add volume widget

include/bar/bar.hpp

@@ -27,6 +27,7 @@ class Bar : public Gtk::Window
     int m_monitorId;
     WorkspaceIndicator *m_workspaceIndicator = nullptr;
     TrayWidget *m_trayWidget = nullptr;
+    class VolumeWidget *m_volumeWidget = nullptr;
 
     void setup_ui();
     void load_css();

include/helpers/systemHelper.hpp

@@ -1,7 +1,10 @@
 #pragma once
 
+#include <array>
 #include <memory>
 #include <string>
+#include <fstream>
+#include <sstream>
 
 class SystemHelper
 {
@@ -25,4 +28,18 @@ class SystemHelper
 
         return result;
     }
+
+    // Read an entire file into a string. Throws std::runtime_error on failure.
+    static std::string read_file_to_string(const std::string &path)
+    {
+        std::ifstream in(path, std::ios::in | std::ios::binary);
+        if (!in)
+        {
+            throw std::runtime_error("Failed to open file: " + path);
+        }
+
+        std::ostringstream ss;
+        ss << in.rdbuf();
+        return ss.str();
+    }
 };

include/widgets/spacer.hpp

@@ -0,0 +1,17 @@
+#pragma once
+
+#include <gtk4-layer-shell/gtk4-layer-shell.h>
+#include <gtkmm.h>
+#include <gtkmm/label.h>
+
+
+class Spacer : public Gtk::Label 
+{
+  public:
+    Spacer()
+    {
+        set_hexpand(true);
+        set_text("|");
+        set_name("spacer");
+    }
+};

include/widgets/volumeWidget.hpp

@@ -0,0 +1,24 @@
+#pragma once
+
+#include <gtkmm.h>
+#include <string>
+#include <sigc++/sigc++.h>
+
+class VolumeWidget : public Gtk::Box
+{
+  public:
+    VolumeWidget();
+    virtual ~VolumeWidget();
+
+    // Refresh displayed volume from the system
+    void update();
+
+  protected:
+    // timeout handler for periodic polling; return true to keep polling
+    bool on_timeout();
+
+  private:
+    Gtk::Label m_label;
+    Glib::RefPtr<Gtk::GestureClick> m_click;
+    sigc::connection m_timeoutConn;
+};