From 992804cb27993d5de8e6830a8ab9268045ce6892 Mon Sep 17 00:00:00 2001
From: Laurence de Bruxelles <lfdebrux@gmail.com>
Date: Fri, 19 Sep 2025 10:19:10 +0300
Subject: Use STYLE_WHITESPACE for spaces, newlines, and tabs

Allow theming the replacement characters shown for showspaces, showtabs,
and/or shownewlines.
---
 lua/vis.lua |  1 +
 ui.h        |  1 +
 view.c      | 23 ++++++++++++++++++-----
 vis-lua.c   |  1 +
 4 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/lua/vis.lua b/lua/vis.lua
index 9ac41b0..42c536b 100644
--- a/lua/vis.lua
+++ b/lua/vis.lua
@@ -272,6 +272,7 @@ vis.types.window.set_syntax = function(win, syntax)
 	win:style_define(win.STYLE_SEPARATOR, lexers.STYLE_SEPARATOR or '')
 	win:style_define(win.STYLE_INFO, lexers.STYLE_INFO or '')
 	win:style_define(win.STYLE_EOF, lexers.STYLE_EOF or '')
+	win:style_define(win.STYLE_WHITESPACE, lexers.STYLE_WHITESPACE or '')
 
 	if syntax == nil or syntax == 'off' then
 		win.syntax = nil
diff --git a/ui.h b/ui.h
index c0ca4e3..c4d81db 100644
--- a/ui.h
+++ b/ui.h
@@ -48,6 +48,7 @@ enum UiStyle {
 	UI_STYLE_SEPARATOR,
 	UI_STYLE_INFO,
 	UI_STYLE_EOF,
+	UI_STYLE_WHITESPACE,
 	UI_STYLE_MAX,
 };
 
diff --git a/view.c b/view.c
index 28f33e9..0a69499 100644
--- a/view.c
+++ b/view.c
@@ -266,6 +266,9 @@ static bool view_add_cell(View *view, const Cell *cell) {
 }
 
 static bool view_expand_tab(View *view, Cell *cell) {
+	Win *win = (Win *)((char *)view - offsetof(Win, view));
+	ui_window_style_set(&win->vis->ui, win->id, cell, UI_STYLE_WHITESPACE, false);
+
 	cell->width = 1;
 
 	int displayed_width = view->tabwidth - (view->col % view->tabwidth);
@@ -287,6 +290,9 @@ static bool view_expand_newline(View *view, Cell *cell) {
 	size_t lineno = view->line->lineno;
 	const char *symbol = view->symbols[SYNTAX_SYMBOL_EOL];
 
+	Win *win = (Win *)((char *)view - offsetof(Win, view));
+	ui_window_style_set(&win->vis->ui, win->id, cell, UI_STYLE_WHITESPACE, false);
+
 	strncpy(cell->data, symbol, sizeof(cell->data) - 1);
 	cell->width = 1;
 	if (!view_add_cell(view, cell))
@@ -299,6 +305,15 @@ static bool view_expand_newline(View *view, Cell *cell) {
 	return true;
 }
 
+static bool view_expand_space(View *view, Cell *cell) {
+	Win *win = (Win *)((char *)view - offsetof(Win, view));
+	ui_window_style_set(&win->vis->ui, win->id, cell, UI_STYLE_WHITESPACE, false);
+
+	const char *symbol = view->symbols[SYNTAX_SYMBOL_SPACE];
+	strncpy(cell->data, symbol, sizeof(cell->data) - 1);
+	return view_add_cell(view, cell);
+}
+
 /* try to add another character to the view, return whether there was space left */
 static bool view_addch(View *view, Cell *cell) {
 	if (!view->line)
@@ -318,11 +333,9 @@ static bool view_addch(View *view, Cell *cell) {
 		return view_expand_tab(view, cell);
 	case '\n':
 		return view_expand_newline(view, cell);
-	case ' ': {
-		const char *symbol = view->symbols[SYNTAX_SYMBOL_SPACE];
-		strncpy(cell->data, symbol, sizeof(cell->data) - 1);
-		return view_add_cell(view, cell);
-	}}
+	case ' ':
+		return view_expand_space(view, cell);
+	}
 
 	if (ch < 128 && !isprint(ch)) {
 		/* non-printable ascii char, represent it as ^(char + 64) */
diff --git a/vis-lua.c b/vis-lua.c
index e226d18..fa7ef35 100644
--- a/vis-lua.c
+++ b/vis-lua.c
@@ -3316,6 +3316,7 @@ static void vis_lua_init(Vis *vis) {
 		{ UI_STYLE_SEPARATOR,         "STYLE_SEPARATOR"         },
 		{ UI_STYLE_INFO,              "STYLE_INFO"              },
 		{ UI_STYLE_EOF,               "STYLE_EOF"               },
+		{ UI_STYLE_WHITESPACE,        "STYLE_WHITESPACE"        },
 	};
 
 	for (size_t i = 0; i < LENGTH(styles); i++) {
-- 
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