Re: "Final" version of tty child frames

[martin rudalics]

>>   > Imagine a line that has a 'display' property whose value is a string
>>   > in the middle of the line.  Then that line on display will look like
>>   > this:
>>   >
>>   >     BBBBBBBBBBBBBSSSSSSSSSBBBBBBBBB
>>   >
>>   > where the B's are glyphs produced from buffer text, and S's are glyphs
>>   > produced from the display string.  Now arrange for a child frame to be
>>   > displayed such that its left border crosses the above line somewhere
>>   > in the middle of the S's.  That's the situation I was talking about.
>>
>> When set_cursor_from_row is on an S glyph, what is the glyph's object?
>
> The Lisp string from which the glyph came.

If every string glyph's frame has been set up correctly I see no
particular problem.  For a visible string glyph of the underlying frame
on either side of the child frame we would do the same as we do if the
child frame didn't exist at all.  An invisible string glyph would be
skipped.  Maybe step 2 would need some fixing as well but in the worst
case this would move the cursor to the end of the line where it is now.

More annoying is that we should examine the glyph_before and glyph_after
assignments because the involved glyphs might be part of different
frames.  But let's see what Gerd accomplishes.

martin