/* Copyright (C) 1995, 2000 Aladdin Enterprises.  All rights reserved.
  
  This file is part of AFPL Ghostscript.
  
  AFPL Ghostscript is distributed with NO WARRANTY OF ANY KIND.  No author or
  distributor accepts any responsibility for the consequences of using it, or
  for whether it serves any particular purpose or works at all, unless he or
  she says so in writing.  Refer to the Aladdin Free Public License (the
  "License") for full details.
  
  Every copy of AFPL Ghostscript must include a copy of the License, normally
  in a plain ASCII text file named PUBLIC.  The License grants you the right
  to copy, modify and redistribute AFPL Ghostscript, but only under certain
  conditions described in the License.  Among other things, the License
  requires that the copyright notice and this notice be preserved on all
  copies.
*/

/*$Id: gsropt.h,v 1.4 2001/04/05 23:21:15 raph Exp $ */
/* RasterOp / transparency type definitions */

#ifndef gsropt_INCLUDED
#  define gsropt_INCLUDED

/*
 * This file defines the types for some library extensions that are
 * motivated by PCL5 and also made available for PostScript:
 * RasterOp, source and pattern white-pixel transparency, and
 * per-pixel "render algorithm" information.
 */

/*
 * Define whether we implement transparency correctly, or whether we
 * implement it as documented in the H-P manuals.
 */
#define TRANSPARENCY_PER_H_P

/*
 * By the magic of Boolean algebra, we can operate on the rop codes using
 * Boolean operators and get the right result.  E.g., the value of
 * (rop3_S & rop3_D) is the rop3 code for S & D.  We just have to remember
 * to mask results with rop2_1 or rop3_1 if necessary.
 */

/* 2-input RasterOp */
typedef enum {
    rop2_0 = 0,
    rop2_S = 0xc,		/* source */
#define rop2_S_shift 2
    rop2_D = 0xa,		/* destination */
#define rop2_D_shift 1
    rop2_1 = 0xf,
#define rop2_operand(shift, d, s)\
  ((shift) == 2 ? (s) : (d))
    rop2_default = rop2_S
} gs_rop2_t;

/*
 * For the 3-input case, we follow H-P's inconsistent terminology:
 * the transparency mode is called pattern transparency, but the third
 * RasterOp operand is called texture, not pattern.
 */

/* 3-input RasterOp */
typedef enum {
    rop3_0 = 0,
    rop3_T = 0xf0,		/* texture */
#define rop3_T_shift 4
    rop3_S = 0xcc,		/* source */
#define rop3_S_shift 2
    rop3_D = 0xaa,		/* destination */
#define rop3_D_shift 1
    rop3_1 = 0xff,
    rop3_default = rop3_T | rop3_S
} gs_rop3_t;

/* All the transformations on rop3s are designed so that */
/* they can also be used on lops.  The only place this costs anything */
/* is in rop3_invert. */

/*
 * Invert an operand.
 */
#define rop3_invert_(op, mask, shift)\
  ( (((op) & mask) >> shift) | (((op) & (rop3_1 - mask)) << shift) |\
    ((op) & ~rop3_1) )
#define rop3_invert_D(op) rop3_invert_(op, rop3_D, rop3_D_shift)
#define rop3_invert_S(op) rop3_invert_(op, rop3_S, rop3_S_shift)
#define rop3_invert_T(op) rop3_invert_(op, rop3_T, rop3_T_shift)
/*
 * Pin an operand to 0.
 */
#define rop3_know_0_(op, mask, shift)\
  ( (((op) & (rop3_1 - mask)) << shift) | ((op) & ~mask) )
#define rop3_know_D_0(op) rop3_know_0_(op, rop3_D, rop3_D_shift)
#define rop3_know_S_0(op) rop3_know_0_(op, rop3_S, rop3_S_shift)
#define rop3_know_T_0(op) rop3_know_0_(op, rop3_T, rop3_T_shift)
/*
 * Pin an operand to 1.
 */
#define rop3_know_1_(op, mask, shift)\
  ( (((op) & mask) >> shift) | ((op) & ~(rop3_1 - mask)) )
#define rop3_know_D_1(op) rop3_know_1_(op, rop3_D, rop3_D_shift)
#define rop3_know_S_1(op) rop3_know_1_(op, rop3_S, rop3_S_shift)
#define rop3_know_T_1(op) rop3_know_1_(op, rop3_T, rop3_T_shift)
/*
 * Swap S and T.
 */
#define rop3_swap_S_T(op)\
  ( (((op) & rop3_S & ~rop3_T) << (rop3_T_shift - rop3_S_shift)) |\
    (((op) & ~rop3_S & rop3_T) >> (rop3_T_shift - rop3_S_shift)) |\
    ((op) & (~rop3_1 | (rop3_S ^ rop3_T))) )
/*
 * Account for transparency.
 */
#define rop3_use_D_when_0_(op, mask)\
  (((op) & ~(rop3_1 - mask)) | (rop3_D & ~mask))
#define rop3_use_D_when_1_(op, mask)\
  (((op) & ~mask) | (rop3_D & mask))
#define rop3_use_D_when_S_0(op) rop3_use_D_when_0_(op, rop3_S)
#define rop3_use_D_when_S_1(op) rop3_use_D_when_1_(op, rop3_S)
#define rop3_use_D_when_T_0(op) rop3_use_D_when_0_(op, rop3_T)
#define rop3_use_D_when_T_1(op) rop3_use_D_when_1_(op, rop3_T)
/*
 * Invert the result.
 */
#define rop3_not(op) ((op) ^ rop3_1)
/*
 * Test whether an operand is used.
 */
#define rop3_uses_(op, mask, shift)\
  ( ((((op) << shift) ^ (op)) & mask) != 0 )
#define rop3_uses_D(op) rop3_uses_(op, rop3_D, rop3_D_shift)
#define rop3_uses_S(op) rop3_uses_(op, rop3_S, rop3_S_shift)
#define rop3_uses_T(op) rop3_uses_(op, rop3_T, rop3_T_shift)
/*
 * Test whether an operation is idempotent, i.e., whether
 * f(D, S, T) = f(f(D, S, T), S, T).  This is equivalent to the condition that
 * for all values s and t, !( f(0,s,t) == 1 && f(1,s,t) == 0 ).
 */
#define rop3_is_idempotent(op)\
  !( (op) & ~((op) << rop3_D_shift) & rop3_D )

/* Transparency */
#define source_transparent_default false
#define pattern_transparent_default false

/*
 * We define a logical operation as a RasterOp, transparency flags,
 * and render algorithm all packed into a single integer.
 * In principle, we should use a structure, but most C implementations
 * implement structure values very inefficiently.
 *
 * In addition, we define a "pdf14" flag which indicates that PDF
 * transparency is in effect. This doesn't change rendering in any way,
 * but does force the lop to be considered non-idempotent.
 */
#define lop_rop(lop) ((gs_rop3_t)((lop) & 0xff))	/* must be low-order bits */
#define lop_S_transparent 0x100
#define lop_T_transparent 0x200
#define lop_pdf14 0x4000
#define lop_ral_shift 10
#define lop_ral_mask 0xf
typedef uint gs_logical_operation_t;

#define lop_default\
  (rop3_default |\
   (source_transparent_default ? lop_S_transparent : 0) |\
   (pattern_transparent_default ? lop_T_transparent : 0))

     /* Test whether a logical operation uses S or T. */
#ifdef TRANSPARENCY_PER_H_P	/* bizarre but necessary definition */
#define lop_uses_S(lop)\
  (rop3_uses_S(lop) || ((lop) & (lop_S_transparent | lop_T_transparent)))
#else				/* reasonable definition */
#define lop_uses_S(lop)\
  (rop3_uses_S(lop) || ((lop) & lop_S_transparent))
#endif
#define lop_uses_T(lop)\
  (rop3_uses_T(lop) || ((lop) & lop_T_transparent))
/* Test whether a logical operation just sets D = x if y = 0. */
#define lop_no_T_is_S(lop)\
  (((lop) & (lop_S_transparent | (rop3_1 - rop3_T))) == (rop3_S & ~rop3_T))
#define lop_no_S_is_T(lop)\
  (((lop) & (lop_T_transparent | (rop3_1 - rop3_S))) == (rop3_T & ~rop3_S))
/* Test whether a logical operation is idempotent. */
#define lop_is_idempotent(lop) (rop3_is_idempotent(lop) && !(lop & lop_pdf14))

/*
 * Define the logical operation versions of some RasterOp transformations.
 * Note that these also affect the transparency flags.
 */
#define lop_know_S_0(lop)\
  (rop3_know_S_0(lop) & ~lop_S_transparent)
#define lop_know_T_0(lop)\
  (rop3_know_T_0(lop) & ~lop_T_transparent)
#define lop_know_S_1(lop)\
  (lop & lop_S_transparent ? rop3_D : rop3_know_S_1(lop))
#define lop_know_T_1(lop)\
  (lop & lop_T_transparent ? rop3_D : rop3_know_T_1(lop))

/* Define the interface to the table of 256 RasterOp procedures. */
typedef unsigned long rop_operand;
typedef rop_operand (*rop_proc)(P3(rop_operand D, rop_operand S, rop_operand T));

/* Define the table of operand usage by the 256 RasterOp operations. */
typedef enum {
    rop_usage_none = 0,
    rop_usage_D = 1,
    rop_usage_S = 2,
    rop_usage_DS = 3,
    rop_usage_T = 4,
    rop_usage_DT = 5,
    rop_usage_ST = 6,
    rop_usage_DST = 7
} rop_usage_t;

/* Define the table of RasterOp implementation procedures. */
extern const rop_proc rop_proc_table[256];

/* Define the table of RasterOp operand usage. */
extern const byte /*rop_usage_t*/ rop_usage_table[256];

#endif /* gsropt_INCLUDED */
