Subject: Re: bug#16691: 24.3.50; emacs_backtrace.txt

From: martin rudalics <[email-masked]>
Date: Mon, 10 Feb 2014 19:35:25 +0100

>> 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