## Summary
* **What is the goal of this PR?**
I flashed the last revision before commit f1740dbe, and chapter indexing
worked without any crashes.
After applying f1740dbe, the same chapter consistently triggered a
device reboot during indexing.
The affected chapter contains inline equation images surrounded by
styled (bold/italic) text that includes special math/symbol characters.
## Additional Context
Prior to f1740dbe, both `getTextAdvanceX()` and `getSpaceWidth()` always
measured text using `EpdFontFamily::REGULAR`, regardless of the actual
style.
Commit f1740dbe improved correctness by passing the active style so
spacing is calculated using the actual bold/italic font variant.
However, bold and italic variants have narrower Unicode coverage than
the regular font. When a character exists in the regular font but not in
the selected styled variant, `pdFont::getGlyph()` returns `nullptr`.
The updated measurement functions did not check for this and immediately
dereferenced the pointer:
`width += font.getGlyph(cp, style)->advanceX; // nullptr->advanceX`
Because `advanceX` is located at byte offset 2 within `EpdGlyph`,
dereferencing a null pointer caused the CPU to attempt a load from
address `0x00000002`, resulting in a RISC-V:
Load access fault
MCAUSE = 5
MTVAL = 2
## Fix
Added null-safety checks to both `getTextAdvanceX()` and
`getSpaceWidth()`, following the same pattern used in the rendering
path:
If the glyph is missing in the selected style → fall back to the
replacement glyph.
If the replacement glyph is also unavailable → treat the character as
zero-width.
This preserves the improved style-correct spacing while preventing
crashes.
No behavioral changes occur for characters that are supported by the
selected font variant.
---
### AI Usage
Did you use AI tools to help write this code? _**< YES >**_
I encounter this bug while testing 1.1.0 RC.
I pasted the serial log to Claude, which identify the bug and fixed it.
I can confirm now the chapter in question is indexed and loaded
correctly.
I've been reading "Children of Time" over the last days and that book,
annyoingly, has some tabular content.
This content is relevant for the story so I needed some really basic way
to at least be able to read those tables.
This commit simply renders the contents of table cells as separate
paragraphs with a small header describing its position in the table. For
me, it's better than nothing.
## Summary
* **What is the goal of this PR?**
Implements really basic table support
* **What changes are included?**
* Minimal changes to ChapterHtmlSlimParser
* A demo book in test/epubs
## Additional Context
Here's some screenshots of the demo-book I provide with this PR.
---
### 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**_
_Little bit of guidance on what to touch, parts of the impl, rest
manually._
## Summary
**What is the goal of this PR?**
* Implement feature request
[#954](https://github.com/crosspoint-reader/crosspoint-reader/issues/954)
* Ensure cover images are scaled up to match the dimensions of the
screen, as well as scaled down
**What changes are included?**
* Naïve implementation for scaling up the source image
## Additional Context
If you find the extra comments to be excessive I can pare them back.
Edit: Fixed title
---
### 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? _**< YES >**_
## Summary
* What is the goal of this PR?
- Allow users to create custom sleep screen images with standard tools
(ImageMagick, GIMP, etc.) that render cleanly on the e-ink display
without dithering artifacts. Previously, avoiding dithering required
non-standard 2-bit BMPs that no standard image editor can produce. ( see
issue #931 )
* What changes are included?
- Add 4-bit BMP format support to Bitmap.cpp (standard format, widely
supported by image tools)
- Auto-detect "native palette" images: if a BMP has ≤4 palette entries
and all luminances map within ±21 of the display's native gray levels
(0, 85, 170, 255), skip dithering entirely and direct-map pixels
- Clarify pixel processing strategy with three distinct paths:
error-diffusion dithering, simple quantization, or direct mapping
- Add scripts/generate_test_bmps.py for generating test images across
all supported BMP formats
## Additional Context
* The e-ink display has 4 native gray levels. When a BMP already uses
exactly those levels, dithering adds noise to what should be clean
output. The native palette detection uses a ±21 tolerance (~10%) to
handle slight rounding from color space conversions in image tools.
Users can now create a 4-color grayscale BMP with (imagemagic example):
```
convert input.png -colorspace Gray -colors 4 -depth
```
---
### 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? _** YES**_
## Summary
**What is the goal of this PR?**
`hasPrintableChars` does a pass over text before rendering. It looks up
glyphs in the font and measures dimensions, returning early if the text
results in zero size.
This additional pass doesn't offer any benefit over moving straight to
rendering the text, because the rendering loop already gracefully
handles missing glyphs. This change saves an extra pass over all
rendered text.
Note that both `hasPrintableChars` and `renderChar` replace missing
glyphs with `glyph = getGlyph(REPLACEMENT_GLYPH)`, so there's no
difference for characters which are not present in the font.
---
### 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? _**NO**_
## Summary
**What is the goal of this PR?** (e.g., Implements the new feature for
file uploading.)
* Fixes:
https://github.com/crosspoint-reader/crosspoint-reader/issues/947
**What changes are included?**
* Check to see if there's free heap memory before processing CSS (should
we be doing this type of check or is it better to just crash if we
exhaust the memory?)
* Skip CSS files larger than 128kb
## Additional Context
* I found that a copy of `Release it` contained a 250kb+ CSS file, from
the homepage of the publisher. It has nothing to do with the epub, so we
should just skip it
* Major question: Are there better ways to detect CSS that doesn't
belong in a book, or is this size-based approach valid?
* Another question: Are there any epubs we know of that legitimately
include >128kb CSS files?
Code changes themselves created with an agent, all investigation and
write-up done by human. If you (the maintainers) would prefer a
different fix for this issue, let me know.
---
### 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? _**< YES >**_
## Summary
* GfxRender did handle horizontal and vertical lines but had a TODO for
arbitrary lines.
* Added integer based Bresenham line drawing
## Additional Context
---
### 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? _**NO**_
## Summary
* Original implementation had inconsistent positioning logic:
- When XPath parsing succeeded: incorrectly set pageNumber = 0 (always
beginning of chapter)
- When XPath parsing failed: used percentage for positioning (worked
correctly)
- Result: Positions restored to wrong locations depending on XPath
parsing success
- Mentioned in Issue #581
* Solution
- Unified ProgressMapper::toCrossPoint() to use percentage-based
positioning exclusively for both spine identification and intra-chapter
page calculation, eliminating unreliable XPath parsing entirely.
## Additional Context
* ProgressMapper.cpp: Simplified toCrossPoint() to always use percentage
for positioning, removed parseDocFragmentIndex() function
* ProgressMapper.h: Updated comments and removed unused function
declaration
* Tests confirmed appropriate positioning
* __Notabene: the syncing to another device will (most probably) end up
at the current chapter of crosspoints reading position. There is not
much we can do about it, as KOReader needs to have the correct XPath
information - we can only provide an apporximate position (plus
percentage) - the percentage information is not used in KOReaders
current implementation__
---
### 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? YES
## Summary
* **What is the goal of this PR?**
Add proper hyphenation support for the Ukrainian language.
* **What changes are included?**
- Added Ukrainian hyphenation rules/dictionary
## Additional Context
---
### AI Usage
Did you use AI tools to help write this code? _**NO**_
## Summary
**What is the goal of this PR?**
This change fixes an issue I noticed while reading where occasionally,
especially in italics, some words would have too much space between
them. The problem was that word width calculations were including any
negative X overhang, and combined with a space before the word, that can
lead to an inconsistently large space.
## Additional Context
Screenshots of some problematic text:
| In CrossPoint 1.0 | With this change |
| -- | -- |
| <img
src="https://github.com/user-attachments/assets/87bf0e4b-341f-4ba9-b3ea-38c13bd26363"
width="400" /> | <img
src="https://github.com/user-attachments/assets/bf11ba20-c297-4ce1-aa07-43477ef86fc2"
width="400" /> |
---
### 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? _**NO**_
## Summary
* During chapter parsing, every <img> tag triggered ZIP decompression
and an SD card write regardless of whether the image format was
supported. The mandatory delay(50) after each SD write compounded the
cost. A chapter with 6 GIF images (a common decorative element in older
EPUBs) wasted ~750 ms before any text rendering began.
* **What changes are included?**
Added an ``ImageDecoderFactory::isFormatSupported()`` check before any
file I/O in the img-handler. Only JPEG and PNG proceed to extraction;
all other formats (GIF, SVG, WebP, etc.) fall through immediately to
alt-text rendering with no SD card access.
## Additional Context
Measured impact on a representative chapter with 6 GIF decorations:
| | Before | After|
|-- | -- | --|
|Total parse time | ~882 ms | ~207 ms|
|Image handling | ~750 ms | ~76 ms|
---
### 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? _**NO**_
## Summary
**What is the goal of this PR?**
Compress reader font bitmaps to reduce flash usage by 30.7%.
**What changes are included?**
- New `EpdFontGroup` struct and extended `EpdFontData` with
`groups`/`groupCount` fields
- `--compress` flag in `fontconvert.py`: groups glyphs (ASCII base group
+ groups of 8) and compresses each with raw DEFLATE
- `FontDecompressor` class with 4-slot LRU cache for on-demand
decompression during rendering
- `GfxRenderer` transparently routes bitmap access through
`getGlyphBitmap()` (compressed or direct flash)
- Uses `uzlib` for decompression with minimal heap overhead.
- 48 reader fonts (Bookerly, NotoSans 12-18pt, OpenDyslexic) regenerated
with compression; 5 UI fonts unchanged
- Round-trip verification script (`verify_compression.py`) runs as part
of font generation
## Additional Context
## Flash & RAM
| | baseline | font-compression | Difference |
|--|--------|-----------------|------------|
| Flash (ELF) | 6,302,476 B (96.2%) | 4,365,022 B (66.6%) | -1,937,454 B
(-30.7%) |
| firmware.bin | 6,468,192 B | 4,531,008 B | -1,937,184 B (-29.9%) |
| RAM | 101,700 B (31.0%) | 103,076 B (31.5%) | +1,376 B (+0.5%) |
## Script-Based Grouping (Cold Cache)
Comparison of uncompressed baseline vs script-based group compression
(4-slot LRU cache, cleared each page). Glyphs are grouped by Unicode
block (ASCII, Latin-1, Latin Extended-A, Combining Marks, Cyrillic,
General Punctuation, etc.) instead of sequential groups of 8.
### Render Time
| | Baseline | Compressed (cold cache) | Difference |
|---|---|---|---|
| **Median** | 414.9 ms | 431.6 ms | +16.7 ms (+4.0%) |
| **Pages** | 37 | 37 | |
### Memory Usage
| | Baseline | Compressed (cold cache) | Difference |
|---|---|---|---|
| **Heap free (median)** | 187.0 KB | 176.3 KB | -10.7 KB |
| **Heap free (min)** | 186.0 KB | 166.5 KB | -19.5 KB |
| **Largest block (median)** | 148.0 KB | 128.0 KB | -20.0 KB |
| **Largest block (min)** | 148.0 KB | 120.0 KB | -28.0 KB |
### Cache Effectiveness
| | Misses/page | Hit rate |
|---|---|---|
| **Compressed (cold cache)** | 2.1 | 99.85% |
------
### 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? _**YES**_
Implementation was done by Claude Code (Opus 4.6) based on a plan
developed collaboratively. All generated font headers were verified with
an automated round-trip decompression test. The firmware was compiled
successfully but has not yet been tested on-device.
---------
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
## Summary
I want to preface this PR by stating that the proposed changes are
subjective to people's opinions. The following is just my suggestion,
but I'm of course open to changes.
The popups in the currently implemented version of the Lyra theme feel a
bit out of place. This PR suggests an updated version which looks a bit
more polished and in line with the rest of the theme.
I've also taken the liberty to remove the ellipsis behind the text of
the popups, as they made the popup feel a bit off balance (example
below).
With the applied changes, popups will look like this.
The vertical position is (more or less) aligned to be in line with the
sleep button. I'm aware the popup is used for other purposes aside from
the sleep message, but this still felt like a good place. It's also a
place where your eyes naturally 'rest'.
The popup has a small 2px white outline, neatly separating it from
whatever is behind it.
### Alternatives considered and rationale behind proposal
Initially I started out worked off the Figma design for the Lyra theme,
which [moves the
popups](https://www.figma.com/design/UhxoV4DgUnfrDQgMPPTXog/Lyra-Theme?node-id=2011-19296&t=Ppj6B2MrFRfUo9YX-1)
to the bottom of the screen. To me, this results in popups that are much
too easy to miss:
After this, I tried moving the popup back up (to the position of the
sleep button), but to me it still kinda disappeared into the text of the
book:
Inverting the colors of the popup made things stand out the perfect
amount in my opinion. The white outline separates the popup from what is
behind it.
This looked much better to me. The only thing that felt a bit off to me,
was the balance due to the ellipsis at the end of the popup text. Also,
"Entering Sleep..." felt a bit.. engineer-y. I felt something a bit more
'conversational' makes at all feel a bit more human-centric. But I'm no
copywriter, and English is not even my native language. So feel free to
chip in!
After tweaking that, I ended up with the final result:
_(Same picture as the first one shown in this PR)_
## Additional Context
* Figma design:
https://www.figma.com/design/UhxoV4DgUnfrDQgMPPTXog/Lyra-Theme?node-id=2011-19296&t=Ppj6B2MrFRfUo9YX-1
---
### 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? _**NO**_
## Summary
Continue my experiment from
https://github.com/crosspoint-reader/crosspoint-reader/pull/801
This PR add the ability to lower the CPU frequency on extended idle
period (currently set to 3 seconds). By default, the esp32c3 CPU is set
to 160MHz, and now on idle, we can reduce it to just 10MHz.
Note that while this functionality is already provided by [esp power
management](https://docs.espressif.com/projects/esp-idf/en/v4.3/esp32c3/api-reference/system/power_management.html),
the current Arduino build lacks of this, and enabling it is just too
complicated (not worth the effort compared to this PR)
Update: more info in
https://github.com/crosspoint-reader/crosspoint-reader/pull/852#issuecomment-3904562827
## Testing
Pre-condition for each test case: the battery is charged to 100%, and is
left plugged in after fully charged for an extra 1 hour.
The table below shows how much battery is **used** for a given duration:
| case / duration | 6 hrs | 12 hrs |
| --- | --- | --- |
| `delay(10)` | 26% | 48% |
| `delay(50)`, PR
https://github.com/crosspoint-reader/crosspoint-reader/pull/801 | 20% |
Not tested |
| `delay(50)` + low CPU freq (This PR) | Not tested | 25% |
| `delay(10)` + low CPU freq (1) | Not tested | Not tested |
(1) I decided not to test this case because it may not make sense. The
problem is that CPU frequency vs power consumption do not follow a
linear relationship, see
[this](https://www.arrow.com/en/research-and-events/articles/esp32-power-consumption-can-be-reduced-with-sleep-modes)
as an example. So, tight loop (10ms) + lower CPU freq significantly
impact battery life, because the active CPU time is now much higher
compared to the wall time.
**So in conclusion, this PR improves ~150% to ~200% battery use time per
charge.**
The projected battery life is now: ~36-48 hrs of reading time (normal
reading, no wifi)
---
### 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? **NO**
## Summary
**What is the goal of this PR?**
Several methods in GfxRenderer were doing a `count()` followed by `at()`
on the fonts map, effectively doing the same map lookup unnecessarily.
This can be avoided by doing a single `find()` and reusing the iterator.
---
### AI Usage
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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**_
## Summary
**What is the goal of this PR?**
Skip constructing a `std::string` just to get the underlying `c_str()`
buffer, when a string literal gives the same end result.
---
### 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? _**NO**_
## Summary
This PR includes vocabulary and grammar fixes for Russian translation,
originally made as review comments
[here](https://github.com/crosspoint-reader/crosspoint-reader/pull/728).
---
### 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? _**NO**_
## Summary
**What is the goal of this PR?**
This PR introduces Internationalization (i18n) support, enabling users
to switch the UI language dynamically.
**What changes are included?**
- Core Logic: Added I18n class (`lib/I18n/I18n.h/cpp`) to manage
language state and string retrieval.
- Data Structures:
- `lib/I18n/I18nStrings.h/cpp`: Static string arrays for each supported
language.
- `lib/I18n/I18nKeys.h`: Enum definitions for type-safe string access.
- `lib/I18n/translations.csv`: single source of truth.
- Documentation: Added `docs/i18n.md` detailing the workflow for
developers and translators.
- New Settings activity:
`src/activities/settings/LanguageSelectActivity.h/cpp`
## Additional Context
This implementation (building on concepts from #505) prioritizes
performance and memory efficiency.
The core approach is to store all localized strings for each language in
dedicated arrays and access them via enums. This provides O(1) access
with zero runtime overhead, and avoids the heap allocations, hashing,
and collision handling required by `std::map` or `std::unordered_map`.
The main trade-off is that enums and string arrays must remain perfectly
synchronized—any mismatch would result in incorrect strings being
displayed in the UI.
To eliminate this risk, I added a Python script that automatically
generates `I18nStrings.h/.cpp` and `I18nKeys.h` from a CSV file, which
will serve as the single source of truth for all translations. The full
design and workflow are documented in `docs/i18n.md`.
### Next Steps
- [x] Python script `generate_i18n.py` to auto-generate C++ files from
CSV
- [x] Populate translations.csv with initial translations.
Currently available translations: English, Español, Français, Deutsch,
Čeština, Português (Brasil), Русский, Svenska.
Thanks, community!
**Status:** EDIT: ready to be merged.
As a proof of concept, the SPANISH strings currently mirror the English
ones, but are fully uppercased.
---
### AI Usage
Did you use AI tools to help write this code? _**< PARTIALLY >**_
I used AI for the black work of replacing strings with I18n references
across the project, and for generating the documentation. EDIT: also
some help with merging changes from master.
---------
Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>
Co-authored-by: yeyeto2788 <juanernestobiondi@gmail.com>
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>
## Summary
- EPUB books with PNG cover images now display covers on the home screen
instead of blank rectangles
- Adds `PngToBmpConverter` library mirroring the existing
`JpegToBmpConverter` pattern
- Uses miniz (already in the project) for streaming zlib decompression
of PNG IDAT data
- Supports all PNG color types (Grayscale, RGB, RGBA, Palette,
Gray+Alpha)
- Optimized for ESP32-C3: batch grayscale conversion, 2KB read buffer,
same area-averaging scaling and Atkinson dithering as the JPEG path
## Changes
- **New:** `lib/PngToBmpConverter/PngToBmpConverter.h` — Public API
matching JpegToBmpConverter's interface
- **New:** `lib/PngToBmpConverter/PngToBmpConverter.cpp` — Streaming PNG
decoder + BMP converter
- **Modified:** `lib/Epub/Epub.cpp` — Added `.png` handling in
`generateCoverBmp()` and `generateThumbBmp()`
## Test plan
- [x] Tested with EPUB files using PNG covers — covers appear correctly
on home screen
- [ ] Verify with various PNG color types (most stock EPUBs use 8-bit
RGB)
- [ ] Confirm no regressions with JPEG cover EPUBs
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
**New Features**
- Added PNG format support for EPUB cover and thumbnail images. PNG
files are automatically processed and cached alongside existing
supported formats. This enhancement enables users to leverage PNG cover
artwork when generating EPUB files, improving workflow flexibility and
compatibility with common image sources.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
---------
Co-authored-by: Nik Outchcunis <outchy@gmail.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: Dave Allie <dave@daveallie.com>
## Summary
* If an EPUB has:
```
<dc:creator>J.R.R. Tolkien</dc:creator>
<dc:creator>Christopher Tolkien</dc:creator>
```
the current result for epub.author would provide : "J.R.R.
TolkienChristopher Tolkien" (no separator!)
* The fix will seperate multiple authors: "J.R.R. Tolkien, Christopher
Tolkien"
## Additional Context
* Simple fix in ContentOpfParser - I am not seeing any dependence on the
wrong concatenated result.
---
### 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? NO
## Summary
This PR applies a micro optimization on `SerializedHyphenationPatterns`,
which allow reading `rootOffset` directly without having to parse then
cache it.
It should not affect storage space since no new bytes are added.
This also gets rid of the linear cache search whenever
`liangBreakIndexes` is called. In theory, the performance should be
improved a bit, although it may be too small to be noticeable in
practice.
## Testing
master branch:
```
english: 99.1023%
french: 100%
german: 97.7289%
russian: 97.2167%
spanish: 99.0236%
```
This PR:
```
english: 99.1023%
french: 100%
german: 97.7289%
russian: 97.2167%
spanish: 99.0236%
```
---
### 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 - mostly IDE
tab-autocompletions
## Summary
- Add embedded image support to EPUB rendering with JPEG and PNG
decoders
- Implement pixel caching system to cache decoded/dithered images to SD
card for faster re-rendering
- Add 4-level grayscale support for display
## Changes
### New Image Rendering System
- Add `ImageBlock` class to represent an image with its cached path and
display dimensions
- Add `PageImage` class as a new `PageElement` type for images on pages
- Add `ImageToFramebufferDecoder` interface for format-specific image
decoders
- Add `JpegToFramebufferConverter` - JPEG decoder with Bayer dithering
and scaling
- Add `PngToFramebufferConverter` - PNG decoder with Bayer dithering and
scaling
- Add `ImageDecoderFactory` to select appropriate decoder based on file
extension
- Add `getRenderMode()` to GfxRenderer for grayscale render mode queries
### Dithering and Grayscale
- Implement 4x4 Bayer ordered dithering for 4-level grayscale output
- Stateless algorithm works correctly with MCU block decoding
- Handles scaling without artifacts
- Add grayscale render mode support (BW, GRAYSCALE_LSB, GRAYSCALE_MSB)
- Image decoders and cache renderer respect current render mode
- Enables proper 4-level e-ink grayscale when anti-aliasing is enabled
### Pixel Caching
- Cache decoded/dithered images to `.pxc` files on SD card
- Cache format: 2-bit packed pixels (4 pixels per byte) with
width/height header
- On subsequent renders, load directly from cache instead of re-decoding
- Cache renderer supports grayscale render modes for multi-pass
rendering
- Significantly improves page navigation speed for image-heavy EPUBs
### HTML Parser Integration
- Update `ChapterHtmlSlimParser` to process `<img>` tags and extract
images from EPUB
- Resolve relative image paths within EPUB ZIP structure
- Extract images to cache directory before decoding
- Create `PageImage` elements with proper scaling to fit viewport
- Fall back to alt text display if image processing fails
### Build Configuration
- Add `PNG_MAX_BUFFERED_PIXELS=6402` to support up to 800px wide images
### Test Script
- Generate test EPUBs with annotated JPEG and PNG images
- Test cases cover: grayscale (4 levels), centering, scaling, cache
performance
## Test plan
- [x] Open EPUB with JPEG images - verify images display with proper
grayscale
- [x] Open EPUB with PNG images - verify images display correctly and no
crash
- [x] Navigate away from image page and back - verify faster load from
cache
- [x] Verify grayscale tones render correctly (not just black/white
dithering)
- [x] Verify large images are scaled down to fit screen
- [x] Verify images are centered horizontally
- [x] Verify page serialization/deserialization works with images
- [x] Verify images rendered in landscape mode
## Test Results
[png](https://photos.app.goo.gl/5zFUb8xA8db3dPd19)
[jpeg](https://photos.app.goo.gl/SwtwaL2DSQwKybhw7)
---
### AI Usage
Did you use AI tools to help write this code? _**< YES >**_
---------
Co-authored-by: Matthías Páll Gissurarson <mpg@mpg.is>
Co-authored-by: Dave Allie <dave@daveallie.com>
## Summary
Closes#766. Thank you for the help @bramschulting!
**What is the goal of this PR?**
- First and foremost, fix issue #766.
- Through working on that, I realized the current CSS parsing/loading
code can be improved dramatically for large files and still had
additional performance improvements to be made, even with EPUBs with
small CSS.
**What changes are included?**
- Stream CSS parsing and reuse normalization buffers to cut allocations
- Add rule limits and selector validation to release rules and free up
memory when needed
- Skip CSS parsing/loading entirely when "Book's Embedded Style" is off
## Additional Context
- My test EPUB has been updated
[here](https://github.com/jdk2pq/css-test-epub) to include a very large
CSS file to test this out
---
### 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? _**YES**_, Codex
## Summary
Closes#743.
**What is the goal of this PR?**
- Add back handling for HTML entities in expat. This was originally part
of the code that got removed
[here](https://github.com/crosspoint-reader/crosspoint-reader/pull/274)
- Handle ` ` characters to resolve issue #743
**What changes are included?**
- Brought back HTML entity table from previous commit and refactored it
to use a static const char * table with linear lookup to reduce heap
allocations.
- Used `XML_SetDefaultHandlerExpand` in expat to parse out the entities
correctly, without needing them defined in DOCTYPE
- Added handling for ` ` so that the text stays together and
doesn't break onto a new line with text separated by an ` `
## Additional Context
- This supersedes [this
PR](https://github.com/crosspoint-reader/crosspoint-reader/pull/751)
that simply handled `nbsp;` as whitespace. Instead, we want that
character to serve its true purpose and affect the line-breaking
algorithm.
- Updated my test EPUB [here](https://github.com/jdk2pq/css-test-epub)
with ` ` characters examples at the end of the book
---
### AI Usage
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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? _**YES**_, Claude Code
## Summary
* Definition and use of a central LOG function, that can later be
extended or completely be removed (for public use where debugging
information may not be required) to save flash by suppressing the
-DENABLE_SERIAL_LOG like in the slim branch
* **What changes are included?**
## Additional Context
* By using the central logger the usual:
```
#include <HardwareSerial.h>
...
Serial.printf("[%lu] [WCS] Obfuscating/deobfuscating %zu bytes\n", millis(), data.size());
```
would then become
```
#include <Logging.h>
...
LOG_DBG("WCS", "Obfuscating/deobfuscating %zu bytes", data.size());
```
You do have ``LOG_DBG`` for debug messages, ``LOG_ERR`` for error
messages and ``LOG_INF`` for informational messages. Depending on the
verbosity level defined (see below) soe of these message types will be
suppressed/not-compiled.
* The normal compilation (default) will create a firmware.elf file of
42.194.356 bytes, the same code via slim will create 42.024.048 bytes -
170.308 bytes less
* Firmware.bin : 6.469.984 bytes for default, 6.418.672 bytes for slim -
51.312 bytes less
### AI Usage
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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_
---------
Co-authored-by: Xuan Son Nguyen <son@huggingface.co>
Noticed that the Indexing... popup went missing despite 3-5 seconds
delay. Reducing to 10KB, so we get a popup for delays > ~2s.
### 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? no
## Summary
* **What is the goal of this PR?** Add Italian language hyphenation
support to improve text rendering for Italian books.
* **What changes are included?**
* Added Italian hyphenation trie (hyph-it.trie.h) generated from Typst's
hypher patterns
* Registered italianHyphenator in LanguageRegistry.cpp for language tag
it
* Added Italian to the hyphenation evaluation test suite
* Added Italian test data file with 5000 test cases
## Additional Context
* Add any other information that might be helpful for the reviewer
(e.g., performance implications, potential risks,
specific areas to focus on).
---
### AI Usage
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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**_
---------
Co-authored-by: drbourbon <fabio@MacBook-Air-di-Fabio.local>
## Summary
- Closes#730
**What is the goal of this PR?**
- Adds percentage-based value support to CSS properties that accept
percentages (padding, margin, text-indent)
**What changes are included?**
- Adds `Percent` as another CSS unit
- Passes the viewport width to `fromCssStyle` so that we can resolve
percentage-based values
- Adds a fallback of using an emspace for text-indent if we have an
unresolvable value for whatever reason
## Additional Context
- This was missed in my CSS support feature, and the fallback when we
encounter a percentage value is to use px instead. This means 5% (which
would be ~30px on the screen) turns into 5px. When percentages are used
in `text-indent`, this fallback behavior makes the indent look like a
single space character. Whoops! 😬
My test EPUB has been updated
[here](https://github.com/jdk2pq/css-test-epub) with percentage based
CSS values at the end of the book.
---
### 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? _**YES**_, Claude Code
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
## Summary
Continue my changes to introduce the HAL infrastructure from
https://github.com/crosspoint-reader/crosspoint-reader/pull/522
This PR touches quite a lot of files, but most of them are just name
changing. It should not have any impacts to the end behavior.
## Additional Context
My plan is to firstly add this small shim layer, which sounds useless at
first, but then I'll implement an emulated driver which can be helpful
for testing and for development.
Currently, on my fork, I'm using a FS driver that allow "mounting" a
local directory from my computer to the device, much like the `-v` mount
option on docker. This allows me to quickly reset `.crosspoint`
directory if anything goes wrong. I plan to upstream this feature when
this PR get merged.
---
### AI Usage
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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
## Summary
Ref https://github.com/crosspoint-reader/crosspoint-reader/pull/737
This PR further reduce ~25ms from rendering time, testing inside the
Setting screen:
```
master:
[68440] [GFX] Time = 73 ms from clearScreen to displayBuffer
PR:
[97806] [GFX] Time = 47 ms from clearScreen to displayBuffer
```
And in extreme case (fill the entire screen with black or gray color):
```
master:
[1125] [ ] Test fillRectDither drawn in 327 ms
[1347] [ ] Test fillRect drawn in 222 ms
PR:
[1334] [ ] Test fillRectDither drawn in 225 ms
[1455] [ ] Test fillRect drawn in 121 ms
```
Note that
https://github.com/crosspoint-reader/crosspoint-reader/pull/737 is NOT
applied on top of this PR. But with 2 of them combined, it should reduce
from 47ms --> 42ms
## Details
This PR based on the fact that function calls are costly if the function
is small enough. For example, this simple call:
```
int rotatedX = 0;
int rotatedY = 0;
rotateCoordinates(x, y, &rotatedX, &rotatedY);
```
Generated assembly code:
<img width="771" height="215" alt="image"
src="https://github.com/user-attachments/assets/37991659-3304-41c3-a3b2-fb967da53f82"
/>
This adds ~10 instructions just to prepare the registers prior to the
function call, plus some more instructions for the function's
epilogue/prologue. Inlining it removing all of these:
<img width="1471" height="832" alt="image"
src="https://github.com/user-attachments/assets/b67a22ee-93ba-4017-88ed-c973e28ec914"
/>
Of course, this optimization is not magic. It's only beneficial under 3
conditions:
- The function is small, not in size, but in terms of effective
instructions. For example, the `rotateCoordinates` is simply a jump
table, where each branch is just 3-4 inst
- The function has multiple input arguments, which requires some move to
put it onto the correct place
- The function is called very frequently (i.e. critical path)
---
### AI Usage
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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**
## Summary
This PR optimizes the `fillRectDither` function, making it as fast as a
normal `fillRect`
Testing code:
```cpp
{
auto start_t = millis();
renderer.fillRectDither(0, 0, renderer.getScreenWidth(), renderer.getScreenHeight(), Color::LightGray);
auto elapsed = millis() - start_t;
Serial.printf("[%lu] [ ] Test fillRectDither drawn in %lu ms\n", millis(), elapsed);
}
{
auto start_t = millis();
renderer.fillRect(0, 0, renderer.getScreenWidth(), renderer.getScreenHeight(), true);
auto elapsed = millis() - start_t;
Serial.printf("[%lu] [ ] Test fillRect drawn in %lu ms\n", millis(), elapsed);
}
```
Before:
```
[1125] [ ] Test fillRectDither drawn in 327 ms
[1347] [ ] Test fillRect drawn in 222 ms
```
After:
```
[1065] [ ] Test fillRectDither drawn in 238 ms
[1287] [ ] Test fillRect drawn in 222 ms
```
## Visual validation
Before:
<img width="415" height="216" alt="Screenshot 2026-02-07 at 01 04 19"
src="https://github.com/user-attachments/assets/5802dbba-187b-4d2b-a359-1318d3932d38"
/>
After:
<img width="420" height="191" alt="Screenshot 2026-02-07 at 01 36 30"
src="https://github.com/user-attachments/assets/3c3c8e14-3f3a-4205-be78-6ed771dcddf4"
/>
## Details
The original version is quite slow because it does quite a lot of
computations. A single pixel needs around 20 instructions just to know
if it's black or white:
<img width="1170" height="693" alt="Screenshot 2026-02-07 at 00 15 54"
src="https://github.com/user-attachments/assets/7c5a55e7-0598-4340-8b7b-17307d7921cb"
/>
With the new, templated and more light-weight approach, each pixel takes
only 3-4 instructions, the modulo operator is translated into bitwise
ops:
<img width="1175" height="682" alt="Screenshot 2026-02-07 at 01 47 51"
src="https://github.com/user-attachments/assets/4ec2cf74-6cc0-4b5b-87d5-831563ef164f"
/>
---
### AI Usage
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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**
Closes#182. Closes#710. Closes#711.
## Summary
**What is the goal of this PR?**
- A longer-term, more robust fix for the issue with spurious spaces
appearing after style changes. Replaces solution from #694.
**What changes are included?**
- Add continuation flags to determine if to add a space after a word or
if the word connects to the previous word. Replaces simple solution that
only considered ending punctuation.
- Fixed an issue with greedy line-breaking algorithm where punctuation
could appear on the next line, separated from the word, if there was a
style change between the word and punctuation
---
### AI Usage
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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? _**YES**_, Claude Code
## Summary
Reduce/fix the lag on the home screen before recent book covers are
rendered
## Additional Context
We were previously rendering the screen in two steps, delaying the
recent book covers render to avoid a lag before the screen loads.
In this PR, we are now doing that only if at least one book doesn't have
the cover thumbnail generated yet. If all thumbs are already generated,
we load and display them right away, with no lag.
---
### AI Usage
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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 **_
Closes#712
## Summary
**What is the goal of this PR?**
- To add new settings for toggling on/off embedded CSS styles in the
reader. This gives more control and customization to the user over how
the ereader experience looks.
**What changes are included?**
- Added new "Embedded Style" option to the Reader settings
- Added new "Book's Style" option for "Paragraph Alignment"
- User's selected "Paragraph Alignment" will take precedence and
override the embedded CSS `text-align` property, _unless_ the user has
"Book's Style" set as their "Paragraph Alignment"
## Additional Context
https://github.com/user-attachments/assets/9e404b13-c7e0-41c7-9406-4715f389166a
Addresses feedback from the community about the new CSS feature:
https://github.com/crosspoint-reader/crosspoint-reader/pull/700
---
### AI Usage
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helps set the right context for reviewers.
Did you use AI tools to help write this code? _**YES**_, Claude Code
Fixes issue #182
## Summary
**What is the goal of this PR?**
When inline styles change mid-paragraph, words like periods, commas, and
quotes could end up as separate tokens. The justified text algorithm was
treating these as regular words, adding space before them.
**What changes are included?**
Now tracks which words are "attaching punctuation" (., , ! ? ; : " ' and
smart quotes) and excludes them from gap counting. These punctuation
marks attach directly to the preceding word without spacing.
## Additional Context
This is split out from code in #411 to address this comment
https://github.com/crosspoint-reader/crosspoint-reader/pull/411#discussion_r2751166631
---
### AI Usage
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helps set the right context for reviewers.
Did you use AI tools to help write this code? _**YES**_, Claude Code
## Summary
* **What is the goal of this PR?**
The goal of this PR is to deliver a fix for or at least mitigate the
impact of the issue described in #561
* **What changes are included?**
This PR includes a new option "Sunlight Fading Fix" under "Settings ->
Display".
When set to ON, we will disable the displays analog supply voltage after
every update and turn it back on before the next update.
## Additional Context
* Until now, I was only able to do limited testing because of limited
sunlight at my location, but the fix seems to be working. I'll also
attach a pre-built binary based on 0.16.0 (current master) with the fix
applied to the linked ticket, as building this fix is a bit annoying
because the submodule open-x4-sdk also needs an update.
* [PR in
open-x4-sdk](https://github.com/open-x4-epaper/community-sdk/pull/15)
needs to be merged first, we also need to add another commit to this
here PR, updating this dependency.
* I decided to hide this behind a default-OFF option. While I'm not
really concerned that this fix might potentially damage the display,
someone more knowledgeable on E-Ink technology could maybe have a look
at this.
* There's a binary attached in the linked issue, if someone has the
required sunlight to test this in-depth.
---
### AI Usage
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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**_
---------
Co-authored-by: Dave Allie <dave@daveallie.com>
## Summary
* **What is the goal of this PR?** Provide support to koreader sync
server embedded in the popular *Calibre Web Automated* self-hosted
digital library solution.
* **What changes are included?**
* Trivial addition of **HTTP Basic Auth (RFC 7617) header** to
`lib/KOReaderSync/KOReaderSyncClient.cpp`
## Additional Context
None
---
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please be transparent about their usage as it
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---------
Co-authored-by: drbourbon <fabio@MacBook-Air-di-Fabio.local>
## Summary
Use non-crop mode as expected for home thumb generation. I likely broke
this when I fixed the artifacts on the sleep screen.
---
### AI Usage
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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
## Summary
### What is the goal of this PR?
- Visual UI overhaul
- UI theme selection
### What changes are included?
- Added a setting "UI Theme": Classic, Lyra
- The classic theme is the current Crosspoint theme
- The Lyra theme implements these mockups:
https://www.figma.com/design/UhxoV4DgUnfrDQgMPPTXog/Lyra-Theme?node-id=2003-7596&t=4CSOZqf0n9uQMxDt-0
by Discord users yagofarias, ruby and gan_shu
- New functions in GFXRenderer to render rounded rectangles, greyscale
fills (using dithering) and thick lines
- Basic UI components are factored into BaseTheme methods which can be
overridden by each additional theme. Methods that are not overridden
will fallback to BaseTheme behavior. This means any new
features/components in CrossPoint only need to be developed for the
"Classic" BaseTheme.
- Additional themes can easily be developed by the community using this
foundation
## Additional Context
- Only the Home, Library and main Settings screens have been implemented
so far, this will be extended to the transfer screens and chapter
selection screen later on, but we need to get the ball rolling somehow
:)
- Loading extra covers on the home screen in the Lyra theme takes a
little more time (about 2 seconds), I added a loading bar popup (reusing
the Indexing progress bar from the reader view, factored into a neat UI
component) but the popup adds ~400ms to the loading time.
- ~~Home screen thumbnails will need to be generated separately for each
theme, because they are displayed in different sizes. Because we're
using dithering, displaying a thumb with the wrong size causes the
picture to look janky or dark as it does on the screenshots above. No
worries this will be fixed in a future PR.~~ Thumbs are now generated
with a size parameter
- UI Icons will need to be implemented in a future PR.
---
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please be transparent about their usage as it
helps set the right context for reviewers.
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This is not a vibe coded PR. Copilot was used for autocompletion to save
time but I reviewed, understood and edited all generated code.
---------
Co-authored-by: Dave Allie <dave@daveallie.com>
## Summary
* **What is the goal of this PR?**
- Adds basic CSS parsing to EPUBs and determine the CSS rules when
rendering to the screen so that text is styled correctly. Currently
supports bold, underline, italics, margin, padding, and text alignment
## Additional Context
- My main reason for wanting this is that the book I'm currently
reading, Carl's Doomsday Scenario (2nd in the Dungeon Crawler Carl
series), relies _a lot_ on styled text for telling parts of the story.
When text is bolded, it's supposed to be a message that's rendered
"on-screen" in the story. When characters are "chatting" with each
other, the text is bolded and their names are underlined. Plus, normal
emphasis is provided with italicizing words here and there. So, this
greatly improves my experience reading this book on the Xteink, and I
figured it was useful enough for others too.
- For transparency: I'm a software engineer, but I'm mostly frontend and
TypeScript/JavaScript. It's been _years_ since I did any C/C++, so I
would not be surprised if I'm doing something dumb along the way in this
code. Please don't hesitate to ask for changes if something looks off. I
heavily relied on Claude Code for help, and I had a lot of inspiration
from how [microreader](https://github.com/CidVonHighwind/microreader)
achieves their CSS parsing and styling. I did give this as good of a
code review as I could and went through everything, and _it works on my
machine_ 😄
### Before
### After
---
### AI Usage
Did you use AI tools to help write this code? **YES**, Claude Code
## Summary
* Truncating chapter titles using utf8 safe functions (Cyrillic titles
were split mid codepoint)
* refactoring of lib/Utf8
---
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## Summary
* refactors Indexing popups into ScreenComponents (they had different
implementations in different files)
* removes Indexing popup for small chapters
* only show Indexing popup (without progress bar) for large chapters
(using same minimum file size condition as for progress bar before)
## Additional Context
* Having to show even single popup message and redraw the screen slows
down the flow significantly
* Testing results:
* Opening large chapter with progress bar - 11 seconds
* Same chapter without progress bar, only single Indexing popup - 5
seconds
---
### AI Usage
Did you use AI tools to help write this code? _**< PARTIALLY>**_
