FONTLOG for the Akasia font family

This file should be distributed with the Akasia fonts and any derivative
works.

About

Akasia is a libre, metric-compatible companion to Microsoft Aptos: a
sans-serif family whose advance widths, ink-centre seating, committed kerning
repertoire and vertical metrics match Aptos, so that the tested documents
re-flow and paginate identically when Akasia is substituted for it. The advance
delta against Aptos is 0.00%, and the family asserts USE_TYPO_METRICS.

Akasia is a composite of eight OFL-1.1 families. The base outlines are
Adobe's Source Sans 3, instanced to Aptos's stem weight and re-spaced onto
Aptos's advances with proportional sidebearings. The close-matching majority
of the alphabet stays Source Sans. In the uprights, the twenty-eight letters
whose Source Sans shape diverges most from Aptos are grafted, per letter, from
the closest-matching OFL donor: Hanken Grotesk (eleven letters), Albert Sans
(five), Figtree (five), Open Sans (four), Public Sans (two) and Arimo (one).
The italics independently retain twenty-four of those outliers under a
six-weight non-regression rule: Figtree (nine), Public Sans (seven), Hanken
Grotesk (four), Albert Sans (three) and Arimo (one).
Sixty-eight upright and seventy-six italic precomposed derivatives use the same
donor as their base letter after independently passing that six-weight threshold
and non-regression rule; unsupported or unproven derivatives stay Source Sans.
Sixty-seven per-style core-glyph corrections then use the donors' variable
weight axes to reduce stroke-colour differences. Each correction is checked in
the actual final font at three raster sizes and retained only if neither its
base letter nor its committed canonical derivatives move farther from Aptos.
The rest of Aptos's repertoire beyond the Latin core -- Greek, Cyrillic,
currency, symbols, box-drawing -- is covered from Open Sans and Arimo, plus Noto
Sans Symbols for the circled and dingbat symbols; these glyphs are re-spaced
onto Aptos's advances like every other. Grafted and covered outlines are
weight-matched to the target style and stripped of hinting. All eight donors are
licensed under OFL-1.1. Every outline is from an OFL donor; Akasia copies no
Aptos outline.

The family ships twelve static styles: Light, Regular, SemiBold, Bold,
ExtraBold and Black, each with a true italic. Italic styles use their separately
scored map and graft from the donors' italic variable fonts. The repertoire is
subset to Aptos's, and
kerning is replaced with Aptos's pairs while mark and mark-to-mark
positioning is preserved. Re-spacing moves each GPOS anchor by the exact
translation applied to its glyph outline.

Legal basis (this is a description, not legal advice): font metrics -- advance
widths, sidebearings and kerning -- are facts, not copyrightable expression.
Matching them is the established, long-practised basis of metric-compatible
fonts (Arial and Helvetica; Liberation and Arimo; Carlito and Caladea). The
only step that reads the licensed Aptos binary extracts these metric numbers
into committed data; the Aptos binary is never copied or redistributed.
"Aptos" is a trademark of Microsoft Corporation; Akasia is not used as, or
confusable with, that name, and is not affiliated with or endorsed by
Microsoft or Monotype. Among the donors, only "Source" (Adobe) is a declared
OFL Reserved Font Name; it is respected and never reused. Akasia declares its
own Reserved Font Name, "Akasia". Everything ships under OFL-1.1, with the
combined copyright carried in OFL.txt.

ChangeLog

0.0.2 (2026-07-22)
- Compatibility is now enforced on the final binaries: every encoded advance
  and vertical metric is gated against Aptos 2.010, and outlines are seated on
  its committed ink centres. Default substitutions and the committed kern
  repertoire have zero shaped-run divergence; the pagination oracle preserves
  every break across all twelve styles, 400 documents and four feature profiles.
- Italics are independently stem-matched, use separately selected true-italic
  donor outlines and have their native slants normalised to the reference angle.
  Sixty-eight upright and seventy-six italic precomposed derivatives propagate
  proven donor constructions, with GPOS anchors moving alongside re-seated
  outlines.
- Sixty-seven audited per-style glyph weights reduce colour differences between
  donors. Each accepted correction and its committed derivatives is checked in
  the actual final TTF at 64, 128 and 256 px without regressing from Aptos.
- Coverage is gated at 1072 of Aptos's 1086 encoded codepoints; the remaining
  fourteen have no audited OFL donor. The build writes a compatibility
  certificate, reproduces byte-for-byte and passes the configured FontBakery
  universal profile with no failures or errors.
- Added family specimens, full-document Aptos difference overlays and explicit
  local audits for kerning, mark attachment, glyph shape and pagination.

0.0.1 (2026-06-22)
- Initial pre-release: twelve static styles (Light, Regular, SemiBold, Bold,
  ExtraBold and Black, each with a true italic), the eight-family OFL composite
  described above. The donor map is committed to data/graft.json.
- Metric-compatible with Aptos: advances, sidebearings and kerning matched
  exactly (0.00% advance delta), super/subscripts and floating symbols seated on
  Aptos's vertical placement, and Aptos's vertical metrics with USE_TYPO_METRICS.
  The repertoire is subset to Aptos's, covering ~99% of its codepoints. Passes
  the FontBakery universal profile with no failures or errors.
- Known limits: the Black weights reach Aptos's stem by extrapolating Source
  Sans past its axis maximum; Arimo's grafted letter keeps the extrapolated base
  at Black, and Arimo's currency, maths and box-drawing coverage runs
  lighter than the base at ExtraBold and Black. Eleven currency signs and three
  dingbats no audited OFL donor carries are uncovered. The fonts are unhinted.

Acknowledgements

N: The Akasia Project Authors
E: hello@bloudraad.io
W: https://codeberg.org/bloudraad/akasia
D: Engineering of the metric-compatible composite.

N: Source Sans 3
D: Paul D. Hunt (Adobe). OFL-1.1, Reserved Font Name "Source".
   The base outlines from which Akasia is built.
W: https://github.com/adobe-fonts/source-sans

N: Hanken Grotesk
D: Alfredo Marco Pradil (Hanken Design Co.). OFL-1.1. Donor for eleven upright
   and four italic grafted letters.
W: https://github.com/marcologous/hanken-grotesk

N: Albert Sans
D: Andreas Rasmussen (a.Foundry). OFL-1.1. Donor for five upright and three
   italic grafted letters.
W: https://github.com/usted/Albert-Sans

N: Figtree
D: Erik Kennedy. OFL-1.1. Donor for five upright and nine italic grafted
   letters.
W: https://github.com/erikdkennedy/figtree

N: Open Sans
D: The Open Sans Project Authors; Monotype Design Team. OFL-1.1. Donor for four
   upright grafted letters and the humanist source for Greek/Cyrillic coverage.
W: https://github.com/googlefonts/opensans

N: Public Sans
D: The Public Sans Project Authors (USWDS/GSA), a fork of Libre Franklin by
   Pablo Impallari and Rodrigo Fuenzalida. OFL-1.1. Donor for two upright and
   seven italic grafted letters.
W: https://github.com/uswds/public-sans

N: Arimo
D: Steve Matteson (Monotype). OFL-1.1. Donor for one upright and one italic
   grafted letter and the broad-repertoire source for currency, box-drawing and
   other symbol coverage.
W: https://github.com/googlefonts/arimo

N: Noto Sans Symbols
D: The Noto Project Authors. OFL-1.1. Non-letter coverage donor for the
   circled and dingbat symbols; it has no italic, so its upright forms serve the
   italic styles too.
W: https://github.com/notofonts/symbols

Akasia is released under the SIL Open Font License, Version 1.1. Aptos is a
trademark of Microsoft Corporation; Akasia is independent and unaffiliated.
