/*

 * Copyright 2018 Google Inc.

 *

 * Use of this source code is governed by a BSD-style license that can be

 * found in the LICENSE file.

 */

#pragma once

// skcms.h contains the entire public API for skcms.

#ifndef SKCMS_API

    #define SKCMS_API

#endif

#include <stdbool.h>

#include <stddef.h>

#include <stdint.h>

#include <string.h>

#ifdef __cplusplus

extern "C" {

#endif

// A row-major 3x3 matrix (ie vals[row][col])

typedef struct skcms_Matrix3x3 {

    float vals[3][3];

} skcms_Matrix3x3;

// It is _not_ safe to alias the pointers to invert in-place.

SKCMS_API bool            skcms_Matrix3x3_invert(const skcms_Matrix3x3*, skcms_Matrix3x3*);

SKCMS_API skcms_Matrix3x3 skcms_Matrix3x3_concat(const skcms_Matrix3x3*, const skcms_Matrix3x3*);

// A row-major 3x4 matrix (ie vals[row][col])

typedef struct skcms_Matrix3x4 {

    float vals[3][4];

} skcms_Matrix3x4;

// A transfer function mapping encoded values to linear values,

// represented by this 7-parameter piecewise function:

//

//   linear = sign(encoded) *  (c*|encoded| + f)       , 0 <= |encoded| < d

//          = sign(encoded) * ((a*|encoded| + b)^g + e), d <= |encoded|

//

// (A simple gamma transfer function sets g to gamma and a to 1.)

typedef struct skcms_TransferFunction {

    float g, a,b,c,d,e,f;

} skcms_TransferFunction;

SKCMS_API float skcms_TransferFunction_eval  (const skcms_TransferFunction*, float);

SKCMS_API bool  skcms_TransferFunction_invert(const skcms_TransferFunction*,

                                              skcms_TransferFunction*);

// We can jam a couple alternate transfer function forms into skcms_TransferFunction,

// including those matching the general forms of the SMPTE ST 2084 PQ function or HLG.

//

// PQish:

//                              max(A + B|encoded|^C, 0)

//    linear = sign(encoded) * (------------------------) ^ F

//                                  D + E|encoded|^C

SKCMS_API bool skcms_TransferFunction_makePQish(skcms_TransferFunction*,

                                                float A, float B, float C,

                                                float D, float E, float F);

// HLGish:

//            { sign(encoded) * ( (R|encoded|)^G )          when 0   <= |encoded| <= 1/R

//   linear = { sign(encoded) * ( e^(a(|encoded|-c)) + b )  when 1/R <  |encoded|

SKCMS_API bool skcms_TransferFunction_makeHLGish(skcms_TransferFunction*,

                                                float R, float G,

                                                float a, float b, float c);

// PQ mapping encoded [0,1] to linear [0,1].

static inline bool skcms_TransferFunction_makePQ(skcms_TransferFunction* tf) {

    return skcms_TransferFunction_makePQish(tf, -107/128.0f,         1.0f,   32/2523.0f

                                              , 2413/128.0f, -2392/128.0f, 8192/1305.0f);

}

Unexecuted instantiation: enc_color_management.cc:skcms_TransferFunction_makePQ(skcms_TransferFunction*)

Unexecuted instantiation: skcms.cc:skcms_TransferFunction_makePQ(skcms_TransferFunction*)

// HLG mapping encoded [0,1] to linear [0,12].

static inline bool skcms_TransferFunction_makeHLG(skcms_TransferFunction* tf) {

    return skcms_TransferFunction_makeHLGish(tf, 2.0f, 2.0f

                                               , 1/0.17883277f, 0.28466892f, 0.55991073f);

}

Unexecuted instantiation: enc_color_management.cc:skcms_TransferFunction_makeHLG(skcms_TransferFunction*)

Unexecuted instantiation: skcms.cc:skcms_TransferFunction_makeHLG(skcms_TransferFunction*)

// Unified representation of 'curv' or 'para' tag data, or a 1D table from 'mft1' or 'mft2'

typedef union skcms_Curve {

    struct {

        uint32_t alias_of_table_entries;

        skcms_TransferFunction parametric;

    };

    struct {

        uint32_t table_entries;

        const uint8_t* table_8;

        const uint8_t* table_16;

    };

} skcms_Curve;

typedef struct skcms_A2B {

    // Optional: N 1D curves, followed by an N-dimensional CLUT.

    // If input_channels == 0, these curves and CLUT are skipped,

    // Otherwise, input_channels must be in [1, 4].

    uint32_t        input_channels;

    skcms_Curve     input_curves[4];

    uint8_t         grid_points[4];

    const uint8_t*  grid_8;

    const uint8_t*  grid_16;

    // Optional: 3 1D curves, followed by a color matrix.

    // If matrix_channels == 0, these curves and matrix are skipped,

    // Otherwise, matrix_channels must be 3.

    uint32_t        matrix_channels;

    skcms_Curve     matrix_curves[3];

    skcms_Matrix3x4 matrix;

    // Required: 3 1D curves. Always present, and output_channels must be 3.

    uint32_t        output_channels;

    skcms_Curve     output_curves[3];

} skcms_A2B;

typedef struct skcms_ICCProfile {

    const uint8_t* buffer;

    uint32_t size;

    uint32_t data_color_space;

    uint32_t pcs;

    uint32_t tag_count;

    // skcms_Parse() will set commonly-used fields for you when possible:

    // If we can parse red, green and blue transfer curves from the profile,

    // trc will be set to those three curves, and has_trc will be true.

    bool                   has_trc;

    skcms_Curve            trc[3];

    // If this profile's gamut can be represented by a 3x3 transform to XYZD50,

    // skcms_Parse() sets toXYZD50 to that transform and has_toXYZD50 to true.

    bool                   has_toXYZD50;

    skcms_Matrix3x3        toXYZD50;

    // If the profile has a valid A2B0 tag, skcms_Parse() sets A2B to that data,

    // and has_A2B to true.

    bool                   has_A2B;

    skcms_A2B              A2B;

} skcms_ICCProfile;

// The sRGB color profile is so commonly used that we offer a canonical skcms_ICCProfile for it.

SKCMS_API const skcms_ICCProfile* skcms_sRGB_profile(void);

// Ditto for XYZD50, the most common profile connection space.

SKCMS_API const skcms_ICCProfile* skcms_XYZD50_profile(void);

SKCMS_API const skcms_TransferFunction* skcms_sRGB_TransferFunction(void);

SKCMS_API const skcms_TransferFunction* skcms_sRGB_Inverse_TransferFunction(void);

SKCMS_API const skcms_TransferFunction* skcms_Identity_TransferFunction(void);

// Practical equality test for two skcms_ICCProfiles.

// The implementation is subject to change, but it will always try to answer

// "can I substitute A for B?" and "can I skip transforming from A to B?".

SKCMS_API bool skcms_ApproximatelyEqualProfiles(const skcms_ICCProfile* A,

                                                const skcms_ICCProfile* B);

// Practical test that answers: Is curve roughly the inverse of inv_tf? Typically used by passing

// the inverse of a known parametric transfer function (like sRGB), to determine if a particular

// curve is very close to sRGB.

SKCMS_API bool skcms_AreApproximateInverses(const skcms_Curve* curve,

                                            const skcms_TransferFunction* inv_tf);

// Similar to above, answering the question for all three TRC curves of the given profile. Again,

// passing skcms_sRGB_InverseTransferFunction as inv_tf will answer the question:

// "Does this profile have a transfer function that is very close to sRGB?"

SKCMS_API bool skcms_TRCs_AreApproximateInverse(const skcms_ICCProfile* profile,

                                                const skcms_TransferFunction* inv_tf);

// Parse an ICC profile and return true if possible, otherwise return false.

// The buffer is not copied, it must remain valid as long as the skcms_ICCProfile

// will be used.

SKCMS_API bool skcms_Parse(const void*, size_t, skcms_ICCProfile*);

SKCMS_API bool skcms_ApproximateCurve(const skcms_Curve* curve,

                                      skcms_TransferFunction* approx,

                                      float* max_error);

SKCMS_API bool skcms_GetCHAD(const skcms_ICCProfile*, skcms_Matrix3x3*);

SKCMS_API bool skcms_GetWTPT(const skcms_ICCProfile*, float xyz[3]);

// These are common ICC signature values

enum {

    // data_color_space

    skcms_Signature_CMYK = 0x434D594B,

    skcms_Signature_Gray = 0x47524159,

    skcms_Signature_RGB  = 0x52474220,

    // pcs

    skcms_Signature_Lab  = 0x4C616220,

    skcms_Signature_XYZ  = 0x58595A20,

};

typedef enum skcms_PixelFormat {

    skcms_PixelFormat_A_8,

    skcms_PixelFormat_A_8_,

    skcms_PixelFormat_G_8,

    skcms_PixelFormat_G_8_,

    skcms_PixelFormat_RGBA_8888_Palette8,

    skcms_PixelFormat_BGRA_8888_Palette8,

    skcms_PixelFormat_RGB_565,

    skcms_PixelFormat_BGR_565,

    skcms_PixelFormat_ABGR_4444,

    skcms_PixelFormat_ARGB_4444,

    skcms_PixelFormat_RGB_888,

    skcms_PixelFormat_BGR_888,

    skcms_PixelFormat_RGBA_8888,

    skcms_PixelFormat_BGRA_8888,

    skcms_PixelFormat_RGBA_1010102,

    skcms_PixelFormat_BGRA_1010102,

    skcms_PixelFormat_RGB_161616LE,     // Little-endian.  Pointers must be 16-bit aligned.

    skcms_PixelFormat_BGR_161616LE,

    skcms_PixelFormat_RGBA_16161616LE,

    skcms_PixelFormat_BGRA_16161616LE,

    skcms_PixelFormat_RGB_161616BE,     // Big-endian.  Pointers must be 16-bit aligned.

    skcms_PixelFormat_BGR_161616BE,

    skcms_PixelFormat_RGBA_16161616BE,

    skcms_PixelFormat_BGRA_16161616BE,

    skcms_PixelFormat_RGB_hhh_Norm,   // 1-5-10 half-precision float in [0,1]

    skcms_PixelFormat_BGR_hhh_Norm,   // Pointers must be 16-bit aligned.

    skcms_PixelFormat_RGBA_hhhh_Norm,

    skcms_PixelFormat_BGRA_hhhh_Norm,

    skcms_PixelFormat_RGB_hhh,        // 1-5-10 half-precision float.

    skcms_PixelFormat_BGR_hhh,        // Pointers must be 16-bit aligned.

    skcms_PixelFormat_RGBA_hhhh,

    skcms_PixelFormat_BGRA_hhhh,

    skcms_PixelFormat_RGB_fff,        // 1-8-23 single-precision float (the normal kind).

    skcms_PixelFormat_BGR_fff,        // Pointers must be 32-bit aligned.

    skcms_PixelFormat_RGBA_ffff,

    skcms_PixelFormat_BGRA_ffff,

} skcms_PixelFormat;

// We always store any alpha channel linearly.  In the chart below, tf-1() is the inverse

// transfer function for the given color profile (applying the transfer function linearizes).

// We treat opaque as a strong requirement, not just a performance hint: we will ignore

// any source alpha and treat it as 1.0, and will make sure that any destination alpha

// channel is filled with the equivalent of 1.0.

// We used to offer multiple types of premultiplication, but now just one, PremulAsEncoded.

// This is the premul you're probably used to working with.

typedef enum skcms_AlphaFormat {

    skcms_AlphaFormat_Opaque,          // alpha is always opaque

                                       //   tf-1(r),   tf-1(g),   tf-1(b),   1.0

    skcms_AlphaFormat_Unpremul,        // alpha and color are unassociated

                                       //   tf-1(r),   tf-1(g),   tf-1(b),   a

    skcms_AlphaFormat_PremulAsEncoded, // premultiplied while encoded

                                       //   tf-1(r)*a, tf-1(g)*a, tf-1(b)*a, a

} skcms_AlphaFormat;

// Convert npixels pixels from src format and color profile to dst format and color profile

// and return true, otherwise return false.  It is safe to alias dst == src if dstFmt == srcFmt.

SKCMS_API bool skcms_Transform(const void*             src,

                               skcms_PixelFormat       srcFmt,

                               skcms_AlphaFormat       srcAlpha,

                               const skcms_ICCProfile* srcProfile,

                               void*                   dst,

                               skcms_PixelFormat       dstFmt,

                               skcms_AlphaFormat       dstAlpha,

                               const skcms_ICCProfile* dstProfile,

                               size_t                  npixels);

// As skcms_Transform(), supporting srcFmts with a palette.

SKCMS_API bool skcms_TransformWithPalette(const void*             src,

                                          skcms_PixelFormat       srcFmt,

                                          skcms_AlphaFormat       srcAlpha,

                                          const skcms_ICCProfile* srcProfile,

                                          void*                   dst,

                                          skcms_PixelFormat       dstFmt,

                                          skcms_AlphaFormat       dstAlpha,

                                          const skcms_ICCProfile* dstProfile,

                                          size_t                  npixels,

                                          const void*             palette);

// If profile can be used as a destination in skcms_Transform, return true. Otherwise, attempt to

// rewrite it with approximations where reasonable. If successful, return true. If no reasonable

// approximation exists, leave the profile unchanged and return false.

SKCMS_API bool skcms_MakeUsableAsDestination(skcms_ICCProfile* profile);

// If profile can be used as a destination with a single parametric transfer function (ie for

// rasterization), return true. Otherwise, attempt to rewrite it with approximations where

// reasonable. If successful, return true. If no reasonable approximation exists, leave the

// profile unchanged and return false.

SKCMS_API bool skcms_MakeUsableAsDestinationWithSingleCurve(skcms_ICCProfile* profile);

// Returns a matrix to adapt XYZ color from given the whitepoint to D50.

SKCMS_API bool skcms_AdaptToXYZD50(float wx, float wy,

                                   skcms_Matrix3x3* toXYZD50);

// Returns a matrix to convert RGB color into XYZ adapted to D50, given the

// primaries and whitepoint of the RGB model.

SKCMS_API bool skcms_PrimariesToXYZD50(float rx, float ry,

                                       float gx, float gy,

                                       float bx, float by,

                                       float wx, float wy,

                                       skcms_Matrix3x3* toXYZD50);

// Utilities for programmatically constructing profiles

static inline void skcms_Init(skcms_ICCProfile* p) {

    memset(p, 0, sizeof(*p));

    p->data_color_space = skcms_Signature_RGB;

    p->pcs = skcms_Signature_XYZ;

}

Unexecuted instantiation: enc_color_management.cc:skcms_Init(skcms_ICCProfile*)

Unexecuted instantiation: skcms.cc:skcms_Init(skcms_ICCProfile*)

static inline void skcms_SetTransferFunction(skcms_ICCProfile* p,

                                             const skcms_TransferFunction* tf) {

    p->has_trc = true;

    for (int i = 0; i < 3; ++i) {

        p->trc[i].table_entries = 0;

        p->trc[i].parametric = *tf;

    }

}

Unexecuted instantiation: enc_color_management.cc:skcms_SetTransferFunction(skcms_ICCProfile*, skcms_TransferFunction const*)

Unexecuted instantiation: skcms.cc:skcms_SetTransferFunction(skcms_ICCProfile*, skcms_TransferFunction const*)

static inline void skcms_SetXYZD50(skcms_ICCProfile* p, const skcms_Matrix3x3* m) {

    p->has_toXYZD50 = true;

    p->toXYZD50 = *m;

}

Unexecuted instantiation: enc_color_management.cc:skcms_SetXYZD50(skcms_ICCProfile*, skcms_Matrix3x3 const*)

Unexecuted instantiation: skcms.cc:skcms_SetXYZD50(skcms_ICCProfile*, skcms_Matrix3x3 const*)

#ifdef __cplusplus

}

#endif