## Summary
* **What is the goal of this PR?**
Add Vietnamese glyphs support for the reader's built-in fonts, enabling
proper rendering of Vietnamese text in EPUB content.
* **What changes are included?**
- Added 3 new Unicode intervals to `fontconvert.py` covering Vietnamese
characters:
- **Latin Extended-B** (Vietnamese subset only): `U+01A0–U+01B0` — Ơ/ơ,
Ư/ư
- **Vietnamese Extended**: `U+1EA0–U+1EF9` — All precomposed Vietnamese
characters with tone marks (Ả, Ấ, Ầ, Ẩ, Ẫ, Ậ, Ắ, …, Ỹ)
- Re-generated all 54 built-in font header files (Bookerly, Noto Sans,
OpenDyslexic, Ubuntu across all sizes and styles) to include the new
Vietnamese glyphs.
## Additional Context
* **Scope**: This PR only covers the **reader** fonts. The outer UI
still uses the Ubuntu font which does not fully support Vietnamese — UI
and i18n will be addressed in a follow-up PR (per discussion in PR
#1124).
* **Memory impact**:
| Metric | Before | After | Delta |
|---|---|---|---|
| Flash Data (`.rodata`) | 2,971,028 B | 3,290,748 B | **+319,720 B
(+10.8%)** |
| Total image size | 4,663,235 B | 4,982,955 B | **+319,720 B (+6.9%)**
|
| Flash usage | 69.1% | 74.0% | **+4.9 pp** |
| RAM usage | 29.0% | 29.0% | **No change** |
* **Risk**: Low — this is a data-only change (font glyph tables in
`.rodata`). No logic changes, no RAM impact. Flash headroom remains
comfortable at 74%.
---
### AI Usage
Did you use AI tools to help write this code? _**PARTIALLY**_
AI was used to identify the minimal set of Unicode ranges needed for
Vietnamese support and to assist with the PR description.
---------
Co-authored-by: danoooob <danoooob@example.com>
## 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>
## 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
* **What is the goal of this PR?** Simple quality of life, ease
maintenance
* **What changes are included?**
Update fontconvert.py to include the command used to generate each font
file in the header comment, making it easier to regenerate fonts when
needed.
I plan on adding options to this scripts (kerning, and maybe ligatures),
thus knowing which command was used, even with already existing options
like `--additional-intervals`, is important.
---
### 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
* Include superscripts and subscripts in fonts
## Additional Context
* Original change came from
https://github.com/crosspoint-reader/crosspoint-reader/pull/248
---
### 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: cor <cor@pruijs.dev>
