1403299 - Support rendering fonts via FreeType on Windows

Status: NEW

(Core :: Graphics: Text, enhancement, P3)

Description

[Jonathan Kew [:jfkthame]]

I suspect the most straightforward approach to supporting Variation Fonts on Windows will be to include FreeType in the build, and rasterize such fonts via FT instead of DirectWrite. This will allow us to support variations across all versions of Windows.

We probably want to continue using DW for standard (non-variation) fonts, for the best consistency with font rasterization in other applications on the platform, so this will mean having two font back-ends and choosing between them on a per-font basis.

Comment 1

[Makoto Kato [:m_kato]]

Fall Creator Update has new APIs (IDWriteFactor6 etc) for axes.

Comment 2

[Makoto Kato [:m_kato]]

s/IDWriteFactor6/IDWriteFactory6/

Comment 3

[Jonathan Kew [:jfkthame]]

Yes, support is beginning to appear in DirectWrite, so we could consider using this; but that would mean that the feature only works on the latest update of Windows, whereas I assume we'll still support Firefox on Win7 for a number of years yet.

Comment 4

[jason]

Just adding a note that the Fall Creator update has shipped with support for variable fonts in DirectWrite. Wondering then if the FT option could be 'scoped' only for use in older versions of Windows?

Comment 6

[Joel Maher ( :jmaher ) (UTC -8)]

:jfkthame, with the upgrade to windows v1803 is this bug resolved?

Comment 7

[Jonathan Kew [:jfkthame]]

No, this is something we could consider doing in order to support variable fonts (and maybe other new stuff in due course, like CFF2-format fonts) on older Windows systems where the OS doesn't handle them. So it's a separate issue from what we're running in our CI for testing purposes.

At this point, we haven't made any decision to put resources into this; our current position is that only users on up-to-date Win10 systems get access to the new font features. Whether that's the final word on the matter is basically a question of priorities. (Note that Chrome does implement this, fwiw.)

Comment 8

[Jeff Muizelaar [:jrmuizel]]

(In reply to Jonathan Kew (:jfkthame) from comment #7)

At this point, we haven't made any decision to put resources into this; our current position is that only users on up-to-date Win10 systems get access to the new font features. Whether that's the final word on the matter is basically a question of priorities. (Note that Chrome does implement this, fwiw.)

How does Chrome implement it?

Comment 9

[Jonathan Kew [:jfkthame]]

They include freetype in their windows build, and dynamically choose which rasterizer to use for any given font.

Comment 10

[Thomas Phinney]

(In reply to Jonathan Kew (:jfkthame) from comment #7)

At this point, we haven't made any decision to put resources into this; our current position is that only users on up-to-date Win10 systems get access to the new font features. Whether that's the final word on the matter is basically a question of priorities.

So, is the current status that variable fonts work for current/recent Firefox users on up-to-date Win10 (and Win11) systems?

Comment 11

[Jonathan Kew [:jfkthame]]

Yes, that should be correct.

Comment 12

[k4sum1]

Any progress regarding this? I would be interested in having a fully non-DirectWrite font renderer in my fork. I was actually thinking of implementing such a thing in my fork, but I'm not sure where to begin. However if you (upstream) do it, that would be very nice.

Comment 13

[Jonathan Kew [:jfkthame]]

No; as far as I'm aware, there hasn't been any work on this, nor is it currently a priority to put resources into.

Are there particular reasons you're interested in this? Would they be relevant to the standard Firefox product (or to other forks), or are they specific to your case?

Comment 14

[k4sum1]

Yeah, it would be more useful for me, but older supported platforms like 10 LTSB could benefit too.