/* Copyright (C) 2001-2018 Artifex Software, Inc.
   All Rights Reserved.

   This software is provided AS-IS with no warranty, either express or
   implied.

   This software is distributed under license and may not be copied,
   modified or distributed except as expressly authorized under the terms
   of the license contained in the file LICENSE in this distribution.

   Refer to licensing information at http://www.artifex.com or contact
   Artifex Software, Inc.,  1305 Grant Avenue - Suite 200, Novato,
   CA 94945, U.S.A., +1(415)492-9861, for further information.
*/


/* pcmtx3.h - 3 x 3 matrix utilities for PCL device independent color spaces */

#ifndef pcmtx3_INCLUDED
#define pcmtx3_INCLUDED

#include "math_.h"
#include "gx.h"
#include "gsmatrix.h"
#include "gscspace.h"
#include "gscolor2.h"
#include "gscie.h"

/*
 * To support device independent color spaces, PCL performs a number of
 * calculations with 3 x 3 matrices. The CIE color space code in the graphic
 * library provides a format for 3 x 3 matrices, but the format is a bit
 * unusual and no corresponding utilities are provided. Hence, a separate
 * (though logically identical) format is provided here.
 *
 * Essentially all of the literature on color spaces deals with column
 * vectors, EXCEPT that specific to PostScript. The latter deals with row
 * vectors to remain consistent with the use of matrices for geometric
 * transformations. The graphics library code, being based on PostScript,
 * uses the latter arrangement of components. The CIE code in the library is
 * documented for column vectors, but specifies matrices in the less usual
 * column-first order. The current code takes the logically equivalent and
 * no less intuitive approach of using row vectors, and specifying
 * matrices in the more normal row-first order.
 *
 * There is actually some reason for these alternate approaches. The CIE code
 * is primarily concerned with transformation of color vectors, and performs
 * relatively few other matrix operations. The current code infrequently
 * transforms color vectors, but does perform other matrix operations.
 * Each code module uses the format that is more intuitive for its more
 * common operation.
 */
typedef union
{
    struct
    {
        double v1, v2, v3;
    } vc;
    double va[3];
} pcl_vec3_t;

typedef union
{
    struct
    {
        double a11, a12, a13, a21, a22, a23, a31, a32, a33;
    } c;
    double a[9];
} pcl_mtx3_t;

/*
 * Vectors in PCL and the graphic library are physically the same structure,
 * but the former are thought of as row vectors and the latter as column
 * vectors, so two different C-language structures are used. The following
 * macros are used for conversion.
 */
#define pcl_vec3_to_gs_vector3(gsv3, pcv3)                                    \
    ((gsv3).u = (pcv3).vc.v1, (gsv3).v = (pcv3).vc.v2, (gsv3).w = (pcv3).vc.v3)

#define pcl_vec3_from_gs_vector3(pcv3, gsv3)                                  \
    ((pcv3).vc.v1 = (gsv3).u, (pcv3).vc.v2 = (gsv3).v, (pcv3).vc.v3 = (gsv3).w)

/*
 * Add and subtract 3 dimensional vectors. These are not currently needed,
 * but are included for completeness.
 *
 * Any of the three pointer operands may be the same.
 */
void pcl_vec3_add(const pcl_vec3_t * pivec1,
                  const pcl_vec3_t * pivec2, pcl_vec3_t * poutvec);

void pcl_vec3_sub(const pcl_vec3_t * pivec1,
                  const pcl_vec3_t * pivec2, pcl_vec3_t * poutvec);

/*
 * Apply a matrix to a 3-dimensional row vector.
 *
 * The code will properly handle the case pinvec == poutvec.
 */
void pcl_vec3_xform(const pcl_vec3_t * pinvec,
                    pcl_vec3_t * poutvec, const pcl_mtx3_t * pmtx);

/*
 * Invert a 3 x 3 matrix.
 *
 * This will properly handle the case of pinmtx == poutmtx.
 *
 * Returns 0 on success, e_Range if the matrix provided is singular.
 */
int pcl_mtx3_invert(const pcl_mtx3_t * pinmtx, pcl_mtx3_t * poutmtx);

/*
 * Add, subtract, and multiply two 3 x 3 matrices. These are not currently
 * needed, but are included for completenese.
 *
 * In all cases, any of the three pointers provided may be identical.
 */
void pcl_mtx3_add(const pcl_mtx3_t * pinmtx1,
                  const pcl_mtx3_t * pinmtx2, pcl_mtx3_t * poutmtx);

void pcl_mtx3_sub(const pcl_mtx3_t * pinmtx1,
                  const pcl_mtx3_t * pinmtx2, pcl_mtx3_t * poutmtx);

void pcl_mtx3_mul(const pcl_mtx3_t * pinmtx1,
                  const pcl_mtx3_t * pinmtx2, pcl_mtx3_t * poutmtx);

/*
 * Convert a pcl_mtx3_t structure to and from a gs_matrix3 struct. Identity
 * transformations are rare in PCL, so no attempt is made to identify them.
 */
void pcl_mtx3_convert_to_gs(const pcl_mtx3_t * pinmtx, gs_matrix3 * pgsmtx);

void pcl_mtx3_convert_from_gs(pcl_mtx3_t * poutmtx,
                              const gs_matrix3 * pgsmtx);

#endif /* pcmtx3_INCLUDED */
