[dev] [PATCH] Measure the single advance width with a heuristic method

[Ryusei Yamaguchi]

This fix is needed to use dual-width fonts, which have double-width
glyphs (e.g. CJK unified ideographs).

Signed-off-by: Ryusei Yamaguchi <mande...@gmail.com>
---
 st.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/st.c b/st.c
index 0536b6f..fc49e67 100644
--- a/st.c
+++ b/st.c
@@ -68,6 +68,7 @@ char *argv0;
 #define LEN(a)                 (sizeof(a) / sizeof(a)[0])
 #define DEFAULT(a, b)          (a) = (a) ? (a) : (b)
 #define BETWEEN(x, a, b)       ((a) <= (x) && (x) <= (b))
+#define DIVCEIL(n, d)          (((n) + ((d) - 1)) / (d))
 #define ISCONTROLC0(c)         (BETWEEN(c, 0, 0x1f) || (c) == '\177')
 #define ISCONTROLC1(c)         (BETWEEN(c, 0x80, 0x9f))
 #define ISCONTROL(c)           (ISCONTROLC0(c) || ISCONTROLC1(c))
@@ -3289,6 +3290,7 @@ xloadfont(Font *f, FcPattern *pattern)
 {
        FcPattern *match;
        FcResult result;
+       XGlyphInfo extents;
 
        match = FcFontMatch(NULL, pattern, &result);
        if (!match)
@@ -3299,6 +3301,15 @@ xloadfont(Font *f, FcPattern *pattern)
                return 1;
        }
 
+#define SINGLE_WIDE_CHARS \
+       " !\"#$%&'()*+,-./0123456789:;<=>?" \
+       "@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_" \
+       "`abcdefghijklmnopqrstuvwxyz{|}~"
+
+       XftTextExtentsUtf8(xw.dpy, f->match,
+               (const FcChar8 *) SINGLE_WIDE_CHARS,
+               LEN(SINGLE_WIDE_CHARS), &extents);
+
        f->set = NULL;
        f->pattern = FcPatternDuplicate(pattern);
 
@@ -3308,7 +3319,9 @@ xloadfont(Font *f, FcPattern *pattern)
        f->rbearing = f->match->max_advance_width;
 
        f->height = f->ascent + f->descent;
-       f->width = f->lbearing + f->rbearing;
+       f->width = DIVCEIL(extents.xOff, LEN(SINGLE_WIDE_CHARS));
+
+#undef SINGLE_WIDE_CHARACTERS
 
        return 0;
 }
-- 
1.9.1