[Pkg-fonts-devel] Bug#774274: fontforge: please use SOURCE_DATE_EPOCH for
Theppitak Karoonboonyanan
theppitak at gmail.com
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/
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