bug#68006: 30.0.50; Image-mode speed

[Manuel Giraud]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Manuel Giraud <manuel@ledu-giraud.fr>
>> Cc: stefankangas@gmail.com,  68006@debbugs.gnu.org
>> Date: Fri, 05 Jan 2024 14:26:20 +0100
>> 
>> Eli Zaretskii <eliz@gnu.org> writes:
>> 
>> >> > But we might need to store additional information there, like the
>> >> > buffer of the image, for example.
>> >> 
>> >> I don't understand.  Where do you think that the buffer of the image
>> >> should be stored?
>> >
>> > In the cache, together with the image, I think.
>> 
>> You mean in struct image_cache?
>
> Yes.
>
>> > How else would the Lisp programs know which images "belong" to them,
>> > and when to uncache them?
>> 
>> I don't know exactly.  My idea was that an image-mode buffer has (buffer
>> local I guess) variable that will hold its image cache.
>
> That is also possible, but then will the cache itself be implemented
> only in Lisp?  I assumed at least some of it will be in C.

I also imagine it would be mostly in C.  But looking at the code, I
think I have overlooked something: lookup_image is what currently does
most of the work (with caching) and this is in called in many places in
"xdisp.c".  Of course, I think we should keep that... but then how could
we design this new cache?
-- 
Manuel Giraud