Improve detection of glyphless characters on TTY frames

* src/term.c (produce_glyphs): If the terminal can report for
which characters it has glyphs, use that to determine whether
a given character should be displayed as glyphless.

1 files changed, 6 insertions, 2 deletions

diff --git a/src/term.c b/src/term.c
index 4c7a90a5773..ddf0e8e2f28 100644
--- a/src/term.c
+++ b/src/term.c
@@ -1632,9 +1632,13 @@ produce_glyphs (struct it *it)
     }
   else
     {
-      Lisp_Object charset_list = FRAME_TERMINAL (it->f)->charset_list;
+      struct terminal *t = FRAME_TERMINAL (it->f);
+      Lisp_Object charset_list = t->charset_list, char_glyph;
 
-      if (char_charset (it->char_to_display, charset_list, NULL))
+      if (char_charset (it->char_to_display, charset_list, NULL)
+          && (char_glyph = terminal_glyph_code (t, it->char_to_display),
+              NILP (char_glyph)
+              || (FIXNUMP (char_glyph) && XFIXNUM (char_glyph) >= 0)))
         {
           it->pixel_width = CHARACTER_WIDTH (it->char_to_display);
           it->nglyphs = it->pixel_width;