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TypeTogether / Playwrite

Sensei primary repository.
SIL Open Font License 1.1
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⚠️ WARN Font has correct post table version? #38

Closed vv-monsalve closed 2 months ago

vv-monsalve commented 2 months ago

@simoncozens, a new Warn is reported for the post table format version. Previous build fonts used format 2.0. What would you advice here?

⚠️ WARN Font has correct post table version?
> > Format 2.5 of the 'post' table was deprecated in OpenType 1.3 and > should not be used. > > According to Thomas Phinney, the possible problem with post format 3 > is that under the right combination of circumstances, one can generate > PDF from a font with a post format 3 table, and not have accurate backing > store for any text that has non-default glyphs for a given codepoint. > > It will look fine but not be searchable. This can affect Latin text with > high-end typography, and some complex script writing systems, especially > with higher-quality fonts. Those circumstances generally involve creating > a PDF by first printing a PostScript stream to disk, and then creating a > PDF from that stream without reference to the original source document. > There are some workflows where this applies,but these are not common > use cases. > > Apple recommends against use of post format version 4 as "no longer > necessary and should be avoided". Please see the Apple TrueType reference > documentation for additional details. > > https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6post.html > > Acceptable post format versions are 2 and 3 for TTF and OTF CFF2 builds, > and post format 3 for CFF builds. > > Original proposal: legacy:check/015 > See also: https://github.com/google/fonts/issues/215 > See also: https://github.com/fonttools/fontbakery/issues/2638 > See also: https://github.com/fonttools/fontbakery/issues/3635 * ⚠️ **WARN**

Post table format 3 use has niche use case problems.Please review the check rationale for additional details.

[code: post-table-version]
simoncozens commented 2 months ago

This is a problem with our build; we are running hb-subset to slim down the fonts, but this removes the glyph names (which the GF subsetter also used to do, but it looks like it doesn't do that any more). I'll change the builder to not remove glyph names.