path: root/base/gsht1.c

/* Copyright (C) 2001-2019 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.
*/


/* Extended halftone operators for Ghostscript library */
#include "memory_.h"
#include "string_.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"


/* Imports from gscolor.c */
void load_transfer_map(gs_gstate *, gx_transfer_map *, double);

/* Forward declarations */
static int process_spot(gx_ht_order *, gs_gstate *,
                         gs_spot_halftone *, gs_memory_t *);
static int process_threshold(gx_ht_order *, gs_gstate *,
                              gs_threshold_halftone *, gs_memory_t *);
static int process_threshold2(gx_ht_order *, gs_gstate *,
                               gs_threshold2_halftone *, gs_memory_t *);
static int process_client_order(gx_ht_order *, gs_gstate *,
                                 gs_client_order_halftone *, gs_memory_t *);

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

/* GC procedures */

static
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
static 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_gstate * 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_gstate * 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_gstate * 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_gstate * 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;
    if ((code = gx_ht_install(pgs, pht, &dev_ht)) < 0)
        gx_device_halftone_release(&dev_ht, pht->rc.memory);
    return code;
}

/* Prepare the halftone, but don't install it. */
int
gs_sethalftone_prepare(gs_gstate * 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 int cindex[4] = {3, 0, 1, 2};
                static const char * color_names[4] = {"Gray", "Red", "Green", "Blue"};
                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), mem);
                    if (code < 0)
                        break;
                    poc->corder = senum.order;
                    poc->comp_number = gs_color_name_component_number(pgs->device,
                                color_names[i], strlen(color_names[i]), pht->type);
                    poc->cname = 0;  /* name index values are not known (or needed) */
                    if (i == 0)	/* Gray = Default */
                        pdht->order = poc->corder;	/* Save default value */
                }
                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->comp_number == GX_DEVICE_COLOR_MAX_COMPONENTS) {
                        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->comp_number = phc->comp_number;
                    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 (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;
                    pdht->num_comp = 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. */
static int
process_transfer(gx_ht_order * porder, gs_gstate * 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;
    /*
     * The transfer funtion is referenced by the order, so start the
     * reference count at 1.
     */
    rc_alloc_struct_1(pmap, gx_transfer_map, &st_transfer_map, mem,
                      return_error(gs_error_VMerror),
                      "process_transfer");
    pmap->proc = proc;		/* 0 => use closure */
    pmap->closure = *pmc;
    pmap->id = gs_next_ids(mem, 1);
    porder->transfer = pmap;
    if (proc == gs_mapped_transfer)
        return 0; /* nothing to load, the source is uninitialzed */
    load_transfer_map(pgs, pmap, 0.0);
    return 0;
}

/* Process a spot plane. */
static int
process_spot(gx_ht_order * porder, gs_gstate * 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. */
static int
process_threshold(gx_ht_order * porder, gs_gstate * 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. */
static int
process_threshold2(gx_ht_order * porder, gs_gstate * 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_debug7m('h', mem, "[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, phtp->transfer, &phtp->transfer_closure, mem);
#undef LOG2_MAX_HT_LEVELS
#undef MAX_HT_LEVELS
}

/* Process a client-order plane. */
static int
process_client_order(gx_ht_order * porder, gs_gstate * 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);
}