Fix XTC grayscale mapping for dark/light gray pixels

Swap the grayscale values for pixel values 1 and 2 to match the cover's kXthToBmp mapping. Previously 1 mapped to 170 (light gray) and 2 to 85 (dark gray), now corrected to 1->85 (dark gray) and 2->170 (light gray). Use lookup table for clarity.

.gitmodules

@@ -1,4 +1,3 @@
-[submodule "freeink-sdk"]
-	path = freeink-sdk
-	url = https://github.com/Free-Ink/freeink-sdk.git
-	branch = main
+[submodule "open-x4-sdk"]
+	path = open-x4-sdk
+	url = https://github.com/crosspoint-reader/community-sdk.git

.skills/SKILL.md

@@ -7,7 +7,7 @@ Mission: Provide a lightweight, high-performance reading experience focused on E
 * Role: Senior Embedded Systems Engineer (ESP-IDF/Arduino-ESP32 specialized).
 * Primary Constraint: 380KB RAM is the hard ceiling. Stability is non-negotiable.
 * Evidence-Based Reasoning: Before proposing a change, you MUST cite the specific file path and line numbers that justify the modification.
-* Anti-Hallucination: Do not assume the existence of libraries or ESP-IDF functions. If you are unsure of an API's availability for the ESP32-C3 RISC-V target, check the freeink-sdk source or the FreeInk SDK docs (https://freeink.org/llms.txt for an LLM-readable index) first.
+* Anti-Hallucination: Do not assume the existence of libraries or ESP-IDF functions. If you are unsure of an API's availability for the ESP32-C3 RISC-V target, check the open-x4-sdk or official docs first.
 * No Unfounded Claims: Do not claim performance gains or memory savings without explaining the technical mechanism (e.g., DRAM vs IRAM usage).
 * Resource Justification: You must justify any new heap allocation (new, malloc, std::vector) or explain why a stack/static alternative was rejected.
 * Verification: After suggesting a fix, instruct the user on how to verify it (e.g., monitoring heap via Serial or checking a specific cache file).
@@ -127,7 +127,7 @@ These flags in `platformio.ini` fundamentally affect firmware behavior:
   * lib/hal/: Hardware Abstraction Layer (HalDisplay, HalGPIO, HalStorage)
   * lib/I18n/: Internationalization (translations in `translations/*.yaml`, generated string tables)
 * src/activities/: UI logic using the Activity Lifecycle (onEnter, loop, onExit)
-* freeink-sdk/: Low-level SDK (EInkDisplay, InputManager, BatteryMonitor, SDCardManager)
+* open-x4-sdk/: Low-level SDK (EInkDisplay, InputManager, BatteryMonitor, SDCardManager)
 * .crosspoint/: SD-based binary cache for EPUB metadata and pre-rendered layout sections
 
 ### Hardware Abstraction Layer (HAL)

README.md

@@ -131,23 +131,6 @@ Convert your own TTF/OTF files into `.cpfont` files that load from the SD card.
 
 Conversion runs the firmware repo's `lib/EpdFont/scripts/fontconvert_sdcard.py` script unmodified, so output matches a local host build.
 
-## Custom SD-card themes
-
-Downloadable themes are packaged in the tools repo under `../crosspoint-tools/public/themes/<theme-id>/`. Each theme folder must contain a `theme.json`; optional assets such as generated BMP icons live beside it, usually under `icons/`.
-
-See [SD-card theme creation](./docs/theme-creation.md) for the full JSON format, device-specific overrides, icon generation, CrossInk extension fields, and packaging rules.
-
-After adding or changing a hosted theme, regenerate the download manifest:
-
-```bash
-python3 scripts/generate-theme-manifest.py \
-  --root ../crosspoint-tools/public/themes \
-  --base-url http://crosspointreader.com/themes \
-  --output ../crosspoint-tools/public/themes/themes.json
-```
-
-The script scans every theme folder, includes every file in each package, and writes size and CRC32 values used by the device downloader. Commit changed theme package files and the regenerated `themes.json` in `crosspoint-tools`.
-
 ---
 
 ## Documentation
@@ -155,7 +138,6 @@ The script scans every theme folder, includes every file in each package, and wr
 - [User Guide](./USER_GUIDE.md)
 - [Web server usage](./docs/webserver.md)
 - [Web server endpoints](./docs/webserver-endpoints.md)
-- [SD-card theme creation](./docs/theme-creation.md)
 - [Project scope](./SCOPE.md)
 - [Contributing docs](./docs/contributing/README.md)
 

USER_GUIDE.md

@@ -122,43 +122,19 @@ A **Wi-Fi signal strength indicator** (dBm) is displayed on-screen during joined
 
 CrossPoint supports sending books from Calibre using the CrossPoint Reader device plugin.
 
-#### Installing the Plugin in Calibre
+1. Install the plugin in Calibre:
+   
+   - Head to https://github.com/crosspoint-reader/calibre-plugins/releases to download the latest version of the crosspoint_reader plugin.
+   
+   - Download the zip file.
+   
+   - Open Calibre → Preferences → Plugins → Load plugin from file → Select the zip file.
 
-If you don't already have the plugin installed:
+2. On the device: File Transfer -> Calibre Wireless, then join a network.
 
-1. Head to https://github.com/crosspoint-reader/calibre-plugins/releases to download the latest version of the crosspoint_reader plugin.
-2. Download the zip file.
-3. Open Calibre → Preferences → Plugins → Load plugin from file → Select the zip file.
-4. Restart Calibre.
+3. Make sure your computer is on the same Wi-Fi network.
 
-#### Configuring the CrossPoint Plugin in Calibre
-1. In Calibre select Preferences.
-2. In the Preferences dialog select Plugins.
-3. In Plugins search for "crosspoint".
-4. Click on "Customize plugin".
-5. Update the value for "Host" to match the IP for your device.
-6. Leave the other settings as they are.
-7. [optional] Modify the "Upload path" to point to a subfolder other than the root "/" folder. Enter this as a path relative to the root folder. Example: `/mybooks`
-8. Restart Calibre.
-
-<img width="420" height="385" alt="Image" src="https://github.com/user-attachments/assets/01fc7e33-a9a7-48ba-9e26-2e68d1f9daec" />
-
-#### Uploading Books
-
-To upload a book using the CrossPoint plugin in Calibre:
-
-1. On the device: File Transfer -> Calibre Wireless, then join a network.
-2. Select one or more books.
-3. Right-click on that selection.
-4. Select "Send to Device" > "Send to main memory"
-
-The CrossPoint plugin will connect to your device, create a folder for the book's author in the root folder (or the folder you configured for the plugin), then copy the book into that folder.
-
-<img width="783" height="310" alt="Image" src="https://github.com/user-attachments/assets/741b0909-2e1d-4f16-8af0-2c43fbda5ce6" />
-
-#### Removing a Book
-
-Books cannot be removed from your device through Calibre. Use the web interface instead.
+4. In Calibre, click "Send to device" to transfer books.
 
 ### 3.6 Settings
 
@@ -174,7 +150,6 @@ The Settings screen allows you to configure the device's behavior. There are a f
   - "Cover" - The book cover image (Note: this is experimental and may not work as expected)
   - "None" - A blank screen
   - "Cover + Custom" - The book cover image while actively reading, falls back to "Custom" behavior otherwise
-  - "Quick resume" - The text of the last page read will be displayed on the sleep screen and a moon icon is shown on the edge of the screen. Waking up the device will return to the same page of the opened book. This is useful for quickly resuming reading without waiting for the device to fully wake up and load the book.
 
 - **Sleep Screen Cover Mode**: How to display the book cover when "Cover" sleep screen is selected:
   
@@ -187,8 +162,6 @@ The Settings screen allows you to configure the device's behavior. There are a f
   - "Contrast" - The image will be displayed as a black & white image without grayscale conversion
   - "Inverted" - The image will be inverted as in white & black and will be displayed without grayscale conversion
 
-- **Quick Resume on Timeout**: Whether to enable the "Quick Resume" sleep screen when the device goes to sleep due to inactivity (System > Time to Sleep). This is useful for quickly resuming reading without waiting for the device to fully wake up and load the book. This overwrites the Sleep Screen Cover Mode when enabled.
-
 - **Status Bar**: Configure the status bar displayed while reading:
   
   - "None" - No status bar
@@ -268,10 +241,6 @@ The Settings screen allows you to configure the device's behavior. There are a f
   
   - "Chapter Skip" (default) - Long-pressing skips to next/previous chapter
   - "Page Scroll" - Long-pressing scrolls a page up/down
-- **Long-press Menu**: Selects the function bound to holding the menu button (Confirm) while reading an EPUB. **Cycles through the available functions** each time the setting is selected — additional functions may be added in future releases, so this is not a binary on/off toggle. A short press of Confirm always opens the reader menu as normal:
-  - "Bookmark" (default) - Hold Confirm (~0.4 second) to drop a bookmark at the current page.
-  - "KOSync" - Hold Confirm (~1 second) to launch KOReader sync directly.
-  - "Disabled" - Long-press is ignored; only short-press opens the reader menu.
 
 - **Short Power Button Click**: Controls the effect of a short click of the power button:
   
@@ -554,14 +523,11 @@ On the **Xteink X3**, the gyroscope can be used to turn pages by tilting the dev
 
 When reading an EPUB that contains footnotes, you can navigate to the footnote text by selecting the footnote reference in the book. From the footnote, you can return to your original reading position.
 
-If the device goes to sleep or you close the book while viewing a footnote, the book reopens to your original reading position, not the footnote.
-
 ### System Navigation
 
 * **Return to Home:** Press the **Back** button to close the book and return to the **[Home](#31-home-screen)** screen.
 * **Return to Browse Files:** Press and hold the **Back** button to close the book and return to the **[Browse Files](#33-browse-files-screen)** screen.
 * **Reader Menu:** Press **Confirm** to open the **[Reader Menu](#5-reader-menu)**, which includes chapter navigation, reading options, and more.
-* **Long-press Confirm (configurable):** Holding **Confirm** runs the function chosen by the **Long-press Menu** setting in **[Controls Settings](#363-controls)** — "Bookmark" (default) drops a bookmark, "KOSync" launches KOReader Sync, "Disabled" does nothing. A short press always opens the Reader Menu.
 
 ### Supported Languages
 
@@ -608,9 +574,9 @@ Accessible by selecting **Chapters** from the Reader Menu.
 
 Bookmarks can be created to quickly save and restore your place in a book.
 
-To create a bookmark, hold **Confirm** for about half a second while inside a book. A popup will appear letting you know a bookmark was created. The popup message will automatically disappear in a couple of seconds.
+To create a bookmark, hold **Confirm** for 1 second while inside a book. A popup will appear letting you know a bookmark was created. The popup message will automatically disappear in a couple of seconds.
 
-To open bookmarks, press **Confirm** while inside a book. Then navigate to the **Bookmarks** menu. Bookmarks can be opened by navigating to them and pressing **Confirm**, which will redirect you to that place in the book. You can delete bookmarks by holding **Confirm** for about 0.7 seconds, and then pressing **Confirm** again to confirm deletion, or **Back** to cancel.
+To open bookmarks, press **Confirm** while inside a book. Then navigate to the **Bookmarks** menu. Bookmarks can be opened by navigating to them and pressing **Confirm**, which will redirect you to that place in the book. You can delete bookmarks by holding **Confirm** for 1 second, and then pressing **Confirm** again to confirm deletion, or **Back** to cancel.
 
 Bookmarks are stored in the `.crosspoint/bookmarks` folder in the JSON format.
 

bin/clang-format-fix.ps1

@@ -4,7 +4,7 @@
 
 .DESCRIPTION
     Formats all C/C++ source and header files in the repository, excluding
-    generated, vendored, and build directories (freeink-sdk, builtinFonts,
+    generated, vendored, and build directories (open-x4-sdk, builtinFonts,
     hyphenation tries, uzlib, .pio, *.generated.h).
 
     The clang-format binary path is resolved once and cached in
@@ -92,7 +92,7 @@ function Resolve-ClangFormat {
 $clangFormat = Resolve-ClangFormat
 
 $exclude = @(
-    'freeink-sdk'
+    'open-x4-sdk'
     'lib\EpdFont\builtinFonts'
     'lib\Epub\Epub\hyphenation\generated'
     'lib\uzlib'

docs/contributing/architecture.md

@@ -8,7 +8,7 @@ At a high level, it is firmware that uses an activity-driven application archite
 
 ```mermaid
 graph TD
-    A[Hardware: ESP32-C3 + SD + E-ink + Buttons] --> B[freeink-sdk]
+    A[Hardware: ESP32-C3 + SD + E-ink + Buttons] --> B[open-x4-sdk]
     B --> C[lib/hal wrappers]
     C --> D[src/main.cpp runtime loop]
     D --> E[Activities layer]
@@ -195,10 +195,10 @@ When editing related source assets, regenerate via normal build steps/scripts.
 - `src/`: app orchestration, settings/state, and activity implementations
 - `src/network/`: web server and OTA/update networking
 - `src/components/`: theming and shared UI components
-- `lib/hal/`: hardware abstraction wrappers around freeink-sdk
+- `lib/hal/`: hardware abstraction wrappers around open-x4-sdk
 - `lib/Epub/`: EPUB parser, layout, CSS handling, and hyphenation
 - `lib/`: supporting libraries (fonts, text, filesystem helpers, etc.)
-- `freeink-sdk/`: hardware SDK submodule (display, input, storage, battery). Docs: https://freeink.org/docs
+- `open-x4-sdk/`: hardware SDK submodule (display, input, storage, battery)
 - `docs/`: user and technical documentation
 
 ## Embedded constraints that shape design

lib/EpdFont/EpdFont.cpp

@@ -101,9 +101,6 @@ static uint8_t lookupKernClass(const EpdKernClassEntry* entries, const uint16_t
 }
 
 int8_t EpdFont::getKerning(const uint32_t leftCp, const uint32_t rightCp) const {
-  if (utf8IsCjkBreakable(leftCp) || utf8IsCjkBreakable(rightCp)) {
-    return 0;
-  }
   if (!data->kernMatrix) {
     return 0;
   }

lib/EpdFont/SdCardFont.cpp

@@ -115,9 +115,6 @@ void SdCardFont::freeStyleAll(PerStyle& s) {
   freeStyleMiniData(s);
   delete[] s.fullIntervals;
   s.fullIntervals = nullptr;
-  delete[] s.bmpIntervals;
-  s.bmpIntervals = nullptr;
-  s.intervalsAreBmp16 = false;
   freeStyleKernLigatureData(s);
   s.present = false;
 }
@@ -519,94 +516,59 @@ bool SdCardFont::load(const char* path) {
   styleCount_ = styleCount;
   contentHash_ = hash;
 
-  // Load full intervals into RAM for each present style. BMP-only fonts with
-  // fewer than 65536 glyphs use a compact 6-byte interval table instead of the
-  // on-disk 12-byte table; large sparse CJK subsets otherwise keep tens of KB
-  // of always-resident heap just for lookup metadata.
+  // Load full intervals into RAM for each present style
   for (uint8_t i = 0; i < MAX_STYLES; i++) {
     auto& s = styles_[i];
     if (!s.present) continue;
 
+    s.fullIntervals = new (std::nothrow) EpdUnicodeInterval[s.header.intervalCount];
+    if (!s.fullIntervals) {
+      LOG_ERR("SDCF", "Failed to allocate %u intervals for style %u", s.header.intervalCount, i);
+      freeAll();
+      return false;
+    }
+
     if (!file.seekSet(s.intervalsFileOffset)) {
       LOG_ERR("SDCF", "Failed to seek to intervals for style %u", i);
       freeAll();
       return false;
     }
+    size_t intervalsBytes = s.header.intervalCount * sizeof(EpdUnicodeInterval);
+    if (file.read(reinterpret_cast<uint8_t*>(s.fullIntervals), intervalsBytes) != static_cast<int>(intervalsBytes)) {
+      LOG_ERR("SDCF", "Failed to read intervals for style %u", i);
+      freeAll();
+      return false;
+    }
 
     // Validate interval contents before any later code (findGlobalGlyphIndex,
     // glyph reads) trusts them. A malformed file could otherwise drive
     // out-of-range glyph indices into bogus on-disk reads.
-    bool canUseBmp16 = s.header.glyphCount <= UINT16_MAX;
-    uint32_t expectedOffset = 0;
-    uint32_t prevLast = 0;
-    EpdUnicodeInterval iv{};
-    for (uint32_t j = 0; j < s.header.intervalCount; ++j) {
-      if (file.read(reinterpret_cast<uint8_t*>(&iv), sizeof(iv)) != sizeof(iv)) {
-        LOG_ERR("SDCF", "Failed to read interval %u for style %u", j, i);
-        freeAll();
-        return false;
-      }
-      if (iv.first > iv.last) {
-        LOG_ERR("SDCF", "Style %u: invalid interval %u (first 0x%lX > last 0x%lX)", i, j,
-                static_cast<unsigned long>(iv.first), static_cast<unsigned long>(iv.last));
-        file.close();
-        freeAll();
-        return false;
-      }
-      const uint32_t span = iv.last - iv.first + 1;
-      const bool overlapsPrev = (j > 0 && iv.first <= prevLast);
-      const bool spanTooBig = (span > s.header.glyphCount);
-      const bool offsetMismatch = (iv.offset != expectedOffset);
-      const bool offsetOverruns = (iv.offset > s.header.glyphCount - span);
-      if (overlapsPrev || spanTooBig || offsetMismatch || offsetOverruns) {
-        LOG_ERR("SDCF", "Style %u: invalid interval layout at %u (overlap=%d span=%u offMis=%d offOver=%d)", i, j,
-                overlapsPrev, span, offsetMismatch, offsetOverruns);
-        file.close();
-        freeAll();
-        return false;
-      }
-      if (iv.first > UINT16_MAX || iv.last > UINT16_MAX || iv.offset > UINT16_MAX) {
-        canUseBmp16 = false;
-      }
-      expectedOffset += span;
-      prevLast = iv.last;
-    }
-
-    if (!file.seekSet(s.intervalsFileOffset)) {
-      LOG_ERR("SDCF", "Failed to seek back to intervals for style %u", i);
-      freeAll();
-      return false;
-    }
-
-    if (canUseBmp16) {
-      s.bmpIntervals = new (std::nothrow) PerStyle::BmpInterval16[s.header.intervalCount];
-      if (!s.bmpIntervals) {
-        LOG_ERR("SDCF", "Failed to allocate compact intervals for style %u", i);
-        freeAll();
-        return false;
-      }
+    {
+      uint32_t expectedOffset = 0;
+      uint32_t prevLast = 0;
       for (uint32_t j = 0; j < s.header.intervalCount; ++j) {
-        if (file.read(reinterpret_cast<uint8_t*>(&iv), sizeof(iv)) != sizeof(iv)) {
-          LOG_ERR("SDCF", "Failed to read compact interval %u for style %u", j, i);
+        const auto& iv = s.fullIntervals[j];
+        if (iv.first > iv.last) {
+          LOG_ERR("SDCF", "Style %u: invalid interval %u (first 0x%lX > last 0x%lX)", i, j,
+                  static_cast<unsigned long>(iv.first), static_cast<unsigned long>(iv.last));
+          file.close();
           freeAll();
           return false;
         }
-        s.bmpIntervals[j] = {static_cast<uint16_t>(iv.first), static_cast<uint16_t>(iv.last),
-                             static_cast<uint16_t>(iv.offset)};
-      }
-      s.intervalsAreBmp16 = true;
-    } else {
-      s.fullIntervals = new (std::nothrow) EpdUnicodeInterval[s.header.intervalCount];
-      if (!s.fullIntervals) {
-        LOG_ERR("SDCF", "Failed to allocate %u intervals for style %u", s.header.intervalCount, i);
-        freeAll();
-        return false;
-      }
-      size_t intervalsBytes = s.header.intervalCount * sizeof(EpdUnicodeInterval);
-      if (file.read(reinterpret_cast<uint8_t*>(s.fullIntervals), intervalsBytes) != static_cast<int>(intervalsBytes)) {
-        LOG_ERR("SDCF", "Failed to read intervals for style %u", i);
-        freeAll();
-        return false;
+        const uint32_t span = iv.last - iv.first + 1;
+        const bool overlapsPrev = (j > 0 && iv.first <= prevLast);
+        const bool spanTooBig = (span > s.header.glyphCount);
+        const bool offsetMismatch = (iv.offset != expectedOffset);
+        const bool offsetOverruns = (iv.offset > s.header.glyphCount - span);
+        if (overlapsPrev || spanTooBig || offsetMismatch || offsetOverruns) {
+          LOG_ERR("SDCF", "Style %u: invalid interval layout at %u (overlap=%d span=%u offMis=%d offOver=%d)", i, j,
+                  overlapsPrev, span, offsetMismatch, offsetOverruns);
+          file.close();
+          freeAll();
+          return false;
+        }
+        expectedOffset += span;
+        prevLast = iv.last;
       }
     }
 
@@ -641,15 +603,13 @@ int32_t SdCardFont::findGlobalGlyphIndex(const PerStyle& s, uint32_t codepoint)
   int right = static_cast<int>(s.header.intervalCount) - 1;
   while (left <= right) {
     int mid = left + (right - left) / 2;
-    const uint32_t first = s.intervalsAreBmp16 ? s.bmpIntervals[mid].first : s.fullIntervals[mid].first;
-    const uint32_t last = s.intervalsAreBmp16 ? s.bmpIntervals[mid].last : s.fullIntervals[mid].last;
-    if (codepoint < first) {
+    const auto& interval = s.fullIntervals[mid];
+    if (codepoint < interval.first) {
       right = mid - 1;
-    } else if (codepoint > last) {
+    } else if (codepoint > interval.last) {
       left = mid + 1;
     } else {
-      const uint32_t offset = s.intervalsAreBmp16 ? s.bmpIntervals[mid].offset : s.fullIntervals[mid].offset;
-      return static_cast<int32_t>(offset + (codepoint - first));
+      return static_cast<int32_t>(interval.offset + (codepoint - interval.first));
     }
   }
   return -1;
@@ -1297,7 +1257,7 @@ const EpdGlyph* SdCardFont::onGlyphMiss(void* ctx, uint32_t codepoint) {
 
   if (!self->loaded_ || styleIdx >= MAX_STYLES || !self->styles_[styleIdx].present) return nullptr;
   const auto& s = self->styles_[styleIdx];
-  if (!s.fullIntervals && !s.bmpIntervals) return nullptr;
+  if (!s.fullIntervals) return nullptr;
 
   // Check overflow cache first (matching both codepoint and style)
   for (uint32_t i = 0; i < self->overflowCount_; i++) {

lib/EpdFont/SdCardFont.h

@@ -58,9 +58,9 @@ class SdCardFont {
   // Returns true if advance table is populated for at least one style.
   bool hasAdvanceTable() const;
 
-  // Free mini data for all styles and restore stub EpdFontData.
-  // Preserves the persistent advance cache so repeated layout passes can reuse
-  // previously fetched metrics.
+  // Free mini data for all styles, restore stub EpdFontData.
+  // Also clears the temporary advance table (built per layout pass) but
+  // preserves the persistent advance cache (reused across passes).
   void clearCache();
 
   // Drop the persistent advance cache. Call when unloading the SD font or
@@ -140,14 +140,6 @@ class SdCardFont {
 
     // Full intervals loaded from file (kept in RAM for codepoint lookup)
     EpdUnicodeInterval* fullIntervals = nullptr;
-    struct BmpInterval16 {
-      uint16_t first;
-      uint16_t last;
-      uint16_t offset;
-    } __attribute__((packed));
-    static_assert(sizeof(BmpInterval16) == 6, "BmpInterval16 must remain compact");
-    BmpInterval16* bmpIntervals = nullptr;
-    bool intervalsAreBmp16 = false;
 
     // Persistent kern-class + ligature tables (lazy-loaded on first prewarm).
     // The full kern MATRIX is NOT resident — on Literata-class fonts a single

lib/EpdFont/SdCardFontManager.cpp

@@ -34,15 +34,19 @@ bool SdCardFontManager::loadFamily(const SdCardFontFamilyInfo& family, GfxRender
     unloadAll(renderer);
   }
 
-  // Select the physical point size closest to the built-in reader sizes. Some
-  // CJK font packs only ship larger sizes, so ordinal selection can make
-  // MEDIUM load 18pt+ and produce oversized pages on small devices.
-  const SdCardFontFileInfo* selected = family.findClosestReaderSize(fontSizeEnum);
-  if (!selected) {
+  // Select by ordinal position: sort available sizes, then map the font size
+  // enum (SMALL=0 .. EXTRA_LARGE=3) to the corresponding slot. When the
+  // family has fewer sizes than 4, clamp to the last available size.
+  auto sizes = family.availableSizes();
+  if (sizes.empty()) {
     LOG_ERR("SDMGR", "Family %s has no files to load", family.name.c_str());
     return false;
   }
 
+  uint8_t idx = fontSizeEnum;
+  if (idx >= sizes.size()) idx = sizes.size() - 1;
+  const SdCardFontFileInfo* selected = family.findFile(sizes[idx]);
+
   auto* font = new (std::nothrow) SdCardFont();
   if (!font) {
     LOG_ERR("SDMGR", "Failed to allocate SdCardFont for %s", selected->path.c_str());

lib/EpdFont/SdCardFontManager.h

@@ -15,10 +15,10 @@ class SdCardFontManager {
   SdCardFontManager(const SdCardFontManager&) = delete;
   SdCardFontManager& operator=(const SdCardFontManager&) = delete;
 
-  // Load the font file whose physical point size is closest to the reader
-  // fontSizeEnum (SMALL=12, MEDIUM=14, LARGE=16, EXTRA_LARGE=18). Only one
-  // .cpfont file is loaded; other sizes remain on disk. This keeps resident
-  // interval + kern/ligature tables to one size's worth of memory.
+  // Load the font file matching fontSizeEnum (SMALL=0 .. EXTRA_LARGE=3) by
+  // ordinal position in the family's sorted size list. Only one .cpfont file
+  // is loaded; other sizes remain on disk. This keeps resident interval +
+  // kern/ligature tables to one size's worth of memory.
   // Returns true on success.
   bool loadFamily(const SdCardFontFamilyInfo& family, GfxRenderer& renderer, uint8_t fontSizeEnum);
 
@@ -32,7 +32,7 @@ class SdCardFontManager {
   // Get name of currently loaded family (empty if none).
   const std::string& currentFamilyName() const { return loadedFamilyName_; };
 
-  // Point size that was actually loaded.
+  // Point size that was actually loaded (closest match to targetPtSize).
   // 0 if nothing loaded.
   uint8_t currentPointSize() const { return loadedPointSize_; };
 

lib/EpdFont/SdCardFontRegistry.cpp

@@ -15,60 +15,6 @@ const SdCardFontFileInfo* SdCardFontFamilyInfo::findFile(uint8_t size, uint8_t s
   return nullptr;
 }
 
-const SdCardFontFileInfo* SdCardFontFamilyInfo::findClosestReaderSize(const uint8_t fontSizeEnum,
-                                                                      const uint8_t style) const {
-  if (files.empty()) return nullptr;
-
-  // Collect sizes matching the requested style, sorted ascending.
-  std::vector<uint8_t> sizes;
-  for (const auto& f : files) {
-    if (f.style != style) continue;
-    sizes.push_back(f.pointSize);
-  }
-  if (sizes.empty()) return nullptr;
-  std::sort(sizes.begin(), sizes.end());
-
-  // When the family provides at least 4 sizes, use ordinal (index-based)
-  // selection so custom-built font sets (e.g. 10/12/14/16) map SMALL to
-  // the smallest file, not to a hardcoded 12pt target.
-  if (sizes.size() >= 4) {
-    uint8_t idx = fontSizeEnum;
-    if (idx >= sizes.size()) idx = sizes.size() - 1;
-    return findFile(sizes[idx], style);
-  }
-
-  // Fewer sizes than enum slots (e.g. CJK packs with only 2-3 sizes):
-  // fall back to closest-match against the built-in reader targets.
-  uint8_t target = 14;
-  switch (fontSizeEnum) {
-    case 0:
-      target = 12;
-      break;
-    case 2:
-      target = 16;
-      break;
-    case 3:
-      target = 18;
-      break;
-    case 1:
-    default:
-      target = 14;
-      break;
-  }
-
-  const SdCardFontFileInfo* best = nullptr;
-  uint8_t bestDelta = 255;
-  for (const auto& f : files) {
-    if (f.style != style) continue;
-    const uint8_t delta = f.pointSize > target ? f.pointSize - target : target - f.pointSize;
-    if (!best || delta < bestDelta || (delta == bestDelta && f.pointSize < best->pointSize)) {
-      best = &f;
-      bestDelta = delta;
-    }
-  }
-  return best;
-}
-
 bool SdCardFontFamilyInfo::hasSize(uint8_t size) const {
   for (const auto& f : files) {
     if (f.pointSize == size) return true;

lib/EpdFont/SdCardFontRegistry.h

@@ -18,7 +18,6 @@ struct SdCardFontFamilyInfo {
   std::vector<SdCardFontFileInfo> files;
 
   const SdCardFontFileInfo* findFile(uint8_t size, uint8_t style = 0) const;
-  const SdCardFontFileInfo* findClosestReaderSize(uint8_t fontSizeEnum, uint8_t style = 0) const;
   bool hasSize(uint8_t size) const;
   std::vector<uint8_t> availableSizes() const;
 };

lib/EpdFont/scripts/fontconvert.py

@@ -248,7 +248,7 @@ unmerged_intervals = sorted(intervals + add_ints)
 intervals = []
 unvalidated_intervals = []
 for i_start, i_end in unmerged_intervals:
-    if len(unvalidated_intervals) > 0 and i_start <= unvalidated_intervals[-1][1] + 1:
+    if len(unvalidated_intervals) > 0 and i_start + 1 <= unvalidated_intervals[-1][1]:
         unvalidated_intervals[-1] = (unvalidated_intervals[-1][0], max(unvalidated_intervals[-1][1], i_end))
         continue
     unvalidated_intervals.append((i_start, i_end))

lib/EpdFont/scripts/fontconvert_sdcard.py

@@ -40,8 +40,7 @@ INTERVAL_PRESETS = {
     "ascii":       [(0x0020, 0x007E)],
     "latin1":      [(0x0080, 0x00FF)],
     "latin-ext":   [(0x0020, 0x007E), (0x0080, 0x00FF), (0x0100, 0x024F),
-                    (0x02B0, 0x02FF), (0x1E00, 0x1EFF), (0x2000, 0x206F),
-                    (0xFB00, 0xFB06)],
+                    (0x1E00, 0x1EFF), (0x2000, 0x206F), (0xFB00, 0xFB06)],
     "greek":       [(0x0370, 0x03FF), (0x1F00, 0x1FFF)],
     "cyrillic":    [(0x0400, 0x04FF), (0x0500, 0x052F)],
     "hebrew":      [(0x0590, 0x05FF), (0xFB1D, 0xFB4F)],
@@ -63,7 +62,7 @@ INTERVAL_PRESETS = {
     # Composite preset for English-language literary fiction including scifi/popsci.
     # Greek for physics terms, math operators, geometric shapes, uncommon
     # dialogue punctuation, CJK quote marks, miscellaneous symbols (♪♫♬), dingbats.
-    "reading":     [(0x0020, 0x024F), (0x02B0, 0x02FF), (0x0300, 0x036F), (0x0370, 0x03FF),
+    "reading":     [(0x0020, 0x024F), (0x0300, 0x036F), (0x0370, 0x03FF),
                     (0x0400, 0x04FF), (0x1E00, 0x1EFF), (0x2000, 0x206F),
                     (0x2070, 0x209F), (0x20A0, 0x20CF), (0x2150, 0x218F),
                     (0x2190, 0x21FF), (0x2200, 0x22FF), (0x2500, 0x257F),

lib/Epub/Epub.cpp

@@ -5,7 +5,6 @@
 #include <JpegToBmpConverter.h>
 #include <Logging.h>
 #include <PngToBmpConverter.h>
-#include <Utf8.h>
 #include <ZipFile.h>
 
 #include "Epub/parsers/ContainerParser.h"
@@ -74,9 +73,8 @@ bool Epub::parseContentOpf(BookMetadataCache::BookMetadata& bookMetadata, const
     return false;
   }
 
-  // Grab data from opfParser into epub. Normalize titles to NFC so NFD (combining
-  // mark) text renders correctly — the device fonts have no mark positioning.
-  bookMetadata.title = utf8ComposeNfc(opfParser.title);
+  // Grab data from opfParser into epub
+  bookMetadata.title = opfParser.title;
   bookMetadata.author = opfParser.author;
   bookMetadata.language = opfParser.language;
   bookMetadata.coverItemHref = opfParser.coverItemHref;

lib/Epub/Epub/BookMetadataCache.cpp

@@ -2,7 +2,6 @@
 
 #include <Logging.h>
 #include <Serialization.h>
-#include <Utf8.h>
 #include <ZipFile.h>
 
 #include <deque>
@@ -10,7 +9,7 @@
 #include "FsHelpers.h"
 
 namespace {
-constexpr uint8_t BOOK_CACHE_VERSION = 8;  // v8: TOC/book titles stored NFC-composed
+constexpr uint8_t BOOK_CACHE_VERSION = 7;
 constexpr char bookBinFile[] = "/book.bin";
 constexpr char tmpSpineBinFile[] = "/spine.bin.tmp";
 constexpr char tmpTocBinFile[] = "/toc.bin.tmp";
@@ -365,9 +364,7 @@ void BookMetadataCache::createTocEntry(const std::string& title, const std::stri
     }
   }
 
-  // Compose the title to NFC at index time so the cache stores precomposed glyphs;
-  // device fonts have no combining-mark positioning, so NFD titles render broken.
-  const TocEntry entry(utf8ComposeNfc(title), href, anchor, level, spineIndex);
+  const TocEntry entry(title, href, anchor, level, spineIndex);
   writeTocEntry(tocFile, entry);
   tocCount++;
 }