## 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
Bookerly's native TrueType hinting is effectively a no-op at the sizes
used here, causing FreeType to place stems at inconsistent sub-pixel
positions. This results in the 'k' stem (8-bit fringe: 0x38=56) falling
just below the 2-bit quantization threshold while 'l' and 'h' stems
(fringes: 0x4C=76, 0x40=64) land above it --- making 'k' visibly
narrower (2.00px vs 2.33px effective width).
FreeType's auto-hinter snaps all stems to consistent grid positions,
normalizing effective stem width to 2.67px across all glyphs.
Adds --force-autohint flag to fontconvert.py and applies it to Bookerly
only. NotoSans, OpenDyslexic, and Ubuntu fonts are unaffected.
Here is an example of before/after. Take notice of the vertical stems on
characters like `l`, `k`, `n`, `i`, etc. The font is Bookerly 12pt
regular:
**BEFORE**:
**AFTER**:
Claude generated this script to quantitatively determine that this
change makes the vertical stems on a variety of characters more
consistent for Bookerly _only_.
<details>
<summary>Python script</summary>
```python
#!/usr/bin/env python3
"""Compare stem consistency across all font families with and without
auto-hinting.
Run from repo root:
python3 compare_all_fonts.py
"""
import freetype
DPI = 150
CHARS = ["k", "l", "h", "i", "b", "d"]
SIZES = [12, 14, 16, 18]
FONTS = {
"Bookerly":
"lib/EpdFont/builtinFonts/source/Bookerly/Bookerly-Regular.ttf",
"NotoSans":
"lib/EpdFont/builtinFonts/source/NotoSans/NotoSans-Regular.ttf",
"OpenDyslexic":
"lib/EpdFont/builtinFonts/source/OpenDyslexic/OpenDyslexic-Regular.otf",
"Ubuntu": "lib/EpdFont/builtinFonts/source/Ubuntu/Ubuntu-Regular.ttf",
}
MODES = {
"default": freetype.FT_LOAD_RENDER,
"autohint": freetype.FT_LOAD_RENDER | freetype.FT_LOAD_FORCE_AUTOHINT,
}
def q4to2(v):
if v >= 12:
return 3
elif v >= 8:
return 2
elif v >= 4:
return 1
else:
return 0
def get_stem_eff(face, char, flags):
gi = face.get_char_index(ord(char))
if gi == 0:
return None
face.load_glyph(gi, flags)
bm = face.glyph.bitmap
w, h = bm.width, bm.rows
if w == 0 or h == 0:
return None
p2 = []
for y in range(h):
row = []
for x in range(w):
row.append(q4to2(bm.buffer[y * bm.pitch + x] >> 4))
p2.append(row)
# Measure leftmost stem in stable middle rows
mid_start, mid_end = h // 4, h - h // 4
widths = []
for y in range(mid_start, mid_end):
first = next((x for x in range(w) if p2[y][x] > 0), -1)
if first < 0:
continue
last = first
for x in range(first, w):
if p2[y][x] > 0:
last = x
else:
break
eff = sum(p2[y][x] for x in range(first, last + 1)) / 3.0
widths.append(eff)
return round(sum(widths) / len(widths), 2) if widths else None
def main():
for font_name, font_path in FONTS.items():
try:
freetype.Face(font_path)
except Exception:
print(f"\n {font_name}: SKIPPED (file not found)")
continue
print(f"\n{'=' * 80}")
print(f" {font_name}")
print(f"{'=' * 80}")
for size in SIZES:
print(f"\n {size}pt:")
print(f" {'':6s}", end="")
for c in CHARS:
print(f" '{c}' ", end="")
print(" | spread")
for mode_name, flags in MODES.items():
face = freetype.Face(font_path)
face.set_char_size(size << 6, size << 6, DPI, DPI)
vals = []
print(f" {mode_name:6s}", end="")
for c in CHARS:
v = get_stem_eff(face, c, flags)
vals.append(v)
print(f" {v:5.2f}" if v else " N/A", end="")
valid = [v for v in vals if v is not None]
spread = max(valid) - min(valid) if len(valid) >= 2 else 0
marker = " <-- inconsistent" if spread > 0.5 else ""
print(f" | {spread:.2f}{marker}")
if __name__ == "__main__":
main()
```
</details>
Here are the results. The table compares how the font-generation
`autohint` flag affects the range of widths of various characters. Lower
`spread` mean that glyph stroke widths should appear more consistent.
```
Spread = max stem width - min stem width across glyphs (lower = more consistent):
┌──────────────┬──────┬─────────┬──────────┬──────────┐
│ Font │ Size │ Default │ Autohint │ Winner │
├──────────────┼──────┼─────────┼──────────┼──────────┤
│ Bookerly │ 12pt │ 1.49 │ 1.12 │ autohint │
├──────────────┼──────┼─────────┼──────────┼──────────┤
│ │ 14pt │ 1.39 │ 1.13 │ autohint │
├──────────────┼──────┼─────────┼──────────┼──────────┤
│ │ 16pt │ 1.38 │ 1.16 │ autohint │
├──────────────┼──────┼─────────┼──────────┼──────────┤
│ │ 18pt │ 1.90 │ 1.58 │ autohint │
├──────────────┼──────┼─────────┼──────────┼──────────┤
│ NotoSans │ 12pt │ 1.16 │ 0.94 │ mixed │
├──────────────┼──────┼─────────┼──────────┼──────────┤
│ │ 14pt │ 0.83 │ 1.14 │ default │
├──────────────┼──────┼─────────┼──────────┼──────────┤
│ │ 16pt │ 1.41 │ 1.51 │ default │
├──────────────┼──────┼─────────┼──────────┼──────────┤
│ │ 18pt │ 1.74 │ 1.63 │ mixed │
├──────────────┼──────┼─────────┼──────────┼──────────┤
│ OpenDyslexic │ 12pt │ 2.22 │ 1.44 │ autohint │
├──────────────┼──────┼─────────┼──────────┼──────────┤
│ │ 14pt │ 2.57 │ 3.29 │ default │
├──────────────┼──────┼─────────┼──────────┼──────────┤
│ │ 16pt │ 3.13 │ 2.60 │ autohint │
├──────────────┼──────┼─────────┼──────────┼──────────┤
│ │ 18pt │ 3.21 │ 3.23 │ ~tied │
├──────────────┼──────┼─────────┼──────────┼──────────┤
│ Ubuntu │ 12pt │ 1.25 │ 1.31 │ default │
├──────────────┼──────┼─────────┼──────────┼──────────┤
│ │ 14pt │ 1.41 │ 1.64 │ default │
├──────────────┼──────┼─────────┼──────────┼──────────┤
│ │ 16pt │ 2.21 │ 1.71 │ autohint │
├──────────────┼──────┼─────────┼──────────┼──────────┤
│ │ 18pt │ 1.80 │ 1.71 │ autohint │
└──────────────┴──────┴─────────┴──────────┴──────────┘
```
---
### 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? I used AI to make sure I'm
not doing something stupid, since I'm not a typography expert. I made
the changes though.
## Summary
**What is the goal of this PR?**
Consolidated repeated logic to fall back to REPLACEMENT_GLYPH.
---
### 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
* Remove miniz and move completely to uzlib
* Move uzlib interfacing to InflateReader to better modularise inflation
code
---
### 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 helped with
the extraction and refactor
## Summary
* This PR fixes decomposed diacritic handling end-to-end:
- Hyphenation: normalize common Latin base+combining sequences to
precomposed codepoints before Liang pattern matching, so decomposed
words hyphenate correctly
- Rendering: correct combining-mark placement logic so non-spacing marks
are attached to the preceding base glyph in normal and rotated text
rendering paths, with corresponding text-bounds consistency updates.
- Hyphenation around non breaking space variants have been fixed (and
extended)
- Hyphenation of terms that already included of hyphens were fixed to
include Liang pattern application (eg "US-Satellitensystem" was
*exclusively* broken at the existing hyphen)
## Additional Context
* Before
<img width="800" height="480" alt="2"
src="https://github.com/user-attachments/assets/b9c515c4-ab75-45cc-8b52-f4d86bce519d"
/>
* After
<img width="480" height="800" alt="fix1"
src="https://github.com/user-attachments/assets/4999f6a8-f51c-4c0a-b144-f153f77ddb57"
/>
<img width="800" height="480" alt="fix2"
src="https://github.com/user-attachments/assets/7355126b-80c7-441f-b390-4e0897ee3fb6"
/>
* Note 1: the hyphenation fix is not a 100% bullet proof implementation.
It adds composition of *common* base+combining sequences (e.g. O +
U+0308 -> Ö) during codepoint collection. A complete solution would
require implementing proper Unicode normalization (at least NFC,
possibly NFKC in specific cases) before hyphenation and rendering,
instead of hand-mapping a few combining marks. That was beyond the scope
of this fix.
* Note 2: the render fix should be universal and not limited to the
constraints outlined above: it properly x-centers the compund glyph over
the previous one, and it uses at least 1pt of visual distance in y.
Before:
<img width="478" height="167" alt="Image"
src="https://github.com/user-attachments/assets/f8db60d5-35b1-4477-96d0-5003b4e4a2a1"
/>
After:
<img width="479" height="180" alt="Image"
src="https://github.com/user-attachments/assets/1b48ef97-3a77-475a-8522-23f4aca8e904"
/>
* This should resolve the issues described in #998
---
### 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**_
## 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?**
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?**
- 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
* **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>
The current behavior of rendering `?` for an unknown Unicode character
can be hard to distinguish from a typo. Use the standard Unicode
"replacement character" instead, that's what it's designed for:
https://en.wikipedia.org/wiki/Specials_(Unicode_block)
I'm making this PR as a draft because I'm not sure I did everything that
was needed to change the character set covered by the fonts. Running
that script is in its own commit. If this is proper, I'll rebase/squash
into one commit and un-draft.
Co-authored-by: Maeve Andrews <maeve@git.mail.maeveandrews.com>
## Summary
* Update EpdFontFamily::Style to be u8 instead of u32 (saving 3 bytes
per word)
* Update layout width/height to be u16 from int
* Update page element count to be u16 from u32
* Update text block element count to be u16 from u32
* Bumped section bin version to version 8
## Summary
* Swap from Aleo to Bookerly for wider glyph support
* Swap from Space Grotesk to a small Noto Sans
## Additional Context
* 0.11.0 swapped to Aleo which has a few issues (things like Cyrillic
support for eg)
Replace linear O(n) search with binary search O(log n) for unicode
interval lookup. Korean fonts have many intervals (~30,000+ glyphs), so
this improves text rendering performance during page navigation.
## Summary
* **What is the goal of this PR?** (e.g., Fixes a bug in the user
authentication module, Implements the new feature for
file uploading.)
Replace linear `O(n)` glyph lookup with binary search `O(log n)` to
improve text rendering performance during page navigation.
* **What changes are included?**
- Modified `EpdFont::getGlyph()` to use binary search instead of linear
search for unicode interval lookup
- Added early return for empty interval count
## Additional Context
* Add any other information that might be helpful for the reviewer
(e.g., performance implications, potential risks, specific areas to
focus on).
- Performance implications: Fonts with many unicode intervals benefit
the most. Korean fonts have ~30,000+ glyphs across multiple intervals,
but any font with significant glyph coverage (CJK, extended Latin,
emoji, etc.) will see improvement.
- Complexity: from `O(n)` to `O(log n)` where n = number of unicode
intervals. For fonts with 10+ intervals, this reduces lookup iterations
significantly.
- Risk: Low - the binary search logic is straightforward and the
intervals are already sorted by unicode codepoint (required for the
original early-exit optimization).
## Summary
* adds cyrillic glyphs to pixel arial font, used as Small font in UI
## Additional Context
* with recent changes pixel arial font lost cyrillic glyphs
## Summary
* Previously, only pure black pixels in the font were marked as black,
this expands the black range, and makes the lightest pixels white
## Additional Context
* Noticed personally it was kind of "thin" and washed out a bit, this
massively helps, should also address concerns raised here:
https://github.com/daveallie/crosspoint-reader/discussions/39
* Enhance TOC parsing and chapter selection logic
- Update .gitignore to include additional paths
- Refactor Epub::parseContentOpf to improve NCX item retrieval
- Modify ContentOpfParser to store media type in ManifestItem
- Implement rebuildVisibleSpineIndices in EpubReaderChapterSelectionScreen for better chapter navigation
- Adjust rendering logic to handle empty chapter lists gracefully
* Refactor TOC parsing logic to streamline cover image and NCX item retrieval
* add cyrillic ranges
* revert
* clang format fix
* First pass at moving to SDK EInkDisplay library
* Add 2-bit grayscale text and anti-aliased rendering of text
* Render status bar for empty chapters
* Refresh screen every 15 pages to avoid ghosting
* Simplify boot and sleep screens
* Give FileSelectionScreen task more stack memory
* Move text around slightly on Boot and Sleep screens
* Re-use existing buffer and write to whole screen for 'partial update'
