Fontconfig - May 2010 - fontconfig not recognizing Luxi Mono as monospace

One of the fonts X.Org distributes is "Luxi Mono", aka luximr.ttf
from either:
  http://cgit.freedesktop.org/xorg/font/bh-ttf/tree/
or:
  http://xorg.freedesktop.org/releases/individual/font/font-bh-ttf-1.0.1.tar.bz2

One of our users complained that he couldn''t get xterm to accept this
font with:  xterm -fa "LuxiMono-10" - it always chose the bold version
instead of the regular, since xterm specifies that it needs a monospaced
font, but fontconfig thinks only the bold font is monospaced and the
roman version is not.

On 05/10/2010 07:13 PM, Alan Coopersmith wrote:
>>From digging around, it seems like there''s a glyph with an
advance width
> of 0 in luximr.ttf that fontconfig doesn''t expect in this font
which is
> confusing it, and making it classify it as not monospaced.
> 
> Is this a bug in fontconfig''s monospace recognition or a bug in
the font?
I''d say both.  Patch welcome.

behdad

Behdad Esfahbod wrote:
> On 05/10/2010 07:13 PM, Alan Coopersmith wrote:
>> >From digging around, it seems like there''s a glyph with an
advance width
>> of 0 in luximr.ttf that fontconfig doesn''t expect in this font
which is
>> confusing it, and making it classify it as not monospaced.
>>
>> Is this a bug in fontconfig''s monospace recognition or a bug
in the font?
> 
> I''d say both.  Patch welcome.
Strangely, when trying to reproduce with a freshly updated git clone,
it''s
now the non-bold variants with spacing=100, and the bold ones failed to match.

By inserting a printf into FcFreeTypeCharSetAndSpacingForSize and running
fc-cache from git master, it''s only finding characters with an advance
of
1229 in luximr.ttf & luximri.ttf, but in luximb.ttf & luximbi.ttf it
finds
4 each with an advance of 1338, and one with advance of 682:

 Glyph: 0x 175  Advance:   682

 Glyph: 0x  c4  Advance:  1338
 Glyph: 0x  c5  Advance:  1338
 Glyph: 0x  c2  Advance:  1338
 Glyph: 0x  c6  Advance:  1338

I''m not sure why these glyphs are different width, or what criteria
fontconfig
should be using to decide they''re not to be counted towards the spacing
calculation, so I can''t suggest a fontconfig patch right now.

I can easily add a fonts.conf file to the X.Org fonts/bh-ttf package to override
it there though.

-- 
	-Alan Coopersmith-        alan.coopersmith at oracle.com
	 Oracle Solaris Platform Engineering: X Window System

fontconfig detects multiple character advances in some of the Luxi Mono
fonts, so doesn''t think they''re monospaced.   This causes
problems when
running xterm -fa "Luxi Mono", since it adds :spacing=100 to the
pattern
when requesting a font from fontconfig to prefer monospaced fonts.

Signed-off-by: Alan Coopersmith <alan.coopersmith at oracle.com>
---

For the background here, see the thread "fontconfig not recognizing Luxi
Mono
 as monospace" on the fontconfig mailing list recently.

 42-luxi-mono.conf |   12 ++++++++++++
 Makefile.am       |    8 ++++++++
 2 files changed, 20 insertions(+), 0 deletions(-)
 create mode 100644 42-luxi-mono.conf

diff --git a/42-luxi-mono.conf b/42-luxi-mono.conf
new file mode 100644
index 0000000..7babe82
--- /dev/null
+++ b/42-luxi-mono.conf
@@ -0,0 +1,12 @@
+<?xml version="1.0"?>
+<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
+<!-- force fontconfig to treat the Luxi Mono fonts as monospaced, even
+     though it detects multiple character widths -->
+<fontconfig>
+  <match target="scan">
+        <test name="family">
+                <string>Luxi Mono</string>
+        </test>
+        <edit
name="spacing"><int>100</int></edit>
+  </match>
+</fontconfig>
diff --git a/Makefile.am b/Makefile.am
index c709ad9..2417e91 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -36,6 +36,11 @@ FONT_FILES = \
 fontdir = @FONTDIR@
 font_DATA = $(FONT_FILES)

+fontconfigdir = $(sysconfdir)/fonts/conf
+actualconfigdir = $(fontconfigdir)/conf.d
+availconfigdir = $(fontconfigdir)/conf.avail
+availconfig_DATA = 42-luxi-mono.conf
+
 EXTRA_DIST = $(FONT_FILES) COPYRIGHT.BH

 MAINTAINERCLEANFILES = ChangeLog INSTALL
@@ -45,6 +50,9 @@ install-data-hook:
 	$(MKFONTSCALE) $(DESTDIR)$(fontdir)
 	@rm -f $(DESTDIR)$(fontdir)/font.dir
 	$(MKFONTDIR) $(DESTDIR)$(fontdir)
+	mkdir -p $(DESTDIR)$(actualconfigdir)
+	@rm -f $(DESTDIR)$(actualconfigdir)/$(availconfig_DATA)
+	ln -s ../conf.avail/$(availconfig_DATA) $(DESTDIR)$(actualconfigdir)
 	@RUN_FCCACHE@

 distuninstallcheck:
-- 
1.5.6.5