gamma.h

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/* === S Y N F I G ========================================================= */
/* ========================================================================= */

/* === S T A R T =========================================================== */

#ifndef __SYNFIG_GAMMA_H
#define __SYNFIG_GAMMA_H

/* === H E A D E R S ======================================================= */

#include <cmath>

/* === M A C R O S ========================================================= */

/* === T Y P E D E F S ===================================================== */

/* === C L A S S E S & S T R U C T S ======================================= */

namespace synfig {

class Gamma
{
    float gamma_r;
    float gamma_g;
    float gamma_b;
    float black_level;
    float red_blue_level;

    unsigned char table_r_U16_to_U8[65536];
    unsigned char table_g_U16_to_U8[65536];
    unsigned char table_b_U16_to_U8[65536];

    float table_r_U8_to_F32[256];
    float table_g_U8_to_F32[256];
    float table_b_U8_to_F32[256];

public:
    Gamma(float x=1):black_level(0) { set_gamma(x); }

    void set_gamma(float x);
    void set_gamma_r(float x);
    void set_gamma_g(float x);
    void set_gamma_b(float x);
    void set_black_level(float x);

    void set_red_blue_level(float x);
    void set_all(float r, float g, float b, float black, float red_blue=1.0f);

    float get_gamma()const { return (gamma_r+gamma_g+gamma_b)*0.33333333; }
    float get_gamma_r()const { return gamma_r; }
    float get_gamma_g()const { return gamma_g; }
    float get_gamma_b()const { return gamma_b; }
    float get_black_level()const { return black_level; }
    float get_red_blue_level()const { return red_blue_level; }

    void refresh_gamma_r();
    void refresh_gamma_g();
    void refresh_gamma_b();

    const unsigned char &r_U16_to_U8(int i)const { return table_r_U16_to_U8[i]; }
    const unsigned char &g_U16_to_U8(int i)const { return table_g_U16_to_U8[i]; }
    const unsigned char &b_U16_to_U8(int i)const { return table_b_U16_to_U8[i]; }

    const unsigned char &r_F32_to_U8(float x)const { return table_r_U16_to_U8[(int)(x*65535.0f)]; }
    const unsigned char &g_F32_to_U8(float x)const { return table_g_U16_to_U8[(int)(x*65535.0f)]; }
    const unsigned char &b_F32_to_U8(float x)const { return table_b_U16_to_U8[(int)(x*65535.0f)]; }

    unsigned short r_F32_to_U16(float x)const { return (unsigned short)table_r_U16_to_U8[(int)(x*65535.0f)]<<8; }
    unsigned short g_F32_to_U16(float x)const { return (unsigned short)table_g_U16_to_U8[(int)(x*65535.0f)]<<8; }
    unsigned short b_F32_to_U16(float x)const { return (unsigned short)table_b_U16_to_U8[(int)(x*65535.0f)]<<8; }

    const float& r_U8_to_F32(int i)const { return table_r_U8_to_F32[i]; }
    const float& g_U8_to_F32(int i)const { return table_g_U8_to_F32[i]; }
    const float& b_U8_to_F32(int i)const { return table_b_U8_to_F32[i]; }

    float r_F32_to_F32(float x)const { return static_cast<float>(pow(x,gamma_r)*(1.0f-black_level)+black_level); }
    float g_F32_to_F32(float x)const { return static_cast<float>(pow(x,gamma_g)*(1.0f-black_level)+black_level); }
    float b_F32_to_F32(float x)const { return static_cast<float>(pow(x,gamma_b)*(1.0f-black_level)+black_level); }
}; // END of class Gamma

}; // END of namespace synfig

/* === E N D =============================================================== */

#endif