Default background color shall either be white or transparent

Definitely not black!

src/hb-view.c

@@ -50,7 +50,7 @@ static int margin_r = 10;
 static int line_space = 0;
 static double font_size = 18;
 static const char *fore = "#000000";
-static const char *back = "#000000";
+static const char *back = "#ffffff";
 static const char *text = NULL;
 static const char *font_file = NULL;
 static const char *out_file = "/dev/stdout";