class HT_Marker_Symbol {
    public:
        enum Enum {
            Dot,
            Plus,
            X,
            Star,

            Circle,
            Circle_With_Dot,
            Circle_With_Plus,
            Circle_With_X,
            Circle_With_Circle,
            Circle_Filled,
 
            Box,
            Box_With_Dot,
            Box_With_X,
            Box_Filled,
 
            Diamond,
            Diamond_With_Dot,
            Diamond_With_Plus,
            Diamond_Filled,
 
            Triangle_Up,
            Triangle_Up_With_Dot,
            Triangle_Up_Filled,
            Triangle_Up_Vertex,
            Triangle_Up_Vertex_Filled,
 
            Triangle_Down,
            Triangle_Down_With_Dot,
            Triangle_Down_Filled,
            Triangle_Down_Vertex,
            Triangle_Down_Vertex_Filled,
 
            Triangle_Left,
            Triangle_Left_With_Dot,
            Triangle_Left_Filled,
            Triangle_Left_Vertex,
            Triangle_Left_Vertex_Filled,
 
            Triangle_Right,
            Triangle_Right_With_Dot,
            Triangle_Right_Filled,
            Triangle_Right_Vertex,
            Triangle_Right_Vertex_Filled,
 
            Count,
            Undefined = -1
        };
};

For more information, see the section , "Marker Symbols" in chapter 2, "Heidi Architecture."