Re: region-based face-remapping

[Eli Zaretskii <eliz@gnu.org>]

> From: JD Smith <jdtsmith@gmail.com>
> Date: Mon, 1 Jan 2024 19:22:29 -0500
> 
> 
> Has there been any discussion of implementing region-based face remapping, perhaps by adding 'face-remap as a property to overlays?  This would be very useful for modes in which local syntax highlighting depends on point, now broadly possible thanks to treesitter (think “brighten surrounding semantic unit” or similar).

If you only want to change the appearance around point, you need a
much smaller revolution than position-dependent faces, which are
something much more general.  E.g., position-dependent faces need to
change all the face-related APIs to pass a position and a buffer
arguments, whereas if it's only "around point", you need nothing like
that because the position of point is always known in each buffer.