/* Copyright (C) 1989, 2000 Aladdin Enterprises.  All rights reserved.
  
  This file is part of GNU Ghostscript.
  
  GNU Ghostscript is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY.  No author or distributor accepts responsibility
  to anyone for the consequences of using it or for whether it serves any
  particular purpose or works at all, unless he says so in writing.  Refer
  to the GNU General Public License for full details.
  
  Everyone is granted permission to copy, modify and redistribute GNU
  Ghostscript, but only under the conditions described in the GNU General
  Public License.  A copy of this license is supposed to have been given
  to you along with GNU Ghostscript so you can know your rights and
  responsibilities.  It should be in a file named COPYING.  Among other
  things, the copyright notice and this notice must be preserved on all
  copies.
*/

/*$RCSfile: gxmatrix.h,v $ $Revision: 1.4.2.1 $ */
/* Internal matrix routines for Ghostscript library */

#ifndef gxmatrix_INCLUDED
#  define gxmatrix_INCLUDED

#include "gsmatrix.h"

/*
 * Define a matrix with a cached fixed-point copy of the translation.
 * This is only used by a few routines in gscoord.c; they are responsible
 * for ensuring the validity of the cache.  Note that the floating point
 * tx/ty values may be too large to fit in a fixed values; txy_fixed_valid
 * is false if this is the case, and true otherwise.
 */
typedef struct gs_matrix_fixed_s {
    _matrix_body;
    fixed tx_fixed, ty_fixed;
    bool txy_fixed_valid;
} gs_matrix_fixed;

/* Make a gs_matrix_fixed from a gs_matrix. */
int gs_matrix_fixed_from_matrix(P2(gs_matrix_fixed *, const gs_matrix *));

/* Coordinate transformations to fixed point. */
int gs_point_transform2fixed(P4(const gs_matrix_fixed *, floatp, floatp,
				gs_fixed_point *));
int gs_distance_transform2fixed(P4(const gs_matrix_fixed *, floatp, floatp,
				   gs_fixed_point *));

/*
 * Define the fixed-point coefficient structure for avoiding
 * floating point in coordinate transformations.
 * Currently this is used only by the Type 1 font interpreter.
 * The setup is in gscoord.c.
 */
typedef struct {
    long xx, xy, yx, yy;
    int skewed;
    int shift;			/* see m_fixed */
    int max_bits;		/* max bits of coefficient */
    fixed round;		/* ditto */
} fixed_coeff;

/*
 * Multiply a fixed point value by a coefficient.  The coefficient has two
 * parts: a value (long) and a shift factor (int), The result is (fixed *
 * coef_value + round_value) >> (shift + _fixed_shift)) where the shift
 * factor and the round value are picked from the fixed_coeff structure, and
 * the coefficient value (from one of the coeff1 members) is passed
 * explicitly.  The last parameter specifies the number of bits available to
 * prevent overflow for integer arithmetic.  (This is a very custom
 * routine.)  The intermediate value may exceed the size of a long integer.
 */
fixed fixed_coeff_mult(P4(fixed, long, const fixed_coeff *, int));

/*
 * Multiply a fixed whose integer part usually does not exceed max_bits
 * in magnitude by a coefficient from a fixed_coeff.
 * We can use a faster algorithm if the fixed is an integer within
 * a range that doesn't cause the multiplication to overflow an int.
 */
#define m_fixed(v, c, fc, maxb)\
  (((v) + (fixed_1 << (maxb - 1))) &\
    ((-fixed_1 << maxb) | _fixed_fraction_v) ?	/* out of range, or has fraction */\
    fixed_coeff_mult((v), (fc).c, &(fc), maxb) : \
   arith_rshift(fixed2int_var(v) * (fc).c + (fc).round, (fc).shift))

#endif /* gxmatrix_INCLUDED */
