desktop: offer different colors for info tab titles

Add a preference option to set the color of the text on the information tab to
either MediumBlue, LightBlue or Black. The last two of these colors are meant
to enable areadable font contrast on displays with dark mode.
The choice is saved with the other preferences.

[Dirk Hohndel: this isn't really about dark mode, so changed many of the types
	       and variable names, changed the user visible texts, and
               addressed some whitespace issues]

Signed-off-by: willemferguson <willemferguson@zoology.up.ac.za>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 12 insertions, 5 deletions

diff --git a/core/pref.h b/core/pref.h
index 90a442b9c..093d346b4 100644
--- a/core/pref.h
+++ b/core/pref.h
@@ -66,6 +66,12 @@ enum unit_system_values {
 	PERSONALIZE
 };
 
+enum headerstyle_color_values {
+	MEDIUMBLUE,
+	LIGHTBLUE,
+	BLACK
+};
+
 // ********** PREFERENCES **********
 // This struct is kept global for all of ssrf
 // most of the fields are loaded from git as
@@ -100,11 +106,12 @@ struct preferences {
 	dive_computer_prefs_t dive_computer4;
 
 	// ********** Display *************
-	bool        display_invalid_dives;
-	const char *divelist_font;
-	double      font_size;
-	double      mobile_scale;
-	bool        show_developer;
+	bool                          display_invalid_dives;
+	const char                   *divelist_font;
+	double                        font_size;
+	double                        mobile_scale;
+	bool                          show_developer;
+	enum headerstyle_color_values headerstyle_color;
 
 	// ********** Equipment tab *******
 	const char *default_cylinder;