Re: Text Properties And Buffer Modification

[martin rudalics]

>>   > Yes.  The display engine sometimes needs to know not only whether the
>>   > buffer needs to be redisplayed, but also _why_.  Search xdisp.c for
>>   > MODIFF, and you will see.
>>
>> I have tried to but still don't see the difference (but for setting
>> last_had_star).
>
> What did you try, exactly?  And what kind of difference did you expect
> to see?

I tried to find all occurrences of the string MODIFF in xdisp.c and
look at the context of every occurrence I found.  I then tried to find
out whether that context provided any clue that the display engine
would handle a text property differently from an overlay change.  In
particular I tried to find out whether there were any redisplay
optimizations where this was the case.  Probably I'm missing something
but the "you will see" hinted at something quite obvious.  Maybe you
can name 2 or 3 such occurrences and I will then try to look harder.

martin