## Summary
**What is the goal of this PR?**
Improved typesetting, including
[kerning](https://en.wikipedia.org/wiki/Kerning) and
[ligatures](https://en.wikipedia.org/wiki/Ligature_(writing)#Latin_alphabet).
**What changes are included?**
- The script to convert built-in fonts now adds kerning and ligature
information to the generated font headers.
- Epub page layout calculates proper kerning spaces and makes ligature
substitutions according to the selected font.
## Additional Context
- I am not a typography expert.
- The implementation has been reworked from the earlier version, so it
is no longer necessary to omit Open Dyslexic, and kerning data now
covers all fonts, styles, and codepoints for which we include bitmap
data.
- Claude Opus 4.6 helped with a lot of this.
- There's an included test epub document with lots of kerning and
ligature examples, shown in the photos.
**_After some time to mature, I think this change is in decent shape to
merge and get people testing._**
After opening this PR I came across #660, which overlaps in adding
ligature support.
---
### 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 Opus 4.6**_
---------
Co-authored-by: Cursor <cursoragent@cursor.com>
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
- 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
* **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
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**_
---------
Co-authored-by: drbourbon <fabio@MacBook-Air-di-Fabio.local>
## Summary
* **What is the goal of this PR?** Add Spanish language hyphenation
support to improve text rendering for Spanish books.
* **What changes are included?**
- Added Spanish hyphenation trie (`hyph-es.trie.h`) generated from
Typst's hypher patterns
- Registered `spanishHyphenator` in `LanguageRegistry.cpp` for language
tag `es`
- Added Spanish to the hyphenation evaluation test suite
- Added Spanish test data file with 5000 test cases
## Additional Context
* **Test Results:** Spanish hyphenation achieves 99.02% F1 Score (97.72%
perfect matches out of 5000 test cases)
* **Compatibility:** Works automatically for EPUBs with
`<dc:language>es</dc:language>` (or es-ES, es-MX, etc.)
<img width="115" height="189" alt="imagen"
src="https://github.com/user-attachments/assets/9b92e7fc-b98d-48af-8d53-dfdc2e68abee"
/>
| Metric | Value |
|--------|-------|
| Perfect matches | 97.72% |
| Overall Precision | 99.33% |
| Overall Recall | 99.42% |
| Overall F1 Score | 99.38% |
---
### AI Usage
Did you use AI tools to help write this code? _**PARTIALLY**_
AI assisted with:
- Guiding and compile
- Preparing the PR description
## Summary
* Adds (optional) Hyphenation for English, French, German, Russian
languages
## Additional Context
* Included hyphenation dictionaries add approximately 280kb to the flash
usage (German alone takes 200kb)
* Trie encoded dictionaries are adopted from hypher project
(https://github.com/typst/hypher)
* Soft hyphens (and other explicit hyphens) take precedence over
dict-based hyphenation. Overall, the hyphenation rules are quite
aggressive, as I believe it makes more sense on our smaller screen.
---------
Co-authored-by: Dave Allie <dave@daveallie.com>
