Subject: bug#40733: 28.0.50; Emacs locks up on paste (yank) of unicode characters

From: Pip Cet <[email-masked]>
Date: Mon, 1 Jun 2020 15:50:36 +0000

On Mon, Jun 1, 2020 at 3:15 PM Eli Zaretskii <[email-masked]> wrote:
> Thanks.
>
> From what I see in the net search, this is a very large font, created
> for some very special circumstances.  Not sure we should spend time on
> this issue.  Maybe submit a bug report to Fontconfig folks.

Every call to fontconfig takes a long time, and we call it 17 times...
But it looks like the code that varies pixel size is there for a
reason:

  for (psize = pixel_size; ; psize++)
    {
      font_object = driver_list->driver->open_font (f, entity, psize);
      if (NILP (font_object))
    return Qnil;
      font = XFONT_OBJECT (font_object);
      if (font->average_width > 0 && font->height > 0)
    break;
      /* Avoid an infinite loop.  */
      if (psize > pixel_size + 15)
    return Qnil;
    }