/* Copyright (C) 1994, 1995, 1996, 1997, 1998, 1999 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: gsht1.c,v 1.2 2000/09/19 19:00:29 lpd Exp $ */
/* Extended halftone operators for Ghostscript library */
#include "memory_.h"
#include "gx.h"
#include "gserrors.h"
#include "gsstruct.h"
#include "gsutil.h"		/* for gs_next_ids */
#include "gzstate.h"
#include "gxdevice.h"		/* for gzht.h */
#include "gzht.h"

/* Define the size of the halftone tile cache. */
#define max_tile_bytes_LARGE 4096
#define max_tile_bytes_SMALL 512
#if arch_small_memory
#  define max_tile_cache_bytes max_tile_bytes_SMALL
#else
#  define max_tile_cache_bytes\
     (gs_debug_c('.') ? max_tile_bytes_SMALL : max_tile_bytes_LARGE)
#endif

/* Imports from gscolor.c */
void load_transfer_map(P3(gs_state *, gx_transfer_map *, floatp));

/* Forward declarations */
private int process_spot(P4(gx_ht_order *, gs_state *,
			    gs_spot_halftone *, gs_memory_t *));
private int process_threshold(P4(gx_ht_order *, gs_state *,
				 gs_threshold_halftone *, gs_memory_t *));
private int process_threshold2(P4(gx_ht_order *, gs_state *,
				  gs_threshold2_halftone *,
				  gs_memory_t *));
private int process_client_order(P4(gx_ht_order *, gs_state *,
				gs_client_order_halftone *, gs_memory_t *));

/* Structure types */
public_st_halftone_component();
public_st_ht_component_element();

/* GC procedures */

private 
ENUM_PTRS_WITH(halftone_component_enum_ptrs, gs_halftone_component *hptr) return 0;
case 0:
switch (hptr->type)
{
    case ht_type_spot:
ENUM_RETURN((hptr->params.spot.transfer == 0 ?
	     hptr->params.spot.transfer_closure.data :
	     0));
    case ht_type_threshold:
ENUM_RETURN_CONST_STRING_PTR(gs_halftone_component,
			     params.threshold.thresholds);
    case ht_type_threshold2:
return ENUM_CONST_BYTESTRING(&hptr->params.threshold2.thresholds);
    case ht_type_client_order:
ENUM_RETURN(hptr->params.client_order.client_data);
    default:			/* not possible */
return 0;
}
case 1:
switch (hptr->type) {
    case ht_type_threshold:
	ENUM_RETURN((hptr->params.threshold.transfer == 0 ?
		     hptr->params.threshold.transfer_closure.data :
		     0));
    case ht_type_threshold2:
	ENUM_RETURN(hptr->params.threshold2.transfer_closure.data);
    case ht_type_client_order:
	ENUM_RETURN(hptr->params.client_order.transfer_closure.data);
    default:
	return 0;
}
ENUM_PTRS_END
private RELOC_PTRS_WITH(halftone_component_reloc_ptrs, gs_halftone_component *hptr)
{
    switch (hptr->type) {
	case ht_type_spot:
	    if (hptr->params.spot.transfer == 0)
		RELOC_VAR(hptr->params.spot.transfer_closure.data);
	    break;
	case ht_type_threshold:
	    RELOC_CONST_STRING_VAR(hptr->params.threshold.thresholds);
	    if (hptr->params.threshold.transfer == 0)
		RELOC_VAR(hptr->params.threshold.transfer_closure.data);
	    break;
	case ht_type_threshold2:
	    RELOC_CONST_BYTESTRING_VAR(hptr->params.threshold2.thresholds);
	    RELOC_OBJ_VAR(hptr->params.threshold2.transfer_closure.data);
	    break;
	case ht_type_client_order:
	    RELOC_VAR(hptr->params.client_order.client_data);
	    RELOC_VAR(hptr->params.client_order.transfer_closure.data);
	    break;
	default:
	    break;
    }
}
RELOC_PTRS_END

/* setcolorscreen */
int
gs_setcolorscreen(gs_state * pgs, gs_colorscreen_halftone * pht)
{
    gs_halftone ht;

    ht.type = ht_type_colorscreen;
    ht.params.colorscreen = *pht;
    return gs_sethalftone(pgs, &ht);
}

/* currentcolorscreen */
int
gs_currentcolorscreen(gs_state * pgs, gs_colorscreen_halftone * pht)
{
    int code;

    switch (pgs->halftone->type) {
	case ht_type_colorscreen:
	    *pht = pgs->halftone->params.colorscreen;
	    return 0;
	default:
	    code = gs_currentscreen(pgs, &pht->screens.colored.gray);
	    if (code < 0)
		return code;
	    pht->screens.colored.red = pht->screens.colored.gray;
	    pht->screens.colored.green = pht->screens.colored.gray;
	    pht->screens.colored.blue = pht->screens.colored.gray;
	    return 0;
    }
}

/* Set the halftone in the graphics state. */
int
gs_sethalftone(gs_state * pgs, gs_halftone * pht)
{
    gs_halftone ht;

    ht = *pht;
    ht.rc.memory = pgs->memory;
    return gs_sethalftone_allocated(pgs, &ht);
}
int
gs_sethalftone_allocated(gs_state * pgs, gs_halftone * pht)
{
    gx_device_halftone dev_ht;
    int code = gs_sethalftone_prepare(pgs, pht, &dev_ht);

    if (code < 0)
	return code;
    dev_ht.rc.memory = pht->rc.memory;
    return gx_ht_install(pgs, pht, &dev_ht);
}
/* Prepare the halftone, but don't install it. */
int
gs_sethalftone_prepare(gs_state * pgs, gs_halftone * pht,
		       gx_device_halftone * pdht)
{
    gs_memory_t *mem = pht->rc.memory;
    gx_ht_order_component *pocs = 0;
    int code = 0;

    switch (pht->type) {
	case ht_type_colorscreen:
	    {
		gs_screen_halftone *phc =
		pht->params.colorscreen.screens.indexed;
		static const gs_ht_separation_name cnames[4] =
		{
		    gs_ht_separation_Default, gs_ht_separation_Red,
		    gs_ht_separation_Green, gs_ht_separation_Blue
		};
		static const int cindex[4] =
		{3, 0, 1, 2};
		int i;

		pocs = gs_alloc_struct_array(mem, 4,
					     gx_ht_order_component,
					     &st_ht_order_component_element,
					     "gs_sethalftone");
		if (pocs == 0)
		    return_error(gs_error_VMerror);
		for (i = 0; i < 4; i++) {
		    gs_screen_enum senum;
		    int ci = cindex[i];
		    gx_ht_order_component *poc = &pocs[i];

		    code = gx_ht_process_screen_memory(&senum, pgs,
				&phc[ci], gs_currentaccuratescreens(), mem);
		    if (code < 0)
			break;
		    poc->corder = senum.order;
		    poc->cname = cnames[i];
		    if (i == 0)	/* Gray = Default */
			pdht->order = senum.order;
		    else {
			uint tile_bytes = senum.order.raster *
			    (senum.order.num_bits / senum.order.width);
			uint num_tiles =
			    max_tile_cache_bytes / tile_bytes + 1;
			gx_ht_cache *pcache =
			    gx_ht_alloc_cache(mem, num_tiles,
					      tile_bytes * num_tiles);

			if (pcache == 0) {
			    code = gs_note_error(gs_error_VMerror);
			    break;
			}
			poc->corder.cache = pcache;
			gx_ht_init_cache(pcache, &poc->corder);
		    }
		}
		if (code < 0)
		    break;
		pdht->components = pocs;
		pdht->num_comp = 4;
	    }
	    break;
	case ht_type_spot:
	    code = process_spot(&pdht->order, pgs, &pht->params.spot, mem);
	    if (code < 0)
		return code;
	    pdht->components = 0;
	    break;
	case ht_type_threshold:
	    code = process_threshold(&pdht->order, pgs,
				     &pht->params.threshold, mem);
	    if (code < 0)
		return code;
	    pdht->components = 0;
	    break;
	case ht_type_threshold2:
	    code = process_threshold2(&pdht->order, pgs,
				      &pht->params.threshold2, mem);
	    if (code < 0)
		return code;
	    pdht->components = 0;
	    break;
	case ht_type_client_order:
	    code = process_client_order(&pdht->order, pgs,
					&pht->params.client_order, mem);
	    if (code < 0)
		return code;
	    pdht->components = 0;
	    break;
	case ht_type_multiple:
	case ht_type_multiple_colorscreen:
	    {
		uint count = pht->params.multiple.num_comp;
		bool have_Default = false;
		uint i;
		gs_halftone_component *phc = pht->params.multiple.components;
		gx_ht_order_component *poc_next;

		pocs = gs_alloc_struct_array(mem, count,
					     gx_ht_order_component,
					     &st_ht_order_component_element,
					     "gs_sethalftone");
		if (pocs == 0)
		    return_error(gs_error_VMerror);
		poc_next = pocs + 1;
		for (i = 0; i < count; i++, phc++) {
		    gx_ht_order_component *poc;

		    if (phc->cname == gs_ht_separation_Default) {
			if (have_Default) {
			    /* Duplicate Default */
			    code = gs_note_error(gs_error_rangecheck);
			    break;
			}
			poc = pocs;
			have_Default = true;
		    } else if (i == count - 1 && !have_Default) {
			/* No Default */
			code = gs_note_error(gs_error_rangecheck);
			break;
		    } else
			poc = poc_next++;
		    poc->cname = phc->cname;
		    switch (phc->type) {
			case ht_type_spot:
			    code = process_spot(&poc->corder, pgs,
						&phc->params.spot, mem);
			    break;
			case ht_type_threshold:
			    code = process_threshold(&poc->corder, pgs,
						&phc->params.threshold, mem);
			    break;
			case ht_type_threshold2:
			    code = process_threshold2(&poc->corder, pgs,
						&phc->params.threshold2, mem);
			    break;
			case ht_type_client_order:
			    code = process_client_order(&poc->corder, pgs,
					    &phc->params.client_order, mem);
			    break;
			default:
			    code = gs_note_error(gs_error_rangecheck);
			    break;
		    }
		    if (code < 0)
			break;
		    if (poc != pocs) {
			gx_ht_cache *pcache =
			gx_ht_alloc_cache(mem, 4,
					  poc->corder.raster *
					  (poc->corder.num_bits /
					   poc->corder.width) * 4);

			if (pcache == 0) {
			    code = gs_note_error(gs_error_VMerror);
			    break;
			}
			poc->corder.cache = pcache;
			gx_ht_init_cache(pcache, &poc->corder);
		    }
		}
		if (code < 0)
		    break;
		pdht->order = pocs[0].corder;	/* Default */
		if (count == 1) {
		    /* We have only a Default; */
		    /* we don't need components. */
		    gs_free_object(mem, pocs, "gs_sethalftone");
		    pdht->components = 0;
		} else {
		    pdht->components = pocs;
		    pdht->num_comp = count;
		}
	    }
	    break;
	default:
	    return_error(gs_error_rangecheck);
    }
    if (code < 0)
	gs_free_object(mem, pocs, "gs_sethalftone");
    return code;
}

/* ------ Internal routines ------ */

/* Process a transfer function override, if any. */
private int
process_transfer(gx_ht_order * porder, gs_state * pgs,
		 gs_mapping_proc proc, gs_mapping_closure_t * pmc,
		 gs_memory_t * mem)
{
    gx_transfer_map *pmap;

    if (proc == 0 && pmc->proc == 0)
	return 0;
    pmap = gs_alloc_struct(mem, gx_transfer_map, &st_transfer_map,
			   "process_transfer");
    if (pmap == 0)
	return_error(gs_error_VMerror);
    pmap->proc = proc;		/* 0 => use closure */
    pmap->closure = *pmc;
    pmap->id = gs_next_ids(1);
    load_transfer_map(pgs, pmap, 0.0);
    porder->transfer = pmap;
    return 0;
}

/* Process a spot plane. */
private int
process_spot(gx_ht_order * porder, gs_state * pgs,
	     gs_spot_halftone * phsp, gs_memory_t * mem)
{
    gs_screen_enum senum;

    int code = gx_ht_process_screen_memory(&senum, pgs, &phsp->screen,
					   phsp->accurate_screens, mem);

    if (code < 0)
	return code;
    *porder = senum.order;
    return process_transfer(porder, pgs, phsp->transfer,
			    &phsp->transfer_closure, mem);
}

/* Construct the halftone order from a threshold array. */
void
gx_ht_complete_threshold_order(gx_ht_order * porder)
{
    int num_levels = porder->num_levels;
    uint *levels = porder->levels;
    uint size = porder->num_bits;
    gx_ht_bit *bits = porder->bit_data;
    uint i, j;

    /* The caller has set bits[i] = max(1, thresholds[i]). */
    gx_sort_ht_order(bits, size);
    /* We want to set levels[j] to the lowest value of i */
    /* such that bits[i].mask > j. */
    for (i = 0, j = 0; i < size; i++) {
	if (bits[i].mask != j) {
	    if_debug3('h', "[h]levels[%u..%u] = %u\n",
		      j, (uint) bits[i].mask, i);
	    while (j < bits[i].mask)
		levels[j++] = i;
	}
    }
    while (j < num_levels)
	levels[j++] = size;
    gx_ht_construct_bits(porder);
}
int
gx_ht_construct_threshold_order(gx_ht_order * porder, const byte * thresholds)
{
    return porder->procs->construct_order(porder, thresholds);
}

/* Process a threshold plane. */
private int
process_threshold(gx_ht_order * porder, gs_state * pgs,
		  gs_threshold_halftone * phtp, gs_memory_t * mem)
{
    int code;

    porder->params.M = phtp->width, porder->params.N = 0;
    porder->params.R = 1;
    porder->params.M1 = phtp->height, porder->params.N1 = 0;
    porder->params.R1 = 1;
    code = gx_ht_alloc_threshold_order(porder, phtp->width, phtp->height,
				       256, mem);
    if (code < 0)
	return code;
    gx_ht_construct_threshold_order(porder, phtp->thresholds.data);
    return process_transfer(porder, pgs, phtp->transfer,
			    &phtp->transfer_closure, mem);
}

/* Process an extended threshold plane. */
private int
process_threshold2(gx_ht_order * porder, gs_state * pgs,
		   gs_threshold2_halftone * phtp, gs_memory_t * mem)
{
    int code;
    /*
     * There are potentially 64K different levels for this plane, but this
     * is more than we're willing to handle.  Try to reduce the number of
     * levels by dropping leading or trailing zero bits from the thresholds;
     * as a last resort, drop (possibly significant) trailing bits.
     */
#define LOG2_MAX_HT_LEVELS 14
#define MAX_HT_LEVELS (1 << LOG2_MAX_HT_LEVELS)
    int bps = phtp->bytes_per_sample;
    const byte *data = phtp->thresholds.data;
    const int w1 = phtp->width, h1 = phtp->height, size1 = w1 * h1;
    const int w2 = phtp->width2, h2 = phtp->height2, size2 = w2 * h2;
    const uint size = size1 + size2;
    const int d = (h2 == 0 ? h1 : igcd(h1, h2));
    const int sod = size / d;
    uint num_levels;
    uint i;
    int rshift = 0;
    int shift;

    {
	uint mask = 0, max_thr = 0;

	for (i = 0; i < size; ++i) {
	    uint thr =
		(bps == 1 ? data[i] : (data[i * 2] << 8) + data[i * 2 + 1]);

	    mask |= thr;
	    max_thr = max(max_thr, thr);
	}
	if (mask == 0)
	    mask = 1, max_thr = 1;
	while (!(mask & 1) || max_thr > MAX_HT_LEVELS)
	    mask >>= 1, max_thr >>= 1, rshift++;
	num_levels = max_thr + 1;
    }
    /*
     * Set nominal values for the params, and don't bother to call
     * gx_compute_cell_values -- the values are only needed for spot
     * halftones.
     */
    porder->params.M = sod, porder->params.N = d;
    porder->params.R = 1;
    porder->params.M1 = d, porder->params.N1 = sod;
    porder->params.R1 = 1;
    /*
     * Determine the shift between strips.  We don't know a closed formula
     * for this, so we do it by enumeration.
     */
    shift = 0;
    {
	int x = 0, y = 0;

	do {
	    if (y < h1)
		x += w1, y += h2;
	    else
		x += w2, y -= h1;
	} while (y > d);
	if (y)
	    shift = x;
    }
    code = gx_ht_alloc_ht_order(porder, sod, d, num_levels, size, shift,
				&ht_order_procs_default, mem);
    if (code < 0)
	return code;
    {
	gx_ht_bit *bits = (gx_ht_bit *)porder->bit_data;
	int row, di;

	if_debug7('h', "[h]rect1=(%d,%d), rect2=(%d,%d), strip=(%d,%d), shift=%d\n",
		  w1, h1, w2, h2, sod, d, shift);
	for (row = 0, di = 0; row < d; ++row) {
	    /* Iterate over destination rows. */
	    int dx, sy = row;	/* sy = row mod d */
	    int w;

	    for (dx = 0; dx < sod; dx += w) {
		/* Iterate within a destination row, over source rows. */
		int si, j;

		if (sy < h1) {
		    /* Copy a row from rect1. */
		    si = sy * w1;
		    w = w1;
		    sy += h2;
		} else {
		    /* Copy a row from rect2. */
		    si = size1 + (sy - h1) * w2;
		    w = w2;
		    sy -= h1;
		}
		for (j = 0; j < w; ++j, ++si, ++di) {
		    uint thr =
			(bps == 1 ? data[si] :
			 (data[si * 2] << 8) + data[si * 2 + 1])
				       >> rshift;

		    if_debug3('H', "[H]sy=%d, si=%d, di=%d\n", sy, si, di);
		    bits[di].mask = max(thr, 1);
		}
	    }
	}
    }
    gx_ht_complete_threshold_order(porder);
    return process_transfer(porder, pgs, NULL, &phtp->transfer_closure, mem);
#undef LOG2_MAX_HT_LEVELS
#undef MAX_HT_LEVELS
}

/* Process a client-order plane. */
private int
process_client_order(gx_ht_order * porder, gs_state * pgs,
		     gs_client_order_halftone * phcop, gs_memory_t * mem)
{
    int code = (*phcop->procs->create_order) (porder, pgs, phcop, mem);

    if (code < 0)
	return code;
    return process_transfer(porder, pgs, NULL,
			    &phcop->transfer_closure, mem);
}
