Re: "Final" version of tty child frames

[martin rudalics]

> You mean, display properties and overlay strings are not shown on
> child frames?  Why not?

They can be shown anywhere.  But they cannot be always handled correctly
by the cursor placement code whenever they cross a coordinate where the
matrix was recombined.

> It is shown because we iterate from the beginning of the screen line,
> even if it is obscured.  During that iteration, we pay attention to
> all the display and overlay properties, but do not produce glyphs.

That's the iterator code.  But here we talk about a cursor producing
code which starts, if I'm not totally mistaken, at the first glyph of a
row.

> We could.  But the problem here is that the above code runs waaay
> before we combine glyph matrices, and doesn't know anything about the
> special case of TTY child frames.

Agreed.  Then the problem must be solved in the iterator code _before_
glyphs are produced.

> And frankly, I don't understand the reason for the problem: by the
> time we combine frame matrices, the glyphs produced from the display
> property are already in the matrix, so it sounds like all we need is
> to leave those glyphs alone where the child matrix doesn't conceal the
> parent?  Or what am I missing?

The problem is a very tiny one: When setting the cursor from the row we
should be able to set it in the visible part right of a child frame (with
RL text left of it) that obscures the basic frame.

martin