emacs-28 ae348b719e: Fix wrong metrics for bitmap-only fonts with HarfBuzz 5

[YAMAMOTO Mitsuharu]

branch: emacs-28
commit ae348b719e8f1c29c3ee6ed5d723326b3bc54883
Author: YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp>
Commit: YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp>

    Fix wrong metrics for bitmap-only fonts with HarfBuzz 5
    
    * src/ftcrfont.c (ftcrhbfont_begin_hb_font): Always use the standard
    position unit value on HarfBuzz 5 and later regardless of whether the
    font is bitmap-only or not.  (Bug#57066)
---
 src/ftcrfont.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/ftcrfont.c b/src/ftcrfont.c
index 39ea068556..d5d3e440af 100644
--- a/src/ftcrfont.c
+++ b/src/ftcrfont.c
@@ -568,7 +568,11 @@ ftcrhbfont_begin_hb_font (struct font *font, double 
*position_unit)
 
   ftcrfont_info->ft_size = ft_face->size;
   hb_font_t *hb_font = fthbfont_begin_hb_font (font, position_unit);
-  if (ftcrfont_info->bitmap_position_unit)
+  /* HarfBuzz 5 correctly scales bitmap-only fonts without position
+     unit adjustment.
+     (https://github.com/harfbuzz/harfbuzz/issues/489) */
+  if (!hb_version_atleast (5, 0, 0)
+      && ftcrfont_info->bitmap_position_unit)
     *position_unit = ftcrfont_info->bitmap_position_unit;
 
   return hb_font;