Files
7993b2bb97 feat: add SD card font support with on-device download and web management
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>
2026-05-08 21:50:06 -05:00

58 lines
1.6 KiB
C++

#pragma once
#include <EpdFontFamily.h>
#include <cstdint>
#include <map>
#include <string>
class FontDecompressor;
class SdCardFont;
class FontCacheManager {
public:
FontCacheManager(const std::map<int, EpdFontFamily>& fontMap, const std::map<int, SdCardFont*>& sdCardFonts);
void setFontDecompressor(FontDecompressor* d);
void clearCache();
void prewarmCache(int fontId, const char* utf8Text, uint8_t styleMask = 0x0F);
void logStats(const char* label = "render");
void resetStats();
// Scan-mode API: called by GfxRenderer::drawText() during scan pass
bool isScanning() const;
void recordText(const char* text, int fontId, EpdFontFamily::Style style);
// The FontDecompressor pointer, needed by GfxRenderer::getGlyphBitmap()
FontDecompressor* getDecompressor() const { return fontDecompressor_; }
// RAII scope for two-pass prewarm pattern
class PrewarmScope {
public:
explicit PrewarmScope(FontCacheManager& manager);
~PrewarmScope();
void endScanAndPrewarm();
PrewarmScope(PrewarmScope&& other) noexcept;
PrewarmScope& operator=(PrewarmScope&&) = delete;
PrewarmScope(const PrewarmScope&) = delete;
PrewarmScope& operator=(const PrewarmScope&) = delete;
private:
FontCacheManager* manager_;
bool active_ = true;
};
PrewarmScope createPrewarmScope();
private:
const std::map<int, EpdFontFamily>& fontMap_;
const std::map<int, SdCardFont*>& sdCardFonts_;
FontDecompressor* fontDecompressor_ = nullptr;
enum class ScanMode : uint8_t { None, Scanning };
ScanMode scanMode_ = ScanMode::None;
std::string scanText_;
uint32_t scanStyleCounts_[4] = {};
int scanFontId_ = -1;
};