Currently, each activity has to manage their own `displayTaskLoop` which
adds redundant boilerplate code. The loop is a wait loop which is also
not the best practice, as the `updateRequested` boolean is not protected
by a mutex.
In this PR:
- Move `displayTaskLoop` to the super `Activity` class
- Replace `updateRequested` with freeRTOS's [direct to task
notification](https://www.freertos.org/Documentation/02-Kernel/02-Kernel-features/03-Direct-to-task-notifications/01-Task-notifications)
- For `ActivityWithSubactivity`, whenever a sub-activity is present, the
parent's `render()` automatically goes inactive
With this change, activities now only need to expose `render()`
function, and anywhere in the code base can call `requestUpdate()` to
request a new rendering pass.
In theory, this change may also make the battery life a bit better,
since one wait loop is removed. Although the equipment in my home lab
wasn't been able to verify it (the electric current is too noisy and
small). Would appreciate if anyone has any insights on this subject.
Update: I managed to hack [a small piece of
code](https://github.com/ngxson/crosspoint-reader/tree/xsn/measure_cpu_usage)
that allow tracking CPU idle time.
The CPU load does decrease a bit (1.47% down to 1.39%), which make
sense, because the display task is now sleeping most of the time unless
notified. This should translate to a slightly increase in battery life
in the long run.
```
PR:
[40012] [MEM] Free: 185856 bytes, Total: 231004 bytes, Min Free: 123316 bytes
[40012] [IDLE] Idle time: 98.61% (CPU load: 1.39%)
[50017] [MEM] Free: 185856 bytes, Total: 231004 bytes, Min Free: 123316 bytes
[50017] [IDLE] Idle time: 98.61% (CPU load: 1.39%)
[60022] [MEM] Free: 185856 bytes, Total: 231004 bytes, Min Free: 123316 bytes
[60022] [IDLE] Idle time: 98.61% (CPU load: 1.39%)
master:
[20012] [MEM] Free: 195016 bytes, Total: 231532 bytes, Min Free: 132460 bytes
[20012] [IDLE] Idle time: 98.53% (CPU load: 1.47%)
[30017] [MEM] Free: 195016 bytes, Total: 231532 bytes, Min Free: 132460 bytes
[30017] [IDLE] Idle time: 98.53% (CPU load: 1.47%)
[40022] [MEM] Free: 195016 bytes, Total: 231532 bytes, Min Free: 132460 bytes
[40022] [IDLE] Idle time: 98.53% (CPU load: 1.47%)
```
---
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? **NO**
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
* **Refactor**
* Streamlined rendering architecture by consolidating update mechanisms
across all activities, improving efficiency and consistency.
* Modernized synchronization patterns for display updates to ensure
reliable, conflict-free rendering.
* **Bug Fixes**
* Enhanced rendering stability through improved locking mechanisms and
explicit update requests.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
---------
Co-authored-by: znelson <znelson@users.noreply.github.com>
This PR unifies navigation handling & adds system-wide support for
continuous navigation.
## Summary
Holding down a navigation button now continuously advances through items
until the button is released. This removes the need for repeated
press-and-release actions and makes navigation faster and smoother,
especially in long menus or documents.
When page-based navigation is available, it will navigate through pages.
If not, it will progress through menu items or similar list-based UI
elements.
Additionally, this PR fixes inconsistencies in wrap-around behavior and
navigation index calculations.
Places where the navigation system was updated:
- Home Page
- Settings Pages
- My Library Page
- WiFi Selection Page
- OPDS Browser Page
- Keyboard
- File Transfer Page
- XTC Chapter Selector Page
- EPUB Chapter Selector Page
I’ve tested this on the device as much as possible and tried to match
the existing behavior. Please let me know if I missed anything. Thanks 🙏

---
Following the request from @osteotek and @daveallie for system-wide
support, the old PR (#379) has been closed in favor of this
consolidated, system-wide implementation.
---
### AI Usage
Did you use AI tools to help write this code? _**PARTIALLY**_
---------
Co-authored-by: Dave Allie <dave@daveallie.com>
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 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>