Re: C equivalent for: (face-attribute 'region :background (selected-frame) 'default)

[YAMAMOTO Mitsuharu]

>>>>> On Thu, 05 Oct 2017 09:47:15 +0300, Eli Zaretskii <address@hidden> said:

>> Date: Wed, 04 Oct 2017 17:24:50 -0700 From: Keith David Bershatsky
>> <address@hidden> Cc: address@hidden
>> 
>> My preference is that multiple fake cursors and crosshairs be
>> implemented entirely in C, with just a little bit of Lisp to access
>> those tools.  I also felt that relying on Lisp might somehow slow
>> things down a bit, and speed is really important.

> I don't think you will gain speed by moving these functions to C,
> because their slow part is already implemented in C.

And as I already commented, creating LSL vector or something from a
face in a platform-independent code is not a good design in the sense
that it is inconsistent with the current code.  Each drawing backend
can get color information (as GC, in all the platforms other than NS)
from a given face as I showed in the code `mac_gc_for_face_id'.

Also, erasing crosshairs or cursors could be done by imitating the
code in `expose_area'.  I think you don't need to know which face is
used in the erased area.

                                     YAMAMOTO Mitsuharu
                                address@hidden