/* Copyright (C) 1998, 1999 artofcode LLC.  All rights reserved.
  
  This program is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by the
  Free Software Foundation; either version 2 of the License, or (at your
  option) any later version.

  This program is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License along
  with this program; if not, write to the Free Software Foundation, Inc.,
  59 Temple Place, Suite 330, Boston, MA, 02111-1307.

*/

/*$Id: gshtx.c,v 1.2.6.1.2.1 2003/01/17 00:49:02 giles Exp $ */
/* Stand-alone halftone/transfer function related code */
#include "memory_.h"
#include "gx.h"
#include "gserrors.h"
#include "gsstruct.h"
#include "gsutil.h"		/* for gs_next_ids */
#include "gxfmap.h"
#include "gzstate.h"
#include "gzht.h"
#include "gshtx.h"		/* must come after g*ht.h */

/*
 * Procedure to free the set of components when a halftone is released.
 */
private void
free_comps(
	      gs_memory_t * pmem,
	      void *pvht,
	      client_name_t cname
)
{
    gs_ht *pht = (gs_ht *) pvht;

    gs_free_object(pmem, pht->params.ht_multiple.components, cname);
    gs_free_object(pmem, pvht, cname);
}

/*
 * Stub transfer function, to be applied to components that are not provided
 * with a transfer function.
 */
private float
null_closure_transfer(
			 floatp val,
			 const gx_transfer_map * pmap_dummy,	/* NOTUSED */
			 const void *dummy	/* NOTUSED */
)
{
    return val;
}


/*
 * Build a gs_ht halftone structure.
 */
int
gs_ht_build(
	       gs_ht ** ppht,
	       uint num_comps,
	       gs_memory_t * pmem
)
{
    gs_ht *pht;
    gs_ht_component *phtc;
    int i;

    /* must have at least one component */
    *ppht = 0;
    if (num_comps == 0)
	return_error(gs_error_rangecheck);

    /* allocate the halftone and the array of components */
    rc_alloc_struct_1(pht,
		      gs_ht,
		      &st_gs_ht,
		      pmem,
		      return_error(gs_error_VMerror),
		      "gs_ht_build"
	);
    phtc = gs_alloc_struct_array(pmem,
				 num_comps,
				 gs_ht_component,
				 &st_ht_comp_element,
				 "gs_ht_build"
	);
    if (phtc == 0) {
	gs_free_object(pmem, pht, "gs_ht_build");
	return_error(gs_error_VMerror);
    }
    /* initialize the halftone */
    pht->type = ht_type_multiple;
    pht->rc.free = free_comps;
    pht->params.ht_multiple.components = phtc;
    pht->params.ht_multiple.num_comp = num_comps;

    for (i = 0; i < num_comps; i++) {
	phtc[i].cname = gs_ht_separation_Default;
	phtc[i].type = ht_type_none;
    }

    *ppht = pht;

    return 0;
}

/*
 * Set a spot-function halftone component in a gs_ht halftone.
 */
int
gs_ht_set_spot_comp(
		       gs_ht * pht,
		       int comp,
		       gs_ht_separation_name sepname,
		       floatp freq,
		       floatp angle,
		       float (*spot_func) (floatp, floatp),
		       bool accurate,
		       gs_ht_transfer_proc transfer,
		       const void *client_data
)
{
    gs_ht_component *phtc = &(pht->params.ht_multiple.components[comp]);

    if (comp >= pht->params.ht_multiple.num_comp)
	return_error(gs_error_rangecheck);
    if (phtc->type != ht_type_none)
	return_error(gs_error_invalidaccess);

    phtc->cname = (pht->params.ht_multiple.num_comp == 1
		   ? gs_ht_separation_Default
		   : sepname);
    phtc->type = ht_type_spot;
    phtc->params.ht_spot.screen.frequency = freq;
    phtc->params.ht_spot.screen.angle = angle;
    phtc->params.ht_spot.screen.spot_function = spot_func;
    phtc->params.ht_spot.accurate_screens = accurate;
    phtc->params.ht_spot.transfer = gs_mapped_transfer;

    phtc->params.ht_spot.transfer_closure.proc =
	(transfer == 0 ? null_closure_transfer : transfer);
    phtc->params.ht_spot.transfer_closure.data = client_data;

    return 0;
}

/*
 * Set a threshold halftone component in a gs_ht halftone. Note that the
 * caller is responsible for releasing the threshold data.
 */
int
gs_ht_set_threshold_comp(
			    gs_ht * pht,
			    int comp,
			    gs_ht_separation_name sepname,
			    int width,
			    int height,
			    const gs_const_string * thresholds,
			    gs_ht_transfer_proc transfer,
			    const void *client_data
)
{
    gs_ht_component *phtc = &(pht->params.ht_multiple.components[comp]);

    if (comp >= pht->params.ht_multiple.num_comp)
	return_error(gs_error_rangecheck);
    if (phtc->type != ht_type_none)
	return_error(gs_error_invalidaccess);

    phtc->cname = (pht->params.ht_multiple.num_comp == 1
		   ? gs_ht_separation_Default
		   : sepname);
    phtc->type = ht_type_threshold;
    phtc->params.ht_threshold.width = width;
    phtc->params.ht_threshold.height = height;
    phtc->params.ht_threshold.thresholds = *thresholds;
    phtc->params.ht_threshold.transfer = gs_mapped_transfer;

    phtc->params.ht_threshold.transfer_closure.proc =
	(transfer == 0 ? null_closure_transfer : transfer);
    phtc->params.ht_threshold.transfer_closure.data = client_data;

    return 0;
}

/*
 * Increase the reference count of a gs_ht structure by 1.
 */
void
gs_ht_reference(
		   gs_ht * pht
)
{
    rc_increment(pht);
}

/*
 * Decrement the reference count of a gs_ht structure by 1. Free the
 * structure if the reference count reaches 0.
 */
void
gs_ht_release(
		 gs_ht * pht
)
{
    rc_decrement_only(pht, "gs_ht_release");
}


/*
 *  Verify that a gs_ht halftone is legitimate.
 */
private int
check_ht(
	    gs_ht * pht
)
{
    int i;
    bool have_default = false;
    int num_comps = pht->params.ht_multiple.num_comp;

    if (pht->type != ht_type_multiple)
	return_error(gs_error_unregistered);
    for (i = 0; i < num_comps; i++) {
	gs_ht_component *phtc = &(pht->params.ht_multiple.components[i]);

	if ((phtc->type != ht_type_spot) && (phtc->type != ht_type_threshold))
	    return_error(gs_error_unregistered);
	if (phtc->cname == gs_ht_separation_Default) {
	    if (have_default)
		return_error(gs_error_rangecheck);
	    else
		have_default = true;
	}
    }
    return have_default ? 0 : gs_error_rangecheck;
}

/*
 *  Load a transfer map from a gs_ht_transfer_proc function.
 */
private void
build_transfer_map(
		      gs_ht_component * phtc,
		      gx_transfer_map * pmap
)
{
    gs_ht_transfer_proc proc;
    const void *client_info;
    int i;
    frac *values = pmap->values;

    if (phtc->type == ht_type_spot) {
	proc = phtc->params.ht_spot.transfer_closure.proc;
	client_info = phtc->params.ht_spot.transfer_closure.data;
    } else {
	proc = phtc->params.ht_threshold.transfer_closure.proc;
	client_info = phtc->params.ht_threshold.transfer_closure.data;
    }

    for (i = 0; i < transfer_map_size; i++) {
	float fval =
	    proc(i * (1 / (double)(transfer_map_size - 1)), pmap, client_info);

	values[i] =
	    (fval <= 0.0 ? frac_0 : fval >= 1.0 ? frac_1 :
	     float2frac(fval));
    }
}

/*
 *  Allocate the order and transfer maps required by a halftone, and perform
 *  some elementary initialization. This will also build the component index
 *  to order index map.
 */
private gx_ht_order_component *
alloc_ht_order(
		  const gs_ht * pht,
		  gs_memory_t * pmem,
		  byte * comp2order
)
{
    int num_comps = pht->params.ht_multiple.num_comp;
    gx_ht_order_component *pocs = gs_alloc_struct_array(
							   pmem,
					   pht->params.ht_multiple.num_comp,
						      gx_ht_order_component,
					     &st_ht_order_component_element,
							   "alloc_ht_order"
    );
    int inext = 1;
    int i;

    if (pocs == 0)
	return 0;
    pocs->corder.transfer = 0;

    for (i = 0; i < num_comps; i++) {
	gs_ht_component *phtc = &(pht->params.ht_multiple.components[i]);
	gx_transfer_map *pmap = gs_alloc_struct(pmem,
						gx_transfer_map,
						&st_transfer_map,
						"alloc_ht_order"
	);

	if (pmap == 0) {
	    int j;

	    for (j = 0; j < inext; j++)
		gs_free_object(pmem, pocs[j].corder.transfer, "alloc_ht_order");
	    gs_free_object(pmem, pocs, "alloc_ht_order");
	    return 0;
	}
	pmap->proc = gs_mapped_transfer;
	pmap->id = gs_next_ids(1);
	if (phtc->cname == gs_ht_separation_Default) {
	    pocs->corder.levels = 0;
	    pocs->corder.bit_data = 0;
	    pocs->corder.cache = 0;
	    pocs->corder.transfer = pmap;
	    pocs->cname = gs_ht_separation_Default;
	    comp2order[i] = 0;
	} else {
	    pocs[inext].corder.levels = 0;
	    pocs[inext].corder.bit_data = 0;
	    pocs[inext].corder.cache = 0;
	    pocs[inext].corder.transfer = pmap;
	    pocs[inext].cname = phtc->cname;
	    comp2order[i] = inext++;
	}
    }

    return pocs;
}

/*
 *  Build the halftone order for one component.
 */
private int
build_component(
		   gs_ht_component * phtc,
		   gx_ht_order * porder,
		   gs_state * pgs,
		   gs_memory_t * pmem
)
{
    if (phtc->type == ht_type_spot) {
	gs_screen_enum senum;
	int code;

	code = gx_ht_process_screen_memory(&senum,
					   pgs,
					   &phtc->params.ht_spot.screen,
				      phtc->params.ht_spot.accurate_screens,
					   pmem
	    );
	if (code < 0)
	    return code;

	/* avoid wiping out the transfer structure pointer */
	senum.order.transfer = porder->transfer;
	*porder = senum.order;

    } else {			/* ht_type_threshold */
	int code;
	gx_transfer_map *transfer = porder->transfer;

	porder->params.M = phtc->params.ht_threshold.width;
	porder->params.N = 0;
	porder->params.R = 1;
	porder->params.M1 = phtc->params.ht_threshold.height;
	porder->params.N1 = 0;
	porder->params.R1 = 1;
	code = gx_ht_alloc_threshold_order(porder,
					   phtc->params.ht_threshold.width,
					   phtc->params.ht_threshold.height,
					   256,
					   pmem
	    );
	if (code < 0)
	    return code;
	gx_ht_construct_threshold_order(
				porder,
				phtc->params.ht_threshold.thresholds.data
	    );
	/*
	 * gx_ht_construct_threshold_order wipes out transfer map pointer,
	 * restore it here.
	 */
	porder->transfer = transfer;
    }

    build_transfer_map(phtc, porder->transfer);
    return 0;
}

/*
 * Free an order array and all elements it points to.
 */
private void
free_order_array(
		    gx_ht_order_component * pocs,
		    int num_comps,
		    gs_memory_t * pmem
)
{
    int i;

    for (i = 0; i < num_comps; i++)
	gx_ht_order_release(&(pocs[i].corder), pmem, true);
    gs_free_object(pmem, pocs, "gs_ht_install");
}


/*
 *  Install a gs_ht halftone as the current halftone in the graphic state.
 */
int
gs_ht_install(
		 gs_state * pgs,
		 gs_ht * pht
)
{
    int code = 0;
    gs_memory_t *pmem = pht->rc.memory;
    gx_device_halftone dev_ht;
    gx_ht_order_component *pocs;
    byte comp2order[32];	/* ample component to order map */
    int num_comps = pht->params.ht_multiple.num_comp;
    int i;

    /* perform so sanity checks (must have one default component) */
    if ((code = check_ht(pht)) != 0)
	return code;

    /* allocate the halftone order structure and transfer maps */
    if ((pocs = alloc_ht_order(pht, pmem, comp2order)) == 0)
	return_error(gs_error_VMerror);

    /* build all of the order for each component */
    for (i = 0; i < num_comps; i++) {
	int j = comp2order[i];

	code = build_component(&(pht->params.ht_multiple.components[i]),
			       &(pocs[j].corder),
			       pgs,
			       pmem
	    );

	if ((code >= 0) && (j != 0)) {
	    gx_ht_cache *pcache;

	    pcache = gx_ht_alloc_cache(pmem,
				       4,
				       pocs[j].corder.raster *
				       (pocs[j].corder.num_bits /
					pocs[j].corder.width) * 4
		);

	    if (pcache == 0)
		code = gs_note_error(gs_error_VMerror);
	    else {
		pocs[j].corder.cache = pcache;
		gx_ht_init_cache(pcache, &(pocs[j].corder));
	    }
	}
	if (code < 0)
	    break;
    }

    if (code < 0) {
	free_order_array(pocs, num_comps, pmem);
	return code;
    }
    /* initialize the device halftone structure */
    dev_ht.rc.memory = pmem;
    dev_ht.order = pocs[0].corder;	/* Default */
    if (num_comps == 1) {
	/* we have only a Default; we don't need components. */
	gs_free_object(pmem, pocs, "gs_ht_install");
	dev_ht.components = 0;
    } else {
	dev_ht.components = pocs;
	dev_ht.num_comp = num_comps;
    }

    /* at last, actually install the halftone in the graphic state */
    return gx_ht_install(pgs, (gs_halftone *) pht, &dev_ht);
}

/* ---------------- Mask-defined halftones ---------------- */

/*
 * Create a halftone order from an array of explicit masks.  This is
 * silly, because the rendering machinery actually wants masks, but doing
 * it right seems to require too many changes in existing code.
 */
private int
create_mask_bits(const byte * mask1, const byte * mask2,
		 int width, int height, gx_ht_bit * bits)
{
    /*
     * We do this with the slowest, simplest possible algorithm....
     */
    int width_bytes = (width + 7) >> 3;
    int x, y;
    int count = 0;

    for (y = 0; y < height; ++y)
	for (x = 0; x < width; ++x) {
	    int offset = y * width_bytes + (x >> 3);
	    byte bit_mask = 0x80 >> (x & 7);

	    if ((mask1[offset] ^ mask2[offset]) & bit_mask) {
		if (bits)
		    gx_ht_construct_bit(&bits[count], width, y * width + x);
		++count;
	    }
	}
    return count;
}
private int
create_mask_order(gx_ht_order * porder, gs_state * pgs,
		  const gs_client_order_halftone * phcop,
		  gs_memory_t * mem)
{
    int width_bytes = (phcop->width + 7) >> 3;
    const byte *masks = (const byte *)phcop->client_data;
    int bytes_per_mask = width_bytes * phcop->height;
    const byte *prev_mask;
    int num_levels = phcop->num_levels;
    int num_bits = 0;
    int i;
    int code;

    /* Do a first pass to compute how many bits entries will be needed. */
    for (prev_mask = masks, num_bits = 0, i = 0;
	 i < num_levels - 1;
	 ++i, prev_mask += bytes_per_mask
	)
	num_bits += create_mask_bits(prev_mask, prev_mask + bytes_per_mask,
				     phcop->width, phcop->height, NULL);
    code = gx_ht_alloc_client_order(porder, phcop->width, phcop->height,
				    num_levels, num_bits, mem);
    if (code < 0)
	return code;
    /* Fill in the bits and levels entries. */
    for (prev_mask = masks, num_bits = 0, i = 0;
	 i < num_levels - 1;
	 ++i, prev_mask += bytes_per_mask
	) {
	porder->levels[i] = num_bits;
	num_bits += create_mask_bits(prev_mask, prev_mask + bytes_per_mask,
				     phcop->width, phcop->height,
				     ((gx_ht_bit *)porder->bit_data) +
				      num_bits);
    }
    porder->levels[num_levels - 1] = num_bits;
    return 0;
}

/* Define the client-order halftone procedure structure. */
private const gs_client_order_ht_procs_t mask_order_procs =
{
    create_mask_order
};

/*
 * Define a halftone by an explicit set of masks.  We translate these
 * internally into a threshold array, since that's what the halftone
 * rendering machinery knows how to deal with.
 */
int
gs_ht_set_mask_comp(gs_ht * pht,
		    int component_index, gs_ht_separation_name sepr_name,
		    int width, int height, int num_levels,
		    const byte * masks,		/* width x height x num_levels bits */
		    gs_ht_transfer_proc transfer,
		    const void *client_data)
{
    gs_ht_component *phtc =
    &(pht->params.ht_multiple.components[component_index]);

    if (component_index >= pht->params.ht_multiple.num_comp)
	return_error(gs_error_rangecheck);
    if (phtc->type != ht_type_none)
	return_error(gs_error_invalidaccess);

    phtc->cname =
	(pht->params.ht_multiple.num_comp == 1 ? gs_ht_separation_Default :
	 sepr_name);
    phtc->type = ht_type_client_order;
    phtc->params.client_order.width = width;
    phtc->params.client_order.height = height;
    phtc->params.client_order.num_levels = num_levels;
    phtc->params.client_order.procs = &mask_order_procs;
    phtc->params.client_order.client_data = masks;
    phtc->params.client_order.transfer_closure.proc =
	(transfer == 0 ? null_closure_transfer : transfer);
    phtc->params.client_order.transfer_closure.data = client_data;

    return 0;

}