basic code to use SVModifier plus one definition in dark.colors

gtk2_ardour/dark.colors

@@ -482,4 +482,6 @@
     <ColorAlias name="zoom button: fill active" alias="color 48"/>
     <ColorAlias name="zoom button: led active" alias="color 8"/>
   </ColorAliases>    
+  <Modifiers>
+    <Modifer name="region note edit" modifier="= alpha:0"/>
 </Ardour>

gtk2_ardour/ui_config.cc

@@ -262,7 +262,16 @@ UIConfiguration::store_color_theme ()
 		parent->add_child_nocopy (*node);
 	}
 	root->add_child_nocopy (*parent);
-	
+
+	parent = new XMLNode (X_("Modifiers"));
+	for (Modifiers::const_iterator i = modifiers.begin(); i != modifiers.end(); ++i) {
+		XMLNode* node = new XMLNode (X_("Modifier"));
+		node->add_property (X_("name"), i->first);
+		node->add_property (X_("modifier"), i->second.to_string());
+		parent->add_child_nocopy (*node);
+	}
+	root->add_child_nocopy (*parent);
+
 	XMLTree tree;
 	std::string colorfile = Glib::build_filename (user_config_directory(), (string ("my-") + color_file.get() + ".colors"));
 	
@@ -435,6 +444,12 @@ UIConfiguration::set_state (const XMLNode& root, int /*version*/)
 		load_color_aliases (*aliases);
 	}
 
+	XMLNode* modifiers = find_named_node (root, X_("Modifiers"));
+
+	if (modifiers) {
+		load_modifiers (*modifiers);
+	}
+
 	return 0;
 }
 
@@ -486,6 +501,30 @@ UIConfiguration::load_colors (XMLNode const & node)
 	}
 }
 
+void
+UIConfiguration::load_modifiers (XMLNode const & node)
+{
+	XMLNodeList const nlist = node.children();
+	XMLNodeConstIterator niter;
+	XMLProperty const *name;
+	XMLProperty const *mod;
+	
+	modifiers.clear ();
+
+	for (niter = nlist.begin(); niter != nlist.end(); ++niter) {
+		if ((*niter)->name() != X_("Modifier")) {
+			continue;
+		}
+		name = (*niter)->property (X_("name"));
+		mod = (*niter)->property (X_("modifier"));
+
+		if (name && mod) {
+			SVAModifier svam (mod->value());
+			modifiers.insert (make_pair (name->value(), svam));
+		}
+	}
+}
+
 void
 UIConfiguration::set_variables (const XMLNode& node)
 {

gtk2_ardour/ui_config.h

@@ -56,9 +56,11 @@ class UIConfiguration : public PBD::Stateful
 
 	typedef std::map<std::string,ArdourCanvas::Color> Colors;
 	typedef std::map<std::string,std::string> ColorAliases;
+	typedef std::map<std::string,ArdourCanvas::SVAModifier> Modifiers;
 
 	Colors         colors;
 	ColorAliases   color_aliases;
+	Modifiers      modifiers;
 
 	void set_alias (std::string const & name, std::string const & alias);
 	void set_color (const std::string& name, ArdourCanvas::Color);
@@ -68,7 +70,8 @@ class UIConfiguration : public PBD::Stateful
 
 	ArdourCanvas::Color color (const std::string&, bool* failed = 0) const;
 	ArdourCanvas::HSV  color_hsv (const std::string&) const;
-
+	ArdourCanvas::SVAModifier modifier (const std::string&);
+		
         sigc::signal<void,std::string> ParameterChanged;
 	void map_parameters (boost::function<void (std::string)>&);
 
@@ -108,6 +111,7 @@ class UIConfiguration : public PBD::Stateful
 	int store_color_theme ();
 	void load_color_aliases (XMLNode const &);
 	void load_colors (XMLNode const &);
+	void load_modifiers (XMLNode const &);
 	void reset_gtk_theme ();
 	void colors_changed ();
 	int load_color_theme (bool allow_own=true);