feat(nav): standalone Compass in Tools

Tools › Compass shows the device's course over ground (from the GPS COG
ring — no magnetometer) as a rotating arrow in a ring with a north tick,
plus a large degrees + cardinal readout. "No GPS fix" without a fix;
"move to set heading" when stationary (course undefined). Reuses
UITask::currentCourse, so it works without recording a trail.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

examples/companion_radio/ui-new/CompassScreen.h

@@ -0,0 +1,106 @@
+#pragma once
+// Tools › Compass. A standalone heading view: shows the device's course over
+// ground (derived from GPS movement — there is no magnetometer) as a rotating
+// arrow plus a numeric degrees + cardinal readout. When standing still the
+// heading is undefined, so it shows a hint to move.
+//
+// Reuses UITask's COG ring (currentCourse) — works whether or not a trail is
+// being recorded.
+
+#include "../GeoUtils.h"
+#include <math.h>
+
+class CompassScreen : public UIScreen {
+  UITask* _task;
+
+  static bool gpsValid() {
+#if ENV_INCLUDE_GPS == 1
+    LocationProvider* loc = sensors.getLocationProvider();
+    return loc && loc->isValid();
+#else
+    return false;
+#endif
+  }
+
+  static void drawLine(DisplayDriver& d, int x0, int y0, int x1, int y1) {
+    int dx = abs(x1 - x0), sx = x0 < x1 ? 1 : -1;
+    int dy = -abs(y1 - y0), sy = y0 < y1 ? 1 : -1;
+    int err = dx + dy;
+    while (true) {
+      d.fillRect(x0, y0, 1, 1);
+      if (x0 == x1 && y0 == y1) break;
+      int e2 = err * 2;
+      if (e2 >= dy) { err += dy; x0 += sx; }
+      if (e2 <= dx) { err += dx; y0 += sy; }
+    }
+  }
+
+public:
+  CompassScreen(UITask* task) : _task(task) {}
+  void enter() {}
+
+  int render(DisplayDriver& display) override {
+    display.setTextSize(1);
+    display.setColor(DisplayDriver::LIGHT);
+    display.drawTextCentered(display.width() / 2, 0, "COMPASS");
+    display.fillRect(0, display.headerH() - 1, display.width(), display.sepH());
+
+    const int hdr = display.headerH();
+    const int cx  = display.width() / 2;
+    // Reserve a size-2 row at the bottom for the numeric readout.
+    display.setTextSize(2);
+    const int bigH = display.getLineHeight();
+    display.setTextSize(1);
+    const int top = hdr + 2;
+    const int bottom = display.height() - bigH - 2;
+    const int cy  = (top + bottom) / 2;
+    int r = ((bottom - top) / 2);
+    int rx = (display.width() / 2) - 4;
+    if (rx < r) r = rx;
+    if (r < 6) r = 6;
+
+    if (!gpsValid()) {
+      display.drawTextCentered(cx, cy - display.getLineHeight() / 2, "No GPS fix");
+      return 1000;
+    }
+
+    int cog;
+    bool have = _task->currentCourse(cog);
+
+    // Compass ring ticks: N/E/S/W as short marks; N drawn as a filled wedge top.
+    display.drawRect(cx - r, cy - r, 2 * r + 1, 2 * r + 1);   // bounding box stands in for a ring
+    display.drawTextCentered(cx, cy - r - 1, "N");
+
+    if (!have) {
+      display.drawTextCentered(cx, cy - display.getLineHeight() / 2, "move to");
+      display.drawTextCentered(cx, cy + display.getLineHeight() / 2, "set heading");
+      return 1000;
+    }
+
+    // Arrow from centre toward the course (0° = up = north, clockwise).
+    float rad = cog * (float)M_PI / 180.0f;
+    int ex = cx + (int)(sinf(rad) * (r - 2));
+    int ey = cy - (int)(cosf(rad) * (r - 2));
+    drawLine(display, cx, cy, ex, ey);
+    // Small arrowhead: two short lines back from the tip at ±150°.
+    for (int da = -25; da <= 25; da += 50) {
+      float a = rad + (float)M_PI + da * (float)M_PI / 180.0f;
+      int hx = ex + (int)(sinf(a) * 4);
+      int hy = ey - (int)(cosf(a) * 4);
+      drawLine(display, ex, ey, hx, hy);
+    }
+
+    // Numeric readout below the ring.
+    char buf[16];
+    snprintf(buf, sizeof(buf), "%d %s", cog, geo::bearingCardinal(cog));
+    display.setTextSize(2);
+    display.drawTextCentered(cx, bottom + 1, buf);
+    display.setTextSize(1);
+    return 1000;
+  }
+
+  bool handleInput(char c) override {
+    if (c == KEY_CANCEL || c == KEY_CONTEXT_MENU) { _task->gotoToolsScreen(); return true; }
+    return true;
+  }
+};

examples/companion_radio/ui-new/ToolsScreen.h

@@ -6,7 +6,7 @@ class ToolsScreen : public UIScreen {
   UITask* _task;
   int _sel;
 
-  static const int ITEM_COUNT = 5;
+  static const int ITEM_COUNT = 6;
   static const char* ITEMS[ITEM_COUNT];
 
 public:
@@ -45,8 +45,9 @@ public:
       if (_sel == 2) { _task->gotoNearbyScreen();     return true; }
       if (_sel == 3) { _task->gotoAutoAdvertScreen(); return true; }
       if (_sel == 4) { _task->gotoTrailScreen(); return true; }
+      if (_sel == 5) { _task->gotoCompassScreen(); return true; }
     }
     return false;
   }
 };
-const char* ToolsScreen::ITEMS[5] = { "Ringtone Editor", "Auto-Reply Bot", "Nearby Nodes", "Auto-Advert", "Trail" };
+const char* ToolsScreen::ITEMS[6] = { "Ringtone Editor", "Auto-Reply Bot", "Nearby Nodes", "Auto-Advert", "Trail", "Compass" };

examples/companion_radio/ui-new/UITask.cpp

@@ -118,6 +118,7 @@ static const int QUICK_MSGS_MAX = 10;
 #include "DashboardConfigScreen.h"
 #include "AutoAdvertScreen.h"
 #include "TrailScreen.h"
+#include "CompassScreen.h"
 #include "ToolsScreen.h"
 
 #ifndef BATT_MIN_MILLIVOLTS
@@ -1189,6 +1190,7 @@ void UITask::begin(DisplayDriver* display, SensorManager* sensors, NodePrefs* no
   dashboard_config = new DashboardConfigScreen(this, node_prefs);
   auto_advert_screen = new AutoAdvertScreen(this, node_prefs);
   trail_screen       = new TrailScreen(this, &_trail);
+  compass_screen     = new CompassScreen(this);
   applyBrightness();
   applyFont();
   applyRotation();
@@ -1230,6 +1232,11 @@ void UITask::gotoTrailScreen() {
   setCurrScreen(trail_screen);
 }
 
+void UITask::gotoCompassScreen() {
+  ((CompassScreen*)compass_screen)->enter();
+  setCurrScreen(compass_screen);
+}
+
 void UITask::gotoAutoAdvertScreen() {
   ((AutoAdvertScreen*)auto_advert_screen)->enter();
   setCurrScreen(auto_advert_screen);

examples/companion_radio/ui-new/UITask.h

@@ -76,6 +76,7 @@ class UITask : public AbstractUITask {
   UIScreen* dashboard_config;
   UIScreen* auto_advert_screen;
   UIScreen* trail_screen;
+  UIScreen* compass_screen;
   UIScreen* curr;
   CayenneLPP _dash_lpp;
   TrailStore _trail;
@@ -144,6 +145,7 @@ public:
   void gotoDashboardConfig();
   void gotoAutoAdvertScreen();
   void gotoTrailScreen();
+  void gotoCompassScreen();
   TrailStore& trail() { return _trail; }
   WaypointStore& waypoints() { return _waypoints; }
   void saveWaypoints();   // persist the table to /waypoints