FC_COLOR in src/ftfont.c

FC_COLOR in src/ftfont.c

[jpff]

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Just pulled from git and got

   CC       ftfont.o
ftfont.c: In function ‘ftfont_spec_pattern’:
ftfont.c:771:38: error: ‘FC_COLOR’ undeclared (first use in this function)
        && ! FcPatternAddBool(pattern, FC_COLOR, FcFalse))
                                       ^
ftfont.c:771:38: note: each undeclared identifier is reported only once 
for each function it appears in
Makefile:382: recipe for target 'ftfont.o' failed

OpenSuSE Leap42.3 with GNU/emacs 27.0.50

==John ff

Re: FC_COLOR in src/ftfont.c

[Eli Zaretskii]

> Date: Tue, 3 Apr 2018 14:05:52 +0100 (BST)
> From: jpff <jpff@codemist.co.uk>
> 
> Just pulled from git and got
> 
>    CC       ftfont.o
> ftfont.c: In function ‘ftfont_spec_pattern’:
> ftfont.c:771:38: error: ‘FC_COLOR’ undeclared (first use in this function)
>         && ! FcPatternAddBool(pattern, FC_COLOR, FcFalse))
>                                        ^
> ftfont.c:771:38: note: each undeclared identifier is reported only once 
> for each function it appears in
> Makefile:382: recipe for target 'ftfont.o' failed
> 
> OpenSuSE Leap42.3 with GNU/emacs 27.0.50

What is your version of fontconfig?

I guess the solution depends on whether systems with fontconfig that
doesn't support FC_COLOR are still susceptible to the original bug.

Re: FC_COLOR in src/ftfont.c

[jpff]

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#define FC_MAJOR        2
#define FC_MINOR        11
#define FC_REVISION     1


On Tue, 3 Apr 2018, Eli Zaretskii wrote:

>> Date: Tue, 3 Apr 2018 14:05:52 +0100 (BST)
>> From: jpff <jpff@codemist.co.uk>
>>
>> Just pulled from git and got
>>
>>    CC       ftfont.o
>> ftfont.c: In function ‘ftfont_spec_pattern’:
>> ftfont.c:771:38: error: ‘FC_COLOR’ undeclared (first use in this function)
>>         && ! FcPatternAddBool(pattern, FC_COLOR, FcFalse))
>>                                        ^
>> ftfont.c:771:38: note: each undeclared identifier is reported only once
>> for each function it appears in
>> Makefile:382: recipe for target 'ftfont.o' failed
>>
>> OpenSuSE Leap42.3 with GNU/emacs 27.0.50
>
> What is your version of fontconfig?
>
> I guess the solution depends on whether systems with fontconfig that
> doesn't support FC_COLOR are still susceptible to the original bug.
>

Re: FC_COLOR in src/ftfont.c

[Paul Eggert]

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On 04/03/2018 06:58 AM, Eli Zaretskii wrote:
> I guess the solution depends on whether systems with fontconfig that
> doesn't support FC_COLOR are still susceptible to the original bug.

I doubt whether they're susceptible. Even if they are, we're better off 
compiling Emacs on such systems rather than having the build fail; at 
least that way we can further debug the problem. So I installed the 
attached workaround to help move the ball forward.


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From 0f923ac2629c819cb16860d154945485e48287cb Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Tue, 3 Apr 2018 08:12:41 -0700
Subject: [PATCH] Port FC_COLOR change to older fontconfig
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Problem reported by John ff in:
https://lists.gnu.org/r/emacs-devel/2018-04/msg00058.html
* src/ftfont.c (ftfont_spec_pattern) [!FC_COLOR]:
Don’t use FC_COLOR on older fontconfigs that don’t have it.
---
 src/ftfont.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/ftfont.c b/src/ftfont.c
index 24a92dd52e..84e4a30389 100644
--- a/src/ftfont.c
+++ b/src/ftfont.c
@@ -764,7 +764,7 @@ ftfont_spec_pattern (Lisp_Object spec, char *otlayout, struct OpenTypeSpec **ots
   if (scalable >= 0
       && ! FcPatternAddBool (pattern, FC_SCALABLE, scalable ? FcTrue : FcFalse))
     goto err;
-#ifdef HAVE_XFT
+#if defined HAVE_XFT && defined FC_COLOR
   /* We really don't like color fonts, they cause Xft crashes.  See
      Bug#30874.  */
   if (Vxft_ignore_color_fonts
-- 
2.14.3

Re: FC_COLOR in src/ftfont.c

[Eli Zaretskii]

> Cc: emacs-devel@gnu.org
> From: Paul Eggert <eggert@cs.ucla.edu>
> Date: Tue, 3 Apr 2018 08:17:08 -0700
> 
> On 04/03/2018 06:58 AM, Eli Zaretskii wrote:
> > I guess the solution depends on whether systems with fontconfig that
> > doesn't support FC_COLOR are still susceptible to the original bug.
> 
> I doubt whether they're susceptible. Even if they are, we're better off 
> compiling Emacs on such systems rather than having the build fail

That's a given, but I meant something else: should we just #ifdef away
that part, as you did, or should we find an equivalent code that
rejects color fonts even though FC_COLOR is not defined.