st

commit 8ccab2e68b15e8396effc21fa2ae509b140d7639
parent be5ad5cb8982511d6e32fced9796c5e510851110
Author: Quentin Rameau <quinq@fifth.space>
Date:   Sun, 25 Feb 2024 01:31:31 +0100

Fix cursor move with wide glyphs

st would always move back 1 column,
even with wide glyhps (using more than a single column).

The glyph rune is set on its first column,
and the other ones are to 0,
so loop until we detect the start of the previous glyph.

Diffstat:
M
st.c
 | 
10
+++++++---

1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/st.c b/st.c
@@ -86,8 +86,8 @@ enum escape_state {
 
 typedef struct {
 	Glyph attr; /* current char attributes */
-	int x;
-	int y;
+	int x; /* terminal column */
+	int y; /* terminal row */
 	char state;
 } TCursor;
 
@@ -2175,12 +2175,16 @@ tstrsequence(uchar c)
 void
 tcontrolcode(uchar ascii)
 {
+	size_t i;
+
 	switch (ascii) {
 	case '\t':   /* HT */
 		tputtab(1);
 		return;
 	case '\b':   /* BS */
-		tmoveto(term.c.x-1, term.c.y);
+		for (i = 1; term.c.x && term.line[term.c.y][term.c.x - i].u == 0; ++i)
+			;
+		tmoveto(term.c.x - i, term.c.y);
 		return;
 	case '\r':   /* CR */
 		tmoveto(0, term.c.y);