feat: add keyboard layout support

programs/src/desktop/panel.cpp

@@ -108,8 +108,34 @@ void gui::desktop_draw_panel(DesktopState* ds) {
     int date_x = clock_x - date_w - 10;
     draw_text(fb, date_x, clock_y, date_str, colors::PANEL_TEXT);
 
-    // Volume icon (to the left of the date)
-    int vol_icon_x = date_x - 16 - 12;
+    // Only render switcher if more than one keyboard layout is installed 
+    int enabled_layouts = 0;
+    for (int i = 0; i < ds->keyboard.registry.count; i++)
+        if (ds->keyboard.enabled[i]) enabled_layouts++;
+
+    // Whatever text ends up leftmost is what the volume icon spaces off.
+    int vol_anchor_x = date_x;
+
+    if (enabled_layouts > 1) {
+        const char* layout_short = "en";
+        if (ds->keyboard.active >= 0
+            && ds->keyboard.active < ds->keyboard.registry.count) {
+            layout_short =
+                ds->keyboard.registry.items[ds->keyboard.active].short_name;
+        }
+        int layout_tw = text_width(layout_short);
+        int layout_x = date_x - layout_tw - 10;
+        // Padded evenly past the glyphs so the click target is comfortable.
+        ds->keyboard_layout_rect = {layout_x - 5, 4, layout_tw + 10, 24};
+        draw_text(fb, layout_x, clock_y, layout_short, colors::PANEL_TEXT);
+        vol_anchor_x = layout_x;
+    } else {
+        ds->keyboard_layout_rect = {0, 0, 0, 0};
+    }
+
+    // Volume icon keeps its 12px icon-to-text gap whether it sits next to the
+    // layout tag or, with one layout, the date.
+    int vol_icon_x = vol_anchor_x - 12 - 16;
     int vol_icon_y = (PANEL_HEIGHT - 16) / 2;
     ds->vol_icon_rect = {vol_icon_x, vol_icon_y, 16, 16};