From 6fb87a9dbdbdc344fec14d026adf2c84853794b3 Mon Sep 17 00:00:00 2001
From: 8dcc <8dcc.git@gmail.com>
Date: Sun, 13 Oct 2024 14:45:12 +0200
Subject: [PATCH] Allow user to not render wide characters

This patch adds a new terminal mode, NOWIDE. If it's enabled, wide characters
will be replaced with a faint question mark. This mode can be enabled or
disabled by default with the `renderwide' variable in <config.def.h>, and can be
toggled with a keybind (Ctrl+Shift+W by default).

This mode is specially useful if your font doesn't support wide characters,
since rendering them usually makes the terminal really, really slow, specially
when scrolling.

This patch is intended for ST 0.8.2, but it should be easy to port it to newer
versions.
---
 config.def.h |  7 +++++++
 st.c         | 17 ++++++++++++++++-
 st.h         |  2 ++
 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/config.def.h b/config.def.h
index 0e01717..bc3f06f 100644
--- a/config.def.h
+++ b/config.def.h
@@ -56,6 +56,12 @@ static unsigned int blinktimeout = 800;
  */
 static unsigned int cursorthickness = 2;
 
+/*
+ * should we render wide characters by default? Can be toggled with the
+ * `togglewide' shortcut below.
+ */
+int renderwide = 1;
+
 /*
  * bell volume. It must be a value between -100 and 100. Use 0 for disabling
  * it
@@ -178,6 +184,7 @@ static Shortcut shortcuts[] = {
 	{ TERMMOD,              XK_Y,           selpaste,       {.i =  0} },
 	{ ShiftMask,            XK_Insert,      selpaste,       {.i =  0} },
 	{ TERMMOD,              XK_Num_Lock,    numlock,        {.i =  0} },
+	{ TERMMOD,              XK_W,           togglewide,     {.i =  0} },
 };
 
 /*
diff --git a/st.c b/st.c
index b8e6077..c583b5c 100644
--- a/st.c
+++ b/st.c
@@ -52,6 +52,7 @@ enum term_mode {
 	MODE_PRINT       = 1 << 5,
 	MODE_UTF8        = 1 << 6,
 	MODE_SIXEL       = 1 << 7,
+	MODE_NOWIDE      = 1 << 8,
 };
 
 enum cursor_movement {
@@ -1029,6 +1030,8 @@ treset(void)
 	term.top = 0;
 	term.bot = term.row - 1;
 	term.mode = MODE_WRAP|MODE_UTF8;
+	if (!renderwide)
+		term.mode |= MODE_NOWIDE;
 	memset(term.trantbl, CS_USA, sizeof(term.trantbl));
 	term.charset = 0;
 
@@ -1980,6 +1983,12 @@ tprinter(char *s, size_t len)
 	}
 }
 
+void
+togglewide(const Arg *arg)
+{
+	term.mode ^= MODE_NOWIDE;
+}
+
 void
 toggleprinter(const Arg *arg)
 {
@@ -2427,7 +2436,13 @@ check_control_code:
 	tsetchar(u, &term.c.attr, term.c.x, term.c.y);
 
 	if (width == 2) {
-		gp->mode |= ATTR_WIDE;
+		if (IS_SET(MODE_NOWIDE))  {
+			gp[0].u = '?';
+			gp[0].mode |= ATTR_FAINT;
+		} else {
+			gp[0].mode |= ATTR_WIDE;
+		}
+
 		if (term.c.x+1 < term.col) {
 			gp[1].u = '\0';
 			gp[1].mode = ATTR_WDUMMY;
diff --git a/st.h b/st.h
index 38c61c4..0691246 100644
--- a/st.h
+++ b/st.h
@@ -83,6 +83,7 @@ void draw(void);
 void printscreen(const Arg *);
 void printsel(const Arg *);
 void sendbreak(const Arg *);
+void togglewide(const Arg *);
 void toggleprinter(const Arg *);
 
 int tattrset(int);
@@ -116,6 +117,7 @@ extern char *stty_args;
 extern char *vtiden;
 extern char *worddelimiters;
 extern int allowaltscreen;
+extern int renderwide;
 extern char *termname;
 extern unsigned int tabspaces;
 extern unsigned int defaultfg;
-- 
2.46.2