feat: restore settings order and silent indexing display options

- Move Letterbox Fill setting to immediately after Sleep Screen Cover
  Filter in the Display section where it is more relevant.
- Add Indexing Display setting to Display section with three modes:
  Popup (default), Status Bar Text ("Indexing..."), and Status Bar Icon
  (hourglass).
- Restore silent indexing logic in EpubReaderActivity::render() that
  proactively indexes the next chapter when on a text-only page near
  the end of the current chapter (non-popup mode only).
- Draw indexing indicator in renderStatusBar() when silentIndexingActive
  is set and the user has chosen text or icon mode.

Made-with: Cursor

src/activities/reader/EpubReaderActivity.cpp

@@ -40,6 +40,10 @@ constexpr unsigned long longPressConfirmMs = 700;
 // pages per minute, first item is 1 to prevent division by zero if accessed
 const std::vector<int> PAGE_TURN_LABELS = {1, 1, 3, 6, 12};
 
+// 8x8 1-bit hourglass icon for the indexing status bar indicator.
+constexpr uint8_t kIndexingIcon[] = {0x00, 0x81, 0xC3, 0xE7, 0xE7, 0xC3, 0x81, 0x00};
+constexpr int kIndexingIconSize = 8;
+
 int clampPercent(int percent) {
   if (percent < 0) {
     return 0;
@@ -970,19 +974,44 @@ void EpubReaderActivity::render(RenderLock&& lock) {
       LOG_ERR("ERS", "Failed to load page from SD - clearing section cache");
       section->clearCache();
       section.reset();
-      requestUpdate();  // Try again after clearing cache
-                        // TODO: prevent infinite loop if the page keeps failing to load for some reason
+      silentIndexingActive = false;
+      requestUpdate();
       automaticPageTurnActive = false;
       return;
     }
 
+    silentIndexingActive = false;
+
     // Collect footnotes from the loaded page
     currentPageFootnotes = std::move(p->footnotes);
 
+    const bool textOnlyPage = !p->hasImages();
+    if (textOnlyPage && SETTINGS.indexingDisplay != CrossPointSettings::INDEXING_DISPLAY::INDEXING_POPUP &&
+        section->pageCount >= 1 &&
+        ((section->pageCount == 1 && section->currentPage == 0) ||
+         (section->pageCount >= 2 && section->currentPage == section->pageCount - 2)) &&
+        currentSpineIndex + 1 < epub->getSpineItemsCount() && preIndexedNextSpine != currentSpineIndex + 1) {
+      const uint16_t vpW = renderer.getScreenWidth() - orientedMarginLeft - orientedMarginRight;
+      const uint16_t vpH = renderer.getScreenHeight() - orientedMarginTop - orientedMarginBottom;
+      Section probe(epub, currentSpineIndex + 1, renderer);
+      if (probe.loadSectionFile(SETTINGS.getReaderFontId(), SETTINGS.getReaderLineCompression(),
+                                SETTINGS.extraParagraphSpacing, SETTINGS.paragraphAlignment, vpW, vpH,
+                                SETTINGS.hyphenationEnabled, SETTINGS.embeddedStyle, SETTINGS.imageRendering)) {
+        preIndexedNextSpine = currentSpineIndex + 1;
+      } else {
+        silentIndexingActive = true;
+      }
+    }
+
     const auto start = millis();
     renderContents(std::move(p), orientedMarginTop, orientedMarginRight, orientedMarginBottom, orientedMarginLeft);
     LOG_DBG("ERS", "Rendered page in %dms", millis() - start);
     renderer.clearFontCache();
+
+    if (silentIndexingActive) {
+      silentIndexNextChapterIfNeeded();
+      requestUpdate();
+    }
   }
   saveProgress(currentSpineIndex, section->currentPage, section->pageCount);
 
@@ -1105,6 +1134,22 @@ void EpubReaderActivity::renderStatusBar() const {
   }
 
   GUI.drawStatusBar(renderer, bookProgress, currentPage, pageCount, title, 0, textYOffset);
+
+  if (silentIndexingActive && SETTINGS.statusBar != CrossPointSettings::STATUS_BAR_MODE::NONE) {
+    int orientedMarginTop, orientedMarginRight, orientedMarginBottom, orientedMarginLeft;
+    renderer.getOrientedViewableTRBL(&orientedMarginTop, &orientedMarginRight, &orientedMarginBottom,
+                                     &orientedMarginLeft);
+    const int textY = renderer.getScreenHeight() - UITheme::getInstance().getStatusBarHeight() - orientedMarginBottom - 4;
+    const bool showBatteryPercentage =
+        SETTINGS.hideBatteryPercentage == CrossPointSettings::HIDE_BATTERY_PERCENTAGE::HIDE_NEVER;
+    const int batteryWidth = SETTINGS.statusBarBattery ? (showBatteryPercentage ? 50 : 20) : 0;
+    const int indicatorX = orientedMarginLeft + batteryWidth + 8;
+    if (SETTINGS.indexingDisplay == CrossPointSettings::INDEXING_DISPLAY::INDEXING_STATUS_TEXT) {
+      renderer.drawText(SMALL_FONT_ID, indicatorX, textY, tr(STR_INDEXING));
+    } else if (SETTINGS.indexingDisplay == CrossPointSettings::INDEXING_DISPLAY::INDEXING_STATUS_ICON) {
+      renderer.drawIcon(kIndexingIcon, indicatorX, textY - kIndexingIconSize + 2, kIndexingIconSize, kIndexingIconSize);
+    }
+  }
 }
 
 void EpubReaderActivity::navigateToHref(const std::string& hrefStr, const bool savePosition) {