**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
| | 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%) |
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.
| | Baseline | Compressed (cold cache) | Difference |
|---|---|---|---|
| **Median** | 414.9 ms | 431.6 ms | +16.7 ms (+4.0%) |
| **Pages** | 37 | 37 | |
| | 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 |
| | Misses/page | Hit rate |
|---|---|---|
| **Compressed (cold cache)** | 2.1 | 99.85% |
------
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>
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
* 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'
