config: add show_tty option to display active TTY in top right corner

When running multiple ly instances across different TTYs there is no way to
tell which TTY a given login screen belongs to at a glance. Adds a show_tty
boolean config option (default false) that displays the active TTY number
(e.g. tty3) in the top right corner. When the clock is also enabled the TTY
label sits immediately to its right on the same row.

res/config.ini

@@ -333,6 +333,11 @@ setup_cmd = $CONFIG_DIRECTORY/ly/setup.sh
 # Specifies the key combination used for showing the password
 show_password_key = F7
 
+# Display the active TTY number (e.g. tty3) to the right of the clock in the top right corner
+# If the clock is disabled, the TTY label occupies the top right corner on its own
+# If false, the TTY number will not be shown
+show_tty = false
+
 # Command executed when pressing shutdown_key
 shutdown_cmd = /sbin/shutdown $PLATFORM_SHUTDOWN_ARG now
 

src/config/Config.zig

@@ -92,6 +92,7 @@ start_cmd: ?[]const u8 = null,
 text_in_center: bool = false,
 vi_default_mode: ViMode = .normal,
 vi_mode: bool = false,
+show_tty: bool = false,
 waylandsessions: []const u8 = build_options.prefix_directory ++ "/share/wayland-sessions",
 x_cmd: []const u8 = build_options.prefix_directory ++ "/bin/X",
 x_vt: ?u8 = null,

src/main.zig

@@ -94,6 +94,7 @@ const UiState = struct {
     capslock_label: Label,
     battery_label: Label,
     clock_label: Label,
+    tty_label: Label,
     session_specifier_label: Label,
     login_label: Label,
     password_label: Label,
@@ -118,6 +119,7 @@ const UiState = struct {
     battery_buf: [16:0]u8,
     bigclock_format_buf: [16:0]u8,
     clock_buf: [64:0]u8,
+    tty_buf: [8:0]u8,
     bigclock_buf: [32:0]u8,
     custom_binds: std.ArrayList(CustomBindLabel),
     custom_info: std.ArrayList(CustomInfoLabel),
@@ -541,6 +543,16 @@ pub fn main() !void {
     );
     defer state.clock_label.deinit();
 
+    state.tty_label = Label.init(
+        "",
+        null,
+        state.buffer.fg,
+        state.buffer.bg,
+        null,
+        null,
+    );
+    defer state.tty_label.deinit();
+
     state.bigclock_label = BigLabel.init(
         &state.buffer,
         "",
@@ -941,6 +953,10 @@ pub fn main() !void {
         };
     }
 
+    if (state.config.show_tty) {
+        try state.tty_label.setTextBuf(&state.tty_buf, "tty{d}", .{state.active_tty});
+    }
+
     // Initialize the animation, if any
     var animation: ?*Widget = null;
     switch (state.config.animation) {
@@ -1148,6 +1164,9 @@ pub fn main() !void {
     if (state.config.clock != null) {
         try layer2.append(state.allocator, state.clock_label.widget());
     }
+    if (state.config.show_tty) {
+        try layer2.append(state.allocator, state.tty_label.widget());
+    }
     if (state.config.bigclock != .none) {
         try layer2.append(state.allocator, state.bigclock_label.widget());
     }
@@ -1918,10 +1937,16 @@ fn positionWidgets(ptr: *anyopaque) !void {
         .add(TerminalBuffer.START_POSITION)
         .addYFromIf(state.brightness_up_label.childrenPosition(), !state.config.hide_key_hints)
         .removeYFromIf(state.edge_margin, !state.config.hide_key_hints));
+    const tty_label_width = if (state.config.show_tty) TerminalBuffer.strWidth(state.tty_label.text) else 0;
+    const tty_label_gap = if (state.config.show_tty and state.config.clock != null) @as(usize, 1) else 0;
+    state.tty_label.positionXY(state.edge_margin
+        .add(TerminalBuffer.START_POSITION)
+        .invertX(state.buffer.width)
+        .removeXIf(tty_label_width, state.buffer.width > tty_label_width + state.edge_margin.x));
     state.clock_label.positionXY(state.edge_margin
         .add(TerminalBuffer.START_POSITION)
         .invertX(state.buffer.width)
-        .removeXIf(TerminalBuffer.strWidth(state.clock_label.text), state.buffer.width > TerminalBuffer.strWidth(state.clock_label.text) + state.edge_margin.x));
+        .removeXIf(TerminalBuffer.strWidth(state.clock_label.text) + tty_label_width + tty_label_gap, state.buffer.width > TerminalBuffer.strWidth(state.clock_label.text) + tty_label_width + tty_label_gap + state.edge_margin.x));
 
     state.numlock_label.positionX(state.edge_margin
         .add(TerminalBuffer.START_POSITION)