Subject: Re: bug#76107: Consider image specs when scanning for a column

From: Thuna <[email-masked]>
Date: Sat, 08 Feb 2025 23:17:02 +0100

> I understand the reason now, but my opinion is still the same: proper
> support for columns requires simulating the display, 

I would _really_ appreciate it if you would point me to the problem
point where calculating the image sizes (not the visible section - the
_whole_ thing) becomes infeasible without access to the full display (or
a simulation thereof).

> and the two functions I mentioned already do that.

I am not very familiar with events, but I don't see any way to do what
`move-to-column' does using any of the things you mentioned.

> So if we want fill-paragraph to work in the presence of images and
> other display features, we need to have a specialized
> fill-paragraph-function which uses posn-col-row instead of
> current-column and vertical-motion instead of move-to-column.

If we can have a version of fill-paragraph which can calculate image
widths, then that should just be _the_ fill-paragraph function.

> I don't see a good reason for adding semi-working image support to
> current-column and move-to-column.

Yes, I also don't want to have a semi-working result, but what part is
not working, other than `slice' support?

As far as I can see, in xdisp.c, `calc_pixel_width_or_height' is what
determines the display width of the image, which returns the basically
same thing Fimage_width does.  If there is some other step that I'm
missing, could you _please_ tell me where or what it is?