From: Eli Zaretskii <eliz@gnu.org>
Date: Tue, 21 Jun 2016 13:14:10 +0000 (+0300)
Subject: Fix vertical layout calculations when newline has line-height property
X-Git-Url: https://code.delx.au/gnu-emacs/commitdiff_plain/6cf8f0b74e45cec12756e99d3735e3906c515c5c

Fix vertical layout calculations when newline has line-height property

* src/xdisp.c (move_it_in_display_line_to): Reset the iterator's
'constrain_row_ascent_descent_p' flag after processing the
newline, similar to what 'display_line' does.  Without this, the
flag remains set once set by x_produce_glyphs, and causes the
vertical layout calculations to go awry, because Emacs thinks the
screen lines have zero height.	(Bug#23850)
---

diff --git a/src/xdisp.c b/src/xdisp.c
index bcb283f8fa..da0e84f004 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -9038,6 +9038,11 @@ move_it_in_display_line_to (struct it *it,
 	    }
 	  else
 	    result = MOVE_NEWLINE_OR_CR;
+	  /* If we've processed the newline, make sure this flag is
+	     reset, as it must only be set when the newline itself is
+	     processed.  */
+	  if (result == MOVE_NEWLINE_OR_CR)
+	    it->constrain_row_ascent_descent_p = false;
 	  break;
 	}