From e3d92df936b97aef3cd51f1e85eb3c47409069c5 Mon Sep 17 00:00:00 2001
From: Simon Tatham <anakin@pobox.com>
Date: Sun, 8 Oct 2017 13:45:08 +0100
Subject: [PATCH] Save and restore true-colour state with the cursor.

I spotted this myself while looking through the code in search of the
cause of the background-colour-erase bug: saving and restoring the
cursor via ESC 7 / ESC 8 ought to also save and restore the current
graphics rendition attributes including foreground and background
colour settings, but it was not saving and restoring the new
term->curr_truecolour along with term->curr_attr.

So there's now a term->save_truecolour to keep that in, and also a
term->alt_save_truecolour to take account of the fact that all the
saved cursor state variables get swapped out _again_ when switching
between the main and alternate screens.

(However, there is not a term->alt_truecolour to complete the cross
product, because the _active_ graphics rendition is carried over when
switching between the terminal screens; it's only the _saved_ one from
ESC 7 / ESC 8 that is saved separately. That's consistent with the
behaviour we've had all along for ordinary fg/bg colour selection.)
---
 terminal.c | 8 ++++++++
 terminal.h | 1 +
 2 files changed, 9 insertions(+)

diff --git a/terminal.c b/terminal.c
index 8c44b906..7a7207a0 100644
--- a/terminal.c
+++ b/terminal.c
@@ -1297,6 +1297,7 @@ static void power_on(Terminal *term, int clear)
     term->default_attr = term->save_attr =
 	term->alt_save_attr = term->curr_attr = ATTR_DEFAULT;
     term->curr_truecolour.fg = term->curr_truecolour.bg = optionalrgb_none;
+    term->save_truecolour = term->alt_save_truecolour = term->curr_truecolour;
     term->term_editing = term->term_echoing = FALSE;
     term->app_cursor_keys = conf_get_int(term->conf, CONF_app_cursor);
     term->app_keypad_keys = conf_get_int(term->conf, CONF_app_keypad);
@@ -1987,6 +1988,7 @@ static void swap_screen(Terminal *term, int which, int reset, int keep_cur_pos)
 {
     int t;
     pos tp;
+    truecolour ttc;
     tree234 *ttr;
 
     if (!which)
@@ -2051,6 +2053,10 @@ static void swap_screen(Terminal *term, int which, int reset, int keep_cur_pos)
         if (!reset && !keep_cur_pos)
             term->save_attr = term->alt_save_attr;
         term->alt_save_attr = t;
+        ttc = term->save_truecolour;
+        if (!reset && !keep_cur_pos)
+            term->save_truecolour = term->alt_save_truecolour;
+        term->alt_save_truecolour = ttc;
         t = term->save_utf;
         if (!reset && !keep_cur_pos)
             term->save_utf = term->alt_save_utf;
@@ -2346,6 +2352,7 @@ static void save_cursor(Terminal *term, int save)
     if (save) {
 	term->savecurs = term->curs;
 	term->save_attr = term->curr_attr;
+	term->save_truecolour = term->curr_truecolour;
 	term->save_cset = term->cset;
 	term->save_utf = term->utf;
 	term->save_wnext = term->wrapnext;
@@ -2360,6 +2367,7 @@ static void save_cursor(Terminal *term, int save)
 	    term->curs.y = term->rows - 1;
 
 	term->curr_attr = term->save_attr;
+	term->curr_truecolour = term->save_truecolour;
 	term->cset = term->save_cset;
 	term->utf = term->save_utf;
 	term->wrapnext = term->save_wnext;
diff --git a/terminal.h b/terminal.h
index 4a205a77..fcb321c4 100644
--- a/terminal.h
+++ b/terminal.h
@@ -140,6 +140,7 @@ struct terminal_tag {
     /* ESC 7 saved state for the alternate screen */
     pos alt_savecurs;
     int alt_save_attr;
+    truecolour alt_save_truecolour;
     int alt_save_cset, alt_save_csattr;
     int alt_save_utf, alt_save_wnext;
     int alt_save_sco_acs;