inline Fl_Boxtype fl_box(Fl_Boxtype b);

function Filled
       (Box : in Box_Kind)
    return Box_Kind;

Fl_Color fl_color_average(Fl_Color c1, Fl_Color c2, float weight);

function Color_Average
       (Tone1, Tone2 : in Color;
        Weight       : in Blend := 0.5)
    return Color;

inline Fl_Color fl_color_cube(int r, int g, int b);

function Color_Cube
       (R, G, B : in Color_Component)
    return Color;

Fl_Color fl_contrast(Fl_Color fg, Fl_Color bg);

function Contrast
       (Fore, Back : in Color)
    return Color;

inline Fl_Color fl_darker(Fl_Color c);

function Darker
       (Tone : in Color)
    return Color;

inline Fl_Boxtype fl_down(Fl_Boxtype b);

function Down
       (Box : in Box_Kind)
    return Box_Kind;

inline Fl_Boxtype fl_frame(Fl_Boxtype b);

function Frame
       (Box : in Box_Kind)
    return Box_Kind;

inline Fl_Color fl_gray_ramp(int i);

function Grey_Ramp
       (Light : in Greyscale)
    return Color;

function Grey_Ramp
       (Light : in Color_Component)
    return Color;

Fl_Color fl_inactive(Fl_Color c);

function Inactive
       (Tone : in Color)
    return Color;

inline Fl_Color fl_lighter(Fl_Color c);

function Lighter
       (Tone : in Color)
    return Color;

inline Fl_Color fl_rgb_color(uchar g);

function RGB_Color
       (Light : in Greyscale)
    return Color;

function RGB_Color
       (Light : in Color_Component)
    return Color;

inline Fl_Color fl_rgb_color(uchar r, uchar g, uchar b);

function RGB_Color
       (R, G, B : in Color_Component)
    return Color;