bug#23574: 24.5; Overzealous underlining in emacs-nox

[martin rudalics]

> I do know about these, but I don't thunk we should document all those
> details, since there are too many possible variations, and it's too
> easy to be inaccurate.  "the last face used on the line" is good
> enough, I think.

Including the quotation marks?

> No, it need not do any of that.  The list is fixed for each redisplay
> cycle of each buffer, so the list can be processed only once into a
> bitmap of flags that tell which face attributes trigger face
> extension.  Then all redisplay needs to do is compare the attributes
> of the face loaded into the iterator object at end of each line with
> these flags.

OK.  But with my property list approach a once calculated bitmap would
have simply overridden the face of the iterator object.  Yet cheaper but
less versatile.

>> And then I thought about the - possibly silly idea - that a user might
>> want to put a property like :background on all lines displayed,
>> regardless of the last character's attributes.  Such a user would have
>> to, before displaying the relevant buffer parts, go through all these
>> lines and add that property to the newline (?) character of each line.
>> Now I bet that the greater part of such users would put the property on
>> all newline characters of the buffer instead of using something like
>> ‘pre-redisplay-functions’ where even I couldn't tell whether it gets the
>> window's start and end positions always right.
>
> Hmm.. not sure how this is related.

Suppose a user wants to use the same background for all spaces at the
ends of all lines of a buffer regardless of "the last face used on the
line".  How would she specify that?

martin