st-flexipatch

commit 400aa4492f28ac6556727aac225bba51decc82b5
parent c089485aa4243ef98b107ba3e26902d0973e9ba3
Author: Bakkeby <bakkeby@gmail.com>
Date:   Thu,  7 Mar 2024 21:43:24 +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.

ref.
https://git.suckless.org/st/commit/7473a8d1a57e5f9aba41b953f4e498c35e1c9dc5.html

Diffstat:
M
st.c
 | 
6
+++++-
M
st.h
 | 
4
++--

2 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/st.c b/st.c
@@ -3079,12 +3079,16 @@ 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);
diff --git a/st.h b/st.h
@@ -155,8 +155,8 @@ typedef struct {
 
 typedef struct {
 	Glyph attr; /* current char attributes */
-	int x;
-	int y;
+	int x; /* terminal column */
+	int y; /* terminal row */
 	char state;
 } TCursor;