display: do spotlighting as part of drawing the screen

When something is spotlighted, it should survive a refresh of
the screen and an excursion to a help text, so the spotlight
should get painted whenever the edit window is drawn.

This fully fixes https://savannah.gnu.org/bugs/?54721.

src/global.c

@@ -259,6 +259,13 @@ char *rcfile_with_errors = NULL;
 		/* The first nanorc file, if any, that produced warnings. */
 #endif
 
+bool spotlighted = FALSE;
+	/* Whether any text is spotlighted. */
+size_t light_from_col = 0;
+	/* Where the spotlighted text starts. */
+size_t light_to_col = 0;
+	/* Where the spotlighted text ends. */
+
 /* Return the number of entries in the shortcut list for a given menu. */
 size_t length_of_list(int menu)
 {

src/proto.h

@@ -175,6 +175,10 @@ extern char *statedir;
 extern char *rcfile_with_errors;
 #endif
 
+extern bool spotlighted;
+extern size_t light_from_col;
+extern size_t light_to_col;
+
 typedef void (*functionptrtype)(void);
 
 /* Most functions in browser.c. */

src/search.c

@@ -575,19 +575,18 @@ ssize_t do_replace_loop(const char *needle, bool whole_word_only,
 			numreplaced = 0;
 
 		if (!replaceall) {
-			size_t from_col = xplustabs();
+			spotlighted = TRUE;
-			size_t to_col = strnlenpt(openfile->current->data,
+			light_from_col = xplustabs();
+			light_to_col = strnlenpt(openfile->current->data,
 										openfile->current_x + match_len);
 
 			/* Refresh the edit window, scrolling it if necessary. */
 			edit_refresh();
 
-			spotlight(TRUE, from_col, to_col);
-
 			/* TRANSLATORS: This is a prompt. */
 			i = do_yesno_prompt(TRUE, _("Replace this instance?"));
 
-			spotlight(FALSE, from_col, to_col);
+			spotlighted = FALSE;
 
 			if (i == -1)  /* The replacing was cancelled. */
 				break;

src/text.c

@@ -2584,21 +2584,20 @@ bool fix_spello(const char *word)
 		proceed = TRUE;
 		napms(2800);
 	} else if (result == 1) {
-		size_t from_col = xplustabs();
+		spotlighted = TRUE;
-		size_t to_col = from_col + strlenpt(word);
+		light_from_col = xplustabs();
+		light_to_col = light_from_col + strlenpt(word);
 #ifndef NANO_TINY
 		filestruct *saved_mark = openfile->mark;
 		openfile->mark = NULL;
 #endif
 		edit_refresh();
 
-		spotlight(TRUE, from_col, to_col);
-
 		/* Let the user supply a correctly spelled alternative. */
 		proceed = (do_prompt(FALSE, FALSE, MSPELL, word, NULL,
 								edit_refresh, _("Edit a replacement")) != -1);
 
-		spotlight(FALSE, from_col, to_col);
+		spotlighted = FALSE;
 
 #ifndef NANO_TINY
 		openfile->mark = saved_mark;

src/winio.c

@@ -2780,6 +2780,9 @@ int update_line(filestruct *fileptr, size_t index)
 	if (strlenpt(fileptr->data) > from_col + editwincols)
 		mvwaddch(edit, row, COLS - 1, '$');
 
+	if (spotlighted && !inhelp)
+		spotlight(TRUE, light_from_col, light_to_col);
+
 	return 1;
 }
 
@@ -2846,6 +2849,9 @@ int update_softwrapped_line(filestruct *fileptr)
 		from_col = to_col;
 	}
 
+	if (spotlighted && !inhelp)
+		spotlight(TRUE, light_from_col, light_to_col);
+
 	return (row - starting_row);
 }
 #endif