From: Eli Zaretskii <eliz@gnu.org>
Date: Fri, 8 Nov 2024 08:03:35 +0000 (+0200)
Subject: ; * src/ftcrfont.c (ftcrhbfont_end_hb_font): Improve commentary (bug#73752).
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=2f00523f45864a95c17bad7647868b8e36a532bf;p=emacs.git

; * src/ftcrfont.c (ftcrhbfont_end_hb_font): Improve commentary (bug#73752).

(cherry picked from commit 775970a7831de930cd25ee592fb40004b1c2bc24)
---

diff --git a/src/ftcrfont.c b/src/ftcrfont.c
index ee111d18763..2ef85d4d566 100644
--- a/src/ftcrfont.c
+++ b/src/ftcrfont.c
@@ -710,8 +710,12 @@ ftcrhbfont_end_hb_font (struct font *font, hb_font_t *hb_font)
 
   eassert (hb_font == ftcrfont_info->hb_font);
   /* ftcrfont_info->hb_font holds a reference to the FT_Face returned by
-     cairo_ft_scaled_font_lock_face. Keeping it around after the
-     matching unlock call would violate the API contract (Bug#73752). */
+     cairo_ft_scaled_font_lock_face.  Keeping it around after the matching
+     unlock call would violate the API contract, and cause corrupted
+     display of composed characters (Bug#73752).  We destroy and NULLify
+     hb_font here, which will then cause fthbfont_begin_hb_font, called by
+     ftcrhbfont_begin_hb_font, to recreate hb_font anew, taking into
+     consideration any scale changes in FT_Face.  */
   hb_font_destroy (ftcrfont_info->hb_font);
   ftcrfont_info->hb_font = NULL;