Re: master bf0aeaa0d7a: Re-enable displaying `han' characters on Android

[pipcet@protonmail.com]

"Benjamin Riefenstahl" <b.riefenstahl@turtle-trading.net> writes:

> Benjamin Riefenstahl writes:
>> I don't know what is going on.  Must have been something I did earlier
>> in that other session.
>
> It's the order.  If I first evaluate the version with fewer characters,
> I get a font for that and for the longer list of characters after that,
> too.

I've looked at that a little, and I don't think 'clear-font-cache', uh,
clears the font cache.

ftfont.c also interns random binary strings as symbols here. This helps:

diff --git a/src/ftfont.c b/src/ftfont.c
index c89feea1d46..882d3eec256 100644
--- a/src/ftfont.c
+++ b/src/ftfont.c
@@ -174,11 +174,11 @@ get_adstyle_property (FcPattern *p)
   USE_SAFE_ALLOCA;
   tmp = SAFE_ALLOCA (end - str);
   for (i = 0; i < end - str; ++i)
-    tmp[i] = ((end[i] != '?'
-	       && end[i] != '*'
-	       && end[i] != '"'
-	       && end[i] != '-')
-	      ? end[i] : ' ');
+    tmp[i] = ((str[i] != '?'
+	       && str[i] != '*'
+	       && str[i] != '"'
+	       && str[i] != '-')
+	      ? str[i] : ' ');
   adstyle = font_intern_prop (tmp, end - str, 1);
   SAFE_FREE ();
   if (font_style_to_value (FONT_WIDTH_INDEX, adstyle, 0) >= 0)

xfont.c is particularly weird: it's limited to 64k characters, of
course, but it also hardcodes 'han as a supported script for all
Japanese or Korean fonts; and xfont_has_char will return false for all
non-ASCII chars in iso10646-1 fonts that don't have "ja" or "ko"
adstyles. In addition, it has its own caching mechanism
(xfont_scripts_cache) which is never cleared, shrunk, or exposed to
Lisp.

sfntfont.c only looks at the first fixnum in a vector specified in
Vscript_representative_chars, and fails if it isn't there, even though
it should continue looking.

w32font.c seems to ignore Vscript_representative_chars entirely. This
also appears to apply to the harfbuzz backend.

GNU Unifont now supports #x20000 (since February), but is split into two
fonts, one for the BMP and one for the upper planes, so it won't be
detected here.

So I'm not sure which font backends the additional required characters
are supposed to have a positive effect on.

Pip