alsamixer: Allow setting the default background color in config

The recent commit c867aa8a84 ("alsamixer: use background color
instead of COLOR_BLACK") changed the behavior of alsamixer to take the
system default background color instead of black.  This caused
problems on the terminal setups that have bright background colors,
e.g. yellow is very hard to read.

It could be "fixed" by setting up the color configurations in
~/.config/alsamixer.rc, but this needs to change the all colors in
every element, which is pretty cumbersome.  Instead, this patch
extends the config set command to allow user to specify the default
background color.  A user like me can create their own
~/.config/alsamixer.rc file containing the line

  set background black

and the old good black background is back again.

Note that, for achieving the above, we also had to shuffle the
function call order, to parse the config at first, then initialize
curses.  This shouldn't matter for other behavior.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

alsamixer/alsamixer.1

@@ -202,6 +202,10 @@ Set the mouse wheel step to \fI<N>\fP
 
 If enabled (\fI1\fP), mixer controls can be changed by hovering over them and scrolling the mouse wheel.
 
+\fBbackground\fP \fIcolor\fP
+
+Set the default background color
+
 .TP
 \fBbind\fP \fIkey_definition\fP \fIcommand\fP
 

alsamixer/cli.c

@@ -152,15 +152,15 @@ int main(int argc, char *argv[])
 
 	parse_options(argc, argv);
 
-	create_mixer_object(&selem_regopt);
-
-	initialize_curses(use_color, use_mouse);
-
 	if (config_file == CONFIG_DEFAULT)
 		parse_default_config_file();
 	else if (config_file)
 		parse_config_file(config_file);
 
+	create_mixer_object(&selem_regopt);
+
+	initialize_curses(use_color, use_mouse);
+
 	create_mixer_widget();
 
 	mainloop();

alsamixer/colors.c

@@ -23,6 +23,7 @@
 #include "colors.h"
 
 struct attributes attrs;
+short background_color = -1;
 
 int get_color_pair(short fg, short bg)
 {
@@ -50,11 +51,11 @@ void init_colors(int use_color)
 		start_color();
 		use_default_colors();
 
-		get_color_pair(COLOR_CYAN, -1); // COLOR_PAIR(1)
+		get_color_pair(COLOR_CYAN, background_color); // COLOR_PAIR(1)
-		get_color_pair(COLOR_YELLOW, -1);
+		get_color_pair(COLOR_YELLOW, background_color);
 		get_color_pair(COLOR_WHITE, COLOR_GREEN);
-		get_color_pair(COLOR_RED, -1);
+		get_color_pair(COLOR_RED, background_color);
-		get_color_pair(COLOR_WHITE, -1);
+		get_color_pair(COLOR_WHITE, background_color);
 		get_color_pair(COLOR_WHITE, COLOR_BLUE);
 		get_color_pair(COLOR_RED, COLOR_BLUE);
 		get_color_pair(COLOR_GREEN, COLOR_GREEN);

alsamixer/colors.h

@@ -34,6 +34,7 @@ struct attributes {
 };
 
 extern struct attributes attrs;
+extern short background_color;
 
 void init_colors(int use_color);
 int get_color_pair(short fg, short bg);

alsamixer/configparser.c

@@ -444,6 +444,15 @@ static int cfg_set(char **argv, unsigned int argc)
 				return ERROR_CONFIG;
 			}
 		}
+		else if (!strcmp(argv[0], "background")) {
+			int bg_color = color_by_name(argv[1]);
+			if (bg_color == -2) {
+				error_message = _("unknown color");
+				error_cause = argv[1];
+				return ERROR_CONFIG;
+			}
+			background_color = bg_color;
+		}
 		else {
 			error_message = _("unknown option");
 			error_cause = argv[0];