04242fa221
## Summary
* **What is the goal of this PR?** Eliminate the 3-file / 4-location
overhead for adding a new setting. Previously, every new setting
required manually editing JsonSettingsIO.cpp in two places (save +
load), duplicating knowledge already present in SettingsList.h. After
this PR, JsonSettingsIO.cpp never needs to be touched again for standard
settings.
* **What changes are included?**
* `SettingInfo` (in `SettingsActivity.h`) gains one new field: `bool
obfuscated` (base64 save/load for passwords), with a fluent builder
method `.withObfuscated()`. The previously proposed
`defaultValue`/`withDefault()` approach was dropped in favour of reading
the struct field's own initializer value as the fallback (see below).
* `SettingsList.h` entries are annotated with `.withObfuscated()` on the
OPDS password entry. The list is now returned as a `static const`
singleton (`const std::vector<SettingInfo>&`), so it is constructed
exactly once. A missing `key`/`category` on the
`statusBarProgressBarThickness` entry was also fixed — it was previously
skipped by the generic save loop, so changes were silently lost on
restart.
* `JsonSettingsIO::saveSettings` and `loadSettings` replace their ~90
lines of manual per-field code with a single generic loop over
`getSettingsList()`. The loop uses `info.key`,
`info.valuePtr`/`info.stringOffset`+`info.stringMaxLen` (for char-array
string fields), `info.enumValues.size()` (for enum clamping), and
`info.obfuscated`.
* **Default values**: instead of a duplicated `defaultValue` field in
`SettingInfo`, `loadSettings` reads `s.*(info.valuePtr)` *before*
overwriting it. Because `CrossPointSettings` is default-constructed
before `loadSettings` is called, this captures each field's struct
initializer value as the JSON-absent fallback. The single source of
truth for defaults is `CrossPointSettings.h`.
* One post-loop special case remains explicitly: the four `frontButton*`
remap fields (managed by the RemapFrontButtons sub-activity, not in
SettingsList) and `validateFrontButtonMapping()`.
* One pre-loop migration guard handles legacy settings files that
predate the status bar refactor: if `statusBarChapterPageCount` is
absent from the JSON, `applyLegacyStatusBarSettings()` is called first
so the generic loop picks up the migrated values as defaults and applies
its normal clamping.
* OPDS password backward-compat migration (plain `opdsPassword` →
obfuscated `opdsPassword_obf`) is preserved inside the generic
obfuscated-string path.
## Additional Context
Say we want to add a new `bookmarkStyle` enum setting with options
`DOT`, `LINE`, `NONE` and a default of `DOT`:
1. `src/CrossPointSettings.h` — add enum and member:
```cpp
enum BOOKMARK_STYLE { BOOKMARK_DOT = 0, BOOKMARK_LINE = 1, BOOKMARK_NONE = 2 };
uint8_t bookmarkStyle = BOOKMARK_DOT;
```
2. `lib/I18n/translations/english.yaml` — add display strings:
```yaml
STR_BOOKMARK_STYLE: "Bookmark Style"
STR_BOOKMARK_DOT: "Dot"
STR_BOOKMARK_LINE: "Line"
```
(Other language files will fall back to English if not translated. Run
`gen_i18n.py` to regenerate `I18nKeys.h`.)
3. `src/SettingsList.h` — add one entry in the appropriate category:
```cpp
SettingInfo::Enum(StrId::STR_BOOKMARK_STYLE, &CrossPointSettings::bookmarkStyle,
{StrId::STR_BOOKMARK_DOT, StrId::STR_BOOKMARK_LINE, StrId::STR_NONE_OPT},
"bookmarkStyle", StrId::STR_CAT_READER),
```
That's it — no default annotation needed anywhere, because
`bookmarkStyle = BOOKMARK_DOT` in the struct already provides the
fallback. The setting will automatically persist to JSON on save, load
with clamping on boot, appear in the device settings UI under the Reader
category, and be exposed via the web API — all with no further changes.
---
### AI Usage
While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.
Did you use AI tools to help write this code? _**< PARTIALLY>**_
CrossPoint Reader
Firmware for the Xteink X4 e-paper display reader (unaffiliated with Xteink). Built using PlatformIO and targeting the ESP32-C3 microcontroller.
CrossPoint Reader is a purpose-built firmware designed to be a drop-in, fully open-source replacement for the official Xteink firmware. It aims to match or improve upon the standard EPUB reading experience.
Motivation
E-paper devices are fantastic for reading, but most commercially available readers are closed systems with limited customisation. The Xteink X4 is an affordable, e-paper device, however the official firmware remains closed. CrossPoint exists partly as a fun side-project and partly to open up the ecosystem and truely unlock the device's potential.
CrossPoint Reader aims to:
- Provide a fully open-source alternative to the official firmware.
- Offer a document reader capable of handling EPUB content on constrained hardware.
- Support customisable font, layout, and display options.
- Run purely on the Xteink X4 hardware.
This project is not affiliated with Xteink; it's built as a community project.
Features & Usage
- EPUB parsing and rendering (EPUB 2 and EPUB 3)
- Image support within EPUB
- Saved reading position
- File explorer with file picker
- Basic EPUB picker from root directory
- Support nested folders
- EPUB picker with cover art
- Custom sleep screen
- Cover sleep screen
- Wifi book upload
- Wifi OTA updates
- KOReader Sync integration for cross-device reading progress
- Configurable font, layout, and display options
- User provided fonts
- Full UTF support
- Screen rotation
Multi-language support: Read EPUBs in various languages, including English, Spanish, French, German, Italian, Portuguese, Russian, Ukrainian, Polish, Swedish, Norwegian, and more.
See the user guide for instructions on operating CrossPoint, including the KOReader Sync quick setup.
For more details about the scope of the project, see the SCOPE.md document.
Installing
Web (latest firmware)
- Connect your Xteink X4 to your computer via USB-C and wake/unlock the device
- Go to https://xteink.dve.al/ and click "Flash CrossPoint firmware"
To revert back to the official firmware, you can flash the latest official firmware from https://xteink.dve.al/, or swap back to the other partition using the "Swap boot partition" button here https://xteink.dve.al/debug.
Web (specific firmware version)
- Connect your Xteink X4 to your computer via USB-C
- Download the
firmware.binfile from the release of your choice via the releases page - Go to https://xteink.dve.al/ and flash the firmware file using the "OTA fast flash controls" section
To revert back to the official firmware, you can flash the latest official firmware from https://xteink.dve.al/, or swap back to the other partition using the "Swap boot partition" button here https://xteink.dve.al/debug.
Manual
See Development below.
Development
Prerequisites
- PlatformIO Core (
pio) or VS Code + PlatformIO IDE - Python 3.8+
- USB-C cable for flashing the ESP32-C3
- Xteink X4
Checking out the code
CrossPoint uses PlatformIO for building and flashing the firmware. To get started, clone the repository:
git clone --recursive https://github.com/crosspoint-reader/crosspoint-reader
# Or, if you've already cloned without --recursive:
git submodule update --init --recursive
Flashing your device
Connect your Xteink X4 to your computer via USB-C and run the following command.
pio run --target upload
Debugging
After flashing the new features, it’s recommended to capture detailed logs from the serial port.
First, make sure all required Python packages are installed:
python3 -m pip install pyserial colorama matplotlib
after that run the script:
# For Linux
# This was tested on Debian and should work on most Linux systems.
python3 scripts/debugging_monitor.py
# For macOS
python3 scripts/debugging_monitor.py /dev/cu.usbmodem2101
Minor adjustments may be required for Windows.
Internals
CrossPoint Reader is pretty aggressive about caching data down to the SD card to minimise RAM usage. The ESP32-C3 only has ~380KB of usable RAM, so we have to be careful. A lot of the decisions made in the design of the firmware were based on this constraint.
Data caching
The first time chapters of a book are loaded, they are cached to the SD card. Subsequent loads are served from the
cache. This cache directory exists at .crosspoint on the SD card. The structure is as follows:
.crosspoint/
├── epub_12471232/ # Each EPUB is cached to a subdirectory named `epub_<hash>`
│ ├── progress.bin # Stores reading progress (chapter, page, etc.)
│ ├── cover.bmp # Book cover image (once generated)
│ ├── book.bin # Book metadata (title, author, spine, table of contents, etc.)
│ └── sections/ # All chapter data is stored in the sections subdirectory
│ ├── 0.bin # Chapter data (screen count, all text layout info, etc.)
│ ├── 1.bin # files are named by their index in the spine
│ └── ...
│
└── epub_189013891/
Deleting the .crosspoint directory will clear the entire cache.
Due the way it's currently implemented, the cache is not automatically cleared when a book is deleted and moving a book file will use a new cache directory, resetting the reading progress.
For more details on the internal file structures, see the file formats document.
Contributing
Contributions are very welcome!
If you are new to the codebase, start with the contributing docs.
If you're looking for a way to help out, take a look at the ideas discussion board. If there's something there you'd like to work on, leave a comment so that we can avoid duplicated effort.
Everyone here is a volunteer, so please be respectful and patient. For more details on our goverance and community principles, please see GOVERNANCE.md.
To submit a contribution:
- Fork the repo
- Create a branch (
feature/dithering-improvement) - Make changes
- Submit a PR
CrossPoint Reader is not affiliated with Xteink or any manufacturer of the X4 hardware.
Huge shoutout to diy-esp32-epub-reader by atomic14, which was a project I took a lot of inspiration from as I was making CrossPoint.