bug#16691: 24.3.50; emacs_backtrace.txt

[martin rudalics]

>> I suppose when exposing the window (another part of Emacs display which
>> I don't understand yet).  What would current_y else be used for?
>
> Why are we suddenly talking about current_y?

Sorry, I meant row->y.

> There's no such member
> in the glyph_row structure.
>
> If you meant row->y, then it is used in many different places,
> including the display back-end,

Where is the display back-end?  If it's update_window we there set

      yb = window_text_bottom_y (w);

and then

          mode_line_row->y = yb;

so any prior notion of that row's y is lost.  And for the header line we
do

          header_line_row->y = 0;

But this still doesn't use row->y.  Where is the backend that uses
row->y to determine where on the screen to draw that row?

martin