Opening XTC files with a high page count (e.g. *The Magic Mountain* at
4,187 pages) causes an immediate `abort()` crash and reboot loop. The
device becomes unusable until the book is removed from the SD card.
**Crash log:**
```
abort() was called at 0x4214a5fb on core 0
```
### Root cause
During `XtcParser::open()`, the parser calls
`m_pageTable.resize(pageCount)` to load the entire page table into RAM.
Each `PageInfo` entry is 16 bytes, so:
- 4,187 pages x 16 bytes = **66,992 bytes (~65KB)** as a single
contiguous heap allocation
On the ESP32-C3 with ~380KB total RAM (no PSRAM), this allocation fails
after firmware, fonts, and the activity system are already loaded.
Because the firmware is compiled with `-fno-exceptions`, the failed
`new` inside `std::vector::resize()` calls `abort()` instead of
throwing.
This affects any XTC file with roughly 3,000+ pages, depending on heap
state at the time of loading.
## Solution
Replace the bulk page table allocation with on-demand reads from the SD
card. Instead of loading all page table entries into a vector at file
open, we now:
1. Read only the **first** page table entry at open time (to get default
page dimensions)
2. Read a **single** 16-byte entry from the SD card each time a page is
loaded
This reduces page table memory usage from `pageCount * 16` bytes to
**zero bytes**, regardless of how many pages the file contains.
### Changes
| File | What changed |
|------|-------------|
| `XtcParser.h` | Removed `std::vector<PageInfo> m_pageTable`. Added
`readPageTableEntry()` for on-demand reads. |
| `XtcParser.cpp` | Replaced `readPageTable()` with
`readFirstPageInfo()`. Updated `getPageInfo()`, `loadPage()`, and
`loadPageStreaming()` to seek and read individual entries from the file.
|
## Trade-offs
### Performance
Each page turn now requires one additional SD card seek + 16-byte read
to look up the page table entry before reading the page data itself.
- SD card sequential read latency: ~0.1-0.5ms for a 16-byte read
- E-ink full display refresh: ~1,000-2,000ms
I personally can't see any performance difference while reading and the
trade off of not boot looping seems to make this well worth it.
### Memory
| Metric | Before | After |
|--------|--------|-------|
| Page table RAM (4,187 pages) | ~65KB | 0 bytes |
| Page table RAM (1,000 pages) | ~16KB | 0 bytes |
| Page table RAM (max 65,535 pages) | ~1MB (impossible) | 0 bytes |
Adds a PlatformIO pre-build script to patch JPEGDEC library. When
decoding progressive JPEGs with AC coefficients, MCU_SKIP (-8) causes
array index 0xFFFFF8, creating a wild pointer ~33MB past the sMCUs
array. The patch redirects pMCU to sMCUs[0] when MCU_SKIP is active,
preventing store-access faults while maintaining correct behavior for
JPEG_SCALE_EIGHTH decoding. Devices with larger framebuffers (like the
x3) (792×528 = 52,272 bytes vs 800×480 = 48,000 bytes) have less free
heap, shifting the allocation and changing where the wild pointer lands.
Commit 8628297 guarded the DC coefficient write (pMCU[0]) with if (iMCU
>= 0), which prevents crashes for progressive JPEGs whose first scan is
DC-only (iScanEnd == 0). However, if the first scan includes AC
coefficients (iScanEnd > 0), the AC decode loop still writes through the
wild pointer and crashes.
Replace hardcoded DISPLAY_WIDTH, DISPLAY_HEIGHT, and DISPLAY_WIDTH_BYTES
constants with runtime values from display object to support multiple
device models (X3 and X4) with different screen dimensions.
## Summary
Adds Xteink X3 hardware support to CrossPoint Reader. The X3 uses the
same SSD1677 e-ink controller as the X4 but with a different panel
(792x528 vs 800x480), different button layout, and an I2C fuel gauge
(BQ27220) instead of ADC-based battery reading.
All X3-specific behavior is gated by runtime device detection — X4
behavior is unchanged.
Depends on community-sdk X3 support: open-x4-epaper/community-sdk#19
(merged).
## Changes
### HAL Layer
**HalGPIO** (`lib/hal/HalGPIO.cpp/.h`)
- I2C-based device fingerprinting at boot: probes for BQ27220 fuel
gauge, DS3231 RTC, and QMI8658 IMU to distinguish X3 from X4
- Detection result cached in NVS for fast subsequent boots
- Exposes `deviceIsX3()` / `deviceIsX4()` helpers used throughout the
codebase
- X3 button mapping (7 GPIOs vs X4's layout)
- USB connection detection and wake classification for X3
**HalDisplay** (`lib/hal/HalDisplay.cpp/.h`)
- Calls `einkDisplay.setDisplayX3()` before init when X3 is detected
- Requests display resync after power button / flash wake events
- Runtime display dimension accessors (`getDisplayWidth()`,
`getDisplayHeight()`, `getBufferSize()`)
- Exposed as global `display` instance for use by image converters
**HalPowerManager** (`lib/hal/HalPowerManager.cpp/.h`)
- X3 battery reading via I2C fuel gauge (BQ27220 at 0x55, SOC register)
- X3 power button uses GPIO hold for deep sleep
### Display & Rendering
**GfxRenderer** (`lib/GfxRenderer/GfxRenderer.cpp/.h`)
- Buffer size and display dimensions are now runtime values (not
compile-time constants) to support both panel sizes
- X3 anti-aliasing tuning: only the darker grayscale level is applied to
avoid washed-out text on the X3 panel. X4 retains both levels via
`deviceIsX4()` gate
**Image Converters** (`lib/JpegToBmpConverter`, `lib/PngToBmpConverter`)
- Cover image prescale target uses runtime display dimensions from HAL
instead of hardcoded 800x480
### UI Themes
**BaseTheme / LyraTheme** (`src/components/themes/`)
- X3 button position mapping for the different physical layout
- Adjusted UI element positioning for 792x528 viewport
### Boot & Init
**main.cpp**
- X3 hardware detection logging
- Adjusted init sequence for X3 (no `HalSystem::begin()` dependency on
X3 path)
**HomeActivity**
- Uses runtime `renderer.getBufferSize()` instead of static
`GfxRenderer::getBufferSize()`
FYI I did not add support for the gyro page turner. That can be it's own
PR.
This partially fixes#769 but is dependent upon PR #827 being merged
along side this @daveallie. I removed my PNG conversion code after
finding out that PR was already created. Without this PR though that
book in #769 will still fail to load because of how it's stored in the
file
---------
Co-authored-by: Dave Allie <dave@daveallie.com>
I had an epub that just showed a blank cover and wouldnt work for the
sleep screen either, turns out it was an epub3 and I guess we didn't
support that. Super simple fix here
Our esp32 consistently dropped the last few packets of the TCP transfer
in the old implementation. Only about 1/5 transfers would complete. I've
refactored that entire system into an actual Calibre Device Plugin that
basically uses the exact same system as the web server's file transfer
protocol. I kept them separate so that we don't muddy up the existing
file transfer stuff even if it's basically the same at the end of the
day I didn't want to limit our ability to change it later.
I've also added basic auth to OPDS and renamed that feature to OPDS
Browser to just disassociate it from Calibre.
---------
Co-authored-by: Arthur Tazhitdinov <lisnake@gmail.com>
Co-authored-by: Dave Allie <dave@daveallie.com>
## Summary
- Adds KOReader progress sync integration, allowing CrossPoint to sync
reading positions with other
KOReader-compatible devices
- Stores credentials securely with XOR obfuscation
- Uses KOReader's partial MD5 document hashing for cross-device book
matching
- Syncs position via percentage with estimated XPath for compatibility
# Features
- Settings: KOReader Username, Password, and Authenticate options
- Sync from chapters menu: "Sync Progress" option appears when
credentials are configured
- Bidirectional sync: Can apply remote progress or upload local progress
---------
Co-authored-by: Dave Allie <dave@daveallie.com>
## Summary
Adds support for browsing and downloading books from a Calibre-web
server via OPDS.
How it works
1. Configure server URL in Settings → Calibre Web URL (e.g.,
https://myserver.com:port I use Cloudflare tunnel to make my server
accessible anywhere fwiw)
2. "Calibre Library" will now show on the the home screen
3. Browse the catalog - navigate through categories like "By Newest",
"By Author", "By Series", etc.
4. Download books - select a book and press Confirm to download the EPUB
to your device
Navigation
- Up/Down - Move through entries
- Confirm - Open folder or download book
- Back - Go to parent catalog, or exit to home if at root
- Navigation entries show with > prefix, books show title and author
- Button hints update dynamically ("Open" for folders, "Download" for
books)
Technical details
- Fetches OPDS catalog from {server_url}/opds
- Parses both navigation feeds (catalog links) and acquisition feeds
(downloadable books)
- Maintains navigation history stack for back navigation
- Handles absolute paths in OPDS links correctly (e.g.,
/books/opds/navcatalog/...)
- Downloads EPUBs directly to the SD card root
Note
The server URL should be typed to include https:// if the server
requires it - HTTP→HTTPS redirects may cause SSL errors on ESP32.
## Additional Context
* I also changed the home titles to use uppercase for each word and
added a setting to change the size of the side margins
---------
Co-authored-by: Dave Allie <dave@daveallie.com>
Justin Mitchell