Support transparent PNG

src/CrossPointSettings.h

@@ -24,6 +24,7 @@ class CrossPointSettings {
     COVER = 3,
     BLANK = 4,
     COVER_CUSTOM = 5,
+    OVERLAY = 6,
     SLEEP_SCREEN_MODE_COUNT
   };
   enum SLEEP_SCREEN_COVER_MODE { FIT = 0, CROP = 1, SLEEP_SCREEN_COVER_MODE_COUNT };

src/SettingsList.h

@@ -16,7 +16,7 @@ inline const std::vector<SettingInfo>& getSettingsList() {
       // --- Display ---
       SettingInfo::Enum(StrId::STR_SLEEP_SCREEN, &CrossPointSettings::sleepScreen,
                         {StrId::STR_DARK, StrId::STR_LIGHT, StrId::STR_CUSTOM, StrId::STR_COVER, StrId::STR_NONE_OPT,
-                         StrId::STR_COVER_CUSTOM},
+                         StrId::STR_COVER_CUSTOM, StrId::STR_PAGE_OVERLAY},
                         "sleepScreen", StrId::STR_CAT_DISPLAY),
       SettingInfo::Enum(StrId::STR_SLEEP_COVER_MODE, &CrossPointSettings::sleepScreenCoverMode,
                         {StrId::STR_FIT, StrId::STR_CROP}, "sleepScreenCoverMode", StrId::STR_CAT_DISPLAY),

src/activities/boot_sleep/SleepActivity.cpp

@@ -4,19 +4,142 @@
 #include <GfxRenderer.h>
 #include <HalStorage.h>
 #include <I18n.h>
+#include <PNGdec.h>
 #include <Txt.h>
 #include <Xtc.h>
 
+#include <new>
+
 #include "CrossPointSettings.h"
 #include "CrossPointState.h"
 #include "components/UITheme.h"
 #include "fontIds.h"
 #include "images/Logo120.h"
+#include "reader/EpubReaderActivity.h"
+#include "reader/TxtReaderActivity.h"
+#include "reader/XtcReaderActivity.h"
 #include "util/StringUtils.h"
 
+namespace {
+
+// Context passed through PNGdec's decode() user-pointer to the per-scanline draw callback.
+struct PngOverlayCtx {
+  const GfxRenderer* renderer;
+  int screenW;
+  int screenH;
+  int srcWidth;
+  int dstWidth;
+  int dstX;
+  int dstY;
+  float yScale;
+  int lastDstY;
+};
+
+// PNGdec file I/O callbacks — mirror the pattern in PngToFramebufferConverter.cpp.
+void* pngSleepOpen(const char* filename, int32_t* size) {
+  FsFile* f = new FsFile();
+  if (!Storage.openFileForRead("SLP", std::string(filename), *f)) {
+    delete f;
+    return nullptr;
+  }
+  *size = f->size();
+  return f;
+}
+void pngSleepClose(void* handle) {
+  FsFile* f = reinterpret_cast<FsFile*>(handle);
+  if (f) {
+    f->close();
+    delete f;
+  }
+}
+int32_t pngSleepRead(PNGFILE* pFile, uint8_t* pBuf, int32_t len) {
+  FsFile* f = reinterpret_cast<FsFile*>(pFile->fHandle);
+  return f ? f->read(pBuf, len) : 0;
+}
+int32_t pngSleepSeek(PNGFILE* pFile, int32_t pos) {
+  FsFile* f = reinterpret_cast<FsFile*>(pFile->fHandle);
+  if (!f) return -1;
+  return f->seek(pos);
+}
+
+// Per-scanline draw callback for PNG overlay compositing.
+// Transparent pixels (alpha < 128) are skipped so the reader page shows through.
+// Opaque pixels are drawn in their grayscale brightness (dark → black, light → white).
+int pngOverlayDraw(PNGDRAW* pDraw) {
+  PngOverlayCtx* ctx = reinterpret_cast<PngOverlayCtx*>(pDraw->pUser);
+
+  const int destY = ctx->dstY + (int)(pDraw->y * ctx->yScale);
+  if (destY == ctx->lastDstY) return 1;  // skip duplicate rows from Y scaling
+  ctx->lastDstY = destY;
+  if (destY < 0 || destY >= ctx->screenH) return 1;
+
+  const int srcWidth = ctx->srcWidth;
+  const int dstWidth = ctx->dstWidth;
+  const uint8_t* pixels = pDraw->pPixels;
+  const int pixelType = pDraw->iPixelType;
+  const int hasAlpha = pDraw->iHasAlpha;
+
+  int srcX = 0, error = 0;
+  for (int dstX = 0; dstX < dstWidth; dstX++) {
+    const int outX = ctx->dstX + dstX;
+    if (outX >= 0 && outX < ctx->screenW) {
+      uint8_t alpha = 255, gray = 0;
+      switch (pixelType) {
+        case PNG_PIXEL_TRUECOLOR_ALPHA: {
+          const uint8_t* p = &pixels[srcX * 4];
+          alpha = p[3];
+          gray = (uint8_t)((p[0] * 77 + p[1] * 150 + p[2] * 29) >> 8);
+          break;
+        }
+        case PNG_PIXEL_GRAY_ALPHA:
+          gray = pixels[srcX * 2];
+          alpha = pixels[srcX * 2 + 1];
+          break;
+        case PNG_PIXEL_TRUECOLOR: {
+          const uint8_t* p = &pixels[srcX * 3];
+          gray = (uint8_t)((p[0] * 77 + p[1] * 150 + p[2] * 29) >> 8);
+          break;
+        }
+        case PNG_PIXEL_GRAYSCALE:
+          gray = pixels[srcX];
+          break;
+        case PNG_PIXEL_INDEXED:
+          if (pDraw->pPalette) {
+            const uint8_t idx = pixels[srcX];
+            const uint8_t* p = &pDraw->pPalette[idx * 3];
+            gray = (uint8_t)((p[0] * 77 + p[1] * 150 + p[2] * 29) >> 8);
+            if (hasAlpha) alpha = pDraw->pPalette[768 + idx];
+          }
+          break;
+        default:
+          gray = pixels[srcX];
+          break;
+      }
+
+      if (alpha >= 128) {
+        ctx->renderer->drawPixel(outX, destY, gray < 128);  // true = black, false = white
+      }
+      // alpha < 128: transparent — leave the reader page pixel intact
+    }
+
+    // Bresenham-style X stepping (handles downscaling; 1:1 when srcWidth == dstWidth)
+    error += srcWidth;
+    while (error >= dstWidth) {
+      error -= dstWidth;
+      srcX++;
+    }
+  }
+  return 1;
+}
+
+}  // namespace
+
 void SleepActivity::onEnter() {
   Activity::onEnter();
-  GUI.drawPopup(renderer, tr(STR_ENTERING_SLEEP));
+  // For OVERLAY mode the popup is suppressed so the frame buffer (reader page) stays intact
+  if (SETTINGS.sleepScreen != CrossPointSettings::SLEEP_SCREEN_MODE::OVERLAY) {
+    GUI.drawPopup(renderer, tr(STR_ENTERING_SLEEP));
+  }
 
   switch (SETTINGS.sleepScreen) {
     case (CrossPointSettings::SLEEP_SCREEN_MODE::BLANK):
@@ -26,6 +149,8 @@ void SleepActivity::onEnter() {
     case (CrossPointSettings::SLEEP_SCREEN_MODE::COVER):
     case (CrossPointSettings::SLEEP_SCREEN_MODE::COVER_CUSTOM):
       return renderCoverSleepScreen();
+    case (CrossPointSettings::SLEEP_SCREEN_MODE::OVERLAY):
+      return renderOverlaySleepScreen();
     default:
       return renderDefaultSleepScreen();
   }
@@ -284,3 +409,163 @@ void SleepActivity::renderBlankSleepScreen() const {
   renderer.clearScreen();
   renderer.displayBuffer(HalDisplay::HALF_REFRESH);
 }
+
+void SleepActivity::renderOverlaySleepScreen() const {
+  const auto pageWidth = renderer.getScreenWidth();
+  const auto pageHeight = renderer.getScreenHeight();
+
+  // Step 1: Ensure the frame buffer contains the reader page.
+  // When coming from a reader activity the frame buffer already holds the page.
+  // When coming from a non-reader activity we re-render it from the saved progress.
+  if (!APP_STATE.lastSleepFromReader && !APP_STATE.openEpubPath.empty()) {
+    const auto& path = APP_STATE.openEpubPath;
+    bool rendered = false;
+
+    if (StringUtils::checkFileExtension(path, ".xtc") || StringUtils::checkFileExtension(path, ".xtch")) {
+      rendered = XtcReaderActivity::drawCurrentPageToBuffer(path, renderer);
+    } else if (StringUtils::checkFileExtension(path, ".txt")) {
+      rendered = TxtReaderActivity::drawCurrentPageToBuffer(path, renderer);
+    } else if (StringUtils::checkFileExtension(path, ".epub")) {
+      rendered = EpubReaderActivity::drawCurrentPageToBuffer(path, renderer);
+    }
+
+    if (!rendered) {
+      LOG_DBG("SLP", "Page re-render failed, using white background");
+      renderer.clearScreen();
+    }
+  }
+
+  // Step 2: Load the overlay image using the same selection logic as renderCustomSleepScreen.
+  // BMP: white pixels are skipped (transparent via drawBitmap), black pixels composited on top.
+  // PNG: pixels with alpha < 128 are skipped; opaque pixels are drawn with their grayscale value.
+  auto tryDrawOverlay = [&](const std::string& filename) -> bool {
+    FsFile file;
+    if (!Storage.openFileForRead("SLP", filename, file)) return false;
+    Bitmap bitmap(file, true);
+    if (bitmap.parseHeaders() != BmpReaderError::Ok) {
+      file.close();
+      return false;
+    }
+
+    int x, y;
+    float cropX = 0, cropY = 0;
+    if (bitmap.getWidth() > pageWidth || bitmap.getHeight() > pageHeight) {
+      float ratio = static_cast<float>(bitmap.getWidth()) / static_cast<float>(bitmap.getHeight());
+      const float screenRatio = static_cast<float>(pageWidth) / static_cast<float>(pageHeight);
+      if (ratio > screenRatio) {
+        x = 0;
+        y = std::round((static_cast<float>(pageHeight) - static_cast<float>(pageWidth) / ratio) / 2);
+      } else {
+        x = std::round((static_cast<float>(pageWidth) - static_cast<float>(pageHeight) * ratio) / 2);
+        y = 0;
+      }
+    } else {
+      x = (pageWidth - bitmap.getWidth()) / 2;
+      y = (pageHeight - bitmap.getHeight()) / 2;
+    }
+
+    // Draw without clearScreen so the reader page remains in the frame buffer beneath
+    renderer.drawBitmap(bitmap, x, y, pageWidth, pageHeight, cropX, cropY);
+    file.close();
+    return true;
+  };
+
+  auto tryDrawPngOverlay = [&](const std::string& filename) -> bool {
+    constexpr size_t MIN_FREE_HEAP = 60 * 1024;  // PNG decoder ~42 KB + overhead
+    if (ESP.getFreeHeap() < MIN_FREE_HEAP) {
+      LOG_ERR("SLP", "Not enough heap for PNG overlay decoder");
+      return false;
+    }
+    PNG* png = new (std::nothrow) PNG();
+    if (!png) return false;
+
+    int rc = png->open(filename.c_str(), pngSleepOpen, pngSleepClose, pngSleepRead, pngSleepSeek, pngOverlayDraw);
+    if (rc != PNG_SUCCESS) {
+      LOG_DBG("SLP", "PNG open failed: %s (%d)", filename.c_str(), rc);
+      delete png;
+      return false;
+    }
+
+    const int srcW = png->getWidth(), srcH = png->getHeight();
+    float yScale = 1.0f;
+    int dstW = srcW, dstH = srcH;
+    if (srcW > pageWidth || srcH > pageHeight) {
+      const float scaleX = (float)pageWidth / srcW, scaleY = (float)pageHeight / srcH;
+      const float scale = (scaleX < scaleY) ? scaleX : scaleY;
+      dstW = (int)(srcW * scale);
+      dstH = (int)(srcH * scale);
+      yScale = (float)dstH / srcH;
+    }
+
+    PngOverlayCtx ctx;
+    ctx.renderer = &renderer;
+    ctx.screenW = pageWidth;
+    ctx.screenH = pageHeight;
+    ctx.srcWidth = srcW;
+    ctx.dstWidth = dstW;
+    ctx.dstX = (pageWidth - dstW) / 2;
+    ctx.dstY = (pageHeight - dstH) / 2;
+    ctx.yScale = yScale;
+    ctx.lastDstY = -1;
+
+    rc = png->decode(&ctx, 0);
+    png->close();
+    delete png;
+    return rc == PNG_SUCCESS;
+  };
+
+  // Try /sleep/ directory first (random selection, same as renderCustomSleepScreen).
+  // Accepts both .bmp and .png files; .bmp headers are validated during the scan.
+  bool overlayDrawn = false;
+  auto dir = Storage.open("/sleep");
+  if (dir && dir.isDirectory()) {
+    std::vector<std::string> files;
+    char name[500];
+    for (auto file = dir.openNextFile(); file; file = dir.openNextFile()) {
+      if (file.isDirectory()) { file.close(); continue; }
+      file.getName(name, sizeof(name));
+      auto filename = std::string(name);
+      if (filename[0] == '.') { file.close(); continue; }
+      const auto flen = filename.length();
+      const bool isBmp = flen >= 4 && filename.substr(flen - 4) == ".bmp";
+      const bool isPng = flen >= 4 && filename.substr(flen - 4) == ".png";
+      if (!isBmp && !isPng) { file.close(); continue; }
+      if (isBmp) {
+        Bitmap bmp(file);
+        if (bmp.parseHeaders() != BmpReaderError::Ok) { file.close(); continue; }
+      }
+      files.emplace_back(filename);
+      file.close();
+    }
+    const auto numFiles = files.size();
+    if (numFiles > 0) {
+      auto randomFileIndex = random(numFiles);
+      while (numFiles > 1 && randomFileIndex == APP_STATE.lastSleepImage) {
+        randomFileIndex = random(numFiles);
+      }
+      APP_STATE.lastSleepImage = randomFileIndex;
+      APP_STATE.saveToFile();
+      const std::string selected = "/sleep/" + files[randomFileIndex];
+      const auto slen = selected.length();
+      if (slen >= 4 && selected.substr(slen - 4) == ".png") {
+        overlayDrawn = tryDrawPngOverlay(selected);
+      } else {
+        overlayDrawn = tryDrawOverlay(selected);
+      }
+    }
+  }
+  if (dir) dir.close();
+
+  if (!overlayDrawn) {
+    overlayDrawn = tryDrawOverlay("/sleep.bmp");
+  }
+  if (!overlayDrawn) {
+    overlayDrawn = tryDrawPngOverlay("/sleep.png");
+  }
+
+  if (!overlayDrawn) {
+    LOG_DBG("SLP", "No overlay image found, displaying page without overlay");
+  }
+
+  renderer.displayBuffer(HalDisplay::HALF_REFRESH);
+}

src/activities/boot_sleep/SleepActivity.h

@@ -15,4 +15,5 @@ class SleepActivity final : public Activity {
   void renderCoverSleepScreen() const;
   void renderBitmapSleepScreen(const Bitmap& bitmap) const;
   void renderBlankSleepScreen() const;
+  void renderOverlaySleepScreen() const;
 };

src/activities/reader/EpubReaderActivity.cpp

@@ -829,3 +829,65 @@ void EpubReaderActivity::restoreSavedPosition() {
   }
   requestUpdate();
 }
+
+bool EpubReaderActivity::drawCurrentPageToBuffer(const std::string& filePath, GfxRenderer& renderer) {
+  auto epub = std::make_shared<Epub>(filePath, "/.crosspoint");
+  // skip CSS (second arg) since we only need layout/section data
+  if (!epub->load(true, false)) {
+    LOG_DBG("SLP", "EPUB: failed to load %s", filePath.c_str());
+    return false;
+  }
+
+  epub->setupCacheDir();
+
+  // Load saved spine index and page number
+  int spineIndex = 0, pageNumber = 0;
+  FsFile f;
+  if (Storage.openFileForRead("SLP", epub->getCachePath() + "/progress.bin", f)) {
+    uint8_t data[6];
+    if (f.read(data, 6) == 6) {
+      spineIndex = data[0] | (data[1] << 8);
+      pageNumber = data[2] | (data[3] << 8);
+    }
+    f.close();
+  }
+  if (spineIndex < 0 || spineIndex >= epub->getSpineItemsCount()) spineIndex = 0;
+
+  // Apply the reader orientation so margins match what the reader would produce
+  applyReaderOrientation(renderer, SETTINGS.orientation);
+
+  // Compute margins exactly as render() does
+  int marginTop, marginRight, marginBottom, marginLeft;
+  renderer.getOrientedViewableTRBL(&marginTop, &marginRight, &marginBottom, &marginLeft);
+  marginTop += SETTINGS.screenMargin;
+  marginLeft += SETTINGS.screenMargin;
+  marginRight += SETTINGS.screenMargin;
+  const uint8_t statusBarHeight = UITheme::getInstance().getStatusBarHeight();
+  marginBottom += std::max(SETTINGS.screenMargin, statusBarHeight);
+
+  const uint16_t viewportWidth = renderer.getScreenWidth() - marginLeft - marginRight;
+  const uint16_t viewportHeight = renderer.getScreenHeight() - marginTop - marginBottom;
+
+  // Load the cached section file (won't rebuild if cache missing — too slow for sleep)
+  auto section = std::unique_ptr<Section>(new Section(epub, spineIndex, renderer));
+  if (!section->loadSectionFile(SETTINGS.getReaderFontId(), SETTINGS.getReaderLineCompression(),
+                                SETTINGS.extraParagraphSpacing, SETTINGS.paragraphAlignment, viewportWidth,
+                                viewportHeight, SETTINGS.hyphenationEnabled, SETTINGS.embeddedStyle)) {
+    LOG_DBG("SLP", "EPUB: section cache not found for spine %d", spineIndex);
+    return false;
+  }
+
+  if (pageNumber < 0 || pageNumber >= section->pageCount) pageNumber = 0;
+  section->currentPage = pageNumber;
+
+  auto page = section->loadPageFromSectionFile();
+  if (!page) {
+    LOG_DBG("SLP", "EPUB: failed to load page %d", pageNumber);
+    return false;
+  }
+
+  renderer.clearScreen();
+  page->render(renderer, SETTINGS.getReaderFontId(), marginLeft, marginTop);
+  // No displayBuffer call — caller (SleepActivity) handles that after compositing the overlay
+  return true;
+}

src/activities/reader/EpubReaderActivity.h

@@ -58,4 +58,9 @@ class EpubReaderActivity final : public Activity {
   void loop() override;
   void render(RenderLock&& lock) override;
   bool isReaderActivity() const override { return true; }
+
+  // Renders the last saved page to the frame buffer without flushing to display.
+  // Used by SleepActivity to prepare the background for the overlay sleep mode.
+  // Returns false if the page cannot be loaded (missing cache / file error).
+  static bool drawCurrentPageToBuffer(const std::string& filePath, GfxRenderer& renderer);
 };

src/activities/reader/TxtReaderActivity.cpp

@@ -600,3 +600,188 @@ void TxtReaderActivity::savePageIndexCache() const {
   f.close();
   LOG_DBG("TRS", "Saved page index cache: %d pages", totalPages);
 }
+
+bool TxtReaderActivity::drawCurrentPageToBuffer(const std::string& filePath, GfxRenderer& renderer) {
+  Txt txt(filePath, "/.crosspoint");
+  if (!txt.load()) {
+    LOG_DBG("SLP", "TXT: failed to load %s", filePath.c_str());
+    return false;
+  }
+
+  // Compute layout values that match what initializeReader() produces
+  const int fontId = SETTINGS.getReaderFontId();
+  const uint8_t screenMargin = SETTINGS.screenMargin;
+  const uint8_t paragraphAlignment = SETTINGS.paragraphAlignment;
+
+  int marginTop, marginRight, marginBottom, marginLeft;
+  renderer.getOrientedViewableTRBL(&marginTop, &marginRight, &marginBottom, &marginLeft);
+  marginTop += screenMargin;
+  marginLeft += screenMargin;
+  marginRight += screenMargin;
+  marginBottom += std::max(screenMargin, static_cast<uint8_t>(UITheme::getInstance().getStatusBarHeight()));
+
+  const int vw = renderer.getScreenWidth() - marginLeft - marginRight;
+  const int vh = renderer.getScreenHeight() - marginTop - marginBottom;
+  const int lineHeight = renderer.getLineHeight(fontId);
+  const int linesPerPage = std::max(1, vh / lineHeight);
+
+  // Load the page offset index from cache (must already exist from normal reading)
+  std::string cachePath = txt.getCachePath() + "/index.bin";
+  FsFile cacheFile;
+  if (!Storage.openFileForRead("SLP", cachePath, cacheFile)) {
+    LOG_DBG("SLP", "TXT: no page index cache");
+    return false;
+  }
+
+  uint32_t magic;
+  serialization::readPod(cacheFile, magic);
+  if (magic != CACHE_MAGIC) {
+    cacheFile.close();
+    return false;
+  }
+
+  uint8_t version;
+  serialization::readPod(cacheFile, version);
+  if (version != CACHE_VERSION) {
+    cacheFile.close();
+    return false;
+  }
+
+  uint32_t cachedFileSize;
+  serialization::readPod(cacheFile, cachedFileSize);
+  if (cachedFileSize != txt.getFileSize()) {
+    cacheFile.close();
+    return false;
+  }
+
+  int32_t cachedVw, cachedLpp, cachedFontId, cachedMargin;
+  serialization::readPod(cacheFile, cachedVw);
+  serialization::readPod(cacheFile, cachedLpp);
+  serialization::readPod(cacheFile, cachedFontId);
+  serialization::readPod(cacheFile, cachedMargin);
+  if (cachedVw != vw || cachedLpp != linesPerPage || cachedFontId != fontId || cachedMargin != screenMargin) {
+    LOG_DBG("SLP", "TXT: cache invalid (settings changed)");
+    cacheFile.close();
+    return false;
+  }
+
+  uint8_t cachedAlignment;
+  serialization::readPod(cacheFile, cachedAlignment);
+  if (cachedAlignment != paragraphAlignment) {
+    cacheFile.close();
+    return false;
+  }
+
+  uint32_t numPages;
+  serialization::readPod(cacheFile, numPages);
+  if (numPages == 0) {
+    cacheFile.close();
+    return false;
+  }
+
+  std::vector<size_t> pageOffsets;
+  pageOffsets.reserve(numPages);
+  for (uint32_t i = 0; i < numPages; i++) {
+    uint32_t offset;
+    serialization::readPod(cacheFile, offset);
+    pageOffsets.push_back(offset);
+  }
+  cacheFile.close();
+
+  // Load saved page number from progress file
+  int savedPage = 0;
+  FsFile progFile;
+  if (Storage.openFileForRead("SLP", txt.getCachePath() + "/progress.bin", progFile)) {
+    uint8_t data[4];
+    if (progFile.read(data, 4) == 4) {
+      savedPage = data[0] + (data[1] << 8);
+    }
+    progFile.close();
+  }
+  if (savedPage < 0 || savedPage >= static_cast<int>(numPages)) savedPage = 0;
+
+  // Load the page lines from file
+  std::vector<std::string> pageLines;
+  const size_t fileSize = txt.getFileSize();
+  size_t offset = pageOffsets[savedPage];
+  if (offset >= fileSize) {
+    LOG_DBG("SLP", "TXT: page offset out of bounds");
+    return false;
+  }
+
+  // Replicate loadPageAtOffset() logic with local layout variables
+  size_t chunkSize = std::min(CHUNK_SIZE, fileSize - offset);
+  auto* buffer = static_cast<uint8_t*>(malloc(chunkSize + 1));
+  if (!buffer) return false;
+
+  if (!txt.readContent(buffer, offset, chunkSize)) {
+    free(buffer);
+    return false;
+  }
+  buffer[chunkSize] = '\0';
+
+  size_t pos = 0;
+  while (pos < chunkSize && static_cast<int>(pageLines.size()) < linesPerPage) {
+    size_t lineEnd = pos;
+    while (lineEnd < chunkSize && buffer[lineEnd] != '\n') lineEnd++;
+    bool lineComplete = (lineEnd < chunkSize) || (offset + lineEnd >= fileSize);
+    if (!lineComplete && !pageLines.empty()) break;
+
+    size_t lineContentLen = lineEnd - pos;
+    bool hasCR = (lineContentLen > 0 && buffer[pos + lineContentLen - 1] == '\r');
+    size_t displayLen = hasCR ? lineContentLen - 1 : lineContentLen;
+    std::string line(reinterpret_cast<char*>(buffer + pos), displayLen);
+    size_t lineBytePos = 0;
+
+    while (!line.empty() && static_cast<int>(pageLines.size()) < linesPerPage) {
+      if (renderer.getTextWidth(fontId, line.c_str()) <= vw) {
+        pageLines.push_back(line);
+        lineBytePos = displayLen;
+        line.clear();
+        break;
+      }
+      size_t breakPos = line.length();
+      while (breakPos > 0 && renderer.getTextWidth(fontId, line.substr(0, breakPos).c_str()) > vw) {
+        size_t spacePos = line.rfind(' ', breakPos - 1);
+        if (spacePos != std::string::npos && spacePos > 0) {
+          breakPos = spacePos;
+        } else {
+          breakPos--;
+          while (breakPos > 0 && (line[breakPos] & 0xC0) == 0x80) breakPos--;
+        }
+      }
+      if (breakPos == 0) breakPos = 1;
+      pageLines.push_back(line.substr(0, breakPos));
+      size_t skipChars = breakPos;
+      if (breakPos < line.length() && line[breakPos] == ' ') skipChars++;
+      lineBytePos += skipChars;
+      line = line.substr(skipChars);
+    }
+    pos = line.empty() ? lineEnd + 1 : pos + lineBytePos;
+  }
+  free(buffer);
+
+  if (pageLines.empty()) return false;
+
+  // Render lines to frame buffer (no displayBuffer call)
+  renderer.clearScreen();
+  int y = marginTop;
+  for (const auto& line : pageLines) {
+    if (!line.empty()) {
+      int x = marginLeft;
+      switch (paragraphAlignment) {
+        case CrossPointSettings::CENTER_ALIGN:
+          x = marginLeft + (vw - renderer.getTextWidth(fontId, line.c_str())) / 2;
+          break;
+        case CrossPointSettings::RIGHT_ALIGN:
+          x = marginLeft + vw - renderer.getTextWidth(fontId, line.c_str());
+          break;
+        default:
+          break;
+      }
+      renderer.drawText(fontId, x, y, line.c_str());
+    }
+    y += lineHeight;
+  }
+  return true;
+}

src/activities/reader/TxtReaderActivity.h

@@ -49,4 +49,9 @@ class TxtReaderActivity final : public Activity {
   void loop() override;
   void render(RenderLock&&) override;
   bool isReaderActivity() const override { return true; }
+
+  // Renders the last saved page to the frame buffer without flushing to display.
+  // Used by SleepActivity to prepare the background for the overlay sleep mode.
+  // Returns false if the page cannot be loaded (missing cache / file error).
+  static bool drawCurrentPageToBuffer(const std::string& filePath, GfxRenderer& renderer);
 };

src/activities/reader/XtcReaderActivity.cpp

@@ -351,3 +351,78 @@ void XtcReaderActivity::loadProgress() {
     f.close();
   }
 }
+
+bool XtcReaderActivity::drawCurrentPageToBuffer(const std::string& filePath, GfxRenderer& renderer) {
+  Xtc xtc(filePath, "/.crosspoint");
+  if (!xtc.load()) {
+    LOG_DBG("SLP", "XTC: failed to load %s", filePath.c_str());
+    return false;
+  }
+
+  // Load saved page number
+  uint32_t savedPage = 0;
+  FsFile f;
+  if (Storage.openFileForRead("SLP", xtc.getCachePath() + "/progress.bin", f)) {
+    uint8_t data[4];
+    if (f.read(data, 4) == 4) {
+      savedPage = data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
+    }
+    f.close();
+  }
+  if (savedPage >= xtc.getPageCount()) savedPage = 0;
+
+  const uint16_t pageWidth = xtc.getPageWidth();
+  const uint16_t pageHeight = xtc.getPageHeight();
+  const uint8_t bitDepth = xtc.getBitDepth();
+
+  // Only use the 1-bit BW path; grayscale is not needed as a background under the overlay
+  const size_t pageBufferSize = (bitDepth == 2) ? ((static_cast<size_t>(pageWidth) * pageHeight + 7) / 8) * 2
+                                                : ((pageWidth + 7) / 8) * pageHeight;
+
+  uint8_t* pageBuffer = static_cast<uint8_t*>(malloc(pageBufferSize));
+  if (!pageBuffer) {
+    LOG_ERR("SLP", "XTC: failed to allocate page buffer");
+    return false;
+  }
+
+  if (xtc.loadPage(savedPage, pageBuffer, pageBufferSize) == 0) {
+    LOG_ERR("SLP", "XTC: failed to load page %lu", savedPage);
+    free(pageBuffer);
+    return false;
+  }
+
+  renderer.clearScreen();
+
+  if (bitDepth == 2) {
+    // 2-bit XTH: draw all non-white pixels as black (BW pass only)
+    const size_t planeSize = (static_cast<size_t>(pageWidth) * pageHeight + 7) / 8;
+    const uint8_t* plane1 = pageBuffer;
+    const uint8_t* plane2 = pageBuffer + planeSize;
+    const size_t colBytes = (pageHeight + 7) / 8;
+    for (uint16_t y = 0; y < pageHeight; y++) {
+      for (uint16_t x = 0; x < pageWidth; x++) {
+        const size_t colIndex = pageWidth - 1 - x;
+        const size_t byteInCol = y / 8;
+        const size_t bitInByte = 7 - (y % 8);
+        const size_t byteOffset = colIndex * colBytes + byteInCol;
+        const uint8_t bit1 = (plane1[byteOffset] >> bitInByte) & 1;
+        const uint8_t bit2 = (plane2[byteOffset] >> bitInByte) & 1;
+        if ((bit1 << 1) | bit2) {
+          renderer.drawPixel(x, y, true);
+        }
+      }
+    }
+  } else {
+    // 1-bit XTG: draw black pixels
+    const size_t srcRowBytes = (pageWidth + 7) / 8;
+    for (uint16_t srcY = 0; srcY < pageHeight; srcY++) {
+      for (uint16_t srcX = 0; srcX < pageWidth; srcX++) {
+        const bool isBlack = !((pageBuffer[srcY * srcRowBytes + srcX / 8] >> (7 - srcX % 8)) & 1);
+        if (isBlack) renderer.drawPixel(srcX, srcY, true);
+      }
+    }
+  }
+
+  free(pageBuffer);
+  return true;
+}

src/activities/reader/XtcReaderActivity.h

@@ -29,4 +29,9 @@ class XtcReaderActivity final : public Activity {
   void loop() override;
   void render(RenderLock&&) override;
   bool isReaderActivity() const override { return true; }
+
+  // Renders the last saved page to the frame buffer without flushing to display.
+  // Used by SleepActivity to prepare the background for the overlay sleep mode.
+  // Returns false if the page cannot be loaded (missing cache / file error).
+  static bool drawCurrentPageToBuffer(const std::string& filePath, GfxRenderer& renderer);
 };