Replace per-page buffer free+realloc pattern with capacity tracking that only reallocates when needed size exceeds current capacity. This prevents heap fragmentation from non-coalescing holes that occurred when each page's freed block rarely fit the next page's allocation. After a few page turns, capacities converge on the book's maximum and page turns stop touching the allocator entirely.
## Summary
SD card font fixes:
- `TxtReaderActivity` needs to call `renderer.ensureSdCardFontReady` to
build the advance lookup table to support rendering with SD card fonts.
This revealed that `TxtReaderActivity` was inconsistently performing
layout with `getTextWidth`, when the renderer actually uses
`getTextAdvanceX`, which can lead to minor inconsistencies in alignment.
- Avoid allocating one big `allText` string in
`ParsedText::layoutAndExtractLines`. Instead, pass the vector of word
strings directly to `SdCardFont::buildAdvanceTable`, where the algorithm
just needs to iterate codepoints anyway.
---
### 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**_
---------
Co-authored-by: Justin Mitchell <justin@jmitch.com>
## Summary
- Fixes#1928 by having the prewarm and advance table functions resolve
fallback styles
---
### AI Usage
Did you use AI tools to help write this code? YES - Codex
---------
Co-authored-by: Uri Tauber <uritaube@gmail.com>
## Summary
* **What is the goal of this PR?** fix#1956.
## Additional Context
[NixOS-and-Flakes-Book_ch3_p7_4pct_130044.bmp](https://github.com/user-attachments/files/27648392/NixOS-and-Flakes-Book_ch3_p7_4pct_130044.bmp)
---
### 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 >**_
Add a complete SD card font subsystem that enables users to install and
use custom fonts beyond the three built-in families. This combines the
back-end firmware support (#1327) with the font configuration, build
pipeline, CI distribution, and user-facing management UI (#1392).
Core font system:
- Custom .cpfont binary format (v4) with multi-style support (regular,
bold, italic, bold-italic) packed into a single file per size
- On-demand glyph loading from SD card with two-pass prewarm rendering
to bulk-read glyphs per page, achieving near-flash performance for
Latin text (~697ms vs ~681ms) and viable CJK rendering (~32% slower)
- Persistent advance cache for layout measurement without SD I/O
- Overflow ring buffer for glyph cache misses during rendering
- Memory-conscious design: only advance tables kept in RAM; glyph
bitmaps, kern tables, and ligatures loaded on demand from SD
Font management:
- On-device WiFi download from GitHub Releases with manifest-based
discovery, install/update detection, and progress UI
- Web interface font upload, listing, and deletion via /fonts page
- Manual SD card copy to /fonts/ or /.fonts/ directories
- Font selection integrated into Settings > Reader > Font Family
Build pipeline:
- Declarative YAML config (sd-fonts.yaml) as single source of truth
for the 17-family font library (serif, sans, mono, accessibility)
- Python converter (fontconvert_sdcard.py) for TTF/OTF to .cpfont with
FreeType rasterization, class-based kerning, and ligature extraction
- Parallel build orchestrator with variable font instance extraction
- CI workflow publishing versioned + stable releases to a dedicated
crosspoint-fonts repository with auto-incrementing revision tags
- Centralized version constants (cpfont_version.py) shared across
build tooling and CI, with firmware headers as manual sync points
Additional fixes:
- CJK characters no longer get hyphens inserted at line breaks
- Advance table eliminates 30+ second stalls during CJK section
indexing for paragraphs with >512 unique codepoints
Closes#930
Co-authored-by: Zach Nelson <zach@zdnelson.com>
Co-authored-by: Justin <itsthisjustin@users.noreply.github.com>
Co-authored-by: jpirnay <jens@pirnay.com>
Co-authored-by: mcrosson <kemonine@kemonine.info>
Justin Mitchell
