clock: scroll through multiple timezones

include/ALabel.hpp

@@ -10,7 +10,7 @@ namespace waybar {
 class ALabel : public AModule {
  public:
   ALabel(const Json::Value &, const std::string &, const std::string &, const std::string &format,
-         uint16_t interval = 0, bool ellipsize = false);
+         uint16_t interval = 0, bool ellipsize = false, bool enable_click = false, bool enable_scroll = false);
   virtual ~ALabel() = default;
   virtual auto        update() -> void;
   virtual std::string getIcon(uint16_t, const std::string &alt = "", uint16_t max = 0);

include/modules/clock.hpp

@@ -28,9 +28,12 @@ class Clock : public ALabel {
   std::locale locale_;
   const date::time_zone* time_zone_;
   bool fixed_time_zone_;
+  int time_zone_idx_;
   date::year_month_day cached_calendar_ymd_;
   std::string cached_calendar_text_;
 
+  bool handleScroll(GdkEventScroll* e);
+
   auto calendar_text(const waybar_time& wtime) -> std::string;
   auto weekdays_header(const date::weekday& first_dow, std::ostream& os) -> void;
   auto first_day_of_week() -> date::weekday;

man/waybar-clock.5.scd

@@ -26,6 +26,11 @@ The *clock* module displays the current date and time.
 	default: inferred local timezone ++
 	The timezone to display the time in, e.g. America/New_York.
 
+*timezones*: ++
+	typeof: list of strings ++
+	A list of timezones to use for time display, changed using the scroll wheel. ++
+	Use "" to represent the system's local timezone.  Using %Z in the format or tooltip format is useful to track which time zone is currently displayed.
+
 *locale*: ++
 	typeof: string ++
 	default: inferred from current locale ++

src/ALabel.cpp

@@ -5,8 +5,9 @@
 namespace waybar {
 
 ALabel::ALabel(const Json::Value& config, const std::string& name, const std::string& id,
-               const std::string& format, uint16_t interval, bool ellipsize)
+               const std::string& format, uint16_t interval, bool ellipsize, bool enable_click,
-    : AModule(config, name, id, config["format-alt"].isString()),
+               bool enable_scroll)
+    : AModule(config, name, id, config["format-alt"].isString() || enable_click, enable_scroll),
       format_(config_["format"].isString() ? config_["format"].asString() : format),
       interval_(config_["interval"] == "once"
                     ? std::chrono::seconds(100000000)

src/modules/clock.cpp

@@ -13,7 +13,7 @@
 using waybar::modules::waybar_time;
 
 waybar::modules::Clock::Clock(const std::string& id, const Json::Value& config)
-    : ALabel(config, "clock", id, "{:%H:%M}", 60), fixed_time_zone_(false) {
+    : ALabel(config, "clock", id, "{:%H:%M}", 60, false, false, true), fixed_time_zone_(false) {
   if (config_["timezone"].isString()) {
     spdlog::warn("As using a timezone, some format args may be missing as the date library havn't got a release since 2018.");
     time_zone_ = date::locate_zone(config_["timezone"].asString());
@@ -71,6 +71,40 @@ auto waybar::modules::Clock::update() -> void {
   ALabel::update();
 }
 
+bool waybar::modules::Clock::handleScroll(GdkEventScroll *e) {
+  // defer to user commands if set
+  if (config_["on-scroll-up"].isString() || config_["on-scroll-down"].isString()) {
+    return AModule::handleScroll(e);
+  }
+
+  auto dir = AModule::getScrollDir(e);
+  if (dir != SCROLL_DIR::UP && dir != SCROLL_DIR::DOWN) {
+    return true;
+  }
+  if (!config_["timezones"].isArray() || config_["timezones"].empty()) {
+    return true;
+  }
+  auto nr_zones = config_["timezones"].size();
+  int new_idx = time_zone_idx_ + ((dir == SCROLL_DIR::UP) ? 1 : -1);
+  if (new_idx < 0) {
+    time_zone_idx_ = nr_zones - 1;
+  } else if (new_idx >= nr_zones) {
+    time_zone_idx_ = 0;
+  } else {
+    time_zone_idx_ = new_idx;
+  }
+  auto zone_name = config_["timezones"][time_zone_idx_];
+  if (!zone_name.isString() || zone_name.empty()) {
+    fixed_time_zone_ = false;
+  } else {
+    time_zone_ = date::locate_zone(zone_name.asString());
+    fixed_time_zone_ = true;
+  }
+
+  update();
+  return true;
+}
+
 auto waybar::modules::Clock::calendar_text(const waybar_time& wtime) -> std::string {
   const auto daypoint = date::floor<date::days>(wtime.ztime.get_local_time());
   const auto ymd = date::year_month_day(daypoint);