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Michael Sharon
a7fe7a20c4
Add text and page_add_text draw Hebrew with the craft-fonts Hebr face (Noto Sans Hebrew) through the shaped path Arabic and Thai already use: - pdfcraft-fonts: ShapedScript::Hebrew, shape_hebrew and hebrew_has. Grapheme clusters keep points and cantillation marks on their letter. - pdfcraft-edit: Hebrew paragraphs are laid out with UAX #9 like Arabic; spaces and punctuation between Hebrew letters take the Hebrew face. first_undrawable refuses Hebrew the face can't draw (or without the face) instead of writing "?"; existing items stay movable without it. - Type 3 glyphs with ToUnicode and per-line ActualText, so extraction, search and the editor get typing order back. Regular style only, as for Arabic and Thai. Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com> Co-authored-by: Brandon Thomas <echelon@gmail.com>
84 lines
6.3 KiB
Markdown
84 lines
6.3 KiB
Markdown
# pdfcraft-fonts
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Layer L2. Font helpers for the appearance streams PdfCraft generates (comments, form fields).
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Today it holds what generated appearances need without a font program:
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- `helvetica_width`: the **exact** standard-14 advance widths, via `Std14::Helvetica`. It was an
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estimate by character class until the generated tables landed; those tables are Adobe-authored
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non-visual technical data, the item `AGENTS.md` §1.1 permits, carried in `std14_metrics.rs` with
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`adobe_data = true` in `ATTRIBUTION.toml`. **No font program or typeface from any vendor is
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bundled** — widths and encodings only. Reach for `Std14` directly for any other face.
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- `wrap`: greedy line breaking with that measure (paragraphs on newlines, long words split).
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- `win_ansi`: Unicode → WinAnsiEncoding bytes (`?` for characters it can't represent), and
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`literal` to write bytes as a PDF literal string. Nothing writes that `?` silently. Callers
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check `first_undrawable` (or `UnicodeCMap::first_unencodable`, for a character beyond U+FFFF in
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UCS-2), then either refuse with `undrawable_message` (one wording that names the character and
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what can be written instead) where the `?` would be permanent page content, or, for a form
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value or a comment's text, which is stored as typed, draw the `?` and mark the annotation with
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`set_undrawn_mark` (`UNDRAWN_MARK`, read back by `undrawn_mark`) so the edit is reported and
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flattening refuses. `script_missing` names what the typed-signature script font and its Inter fallback both lack.
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It also holds the fonts of the optional [craft-fonts](https://github.com/storytold/craft-fonts)
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build input. `build.rs` embeds them as `CRAFT_FONTS` when the build sets
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`CRAFT_FONTS_DIR=<checkout>` (and fails if it can't while `CRAFT_FONTS_REQUIRED=1`, as releases
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set). Without that variable `CRAFT_FONTS` is empty and everything below copes:
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- `ui_japanese_fonts`: the `Jpan` faces for the interface, BIZ UDPGothic first.
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- `ui_chinese_fonts`: the `Hans` faces for the interface, in manifest order (without one,
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Chinese characters the Japanese faces lack show the replacement glyph).
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- `ui_cjk_fonts(prefer_hans)`: both in fallback order for the UI language (Chinese group first
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in Chinese mode, so one line never mixes faces with different vertical metrics).
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- `ui_arabic_fonts`: the `Arab` faces for Arabic-script interface text (file names, document
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titles), in manifest order.
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- `ui_telugu_fonts`: the `Telu` faces for Telugu interface text (the Telugu catalog, file names,
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document titles), in manifest order.
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- `ui_hebrew_fonts` / `document_hebrew_font(bold)`: the `Hebr` faces (Noto Sans Hebrew) for
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Hebrew interface text, and the face whose outlines become the Type 3 fallback for Hebrew text
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written by Edit text (Bold when asked for and present, else Regular). `None` without a
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craft-fonts input that has one; the editor then reports a clear error.
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- `shape_hebrew` / `hebrew_has`: the Regular `Hebr` face shaped with harfrust for Hebrew Add
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Text content, one cluster per letter with its points and cantillation marks (positioned by the
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face), drawn by the same Type 3 writer as Arabic and Thai. `GlyphError::NoFont` without the face.
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- `document_japanese_font` / `japanese_glyph`: the face (Shippori Mincho, then BIZ UDMincho) whose
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outlines become the Type 3 fallback font for Japanese text written into PDFs. Without it,
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`japanese_glyph` returns `GlyphError::NoFont` and the editor reports a clear error.
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- `document_japanese_font_for_style` / `japanese_glyph_from`: select and draw a real Japanese
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fallback face for edited text. Sans sources prefer BIZ UDPGothic Regular/Bold; serif sources
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keep Mincho. Type 3 paths and advances both come from that selected face. Missing weights
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fall back to a real Regular face, never synthetic bold; no italic face is supplied. The
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default `document_japanese_font` / `japanese_glyph` APIs still use regular document Mincho.
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- `document_arabic_font` / `shape_arabic` / `arabic_glyph`: the first `Arab` face, shaped with
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harfrust (joining forms, ligatures, mark positions) into clusters for Arabic text written into
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PDFs; the editor draws each cluster as one Type 3 glyph with a ToUnicode entry and per-line ActualText for logical copy/search order. Without the face
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they return `GlyphError::NoFont` and the editor reports a clear error.
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- `document_japanese_fonts_for_style`: every `Jpan` face in that order of preference, so the
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editor can use the first one that has all of the replacement's glyphs (the faces differ in
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coverage, e.g. of Cyrillic).
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- `ui_thai_fonts` / `document_thai_font` / `shape_thai`: the `Thai` faces for the interface
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and shaped Thai Add Text content. Harfrust positions stacked vowel/tone marks and decomposes
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Sara Am; cluster ToUnicode entries preserve the original text. The shared Type 3 writer
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embeds outlines, so reopening does not depend on installed fonts.
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- `SHIPPORI_MINCHO`: Shippori Mincho's bytes, or `None`.
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Generated Japanese Type 3 fonts record the fallback face's family and style in an indirect
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`FontDescriptor`. `pdf::Metrics::base_font` uses its `FontName` when the Type 3 dictionary has
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no `BaseFont`, so text inspection and edit-tool results identify the fallback after save/reopen.
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The descriptor does not change glyph programs or replace the Type 3 `FontBBox` metrics when
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`Ascent`/`Descent` are omitted (PDF Reference 1.7, tables 5.9 and 5.19). The small web input has
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only Gothic Regular, so it cannot preserve bold. No new font assets or changes to that input are
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needed.
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wasm32 builds embed only BIZ UDPGothic Regular and any `Arab`, `Telu`, `Hebr` or `Thai` face, to keep the web build small: the web build
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currently has no Chinese face, so Chinese there still shows the replacement glyph.
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Font files are never
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committed here (`AGENTS.md` §1.4; team members: [craftrules `standards/fonts.md`](https://github.com/storytold/craftrules/blob/main/standards/fonts.md), internal).
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The full font subsystem (parsing, shaping, subsetting and embedding) arrives with M2.2/M7.
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Document font inputs use `embedding`: bounded static TrueType/OpenType-CFF validation,
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exact program preservation, Unicode/CID/GID mapping and full-face subset completion.
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`shaping` uses the same program with harfrust and UAX #9; source UI fallback fonts are
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never exported. See [existing-text editing](../../docs/editing-existing-text.md).
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