feat(monitor): use primary monitor as default (#1426)

If the monitor option isn't set, the primary monitor (if connected) is chosen as the default display.

include/x11/extensions/randr.hpp

@@ -36,6 +36,7 @@ struct randr_output {
   short int y{0};
   xcb_randr_output_t output;
   backlight_values backlight;
+  bool primary{false};
 
   bool match(const string& o, bool exact = true) const;
   bool match(const position& p) const;
@@ -48,7 +49,8 @@ namespace randr_util {
 
   bool check_monitor_support();
 
-  monitor_t make_monitor(xcb_randr_output_t randr, string name, unsigned short int w, unsigned short int h, short int x, short int y);
+  monitor_t make_monitor(xcb_randr_output_t randr, string name, unsigned short int w, unsigned short int h, short int x, short int y,
+      bool primary);
   vector<monitor_t> get_monitors(connection& conn, xcb_window_t root, bool connected_only = false, bool realloc = false);
   monitor_t match_monitor(vector<monitor_t> monitors, const string& name, bool exact_match);
 

src/components/bar.cpp

@@ -80,6 +80,17 @@ bar::bar(connection& conn, signal_emitter& emitter, const config& config, const
     throw application_error("No monitors found");
   }
 
+  // if monitor_name is not defined, first check for primary monitor
+  if (monitor_name.empty()) {
+    for (auto&& mon : monitors) {
+      if (mon->primary) {
+        monitor_name = mon->name;
+        break;
+      }
+    }
+  }
+
+  // if still not found (and not strict matching), get first connected monitor
   if (monitor_name.empty() && !m_opts.monitor_strict) {
     auto connected_monitors = randr_util::get_monitors(m_connection, m_connection.screen()->root, true);
     if (!connected_monitors.empty()) {
@@ -88,11 +99,13 @@ bar::bar(connection& conn, signal_emitter& emitter, const config& config, const
     }
   }
 
+  // if still not found, get first monitor
   if (monitor_name.empty()) {
     monitor_name = monitors[0]->name;
     m_log.warn("No monitor specified, using \"%s\"", monitor_name);
   }
 
+  // get the monitor data based on the name
   m_opts.monitor = randr_util::match_monitor(monitors, monitor_name, m_opts.monitor_exact);
   monitor_t fallback{};
 

src/main.cpp

@@ -78,9 +78,10 @@ int main(int argc, char** argv) {
     if (cli->has("list-monitors")) {
       for (auto&& mon : randr_util::get_monitors(conn, conn.root(), true)) {
         if (WITH_XRANDR_MONITORS && mon->output == XCB_NONE) {
-          printf("%s: %ix%i+%i+%i (XRandR monitor)\n", mon->name.c_str(), mon->w, mon->h, mon->x, mon->y);
+          printf("%s: %ix%i+%i+%i (XRandR monitor%s)\n", mon->name.c_str(), mon->w, mon->h, mon->x, mon->y,
+              mon->primary ? ", primary" : "");
         } else {
-          printf("%s: %ix%i+%i+%i\n", mon->name.c_str(), mon->w, mon->h, mon->x, mon->y);
+          printf("%s: %ix%i+%i+%i%s\n", mon->name.c_str(), mon->w, mon->h, mon->x, mon->y, mon->primary ? " (primary)" : "");
         }
       }
       return EXIT_SUCCESS;

src/x11/extensions/randr.cpp

@@ -64,7 +64,8 @@ namespace randr_util {
    * Define monitor
    */
   monitor_t make_monitor(
-      xcb_randr_output_t randr, string name, unsigned short int w, unsigned short int h, short int x, short int y) {
+      xcb_randr_output_t randr, string name, unsigned short int w, unsigned short int h, short int x, short int y,
+      bool primary) {
     monitor_t mon{new monitor_t::element_type{}};
     mon->output = randr;
     mon->name = move(name);
@@ -72,6 +73,7 @@ namespace randr_util {
     mon->y = y;
     mon->h = h;
     mon->w = w;
+    mon->primary = primary;
     return mon;
   }
 
@@ -92,13 +94,17 @@ namespace randr_util {
       for (auto&& mon : conn.get_monitors(root, true).monitors()) {
         try {
           auto name = conn.get_atom_name(mon.name).name();
-          monitors.emplace_back(make_monitor(XCB_NONE, move(name), mon.width, mon.height, mon.x, mon.y));
+          monitors.emplace_back(make_monitor(XCB_NONE, move(name), mon.width, mon.height, mon.x, mon.y, mon.primary));
         } catch (const exception&) {
           // silently ignore output
         }
       }
     }
 #endif
+    auto primary_output = conn.get_output_primary(root).output();
+    auto primary_info = conn.get_output_info(primary_output);
+    auto name_iter = primary_info.name();
+    string primary_name = {name_iter.begin(), name_iter.end()};
 
     for (auto&& output : conn.get_screen_resources(root).outputs()) {
       try {
@@ -124,7 +130,8 @@ namespace randr_util {
 #endif
 
         auto crtc = conn.get_crtc_info(info->crtc);
-        monitors.emplace_back(make_monitor(output, move(name), crtc->width, crtc->height, crtc->x, crtc->y));
+        auto primary = (primary_name == name);
+        monitors.emplace_back(make_monitor(output, move(name), crtc->width, crtc->height, crtc->x, crtc->y, primary));
       } catch (const exception&) {
         // silently ignore output
       }