AudioSlider: Add option for scroll speed

There seems to be a floating point error somewhere though, since
sometimes it goes up by AudioScrollSpeed - 1 instead of
AudioScrollSpeed...

For the ping https://github.com/scorpion-26/gBar/issues/5

data/config

@@ -41,6 +41,9 @@ CenterTime: true
 # Sets the audio slider to be on reveal (Just like the sensors) when true. Only affects the bar.
 AudioRevealer: false
 
+# Sets the rate of change of the slider on each scroll. In Percent
+AudioScrollSpeed: 5
+
 # The network adapter to use. You can query /sys/class/net for all possible values
 NetworkAdapter: eno1
 

src/Bar.cpp

@@ -268,6 +268,7 @@ namespace Bar
             slider->AddTimer<Slider>(DynCtx::UpdateAudio, DynCtx::updateTimeFast);
             slider->OnValueChange(DynCtx::OnChangeVolume);
             slider->SetRange({0, 1, 0.01});
+            slider->SetScrollSpeed((double)Config::Get().audioScrollSpeed / 100.);
 
             parent.AddChild(std::move(slider));
         };

src/Config.cpp

@@ -142,6 +142,8 @@ void Config::Load()
         AddConfigVar("MinDownloadBytes", config.minDownloadBytes, lineView, foundProperty);
         AddConfigVar("MaxDownloadBytes", config.maxDownloadBytes, lineView, foundProperty);
 
+        AddConfigVar("AudioScrollSpeed", config.audioScrollSpeed, lineView, foundProperty);
+
         if (foundProperty == false)
         {
             LOG("Warning: unknown config var: " << lineView);

src/Config.h

@@ -26,6 +26,8 @@ public:
     uint32_t minDownloadBytes = 0;                // Bottom limit of the network widgets download. Everything above it is considered "under"
     uint32_t maxDownloadBytes = 10 * 1024 * 1024; // 10 MiB Top limit of the network widgets download. Everything above it is considered "over"
 
+    uint32_t audioScrollSpeed = 5; // 5% each scroll
+
     static void Load();
     static const Config& Get();
 };

src/Widget.cpp

@@ -550,6 +550,11 @@ void Slider::SetInverted(bool inverted)
     m_Inverted = inverted;
 }
 
+void Slider::SetScrollSpeed(double speed)
+{
+    m_ScrollSpeed = speed;
+}
+
 void Slider::Create()
 {
     m_Widget = gtk_scale_new_with_range(Utils::ToGtkOrientation(m_Orientation), m_Range.min, m_Range.max, m_Range.step);
@@ -564,6 +569,29 @@ void Slider::Create()
     };
     g_signal_connect(m_Widget, "change-value", G_CALLBACK(+changedFn), this);
 
+    auto scroll = [](GtkWidget*, GdkEventScroll* event, void* data) -> gboolean
+    {
+        Slider* slider = (Slider*)data;
+        double value = gtk_range_get_value((GtkRange*)slider->m_Widget);
+        // Range generates a 'smooth' event.
+        if (event->delta_y >= 0)
+        {
+            value -= slider->m_ScrollSpeed;
+            slider->SetValue(value);
+            if (slider->m_OnValueChange)
+                slider->m_OnValueChange(*slider, value);
+        }
+        else if (event->delta_y <= 0)
+        {
+            value += slider->m_ScrollSpeed;
+            slider->SetValue(value);
+            if (slider->m_OnValueChange)
+                slider->m_OnValueChange(*slider, value);
+        }
+        return GDK_EVENT_STOP;
+    };
+    g_signal_connect(m_Widget, "scroll-event", G_CALLBACK(+scroll), this);
+
     // Propagate events to any parent eventboxes
     auto propagate = [](GtkWidget*, GdkEventCrossing* data, gpointer widget) -> gboolean
     {
@@ -573,7 +601,7 @@ void Slider::Create()
         slider->PropagateToParent((GdkEvent*)data);
         return GDK_EVENT_PROPAGATE;
     };
-    gtk_widget_set_events(m_Widget, GDK_ENTER_NOTIFY_MASK | GDK_LEAVE_NOTIFY_MASK);
+    gtk_widget_set_events(m_Widget, GDK_ENTER_NOTIFY_MASK | GDK_LEAVE_NOTIFY_MASK | GDK_SCROLL_MASK);
     g_signal_connect(m_Widget, "enter-notify-event", G_CALLBACK(+propagate), this);
     g_signal_connect(m_Widget, "leave-notify-event", G_CALLBACK(+propagate), this);
     ApplyPropertiesToWidget();

src/Widget.h

@@ -314,6 +314,7 @@ public:
     void SetOrientation(Orientation orientation);
     void SetInverted(bool flipped);
     void SetRange(SliderRange range);
+    void SetScrollSpeed(double speed);
 
     void OnValueChange(std::function<void(Slider&, double)>&& callback);
 
@@ -323,5 +324,6 @@ private:
     Orientation m_Orientation = Orientation::Horizontal;
     SliderRange m_Range;
     bool m_Inverted = false;
+    double m_ScrollSpeed = 5. / 100.; // 5%
     std::function<void(Slider&, double)> m_OnValueChange;
 };