bug#57066: 29.0.50; Complex emoji overlaps with text

[YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp>]

On Thu, 11 Aug 2022 15:01:31 +0900,
YAMAMOTO Mitsuharu wrote:
> 
> It seems that position unit adjustment for bitmap fonts is no longer
> necessary on HarfBuzz 5:
> 
>   https://github.com/harfbuzz/harfbuzz/issues/489
> 
> Could you test if the following patch works?
 
Oops, it breaks non-HarfBuzz builds.  Pleae try below instead.

				     YAMAMOTO Mitsuharu
				mituharu@math.s.chiba-u.ac.jp

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;