Add FreeInkBook EPUB engine migration guide

Document migration plan from CrossPoint's lib/Epub to FreeInkBook, a memory-efficient clean-room EPUB engine. Covers advantages (O(paragraph+page) memory via SAX parsing, arena allocation, host-testable, full UAX#14 typography, runtime TTF/OTF support), 9-step migration strategy, ESP32-C3 constraints, and integration approach preserving existing UI layer while replacing parsing/layout stack.
2026-07-08 00:22:21 -04:00
parent 5776911af0
commit 0848649ce2
49 changed files with 1065 additions and 15633 deletions
@@ -12,6 +12,12 @@ class EpdFont {

  const EpdGlyph* getGlyph(uint32_t cp) const;

+  /// True when the font actually provides `cp` (interval table or on-demand
+  /// SD load) — unlike getGlyph(), never satisfied by the replacement glyph.
+  /// Used by layout shaping to decide whether a substitution (ligature,
+  /// Arabic presentation form) can really be drawn.
+  bool hasGlyph(uint32_t cp) const;
+
  /// Returns the kerning adjustment (4.4 fixed-point in pixels) between two codepoints.
  /// Returns 0 if no kerning data exists for the pair.
  int8_t getKerning(uint32_t leftCp, uint32_t rightCp) const;