Merge pull request #1977 from choikwa/master

fix typo error in Color::invert, fixes #1967

core/color.cpp

@@ -161,7 +161,7 @@ void Color::invert() {
 
 	r=1.0-r;
 	g=1.0-g;	
-	g=1.0-b;	
+	b=1.0-b;	
 }
 void Color::contrast() {