Merge branch 'master' into feature/pwr-btn-duration

## Problem
Three `fopen()` calls in ZipFile.cpp did not check for NULL before using
the file handle. If files cannot be opened, `fseek`/`fread`/`fclose`
receive NULL and crash.

## Fix
Added NULL checks with appropriate error logging and early returns for
all three locations:
- `getDataOffset()`
- `readFileToMemory()`
- `readFileToStream()`

## Testing
- Builds successfully with `pio run`
- Affects: `lib/ZipFile/ZipFile.cpp`

lib/Epub/Epub.cpp

@@ -148,23 +148,54 @@ bool Epub::load() {
     return false;
   }
 
-  // determine size of spine items
-  size_t spineItemsCount = getSpineItemsCount();
-  size_t spineItemsSize = 0;
-  for (size_t i = 0; i < spineItemsCount; i++) {
-    std::string spineItem = getSpineItem(i);
-    size_t s = 0;
-    getItemSize(spineItem, &s);
-    spineItemsSize += s;
-    cumulativeSpineItemSize.emplace_back(spineItemsSize);
-  }
-  Serial.printf("[%lu] [EBP] Book size: %u\n", millis(), spineItemsSize);
-
+  initializeSpineItemSizes();
   Serial.printf("[%lu] [EBP] Loaded ePub: %s\n", millis(), filepath.c_str());
 
   return true;
 }
 
+void Epub::initializeSpineItemSizes() {
+  setupCacheDir();
+
+  size_t spineItemsCount = getSpineItemsCount();
+  size_t cumSpineItemSize = 0;
+  if (SD.exists((getCachePath() + "/spine_size.bin").c_str())) {
+    File f = SD.open((getCachePath() + "/spine_size.bin").c_str());
+    uint8_t data[4];
+    for (size_t i = 0; i < spineItemsCount; i++) {
+      f.read(data, 4);
+      cumSpineItemSize = data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
+      cumulativeSpineItemSize.emplace_back(cumSpineItemSize);
+      // Serial.printf("[%lu] [EBP] Loading item %d size %u to %u %u\n", millis(),
+      //     i, cumSpineItemSize, data[1], data[0]);
+    }
+    f.close();
+  } else {
+    File f = SD.open((getCachePath() + "/spine_size.bin").c_str(), FILE_WRITE);
+    uint8_t data[4];
+    // determine size of spine items
+    for (size_t i = 0; i < spineItemsCount; i++) {
+      std::string spineItem = getSpineItem(i);
+      size_t s = 0;
+      getItemSize(spineItem, &s);
+      cumSpineItemSize += s;
+      cumulativeSpineItemSize.emplace_back(cumSpineItemSize);
+
+      // and persist to cache
+      data[0] = cumSpineItemSize & 0xFF;
+      data[1] = (cumSpineItemSize >> 8) & 0xFF;
+      data[2] = (cumSpineItemSize >> 16) & 0xFF;
+      data[3] = (cumSpineItemSize >> 24) & 0xFF;
+      // Serial.printf("[%lu] [EBP] Persisting item %d size %u to %u %u\n", millis(),
+      //     i, cumSpineItemSize, data[1], data[0]);
+      f.write(data, 4);
+    }
+
+    f.close();
+  }
+  Serial.printf("[%lu] [EBP] Book size: %lu\n", millis(), cumSpineItemSize);
+}
+
 bool Epub::clearCache() const {
   if (!SD.exists(cachePath.c_str())) {
     Serial.printf("[%lu] [EPB] Cache does not exist, no action needed\n", millis());
@@ -291,6 +322,11 @@ int Epub::getTocItemsCount() const { return toc.size(); }
 
 // work out the section index for a toc index
 int Epub::getSpineIndexForTocIndex(const int tocIndex) const {
+  if (tocIndex < 0 || tocIndex >= toc.size()) {
+    Serial.printf("[%lu] [EBP] getSpineIndexForTocIndex: tocIndex %d out of range\n", millis(), tocIndex);
+    return 0;
+  }
+
   // the toc entry should have an href that matches the spine item
   // so we can find the spine index by looking for the href
   for (int i = 0; i < spine.size(); i++) {
@@ -305,6 +341,11 @@ int Epub::getSpineIndexForTocIndex(const int tocIndex) const {
 }
 
 int Epub::getTocIndexForSpineIndex(const int spineIndex) const {
+  if (spineIndex < 0 || spineIndex >= spine.size()) {
+    Serial.printf("[%lu] [EBP] getTocIndexForSpineIndex: spineIndex %d out of range\n", millis(), spineIndex);
+    return -1;
+  }
+
   // the toc entry should have an href that matches the spine item
   // so we can find the toc index by looking for the href
   for (int i = 0; i < toc.size(); i++) {
@@ -317,13 +358,21 @@ int Epub::getTocIndexForSpineIndex(const int spineIndex) const {
   return -1;
 }
 
-size_t Epub::getBookSize() const { return getCumulativeSpineItemSize(getSpineItemsCount() - 1); }
+size_t Epub::getBookSize() const {
+  if (spine.empty()) {
+    return 0;
+  }
+  return getCumulativeSpineItemSize(getSpineItemsCount() - 1);
+}
 
 // Calculate progress in book
 uint8_t Epub::calculateProgress(const int currentSpineIndex, const float currentSpineRead) {
+  size_t bookSize = getBookSize();
+  if (bookSize == 0) {
+    return 0;
+  }
   size_t prevChapterSize = (currentSpineIndex >= 1) ? getCumulativeSpineItemSize(currentSpineIndex - 1) : 0;
   size_t curChapterSize = getCumulativeSpineItemSize(currentSpineIndex) - prevChapterSize;
-  size_t bookSize = getBookSize();
   size_t sectionProgSize = currentSpineRead * curChapterSize;
   return round(static_cast<float>(prevChapterSize + sectionProgSize) / bookSize * 100.0);
 }

lib/Epub/Epub.h

@@ -32,6 +32,7 @@ class Epub {
   bool findContentOpfFile(std::string* contentOpfFile) const;
   bool parseContentOpf(const std::string& contentOpfFilePath);
   bool parseTocNcxFile();
+  void initializeSpineItemSizes();
 
  public:
   explicit Epub(std::string filepath, const std::string& cacheDir) : filepath(std::move(filepath)) {

lib/Epub/Epub/ParsedText.cpp

@@ -27,12 +27,16 @@ void ParsedText::layoutAndExtractLines(const GfxRenderer& renderer, const int fo
   const size_t totalWordCount = words.size();
   const int pageWidth = renderer.getScreenWidth() - horizontalMargin;
   const int spaceWidth = renderer.getSpaceWidth(fontId);
-  // width of 1em to indent first line of paragraph if Extra Spacing is enabled
-  const int indentWidth = (!extraParagraphSpacing) ? 1 * renderer.getTextWidth(fontId, "m", REGULAR) : 0;
 
   std::vector<uint16_t> wordWidths;
   wordWidths.reserve(totalWordCount);
 
+  // add em-space at the beginning of first word in paragraph to indent
+  if (!extraParagraphSpacing) {
+    std::string& first_word = words.front();
+    first_word.insert(0, "\xe2\x80\x83");
+  }
+
   auto wordsIt = words.begin();
   auto wordStylesIt = wordStyles.begin();
 
@@ -53,7 +57,7 @@ void ParsedText::layoutAndExtractLines(const GfxRenderer& renderer, const int fo
   ans[totalWordCount - 1] = totalWordCount - 1;
 
   for (int i = totalWordCount - 2; i >= 0; --i) {
-    int currlen = -spaceWidth + indentWidth;
+    int currlen = -spaceWidth;
     dp[i] = MAX_COST;
 
     for (size_t j = i; j < totalWordCount; ++j) {
@@ -125,9 +129,6 @@ void ParsedText::layoutAndExtractLines(const GfxRenderer& renderer, const int fo
 
     // Calculate spacing
     int spareSpace = pageWidth - lineWordWidthSum;
-    if (wordWidthIndex == 0) {
-      spareSpace -= indentWidth;
-    }
 
     int spacing = spaceWidth;
     const bool isLastLine = lineBreak == totalWordCount;
@@ -137,8 +138,7 @@ void ParsedText::layoutAndExtractLines(const GfxRenderer& renderer, const int fo
     }
 
     // Calculate initial x position
-    uint16_t xpos = (wordWidthIndex == 0) ? indentWidth : 0;
-
+    uint16_t xpos = 0;
     if (style == TextBlock::RIGHT_ALIGN) {
       xpos = spareSpace - (lineWordCount - 1) * spaceWidth;
     } else if (style == TextBlock::CENTER_ALIGN) {

lib/Epub/Epub/parsers/ChapterHtmlSlimParser.cpp

@@ -75,6 +75,18 @@ void XMLCALL ChapterHtmlSlimParser::startElement(void* userData, const XML_Char*
     return;
   }
 
+  // Skip blocks with role="doc-pagebreak" and epub:type="pagebreak"
+  if (atts != nullptr) {
+    for (int i = 0; atts[i]; i += 2) {
+      if (strcmp(atts[i], "role") == 0 && strcmp(atts[i + 1], "doc-pagebreak") == 0 ||
+          strcmp(atts[i], "epub:type") == 0 && strcmp(atts[i + 1], "pagebreak") == 0) {
+        self->skipUntilDepth = self->depth;
+        self->depth += 1;
+        return;
+      }
+    }
+  }
+
   if (matches(name, HEADER_TAGS, NUM_HEADER_TAGS)) {
     self->startNewTextBlock(TextBlock::CENTER_ALIGN);
     self->boldUntilDepth = min(self->boldUntilDepth, self->depth);

lib/GfxRenderer/Bitmap.cpp

@@ -0,0 +1,189 @@
+#include "Bitmap.h"
+
+#include <cstdlib>
+#include <cstring>
+
+uint16_t Bitmap::readLE16(File& f) {
+  const int c0 = f.read();
+  const int c1 = f.read();
+  const auto b0 = static_cast<uint8_t>(c0 < 0 ? 0 : c0);
+  const auto b1 = static_cast<uint8_t>(c1 < 0 ? 0 : c1);
+  return static_cast<uint16_t>(b0) | (static_cast<uint16_t>(b1) << 8);
+}
+
+uint32_t Bitmap::readLE32(File& f) {
+  const int c0 = f.read();
+  const int c1 = f.read();
+  const int c2 = f.read();
+  const int c3 = f.read();
+
+  const auto b0 = static_cast<uint8_t>(c0 < 0 ? 0 : c0);
+  const auto b1 = static_cast<uint8_t>(c1 < 0 ? 0 : c1);
+  const auto b2 = static_cast<uint8_t>(c2 < 0 ? 0 : c2);
+  const auto b3 = static_cast<uint8_t>(c3 < 0 ? 0 : c3);
+
+  return static_cast<uint32_t>(b0) | (static_cast<uint32_t>(b1) << 8) | (static_cast<uint32_t>(b2) << 16) |
+         (static_cast<uint32_t>(b3) << 24);
+}
+
+const char* Bitmap::errorToString(BmpReaderError err) {
+  switch (err) {
+    case BmpReaderError::Ok:
+      return "Ok";
+    case BmpReaderError::FileInvalid:
+      return "FileInvalid";
+    case BmpReaderError::SeekStartFailed:
+      return "SeekStartFailed";
+    case BmpReaderError::NotBMP:
+      return "NotBMP (missing 'BM')";
+    case BmpReaderError::DIBTooSmall:
+      return "DIBTooSmall (<40 bytes)";
+    case BmpReaderError::BadPlanes:
+      return "BadPlanes (!= 1)";
+    case BmpReaderError::UnsupportedBpp:
+      return "UnsupportedBpp (expected 1, 2, 8, 24, or 32)";
+    case BmpReaderError::UnsupportedCompression:
+      return "UnsupportedCompression (expected BI_RGB or BI_BITFIELDS for 32bpp)";
+    case BmpReaderError::BadDimensions:
+      return "BadDimensions";
+    case BmpReaderError::PaletteTooLarge:
+      return "PaletteTooLarge";
+
+    case BmpReaderError::SeekPixelDataFailed:
+      return "SeekPixelDataFailed";
+    case BmpReaderError::BufferTooSmall:
+      return "BufferTooSmall";
+
+    case BmpReaderError::OomRowBuffer:
+      return "OomRowBuffer";
+    case BmpReaderError::ShortReadRow:
+      return "ShortReadRow";
+  }
+  return "Unknown";
+}
+
+BmpReaderError Bitmap::parseHeaders() {
+  if (!file) return BmpReaderError::FileInvalid;
+  if (!file.seek(0)) return BmpReaderError::SeekStartFailed;
+
+  // --- BMP FILE HEADER ---
+  const uint16_t bfType = readLE16(file);
+  if (bfType != 0x4D42) return BmpReaderError::NotBMP;
+
+  file.seek(8, SeekCur);
+  bfOffBits = readLE32(file);
+
+  // --- DIB HEADER ---
+  const uint32_t biSize = readLE32(file);
+  if (biSize < 40) return BmpReaderError::DIBTooSmall;
+
+  width = static_cast<int32_t>(readLE32(file));
+  const auto rawHeight = static_cast<int32_t>(readLE32(file));
+  topDown = rawHeight < 0;
+  height = topDown ? -rawHeight : rawHeight;
+
+  const uint16_t planes = readLE16(file);
+  bpp = readLE16(file);
+  const uint32_t comp = readLE32(file);
+  const bool validBpp = bpp == 1 || bpp == 2 || bpp == 8 || bpp == 24 || bpp == 32;
+
+  if (planes != 1) return BmpReaderError::BadPlanes;
+  if (!validBpp) return BmpReaderError::UnsupportedBpp;
+  // Allow BI_RGB (0) for all, and BI_BITFIELDS (3) for 32bpp which is common for BGRA masks.
+  if (!(comp == 0 || (bpp == 32 && comp == 3))) return BmpReaderError::UnsupportedCompression;
+
+  file.seek(12, SeekCur);  // biSizeImage, biXPelsPerMeter, biYPelsPerMeter
+  const uint32_t colorsUsed = readLE32(file);
+  if (colorsUsed > 256u) return BmpReaderError::PaletteTooLarge;
+  file.seek(4, SeekCur);  // biClrImportant
+
+  if (width <= 0 || height <= 0) return BmpReaderError::BadDimensions;
+
+  // Pre-calculate Row Bytes to avoid doing this every row
+  rowBytes = (width * bpp + 31) / 32 * 4;
+
+  for (int i = 0; i < 256; i++) paletteLum[i] = static_cast<uint8_t>(i);
+  if (colorsUsed > 0) {
+    for (uint32_t i = 0; i < colorsUsed; i++) {
+      uint8_t rgb[4];
+      file.read(rgb, 4);  // Read B, G, R, Reserved in one go
+      paletteLum[i] = (77u * rgb[2] + 150u * rgb[1] + 29u * rgb[0]) >> 8;
+    }
+  }
+
+  if (!file.seek(bfOffBits)) {
+    return BmpReaderError::SeekPixelDataFailed;
+  }
+
+  return BmpReaderError::Ok;
+}
+
+// packed 2bpp output, 0 = black, 1 = dark gray, 2 = light gray, 3 = white
+BmpReaderError Bitmap::readRow(uint8_t* data, uint8_t* rowBuffer) const {
+  // Note: rowBuffer should be pre-allocated by the caller to size 'rowBytes'
+  if (file.read(rowBuffer, rowBytes) != rowBytes) return BmpReaderError::ShortReadRow;
+
+  uint8_t* outPtr = data;
+  uint8_t currentOutByte = 0;
+  int bitShift = 6;
+
+  // Helper lambda to pack 2bpp color into the output stream
+  auto packPixel = [&](uint8_t lum) {
+    uint8_t color = (lum >> 6);  // Simple 2-bit reduction: 0-255 -> 0-3
+    currentOutByte |= (color << bitShift);
+    if (bitShift == 0) {
+      *outPtr++ = currentOutByte;
+      currentOutByte = 0;
+      bitShift = 6;
+    } else {
+      bitShift -= 2;
+    }
+  };
+
+  switch (bpp) {
+    case 8: {
+      for (int x = 0; x < width; x++) {
+        packPixel(paletteLum[rowBuffer[x]]);
+      }
+      break;
+    }
+    case 24: {
+      const uint8_t* p = rowBuffer;
+      for (int x = 0; x < width; x++) {
+        uint8_t lum = (77u * p[2] + 150u * p[1] + 29u * p[0]) >> 8;
+        packPixel(lum);
+        p += 3;
+      }
+      break;
+    }
+    case 1: {
+      for (int x = 0; x < width; x++) {
+        uint8_t lum = (rowBuffer[x >> 3] & (0x80 >> (x & 7))) ? 0xFF : 0x00;
+        packPixel(lum);
+      }
+      break;
+    }
+    case 32: {
+      const uint8_t* p = rowBuffer;
+      for (int x = 0; x < width; x++) {
+        uint8_t lum = (77u * p[2] + 150u * p[1] + 29u * p[0]) >> 8;
+        packPixel(lum);
+        p += 4;
+      }
+      break;
+    }
+  }
+
+  // Flush remaining bits if width is not a multiple of 4
+  if (bitShift != 6) *outPtr = currentOutByte;
+
+  return BmpReaderError::Ok;
+}
+
+BmpReaderError Bitmap::rewindToData() const {
+  if (!file.seek(bfOffBits)) {
+    return BmpReaderError::SeekPixelDataFailed;
+  }
+
+  return BmpReaderError::Ok;
+}

lib/GfxRenderer/Bitmap.h

@@ -0,0 +1,52 @@
+#pragma once
+
+#include <FS.h>
+
+enum class BmpReaderError : uint8_t {
+  Ok = 0,
+  FileInvalid,
+  SeekStartFailed,
+
+  NotBMP,
+  DIBTooSmall,
+
+  BadPlanes,
+  UnsupportedBpp,
+  UnsupportedCompression,
+
+  BadDimensions,
+  PaletteTooLarge,
+
+  SeekPixelDataFailed,
+  BufferTooSmall,
+  OomRowBuffer,
+  ShortReadRow,
+};
+
+class Bitmap {
+ public:
+  static const char* errorToString(BmpReaderError err);
+
+  explicit Bitmap(File& file) : file(file) {}
+  BmpReaderError parseHeaders();
+  BmpReaderError readRow(uint8_t* data, uint8_t* rowBuffer) const;
+  BmpReaderError rewindToData() const;
+  int getWidth() const { return width; }
+  int getHeight() const { return height; }
+  bool isTopDown() const { return topDown; }
+  bool hasGreyscale() const { return bpp > 1; }
+  int getRowBytes() const { return rowBytes; }
+
+ private:
+  static uint16_t readLE16(File& f);
+  static uint32_t readLE32(File& f);
+
+  File& file;
+  int width = 0;
+  int height = 0;
+  bool topDown = false;
+  uint32_t bfOffBits = 0;
+  uint16_t bpp = 0;
+  int rowBytes = 0;
+  uint8_t paletteLum[256] = {};
+};

lib/GfxRenderer/GfxRenderer.cpp

@@ -119,6 +119,66 @@ void GfxRenderer::drawImage(const uint8_t bitmap[], const int x, const int y, co
   einkDisplay.drawImage(bitmap, y, x, height, width);
 }
 
+void GfxRenderer::drawBitmap(const Bitmap& bitmap, const int x, const int y, const int maxWidth,
+                             const int maxHeight) const {
+  float scale = 1.0f;
+  bool isScaled = false;
+  if (maxWidth > 0 && bitmap.getWidth() > maxWidth) {
+    scale = static_cast<float>(maxWidth) / static_cast<float>(bitmap.getWidth());
+    isScaled = true;
+  }
+  if (maxHeight > 0 && bitmap.getHeight() > maxHeight) {
+    scale = std::min(scale, static_cast<float>(maxHeight) / static_cast<float>(bitmap.getHeight()));
+    isScaled = true;
+  }
+
+  const uint8_t outputRowSize = (bitmap.getWidth() + 3) / 4;
+  auto* outputRow = static_cast<uint8_t*>(malloc(outputRowSize));
+  auto* rowBytes = static_cast<uint8_t*>(malloc(bitmap.getRowBytes()));
+
+  for (int bmpY = 0; bmpY < bitmap.getHeight(); bmpY++) {
+    // The BMP's (0, 0) is the bottom-left corner (if the height is positive, top-left if negative).
+    // Screen's (0, 0) is the top-left corner.
+    int screenY = y + (bitmap.isTopDown() ? bmpY : bitmap.getHeight() - 1 - bmpY);
+    if (isScaled) {
+      screenY = std::floor(screenY * scale);
+    }
+    if (screenY >= getScreenHeight()) {
+      break;
+    }
+
+    if (bitmap.readRow(outputRow, rowBytes) != BmpReaderError::Ok) {
+      Serial.printf("[%lu] [GFX] Failed to read row %d from bitmap\n", millis(), bmpY);
+      free(outputRow);
+      free(rowBytes);
+      return;
+    }
+
+    for (int bmpX = 0; bmpX < bitmap.getWidth(); bmpX++) {
+      int screenX = x + bmpX;
+      if (isScaled) {
+        screenX = std::floor(screenX * scale);
+      }
+      if (screenX >= getScreenWidth()) {
+        break;
+      }
+
+      const uint8_t val = outputRow[bmpX / 4] >> (6 - ((bmpX * 2) % 8)) & 0x3;
+
+      if (renderMode == BW && val < 3) {
+        drawPixel(screenX, screenY);
+      } else if (renderMode == GRAYSCALE_MSB && (val == 1 || val == 2)) {
+        drawPixel(screenX, screenY, false);
+      } else if (renderMode == GRAYSCALE_LSB && val == 1) {
+        drawPixel(screenX, screenY, false);
+      }
+    }
+  }
+
+  free(outputRow);
+  free(rowBytes);
+}
+
 void GfxRenderer::clearScreen(const uint8_t color) const { einkDisplay.clearScreen(color); }
 
 void GfxRenderer::invertScreen() const {

lib/GfxRenderer/GfxRenderer.h

@@ -2,9 +2,12 @@
 
 #include <EInkDisplay.h>
 #include <EpdFontFamily.h>
+#include <FS.h>
 
 #include <map>
 
+#include "Bitmap.h"
+
 class GfxRenderer {
  public:
   enum RenderMode { BW, GRAYSCALE_LSB, GRAYSCALE_MSB };
@@ -45,6 +48,7 @@ class GfxRenderer {
   void drawRect(int x, int y, int width, int height, bool state = true) const;
   void fillRect(int x, int y, int width, int height, bool state = true) const;
   void drawImage(const uint8_t bitmap[], int x, int y, int width, int height) const;
+  void drawBitmap(const Bitmap& bitmap, int x, int y, int maxWidth, int maxHeight) const;
 
   // Text
   int getTextWidth(int fontId, const char* text, EpdFontStyle style = REGULAR) const;

lib/ZipFile/ZipFile.cpp

@@ -62,6 +62,10 @@ long ZipFile::getDataOffset(const mz_zip_archive_file_stat& fileStat) const {
   const uint64_t fileOffset = fileStat.m_local_header_ofs;
 
   FILE* file = fopen(filePath.c_str(), "r");
+  if (!file) {
+    Serial.printf("[%lu] [ZIP] Failed to open file for reading local header\n", millis());
+    return -1;
+  }
   fseek(file, fileOffset, SEEK_SET);
   const size_t read = fread(pLocalHeader, 1, localHeaderSize, file);
   fclose(file);
@@ -104,6 +108,10 @@ uint8_t* ZipFile::readFileToMemory(const char* filename, size_t* size, const boo
   }
 
   FILE* file = fopen(filePath.c_str(), "rb");
+  if (!file) {
+    Serial.printf("[%lu] [ZIP] Failed to open file for reading\n", millis());
+    return nullptr;
+  }
   fseek(file, fileOffset, SEEK_SET);
 
   const auto deflatedDataSize = static_cast<size_t>(fileStat.m_comp_size);
@@ -175,6 +183,10 @@ bool ZipFile::readFileToStream(const char* filename, Print& out, const size_t ch
   }
 
   FILE* file = fopen(filePath.c_str(), "rb");
+  if (!file) {
+    Serial.printf("[%lu] [ZIP] Failed to open file for streaming\n", millis());
+    return false;
+  }
   fseek(file, fileOffset, SEEK_SET);
 
   const auto deflatedDataSize = static_cast<size_t>(fileStat.m_comp_size);

platformio.ini

@@ -1,5 +1,5 @@
 [platformio]
-crosspoint_version = 0.6.0
+crosspoint_version = 0.7.0
 default_envs = default
 
 [base]

src/activities/boot_sleep/SleepActivity.cpp

@@ -3,10 +3,26 @@
 #include <GfxRenderer.h>
 
 #include "CrossPointSettings.h"
+#include "SD.h"
 #include "config.h"
 #include "images/CrossLarge.h"
 
 void SleepActivity::onEnter() {
+  // Look for sleep.bmp on the root of the sd card to determine if we should
+  // render a custom sleep screen instead of the default.
+  auto file = SD.open("/sleep.bmp");
+  if (file) {
+    Bitmap bitmap(file);
+    if (bitmap.parseHeaders() == BmpReaderError::Ok) {
+      renderCustomSleepScreen(bitmap);
+      return;
+    }
+  }
+
+  renderDefaultSleepScreen();
+}
+
+void SleepActivity::renderDefaultSleepScreen() const {
   const auto pageWidth = GfxRenderer::getScreenWidth();
   const auto pageHeight = GfxRenderer::getScreenHeight();
 
@@ -22,3 +38,50 @@ void SleepActivity::onEnter() {
 
   renderer.displayBuffer(EInkDisplay::HALF_REFRESH);
 }
+
+void SleepActivity::renderCustomSleepScreen(const Bitmap& bitmap) const {
+  int x, y;
+  const auto pageWidth = GfxRenderer::getScreenWidth();
+  const auto pageHeight = GfxRenderer::getScreenHeight();
+
+  if (bitmap.getWidth() > pageWidth || bitmap.getHeight() > pageHeight) {
+    // image will scale, make sure placement is right
+    const 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) {
+      // image wider than viewport ratio, scaled down image needs to be centered vertically
+      x = 0;
+      y = (pageHeight - pageWidth / ratio) / 2;
+    } else {
+      // image taller than viewport ratio, scaled down image needs to be centered horizontally
+      x = (pageWidth - pageHeight * ratio) / 2;
+      y = 0;
+    }
+  } else {
+    // center the image
+    x = (pageWidth - bitmap.getWidth()) / 2;
+    y = (pageHeight - bitmap.getHeight()) / 2;
+  }
+
+  renderer.clearScreen();
+  renderer.drawBitmap(bitmap, x, y, pageWidth, pageHeight);
+  renderer.displayBuffer(EInkDisplay::HALF_REFRESH);
+
+  if (bitmap.hasGreyscale()) {
+    bitmap.rewindToData();
+    renderer.clearScreen(0x00);
+    renderer.setRenderMode(GfxRenderer::GRAYSCALE_LSB);
+    renderer.drawBitmap(bitmap, x, y, pageWidth, pageHeight);
+    renderer.copyGrayscaleLsbBuffers();
+
+    bitmap.rewindToData();
+    renderer.clearScreen(0x00);
+    renderer.setRenderMode(GfxRenderer::GRAYSCALE_MSB);
+    renderer.drawBitmap(bitmap, x, y, pageWidth, pageHeight);
+    renderer.copyGrayscaleMsbBuffers();
+
+    renderer.displayGrayBuffer();
+    renderer.setRenderMode(GfxRenderer::BW);
+  }
+}

src/activities/boot_sleep/SleepActivity.h

@@ -1,8 +1,14 @@
 #pragma once
 #include "../Activity.h"
 
+class Bitmap;
+
 class SleepActivity final : public Activity {
  public:
   explicit SleepActivity(GfxRenderer& renderer, InputManager& inputManager) : Activity(renderer, inputManager) {}
   void onEnter() override;
+
+ private:
+  void renderDefaultSleepScreen() const;
+  void renderCustomSleepScreen(const Bitmap& bitmap) const;
 };

src/activities/reader/EpubReaderActivity.cpp

@@ -33,13 +33,14 @@ void EpubReaderActivity::onEnter() {
 
   epub->setupCacheDir();
 
-  if (SD.exists((epub->getCachePath() + "/progress.bin").c_str())) {
-    File f = SD.open((epub->getCachePath() + "/progress.bin").c_str());
+  File f = SD.open((epub->getCachePath() + "/progress.bin").c_str());
+  if (f) {
     uint8_t data[4];
-    f.read(data, 4);
-    currentSpineIndex = data[0] + (data[1] << 8);
-    nextPageNumber = data[2] + (data[3] << 8);
-    Serial.printf("[%lu] [ERS] Loaded cache: %d, %d\n", millis(), currentSpineIndex, nextPageNumber);
+    if (f.read(data, 4) == 4) {
+      currentSpineIndex = data[0] + (data[1] << 8);
+      nextPageNumber = data[2] + (data[3] << 8);
+      Serial.printf("[%lu] [ERS] Loaded cache: %d, %d\n", millis(), currentSpineIndex, nextPageNumber);
+    }
     f.close();
   }
 
@@ -382,7 +383,7 @@ void EpubReaderActivity::renderStatusBar() const {
     const auto tocItem = epub->getTocItem(tocIndex);
     title = tocItem.title;
     titleWidth = renderer.getTextWidth(SMALL_FONT_ID, title.c_str());
-    while (titleWidth > availableTextWidth) {
+    while (titleWidth > availableTextWidth && title.length() > 11) {
       title = title.substr(0, title.length() - 8) + "...";
       titleWidth = renderer.getTextWidth(SMALL_FONT_ID, title.c_str());
     }

src/main.cpp

@@ -159,7 +159,12 @@ void setup() {
   SPI.begin(EPD_SCLK, SD_SPI_MISO, EPD_MOSI, EPD_CS);
 
   // SD Card Initialization
-  SD.begin(SD_SPI_CS, SPI, SPI_FQ);
+  if (!SD.begin(SD_SPI_CS, SPI, SPI_FQ)) {
+    Serial.printf("[%lu] [   ] SD card initialization failed\n", millis());
+    exitActivity();
+    enterNewActivity(new FullScreenMessageActivity(renderer, inputManager, "SD card error", BOLD));
+    return;
+  }
 
   SETTINGS.loadFromFile();