Overtyping the first half of a wide character with the
second half of a wide character results in display garbage.
This is because the trailing dummy is not cleaned up.
i.e. ATTR_WIDE, ATTR_WDUMMY, ATTR_WDUMMY
Here is a short script for demonstrating the behavior:
#!/bin/sh
alias printf=/usr/bin/printf
printf こんにちは！; sleep 2
printf '\x1b[5D'; sleep 2
printf へ; sleep 2
printf ' '; sleep 2
echo
---
st.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/st.c b/st.c
index de2dd0e..51049ba 100644
--- a/st.c
+++ b/st.c
@@ -2507,6 +2507,10 @@ check_control_code:
if (width == 2) {
gp->mode |= ATTR_WIDE;
if (term.c.x+1 < term.col) {
+ if (gp[1].mode == ATTR_WIDE && term.c.x+2 < term.col) {
+ gp[2].u = ' ';
+ gp[2].mode &= ~ATTR_WDUMMY;
+ }
gp[1].u = '\0';
gp[1].mode = ATTR_WDUMMY;
}
--
2.34.1
