CADR fonts

This repository reproducibly recovers two complementary public MIT CADR System 46 bitmap-font profiles as inspectable JSON and PNG specimens plus usable Unicode BDF 2.1 and OpenType Bitmap (OTB) fonts with complete identities:

• the source profile preserves 151 authored AST, KST, Alto, and archive representations, including meaningful source variants;
• the runtime profile inertly decompiles all 49 reviewed font QFASLs into the serialized FONT arrays that System 46 would draw when loaded: 47 current logical fonts and two explicitly legacy compiled versions.

Each raw profile has a separately named Unicode derivative. The raw BDFs retain CADR codes and Misc-FontSpecific; the derivatives re-encode the same glyphs under ISO10646-1 using the reviewed standard-character map and fixed BMP Private Use Area allocation documented in UNICODE.md. The result is four generated BDF profiles and 400 BDFs. Release archives make the Unicode BDFs and Unicode-derived OTBs the user-facing fonts; raw BDFs are kept under a clearly separated fonts/raw/ tree only for historical traceability. Linux distribution packages install only the Unicode BDFs and OTBs.

All 200 generated artifacts can be inspected without installing anything in the tracked font specimen gallery: Latin fonts use the Lisp-themed pangram and specialty fonts use complete glyph sheets. A fresh build must reproduce every committed PNG and the gallery index exactly.

The source and runtime identities are deliberately not collapsed. The source profiles answer “what surviving authoring representations contain”; the runtime profiles answer “what this System 46 snapshot would display for a defined character.” Unicode derivation changes addressing, not that boundary or any displayed geometry.

The source witness is a pinned Git submodule. Local generated files stay under the ignored dist/ directory. Tags matching v* run the same verification, build two content-partitioned archives, build and install-test Linux packages, and publish a GitHub Release only when that tag has no existing release. See Packaging and Releasing.

Build and verify

git submodule update --init
make check-external
make reproducible
make compare-genera
make audit-runtime-names
make release VERSION=v0.1.2
make check-release VERSION=v0.1.2
make check-specimens

make check-external builds all four profiles under dist/, runs the unit and corpus checks, compiles every BDF to PCF with bdftopcf, independently indexes the result with mkfontdir, and uses a private Xvfb server for alias-load and native rendering checks. For every character actually defined by an emitted BDF, the rendering gate compares framebuffer pixels, advances, and XTextExtents with an independent BDF renderer. Raw CADR encodings are drawn through eight-bit XDrawString; Unicode ISO10646-1 encodings are drawn as BMP scalars through XDrawString16 and must reproduce the corresponding raw glyph exactly. No scaling or antialiasing is involved. It requires bdftopcf, mkfontdir, Xvfb, and Xlib; the build itself needs only Python 3.10 or newer and its standard library. make reproducible performs two isolated builds and compares every output byte. The reviewed build passes this gate for 371 raw aliases and 371 Unicode aliases across the four font paths, 742 aliases total, and for every emitted glyph.

make release creates deterministic Latin and symbols archives under dist/release/; make check-release checks their closed manifests, checksums, content partition, deterministic tar metadata, and every OTB. The OTB gate proves exact character advances and baseline-relative set pixels for all 20,307 encoded glyphs emitted by the Unicode BDFs. fonttosfnt may remove transparent rows or columns from a glyph's stored bitmap box, so storage boxes need not be byte-for-byte copies; the one-bit pixels at display coordinates and advances must be identical. The generated Unicode BDF remains the authoritative derivative record.

make specimens refreshes the tracked GitHub gallery from the reviewed build; make check-specimens is the non-mutating gate used by CI. It closes the gallery over 160 Latin pangrams and 40 symbols glyph sheets and verifies every PNG byte, path, identity, and digest against the generated distribution.

When the sibling ../genera-emu checkout is present, make compare-genera repeats the compatibility audit against its published BDF artifacts. It compares represented glyph repertoires, advances, x bearings, and every baseline-relative set pixel after normalizing the zero-width no-op slots described below, while deliberately ignoring transparent storage padding and the new XLFD metadata.

The runtime build uses the repository's strict, non-evaluating QFASL decoder. It accepts only the serialized-object operations observed in the closed 49-file manifest, rejects every unsupported operation, and never executes Lisp forms or target-machine code. make audit-runtime-names remains an optional lineage cross-check against the separately pinned ancestor in the sibling checkout; it is not a source of unpinned build data.

The current reviewed result is:

• 151 source BDFs from 88 authored logical names;
• 63 preserved source-representation variants;
• 134 proportional, 15 character-cell, and two monospace XLFD classifications;
• 1,855 zero-width, zero-advance, no-ink Alto slots retained in JSON and omitted from 62 installable BDFs;
• six explicitly partial Alto pointer recoveries;
• 45 Alto fonts with 142 glyphs whose observed pixels exceed declared extents;
• zero rejected selected sources;
• 49 runtime BDFs: 30 current source-backed objects, 17 compiled-only current fonts, and two legacy compiled versions representing 47 current runtime logical names;
• 6,170 normalized runtime slots, of which 5,689 are installable BDF glyphs after omitting 481 zero-width, zero-advance, no-ink runtime placeholders;
• 200 raw BDF artifacts containing 20,307 emitted glyphs across the source and runtime profiles;
• 200 Unicode derivative BDFs preserving those same 20,307 bitmap, advance, bearing, and line-metric instances exactly;
• 400 BDFs and 40,614 emitted glyph instances across all four profiles;
• 272 source-path and 99 runtime-path aliases in the raw profiles, 371 total, mirrored by 371 disjoint cadr-unicode-* aliases for 742 aliases overall.
• 160 Unicode Latin pangram specimens: 118 source artifacts and 42 runtime artifacts, retaining distinct authored, current-runtime, and legacy-runtime representations rather than collapsing them by logical name.

The release partition is derived from emitted Unicode content, never from a filename or family label. An artifact is in Latin if it contains any visible Basic Latin letter U+0041-U+005A or U+0061-U+007A. The symbols collection is the exact complement; despite the short name it includes drawing and sprite fonts as well as Greek, Cyrillic, APL, mathematics, and music repertoires. The current closure is:

Collection	Source	Runtime	Total
Latin	118	42	160
Symbols	33	7	40

Every source/runtime artifact belongs to exactly one collection, and no logical family crosses the boundary. The stricter pangram predicate happens to select the same 160 Latin artifacts in the current corpus, but specimen presence is not the release selection rule.

The earlier genera-emu extraction produced 150 artifacts. This repository corrects its AST raster-height model: BUG has a 32-row authored AST raster but a 33-row KST raster, so BUG-KST is now retained as a real 151st source variant. The set pixels, bearings, and advances of the existing artifacts are otherwise retained for every represented glyph; make compare-genera proves that result over all 150 common BDFs.

The permanent corpus gate checks two committed SHA-256 oracles: one over the complete normalized source model, including every JSON-only no-op slot, and one over the installable BDF line metrics and emitted glyph geometry. This prevents a deterministic decoder regression from blessing its own changed JSON and BDF output.

The runtime profile has its own pair of reviewed semantic oracles over all 6,170 decoded FONT slots and all 5,689 installable runtime glyphs. The 30 source-backed QFASLs are also compared with the source profile. Most resident fonts preserve the surviving authored display geometry, but four distinctions matter for actual screen output:

• resident ARROW includes visible codes octal 003 and 006; the source ARROW-KST variant matches it;
• resident BIGFNT is matched by BIGFNT-KST; the source-profile canonical differs at 155 and lacks six visible runtime codes;
• current MEDFNT changes 57 previously visible glyphs and makes six formerly blank slots visible relative to the surviving older/source-backed form;
• resident MOUSE adds visible codes 034 through 036.

The runtime profile carries those resident shapes directly rather than silently rewriting the source artifacts.

What is in dist/

dist/
  bdf/                    source BDFs plus source fonts.dir/fonts.alias
  json/                   lossless normalized source metrics and bitmap rows
  sheets/                 deterministic source PNG specimens
  catalog.json            source artifact/recovery/XLFD catalog
  runtime/
    bdf/                  49 runtime BDFs plus runtime fonts.dir/fonts.alias
    json/                 all normalized resident FONT slots
    sheets/               deterministic runtime PNG specimens
    catalog.json          runtime classification, metrics, and provenance
    runtime-source-manifest.json
  unicode/
    UNICODE-MAPPING.json  release copy of the reviewed mapping contract
    source/
      bdf/                Unicode source BDFs plus fonts.dir/fonts.alias
      pangrams/           Latin-capable source artifact sentence specimens
      catalog.json        resolved source encodings and geometry digest
    runtime/
      bdf/                Unicode runtime BDFs plus fonts.dir/fonts.alias
      pangrams/           Latin-capable runtime artifact sentence specimens
      catalog.json        resolved runtime encodings and geometry digest
  release/
    CADR-fonts-latin-<version>.tar.gz
    CADR-fonts-latin-<version>.tar.gz.sha256
    CADR-fonts-symbols-<version>.tar.gz
    CADR-fonts-symbols-<version>.tar.gz.sha256
  packages/               locally built DEB/RPM/Arch/Void packages
  BUILD-MANIFEST.json     four-profile counts, catalogs, aliases, and specimens
  SOURCE-MANIFEST.json    closed authoring-source manifest
  LICENSE.source          upstream three-clause BSD license
  SHA256SUMS              digest of every other distributed file

Aliases make the profile boundary explicit:

• cadr-source-<artifact> always selects that exact authored artifact;
• cadr-runtime-<runtime-name> selects the current System 46 resident object;
• cadr-runtime-legacy-n43xms and cadr-runtime-legacy-ntog select the two older compiled objects and are never current defaults;
• cadr-<name> is a convenience alias for the current runtime font when that name is resident, otherwise for the unambiguous source artifact.

Current runtime names win intentional collisions such as cadr-arrow; the source form remains available as cadr-source-arrow. Compatibility spellings such as CM10/CPT-CM10, CM12/CPT-CM12, and CPTFON/CPTFONT resolve to the same current resident font, while their exact source forms remain under cadr-source-*. Full XLFD names remain authoritative.

The Unicode aliases preserve the same selection rules under the disjoint cadr-unicode-source-*, cadr-unicode-runtime-*, cadr-unicode-runtime-legacy-*, and cadr-unicode-* namespaces. See the Unicode profile for the exact map, complete repertoire allocation, and X core usage.

The Unicode catalogs select pangram specimens from emitted content, not font names or raw slot numbers. A font qualifies only when U+0020 has positive advance and U+0041-U+005A are all present with visible ink. The specimen is the compact Lisp-themed pangram “The five boxing Lisp wizards jump quickly.” Fonts where a non-space glyph requested by the mixed-case sentence is blank or missing use the same text in uppercase; an unavailable terminal full stop is explicitly omitted and recorded. The dependency-free renderer uses the recovered one-bit pixels and metrics directly, wraps at a 640-source-pixel advance, adds three native pixels of padding, and scales each pixel to a 2-by-2 block without interpolation.

Metric and identity boundaries

These are one-bit bitmap fonts, not vectors or outlines. The build does not trace, scale, hint, or synthesize glyph shapes.

• BDF DWIDTH is the historical per-character advance.
• The source's “left kern” is a signed per-glyph bearing, not pair kerning; the historical renderer draws at X - kern, so BDF BBX x-offset is -kern.
• There is no pair-kerning table. All AST/KST column-position adjustments are zero, so no tracking adjustment is added.
• SPACING is calculated under the XLFD P, M, and C definitions from advances and represented raster boxes.
• Raw CADR codes are direct BDF encodings under Misc-FontSpecific. They are not labelled Unicode or ISO-8859.
• Unicode derivatives retain the same bitmaps and metrics but use ISO10646-1. Artifacts proven to follow the System 46 table use its explicit Unicode map. Older Alto/SAIL and mixed text repertoires use hybrid maps that keep proven ordinary characters at standard Unicode scalars while routing divergent or undocumented slots to family PUA blocks. Twenty-eight fixed 128-code-point blocks are reserved from U+E000 through U+EDFF, including 17 whole-PUA families: the 16 specialty repertoires plus Alto Greek/math. This is a documented project private agreement, not a Unicode assignment inferred from bitmap resemblance.
• Alto's zero-width, zero-advance slots with no set pixels remain in the lossless JSON but are omitted from BDF. Xorg's PCF renderer rejects a font containing such a glyph with BadAlloc; omission changes neither ink nor escapement and lets the complete font load through the X core protocol.
• The sources do not authoritatively classify weight, slant, setwidth, or physical DPI. XLFD uses Unknown-OT-Unknown, while 72 dpi is documented as an interchange convention that preserves one source pixel as one nominal point.

System 46 sheet layout adds two pixels of vertical spacing by default. For a mixed-font map, the sheet baseline is the greatest font baseline and the line height is the greatest character height plus that two-pixel VSP; changing font adds the difference between the sheet and font baselines. BDF preserves each font's metrics but cannot encode this sheet-level policy, so the independent render model tests it separately.

The conformance claim is intentionally limited to native rendering of defined glyphs in both raw and Unicode profiles. What an X server substitutes for a code absent from a BDF is outside the project gate, as requested; no fallback behavior is presented as CADR behavior.

See the font model, the Unicode profile, and the provenance chain for the evidence and exact transformations. The output follows the official BDF 2.1 standard and XLFD conventions.

Releases and packages

Each release publishes two generic archives and their adjacent SHA-256 files:

• CADR-fonts-latin-<version>.tar.gz contains 118 source and 42 runtime artifacts with visible Basic Latin letters;
• CADR-fonts-symbols-<version>.tar.gz contains the complementary 33 source and seven runtime specialty artifacts.

Both archives include usable Unicode BDFs, Unicode-derived OTBs, specimens, closed metadata, and separate project/source BSD-3-Clause notices. Raw CADR-encoded BDFs are present only under fonts/raw/ for provenance comparison. For normal desktop use, install the OTBs; for an X core-font server, install the Unicode BDF directories and their generated indexes.

The same release also publishes separate cadr-fonts-latin and cadr-fonts-symbols packages in DEB, RPM, Arch, and Void formats, each with an adjacent SHA-256 file. The repository flake provides cadr-fonts-latin and cadr-fonts-symbols for x86_64 and AArch64 Linux. See Packaging for paths, local commands, the source-built cadr-fonts AUR package, and the additional manual package recipes.

License

Repository-authored tooling, documentation, metadata, and packaging material are distributed under the root BSD-3-Clause license. The recovered MIT CADR font payload and its direct derivatives retain the pinned upstream BSD-3-Clause notice. Release archives and packages install these separately as LICENSE.project and LICENSE.source so both attribution chains remain explicit.