Justin Mitchell
0848649ce2
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.
45 lines
2.0 KiB
C++
45 lines
2.0 KiB
C++
#pragma once
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#include "EpdFont.h"
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class EpdFontFamily {
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public:
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// Bitmask of text style flags carried per-word through layout and serialized in page cache.
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// Bits 0-1 select the font variant (BOLD/ITALIC); bits 2-5 are decoration/positioning overlays
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// applied at render time without changing the underlying font. getFont() ignores all bits
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// above bit 1 so decorations compose freely with bold/italic (e.g. BOLD | UNDERLINE | SUP).
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enum Style : uint8_t {
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REGULAR = 0,
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BOLD = 1,
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ITALIC = 2,
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BOLD_ITALIC = 3,
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UNDERLINE = 4, // drawn as a line below baseline by TextBlock::render()
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STRIKETHROUGH = 8, // drawn as a line through midline by TextBlock::render()
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SUP = 16, // superscript: glyph scaled 50%, raised ~40% of ascender
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SUB = 32, // subscript: glyph scaled 50%, lowered ~25% of ascender
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};
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static constexpr uint8_t TEXT_DECORATION_MASK = static_cast<uint8_t>(UNDERLINE | STRIKETHROUGH);
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explicit EpdFontFamily(const EpdFont* regular, const EpdFont* bold = nullptr, const EpdFont* italic = nullptr,
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const EpdFont* boldItalic = nullptr)
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: regular(regular), bold(bold), italic(italic), boldItalic(boldItalic) {}
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~EpdFontFamily() = default;
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void getTextDimensions(const char* string, int* w, int* h, Style style = REGULAR) const;
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const EpdFontData* getData(Style style = REGULAR) const;
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const EpdGlyph* getGlyph(uint32_t cp, Style style = REGULAR) const;
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bool hasGlyph(uint32_t cp, Style style = REGULAR) const;
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int8_t getKerning(uint32_t leftCp, uint32_t rightCp, Style style = REGULAR) const;
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uint32_t getLigature(uint32_t leftCp, uint32_t rightCp, Style style = REGULAR) const;
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uint32_t applyLigatures(uint32_t cp, const char*& text, Style style = REGULAR) const;
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static constexpr bool hasTextDecoration(const Style style) {
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return (static_cast<uint8_t>(style) & TEXT_DECORATION_MASK) != 0;
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}
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private:
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const EpdFont* regular;
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const EpdFont* bold;
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const EpdFont* italic;
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const EpdFont* boldItalic;
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const EpdFont* getFont(Style style) const;
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};
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