Re: Ligatures (was: Unify the Platforms: Cairo+FreeType+Harfbuzz Everywhere (except TTY))

[Eli Zaretskii]

> Cc: address@hidden, address@hidden, address@hidden
> From: Clément Pit-Claudel <address@hidden>
> Date: Fri, 22 May 2020 09:26:05 -0400
> 
> > In general, I envision that people would use the font they find
> > acceptable for the ligatures they want/need in each mode or buffer
> > where they need that.  If for some reason different fonts could
> > determine which ligatures you do NOT want to see, then I guess we will
> > have to provide some easy-to-use UI for that, which would manipulate
> > the relevant data structures under the hood.  Alternatively each font
> > could require a separate composition function to go with it.
> 
> It would be weird for Emacs to be the only program that requires re-encoding 
> the entire ligature logic of each font it attempts to use.  Different fonts 
> offer different ligatures, and if I want to select a subset the font itself 
> provides variants that let me do this.  Meanwhile, I hope that we can make 
> Emacs act like browsers or other editors in that if I select a font it will 
> just, by default, use the ligatures that this font provides according to the 
> logic embedded in the font.

If this is a real problem, it should be possible to have a function
that will extract all the ligatures supported by a font, I think.

But I don't think I agree with the "logic embedded in the font" part.
I think we should let the user control which ligatures are really
used.