Re: [PATCH] User-defined fringe tooltips (a request for review)

[Vladimir Kazanov <vekazanov@gmail.com>]

Hi Eli,

> > 1. Record buffer position of the fringe display spec in struct it.
> > Then move it to glyph_row the same way user_fringe_bitmap_id's are
> > copied over.
>
> When you say "move it", what is "it" in this case?

I record the position of the :help-echo message in the buffer in the
iterator (struct it). This is ptrdiff_t
left_user_fringe_help_echo_pos. Then I copy this buffer position into
(struct glyph_row), next to where left_user_fringe_bitmap sits.

> > 2. In note_fringe_highlight it becomes easy to retrieve the fringe
> > display spec using a single call to get_char_property_and_overlay(),
> > no need to iterate over a line, or have the implementation detail leak
> > into text properties.
>
> Why do you need to retrieve the display spec in note_fringe_highlight?

Once I have the position of the help-echo string (saved in the
glyph_row), I still have to retrieve the :help-echo string. That's
what the code calling (get_char_property_and_overlay) does in the
(note_fringe_highlight). This gives me a list/vector/etc of display
specs. Somewhere within the specs there should be a fringe spec as
this is what was recorded by the iterator (struct it).

And the fringe spec contains the help-echo message I need to show in
the tooltip.

> > What I don't really understand is whether I should handle overlays
> > with after-string/before-string properties.
>
> Ideally, yes.  Is there some complication there that would make those
> overlays special?

I am not sure I understand everything about overlays but for some
reason I can't get Qafter_string/Qbefore_string overlay properties
from the position saved in the glyph_row when the overlay is not
represented by any visual element in the row.

> > Should I just go through all overlays touching the spec position and
> > parse into the after-string/before-string as well?
>
> Not sure I understand the question, but maybe if you answer the ones
> above, I will understand, or this question will answer itself.

Hope it all makes sense now. I'll try to get things working for all
variants of fringe definition.

-- 
Regards,

Vladimir Kazanov