Cache current header and mode line height for each window.

* window.h (struct window): New fields mode_line_height
and header_line_height.
* window.c (make_window): Initialize them.
* dispextern.h (CURRENT_MODE_LINE_HEIGHT)
(CURRENT_HEADER_LINE_HEIGHT): Use them.  Adjust comment.
(current_mode_line_height, current_header_line_height):
Remove declaration.
* xdisp.c (current_mode_line_height, current_header_line_height):
Remove.
(pos_visible_p, init_xdisp): Adjust user.
(redisplay_window): Invalidate mode_line_height and
header_line_height if current and desired matrices do not agree.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/window.c b/src/window.c
index d8a6976e090..253e6233fc1 100644
--- a/src/window.c
+++ b/src/window.c
@@ -3419,6 +3419,7 @@ make_window (void)
      non-Lisp data, so do it only for slots which should not be zero.  */
   w->nrows_scale_factor = w->ncols_scale_factor = 1;
   w->left_fringe_width = w->right_fringe_width = -1;
+  w->mode_line_height = w->header_line_height = -1;
   w->phys_cursor_type = -1;
   w->phys_cursor_width = -1;
   w->scroll_bar_width = -1;