further improved monochrome terminal support: fixed reverse text on reverse backgrounds

* Unfortunately we cannot use `wbkgdset(win, A_REVERSE)` if we plan to
  use reverse text on this background, i.e. if we want to cancel out the background A_REVERSE.
* SciTECO therefore no longer uses background attributes, but only foreground attributes.
  When setting a reverse text, we XOR A_REVERSE into the previous attributes.
* This fixes control characters especially in the info line and popups, as well as rendering
  of the popup scroll bars.
* The command-line should now be rendered properly even on a dark-on-bright color theme
  (which does not yet exist).

1 files changed, 17 insertions, 0 deletions

diff --git a/src/interface-curses/curses-utils.h b/src/interface-curses/curses-utils.h
index 9f2e8f3..18cdd3d 100644
--- a/src/interface-curses/curses-utils.h
+++ b/src/interface-curses/curses-utils.h
@@ -34,3 +34,20 @@ teco_curses_add_wc(WINDOW *win, gunichar chr)
 	gchar buf[6];
 	waddnstr(win, buf, g_unichar_to_utf8(chr, buf));
 }
+
+/**
+ * Clear from the current position until the end of the given
+ * curses window with the current \b foreground attributes.
+ * This is similar to wclrtobot(), but does not use the
+ * background attributes.
+ */
+static inline void
+teco_curses_clrtobot(WINDOW *win)
+{
+	int max_x, max_y;
+	getmaxyx(win, max_y, max_x);
+	if (getcurx(win)+1 < max_x)
+		whline(win, ' ', max_x - getcurx(win));
+	for (int y = getcury(win)+1; y <= max_y; y++)
+		mvwhline(win, y, 0, ' ', max_x);
+}