fix(ui): connect mini-map trail points with a line

The Home "Map" page preview only plotted each trail vertex as a single
pixel, leaving gaps wherever the streaming simplifier collapsed a straight
stretch to its two endpoints — so a route looked like scattered dots instead
of a path. The stale "gfx isn't available this early in the TU" comment no
longer holds: GfxUtils.h is already reachable here, so draw the same
Bresenham line the full Trail map uses.

Extracted the shared "walk points, draw a line, break on TRAIL_FLAG_SEG_START"
loop into gfx::drawTrail() (GfxUtils.h) so the full map and the mini-map
preview don't carry two copies of it; they differ only in their projection
and what (if anything) they draw at a segment break.

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

examples/companion_radio/ui-new/GfxUtils.h

@@ -6,6 +6,7 @@
 
 #include <helpers/ui/DisplayDriver.h>
 #include <stdlib.h>   // abs
+#include "../Trail.h"
 
 namespace gfx {
 
@@ -37,4 +38,25 @@ static inline void drawCircle(DisplayDriver& d, int cx, int cy, int r) {
   }
 }
 
+// Walks a TrailStore and renders it as a connected polyline via drawLine(),
+// breaking the line at each TRAIL_FLAG_SEG_START point (trail paused/
+// restarted) instead of bridging the dead-time gap. Shared by the full Trail
+// map and the Home screen's mini-map preview, which only differ in how they
+// project lat/lon to screen coords and what (if anything) they draw at a
+// break. `project(lat, lon, x, y)` fills the screen coords for one point;
+// `on_break(x_prev_end, y_prev_end, x_new_start, y_new_start)` runs at each
+// break instead of drawLine() — pass a no-op lambda for a silent gap.
+template <typename Project, typename OnBreak>
+static void drawTrail(DisplayDriver& d, TrailStore& tr, Project project, OnBreak on_break) {
+  if (tr.count() == 0) return;
+  int x0, y0; project(tr.at(0).lat_1e6, tr.at(0).lon_1e6, x0, y0);
+  for (int i = 1; i < tr.count(); i++) {
+    const TrailPoint& pt = tr.at(i);
+    int x1, y1; project(pt.lat_1e6, pt.lon_1e6, x1, y1);
+    if (pt.flags & TRAIL_FLAG_SEG_START) on_break(x0, y0, x1, y1);
+    else                                  drawLine(d, x0, y0, x1, y1);
+    x0 = x1; y0 = y1;
+  }
+}
+
 }  // namespace gfx

examples/companion_radio/ui-new/TrailScreen.h

@@ -740,19 +740,9 @@ private:
       int x0, y0;
       proj.project(_store->at(0).lat_1e6, _store->at(0).lon_1e6, x0, y0);
       miniIconDrawCentered(display, x0, y0, ICON_MAP_DOT);
-      for (int i = 1; i < _store->count(); i++) {
-        const TrailPoint& pt = _store->at(i);
-        int x1, y1;
-        proj.project(pt.lat_1e6, pt.lon_1e6, x1, y1);
-        if (pt.flags & TRAIL_FLAG_SEG_START) {
-          drawFilledDot(display, x0, y0);
-          drawOpenDot(display, x1, y1);
-        } else {
-          gfx::drawLine(display, x0, y0, x1, y1);
-        }
-        x0 = x1;
-        y0 = y1;
-      }
+      gfx::drawTrail(display, *_store,
+        [&](int32_t la, int32_t lo, int& x, int& y) { proj.project(la, lo, x, y); },
+        [&](int xa, int ya, int xb, int yb) { drawFilledDot(display, xa, ya); drawOpenDot(display, xb, yb); });
       int sx, sy;
       proj.project(_store->first().lat_1e6, _store->first().lon_1e6, sx, sy);
       drawStartMarker(display, sx, sy);

examples/companion_radio/ui-new/UITask.cpp

@@ -34,6 +34,7 @@
 #endif
 
 #include "icons.h"
+#include "GfxUtils.h"   // gfx::drawLine — connects trail points on the Home map preview
 
 // Blinking status indicators: on for the first half of a 4 s cycle, but e-ink
 // can't repaint fast enough to blink, so it shows them steadily.
@@ -554,8 +555,9 @@ public:
 
   // Compact map preview for the Home "Map" page: own position, the GPS trail,
   // and live-tracked contacts (◆) folded into one auto-scaled box. A simplified
-  // cousin of TrailScreen's map (dots, no grid/labels) so the home carousel
-  // stays light. Returns false (and draws nothing) when there's nothing to show.
+  // cousin of TrailScreen's map (no grid/labels, no break markers) so the home
+  // carousel stays light. Returns false (and draws nothing) when there's
+  // nothing to show.
   bool drawMapPreview(DisplayDriver& display, int ax, int ay, int aw, int ah) {
     if (aw < 8 || ah < 8) return false;
     bool init = false;
@@ -608,11 +610,9 @@ public:
       px = off_x + (int)((float)(lo - mnlo) * lon_scale * scale);
       py = off_y + (int)((float)(mxla - la) * scale);
     };
-    // Trail as dots (no line — gfx isn't available this early in the TU).
-    for (int i = 0; i < tr.count(); i++) {
-      int px, py; project(tr.at(i).lat_1e6, tr.at(i).lon_1e6, px, py);
-      display.fillRect(px, py, 1, 1);
-    }
+    // Trail as a connected line, matching the full Trail map (shared helper —
+    // see gfx::drawTrail); no break marker here, just a silent gap.
+    gfx::drawTrail(display, tr, project, [](int, int, int, int) {});
     for (int i = 0; i < LiveTrackStore::CAPACITY; i++) {
       if (!lt.isActive(i, now)) continue;
       int px, py; project(lt.slotAt(i).lat_1e6, lt.slotAt(i).lon_1e6, px, py);