Add active window title widget

This widget called "Title" is a simple text with the title of the
currently active window. To prevent clipping the size of the title is capped by the
config variable "MaxTitleLength".

Implements https://github.com/scorpion-26/gBar/issues/77

css/style.css

@@ -20,6 +20,10 @@
   font-size: 16px;
 }
 
+.title-text {
+  font-size: 16px;
+}
+
 .reboot-button {
   font-size: 28px;
   color: #6272a4;

css/style.scss

@@ -45,6 +45,10 @@ $textsize: 16px;
     font-size: $textsize;
 }
 
+.title-text {
+    font-size: $textsize;
+}
+
 .reboot-button {
     font-size: 28px;
     

data/config

@@ -119,6 +119,10 @@ DateTimeStyle: %a %D - %H:%M:%S %Z
 # Set datetime locale (defaults to system locale if not set or set to empty string)
 #DateTimeLocale: de_DE.utf8
 
+# How many characters of the title can be displayed. Note that higher values *will* cause styling issues, especially when it is in the center.
+# If you have the title in the center, consider also increasing "CenterSpace"
+MaxTitleLength: 30
+
 # Adds a audio input(aka. microphone) widget
 AudioInput: false
 

meson.build

@@ -23,6 +23,15 @@ ext_workspace_header = custom_target('generate-ext-workspace-header',
                                   output: ['ext-workspace-unstable-v1.h'],
                                   command: [wayland_scanner, 'client-header', '@INPUT@', '@OUTPUT@'])
 
+wlr_foreign_toplevel_src = custom_target('generate-wlr-foreign-toplevel-src',
+                                  input: ['protocols/wlr-foreign-toplevel-management-unstable-v1.xml'],
+                                  output: ['wlr-foreign-toplevel-management-unstable-v1.c'],
+                                  command: [wayland_scanner, 'private-code', '@INPUT@', '@OUTPUT@'])
+
+wlr_foreign_toplevel_header = custom_target('generate-wlr-foreign-toplevel-header',
+                                  input: ['protocols/wlr-foreign-toplevel-management-unstable-v1.xml'],
+                                  output: ['wlr-foreign-toplevel-management-unstable-v1.h'],
+                                  command: [wayland_scanner, 'client-header', '@INPUT@', '@OUTPUT@'])
 gtk = dependency('gtk+-3.0')
 gtk_layer_shell = dependency('gtk-layer-shell-0')
 
@@ -46,6 +55,8 @@ headers = [
 sources = [
     ext_workspace_src,
     ext_workspace_header,
+    wlr_foreign_toplevel_src,
+    wlr_foreign_toplevel_header,
    'src/Window.cpp',
    'src/Widget.cpp',
    'src/Wayland.cpp',

src/Bar.cpp

@@ -4,8 +4,8 @@
 #include "Common.h"
 #include "Config.h"
 #include "SNI.h"
-#include <cmath>
 #include <mutex>
+#include <cstdlib>
 
 namespace Bar
 {
@@ -389,6 +389,20 @@ namespace Bar
             return TimerResult::Ok;
         }
 
+        TimerResult UpdateTitle(Text& text)
+        {
+            std::string title = System::GetActiveWindowTitle();
+            if (title.size() > Config::Get().maxTitleLength)
+            {
+                constexpr std::string_view ellipsis = "...";
+                uint32_t newLength = std::max(Config::Get().maxTitleLength - ellipsis.size(), (size_t)0);
+                title.resize(newLength);
+                title += ellipsis;
+            }
+            text.SetText(title);
+            return TimerResult::Ok;
+        }
+
 #ifdef WITH_WORKSPACES
         static std::vector<Button*> workspaces;
         TimerResult UpdateWorkspaces(Box&)
@@ -1085,6 +1099,18 @@ namespace Bar
         parent.AddChild(std::move(time));
     }
 
+    void WidgetTitle(Widget& parent, Side side)
+    {
+        auto title = Widget::Create<Text>();
+        Utils::SetTransform(*title, {-1, side == Side::Center, SideToAlignment(side)});
+        title->SetAngle(Utils::GetAngle());
+        title->SetClass("widget");
+        title->AddClass("title-text");
+        title->SetText("Uninitialized");
+        title->AddTimer<Text>(DynCtx::UpdateTitle, DynCtx::updateTimeFast);
+        parent.AddChild(std::move(title));
+    }
+
     void ChooseWidgetToDraw(const std::string& widgetName, Widget& parent, Side side)
     {
         if (widgetName == "Workspaces")
@@ -1102,6 +1128,11 @@ namespace Bar
             WidgetTime(parent, side);
             return;
         }
+        if (widgetName == "Title")
+        {
+            WidgetTitle(parent, side);
+            return;
+        }
         if (widgetName == "Tray")
         {
 #ifdef WITH_SNI
@@ -1184,7 +1215,7 @@ namespace Bar
         }
         LOG("Warning: Unkwown widget name " << widgetName << "!"
                                             << "\n\tKnown names are: Workspaces, Time, Tray, Packages, Audio, Bluetooth, Network, Sensors, Disk, "
-                                               "VRAM, GPU, RAM, CPU, Battery, Power");
+                                               "VRAM, GPU, RAM, CPU, Battery, Power, Title");
     }
 
     void Create(Window& window, const std::string& monitorName)

src/Config.cpp

@@ -302,6 +302,7 @@ void Config::Load(const std::string& overrideConfigLocation)
 
         AddConfigVar("CheckUpdateInterval", config.checkUpdateInterval, lineView, foundProperty);
         AddConfigVar("CenterSpace", config.centerSpace, lineView, foundProperty);
+        AddConfigVar("MaxTitleLength", config.maxTitleLength, lineView, foundProperty);
         AddConfigVar("NumWorkspaces", config.numWorkspaces, lineView, foundProperty);
         AddConfigVar("AudioScrollSpeed", config.audioScrollSpeed, lineView, foundProperty);
         AddConfigVar("SensorSize", config.sensorSize, lineView, foundProperty);

src/Config.h

@@ -75,6 +75,7 @@ public:
     uint32_t audioScrollSpeed = 5;         // 5% each scroll
     uint32_t checkUpdateInterval = 5 * 60; // Interval to run the "checkPackagesCommand". In seconds
     uint32_t centerSpace = 300;            // How much space should be reserved for the center widgets.
+    uint32_t maxTitleLength = 30;          // Maximum chars of the title widget. Longer titles will be shortened
     uint32_t numWorkspaces = 9;            // How many workspaces to display
     uint32_t sensorSize = 24;              // The size of the circular sensors
     uint32_t networkIconSize = 24;         // The size of the two network arrows

src/System.cpp

@@ -647,6 +647,16 @@ namespace System
         return str.str();
     }
 
+    std::string GetActiveWindowTitle()
+    {
+        Wayland::PollEvents();
+        const Wayland::Window* activeWindow = Wayland::GetActiveWindow();
+        if (!activeWindow)
+            return "No Active Window"; // TODO Customize!!
+
+        return activeWindow->title;
+    }
+
     void Shutdown()
     {
         system("shutdown 0");

src/System.h

@@ -113,6 +113,8 @@ namespace System
 
     std::string GetTime();
 
+    std::string GetActiveWindowTitle();
+
     void Shutdown();
     void Reboot();
     void ExitWM();

src/Wayland.cpp

@@ -2,8 +2,10 @@
 
 #include "Common.h"
 #include "Config.h"
+#include <wayland-client-protocol.h>
 #include <wayland-client.h>
 #include <ext-workspace-unstable-v1.h>
+#include <wlr-foreign-toplevel-management-unstable-v1.h>
 
 namespace Wayland
 {
@@ -11,10 +13,12 @@ namespace Wayland
     static std::unordered_map<wl_output*, Monitor> monitors;
     static std::unordered_map<zext_workspace_group_handle_v1*, WorkspaceGroup> workspaceGroups;
     static std::unordered_map<zext_workspace_handle_v1*, Workspace> workspaces;
+    static std::unordered_map<zwlr_foreign_toplevel_handle_v1*, Window> windows;
 
     static wl_display* display;
     static wl_registry* registry;
     static zext_workspace_manager_v1* workspaceManager;
+    static zwlr_foreign_toplevel_manager_v1* toplevelManager;
 
     static bool registeredMonitor = false;
     static bool registeredGroup = false;
@@ -127,6 +131,52 @@ namespace Wayland
     }
     zext_workspace_manager_v1_listener workspaceManagerListener = {OnWSManagerNewGroup, OnWSManagerDone, OnWSManagerFinished};
 
+    // zwlr_foreign_toplevel_handle_v1
+    static void OnTLTitle(void*, zwlr_foreign_toplevel_handle_v1* toplevel, const char* title)
+    {
+        auto window = windows.find(toplevel);
+        ASSERT(window != windows.end(), "Wayland: OnTLTile called on unknwon toplevel!");
+        window->second.title = title;
+    }
+    static void OnTLOutputEnter(void*, UNUSED zwlr_foreign_toplevel_handle_v1* toplevel, UNUSED wl_output* output) {}
+    static void OnTLOutputLeave(void*, UNUSED zwlr_foreign_toplevel_handle_v1* toplevel, UNUSED wl_output* output) {}
+    static void OnTLState(void*, zwlr_foreign_toplevel_handle_v1* toplevel, wl_array* state)
+    {
+        auto window = windows.find(toplevel);
+        ASSERT(window != windows.end(), "Wayland: OnTLState called on unknwon toplevel!");
+        // Unrolled from wl_array_for_each, but with types defined to compile under C++
+        // There doesn't seem to be any documentation on the element size of the state, so use wlr's internally used uint32_t
+        bool activated = false;
+        for (uint32_t* curPtr = (uint32_t*)state->data; (uint8_t*)curPtr < (uint8_t*)state->data + state->size; curPtr++)
+        {
+            switch (*curPtr)
+            {
+            case ZWLR_FOREIGN_TOPLEVEL_HANDLE_V1_STATE_ACTIVATED: activated = true; break;
+            default: break;
+            }
+        }
+        window->second.activated = activated;
+    }
+    static void OnTLAppID(void*, zwlr_foreign_toplevel_handle_v1* toplevel, const char* appId) {}
+    static void OnTLDone(void*, zwlr_foreign_toplevel_handle_v1*) {}
+    static void OnTLClosed(void*, zwlr_foreign_toplevel_handle_v1* toplevel)
+    {
+        windows.erase(toplevel);
+        zwlr_foreign_toplevel_handle_v1_destroy(toplevel);
+    }
+    static void OnTLParent(void*, zwlr_foreign_toplevel_handle_v1*, zwlr_foreign_toplevel_handle_v1*) {}
+    zwlr_foreign_toplevel_handle_v1_listener toplevelListener = {OnTLTitle, OnTLAppID, OnTLOutputEnter, OnTLOutputLeave,
+                                                                 OnTLState, OnTLDone,  OnTLClosed,      OnTLParent};
+
+    // zwlr_foreign_toplevel_manager_v1
+    static void OnToplevel(void*, zwlr_foreign_toplevel_manager_v1*, zwlr_foreign_toplevel_handle_v1* toplevel)
+    {
+        windows.emplace(toplevel, Window{});
+        zwlr_foreign_toplevel_handle_v1_add_listener(toplevel, &toplevelListener, nullptr);
+    }
+    static void OnTLManagerFinished(void*, zwlr_foreign_toplevel_manager_v1*) {}
+    zwlr_foreign_toplevel_manager_v1_listener toplevelManagerListener = {OnToplevel, OnTLManagerFinished};
+
     // Output Callbacks
     // Very bloated, indeed
     static void OnOutputGeometry(void*, wl_output*, int32_t, int32_t, int32_t, int32_t, int32_t, const char*, const char*, int32_t) {}
@@ -162,11 +212,17 @@ namespace Wayland
             LOG("Wayland: Register <pending> at ID " << mon.ID);
             wl_output_add_listener(output, &outputListener, nullptr);
         }
-        if (strcmp(interface, "zext_workspace_manager_v1") == 0 && !Config::Get().useHyprlandIPC)
+        else if (strcmp(interface, "zext_workspace_manager_v1") == 0 && !Config::Get().useHyprlandIPC)
         {
             workspaceManager = (zext_workspace_manager_v1*)wl_registry_bind(registry, name, &zext_workspace_manager_v1_interface, version);
             zext_workspace_manager_v1_add_listener(workspaceManager, &workspaceManagerListener, nullptr);
         }
+        else if (strcmp(interface, "zwlr_foreign_toplevel_manager_v1") == 0)
+        {
+            toplevelManager = (zwlr_foreign_toplevel_manager_v1*)wl_registry_bind(registry, name, &zwlr_foreign_toplevel_manager_v1_interface,
+                                                                                  version);
+            zwlr_foreign_toplevel_manager_v1_add_listener(toplevelManager, &toplevelManagerListener, nullptr);
+        }
     }
     static void OnRegistryRemove(void*, wl_registry*, uint32_t name)
     {
@@ -305,6 +361,18 @@ namespace Wayland
         return it->second.ID;
     }
 
+    const Window* GetActiveWindow()
+    {
+        auto it = std::find_if(windows.begin(), windows.end(),
+                               [&](const std::pair<zwlr_foreign_toplevel_handle_v1*, Window>& el)
+                               {
+                                   return el.second.activated == true;
+                               });
+        if (it == windows.end())
+            return nullptr;
+        return &it->second;
+    }
+
     const std::unordered_map<wl_output*, Monitor>& GetMonitors()
     {
         return monitors;

src/Wayland.h

@@ -29,6 +29,12 @@ namespace Wayland
         zext_workspace_handle_v1* lastActiveWorkspace;
     };
 
+    struct Window
+    {
+        std::string title;
+        bool activated;
+    };
+
     void Init();
     void PollEvents();
 
@@ -61,5 +67,7 @@ namespace Wayland
             });
     }
 
+    const Window* GetActiveWindow();
+
     void Shutdown();
 }