency(nfreq);
         }
 #ifdef USE_HAMLIB
         if (wxGetApp().rigIsActive() && (!wxGetApp().getRigThread()->getControlMode() || wxGetApp().getRigThread()->getCenterLock())) {
@@ -504,13 +503,12 @@ void WaterfallCanvas::updateHoverState() {
         } else {
             setStatusText("Click and drag to set the current demodulator range.");
         }
-    } else if (demodsHover.size() && !shiftDown) {
+    } else if (!demodsHover.empty() && !shiftDown) {
         long near_dist = getBandwidth();
         
         DemodulatorInstancePtr activeDemodulator = nullptr;
         
-        for (int i = 0, iMax = demodsHover.size(); i < iMax; i++) {
-            auto demod = demodsHover[i];
+        for (auto demod : demodsHover) {
             long long freqDiff = demod->getFrequency() - freqPos;
             long halfBw = (demod->getBandwidth() / 2);
             long long currentBw = getBandwidth();
@@ -708,7 +706,7 @@ void WaterfallCanvas::OnMouseReleased(wxMouseEvent& event) {
 
 
         if (dragState == WF_DRAG_NONE) {
-            if (!isNew && wxGetApp().getDemodMgr().getDemodulators().size()) {
+            if (!isNew && !wxGetApp().getDemodMgr().getDemodulators().empty()) {
                 mgr->updateLastState();
                 demod = wxGetApp().getDemodMgr().getCurrentModem();
             } else {
@@ -809,7 +807,7 @@ void WaterfallCanvas::OnMouseReleased(wxMouseEvent& event) {
         }
 
 
-        if (!isNew && wxGetApp().getDemodMgr().getDemodulators().size()) {
+        if (!isNew && !wxGetApp().getDemodMgr().getDemodulators().empty()) {
             mgr->updateLastState();
             demod = wxGetApp().getDemodMgr().getCurrentModem();
         } else {
diff --git a/src/visual/WaterfallCanvas.h b/src/visual/WaterfallCanvas.h
index d7ba9de..ee4ec16 100644
--- a/src/visual/WaterfallCanvas.h
+++ b/src/visual/WaterfallCanvas.h
@@ -24,7 +24,7 @@ public:
     WaterfallCanvas(wxWindow *parent, const wxGLAttributes& dispAttrs);
     void setup(unsigned int fft_size_in, int waterfall_lines_in);
     void setFFTSize(unsigned int fft_size_in);
-    ~WaterfallCanvas();
+    ~WaterfallCanvas() override;
 
     DragState getDragState();
     DragState getNextDragState();