Extend libteken to support CJK fullwidth characters.

Introduce a new formatting bit (TF_CJK_RIGHT) that is set when putting a
cell that is the right part of a CJK fullwidth character. This will
allow drivers like vt(9) to support fullwidth characters properly.

emaste@ has a patch to extend vt(9)'s font handling to increase the
number of Unicode -> glyph maps from 2 ({normal,bold)} to 4
({normal,bold} x {left,right}). This will need to use this formatting
bit to determine whether to draw the left or right glyph.

Reviewed by:	emaste

1 files changed, 7 insertions, 9 deletions

diff --git a/sys/teken/teken_subr.h b/sys/teken/teken_subr.h
index f25ab6a..be3ce8a 100644
--- a/sys/teken/teken_subr.h
+++ b/sys/teken/teken_subr.h
@@ -791,21 +791,19 @@ teken_subr_do_putchar(teken_t *t, const teken_pos_t *tp, teken_char_t c,
 		teken_funcs_copy(t, &ctr, &ctp);
 	}
 
+	teken_funcs_putchar(t, tp, c, &t->t_curattr);
+
 	if (width == 2 && tp->tp_col + 1 < t->t_winsize.tp_col) {
 		teken_pos_t tp2;
+		teken_attr_t attr;
 
-		/*
-		 * Store a space behind double width characters before
-		 * actually printing them. This prevents artifacts when
-		 * the consumer doesn't render it using double width
-		 * glyphs.
-		 */
+		/* Print second half of CJK fullwidth character. */
 		tp2.tp_row = tp->tp_row;
 		tp2.tp_col = tp->tp_col + 1;
-		teken_funcs_putchar(t, &tp2, BLANK, &t->t_curattr);
+		attr = t->t_curattr;
+		attr.ta_format |= TF_CJK_RIGHT;
+		teken_funcs_putchar(t, &tp2, c, &attr);
 	}
-
-	teken_funcs_putchar(t, tp, c, &t->t_curattr);
 }
 
 static void