Subject: Re: bug#23574: 24.5; Overzealous underlining in emacs-nox

From: martin rudalics <[email-masked]>
Date: Fri, 10 Jun 2016 10:24:30 +0200

>> Which gets me back to my initial concern: If our user does that eagerly
 >> for the entire buffer, the overhead might be non-negligible.
 >
 > I don't see why.  Redisplay only considers the visible portion of the
 > buffer.

I meant the overhead for adding the text property to every newline
character in the buffer.

 > row->pixel_width doesn't count text glyphs, it counts all of the
 > glyphs in a glyph row, including the glyphs produced by the display
 > engine for its own purposes.  E.g., it always includes the space glyph
 > produced at the end of a line, which is needed for displaying the
 > cursor.

Are there any other significant objects but that space glyph?  Is there
any other way to get the size of the empty space after text on each row?

 > row->pixel_width is computed in compute_line_metrics,
 > after the stretch glyph (and any other glyphs needed for line display)
 > were already inserted.  compute_line_metrics doesn't care about what
 > glyphs are there, it counts them all.

Hmm... How would I get the width of that stretch glyph then?

martin