[Pkg-fonts-devel] Bug#774274: fontforge: please use SOURCE_DATE_EPOCH for

Tue Nov 12 05:33:54 GMT 2019

On Tue, Nov 12, 2019 at 11:58 AM Theppitak Karoonboonyanan
<theppitak at gmail.com> wrote:

> By dumping TTX with 'ttx' command from fonttools,
> the differences appear to be:
>   1) the "checkSumAdjustment" in <head>
>   2) the "flags" in <head>: "00000010 00011111" -> "00000000 00011111"
>   3) the "fontDirectionHint" in <head>: "0" -> "2"
>   4) the "underlinePosition" in <post>: "-204" -> "-102"
>   5) the "FFTimeStamp" in <FFTM> (this seems to be fontforge build timestamp)
> I doubt how 2), 3), 4) are changed across different fontforge versions.

Note: By checking OpenType/TrueType documentations [1] [2]:
* 2) is to clear bit 15 as the spec suggests (bits 6-10 are unused)
* 3) is to set direction hint properly (left to right, with some
zero-width glyphs)
* 4) is to fix fontforge underline position handling [3]

[1] https://docs.microsoft.com/en-us/typography/opentype/spec/otff#font-tables
[2] https://developer.apple.com/fonts/TrueType-Reference-Manual/
[3] https://fontforge.org/en-US/bulletins/underline_position_2018_1/

So, all differences are clear to me now. :-)

Regards,
-- 
Theppitak Karoonboonyanan
http://linux.thai.net/~thep/