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Draw correct glyphs for non-embedded Identity TrueType CID fonts - #566
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A non-embedded CIDFontType2 font with Identity encoding and no CIDToGIDMap selects glyphs of the named system font by index. The substitute is a name-keyed CFF with a different glyph order, so using the CID as its glyph index drew the wrong glyphs. TrueType core fonts such as Arial keep the standard Macintosh glyph order for their first 258 glyphs. For such fonts, map CIDs to Unicode through a compile-time table of that order, so the substitute draws glyphs by character. Type0 fonts also now pick the substitute's weight and style from their base font name instead of always regular Helvetica. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Conformance readsNo document reads differently from the base commit any more. 840 documents of the PDFium corpus read as on |
# Conflicts: # crates/pdf-font/src/pdf_font_descriptor.rs # crates/pdf-font/src/pdf_font_spec.rs # crates/pdf-font/src/type0_font_spec.rs
Replace the hand-written 258-entry Unicode table with read-fonts' DEFAULT_GLYPH_NAMES and its Adobe Glyph List lookup, and move CidToUnicode next to CidToGidMap in type0_font_spec.rs. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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Problem
The
fx/FRC_8.2.4_part1/*cover pages (in the #479 cluster) drew "Foxit Ü^æå^¦ or Foxit…" where the text should read "Foxit Reader or Foxit PhantomPDF".The font is a non-embedded Type0
Arial,Boldwith an Identity-H encoding. Its descendant is a CIDFontType2 with noFontFile2,CIDToGIDMaporToUnicode. Its CIDs are glyph indices into the real Arial Bold. Safe-PDF used each CID directly as a glyph index into the bundledFoxitSans.cffsubstitute, whose glyph order is unrelated, and it always picked the regular weight for Type0 substitutes.Change
New
cid_to_unicode.rswith aCidToUnicodeenum:Collectionwraps the existing runtime CJK maps.StandardGlyphOrderreads a compile-time[Option<char>; 258]table that maps the standard Macintosh glyph order to Unicode.TrueType core fonts such as Arial, Times New Roman and Courier New keep that order for their first 258 glyphs.
CidFontSpecusesStandardGlyphOrderfor a non-embedded CIDFontType2 font that has noCIDToGIDMapand names a non-symbolic core font (newStandard14Font::has_standard_glyph_order). The text engine already picks substitute glyphs by Unicode, so the substitute now draws the correct characters.PdfFontSpec::substitute_standard14takes a Type0 font's weight and style from its base font name, soArial,Boldgets the bold substitute.PDFium draws its own wrong text here ("FYUXYf"), so these pages still differ from the reference. The rest of their difference is the logo image, which PDFium downscales more softly.
Testing
cargo clippy --all --workspaceandcargo fmt --checkare clean.cargo test -p pdf-font -p pdf-text-enginepasses.cargo conformance reproof [conformance] Render differs: different shape in image (RGBA8888) #479 and [conformance] Render differs: different shape in text #480 againstmain: only the 14FRC_8.2.4pages changed (mismatch 0.623% → 0.515%), and they now read "Foxit Reader or Foxit PhantomPDF". All other pages are unchanged.🤖 Generated with Claude Code