/* Copyright (C) 2018-2023 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.,  39 Mesa Street, Suite 108A, San Francisco,
   CA 94129, USA, for further information.
*/

/* Graphics state operations for the PDF interpreter */

#include "pdf_int.h"
#include "pdf_doc.h"
#include "pdf_font_types.h"
#include "pdf_gstate.h"
#include "pdf_stack.h"
#include "pdf_dict.h"
#include "pdf_array.h"
#include "pdf_func.h"
#include "pdf_file.h"
#include "pdf_misc.h"
#include "pdf_loop_detect.h"
#include "pdf_image.h"
#include "pdf_pattern.h"
#include "pdf_font.h"
#include "pdf_colour.h"
#include "pdf_trans.h"

#include "gsstate.h"        /* For gs_gstate */
#include "gsmatrix.h"
#include "gslparam.h"
#include "gstparam.h"

#include "gxdht.h"
#include "gxht.h"
#include "gzht.h"
#include "gsht.h"
#include "gscoord.h"        /* For gs_concat() */
#include "gsutil.h"         /* For gs_next_ids() */
#include "gscolor3.h"       /* For gs_setsmoothness() */
#include "gzpath.h"
#include "gspenum.h"

static const char *blend_mode_names[] = {
    GS_BLEND_MODE_NAMES, 0
};

int pdfi_get_blend_mode(pdf_context *ctx, pdf_name *name, gs_blend_mode_t *mode)
{
    const char **p;

    for (p = blend_mode_names; *p; ++p) {
        if (pdfi_name_is(name, *p)) {
            *mode = p - blend_mode_names;
            return 0;
        }
    }
    return -1;
}

void pdfi_gstate_smask_install(pdfi_int_gstate *igs, gs_memory_t *memory, pdf_dict *SMask, gs_gstate *gstate)
{
    void *client_data_save;

    if (!SMask)
        return;
    igs->memory = memory;
    igs->SMask = SMask;
    pdfi_countup(SMask);
    client_data_save = gstate->client_data;
    gstate->client_data = NULL;
    igs->GroupGState = gs_gstate_copy(gstate, memory);
    gstate->client_data = client_data_save;
}

void pdfi_gstate_smask_free(pdfi_int_gstate *igs)
{
    if (!igs->SMask)
        return;
    pdfi_countdown(igs->SMask);
    igs->SMask = NULL;
    if (igs->GroupGState)
        gs_gstate_free(igs->GroupGState);
    igs->GroupGState = NULL;
}


/* Allocate the interpreter's part of a graphics state. */
static void *
pdfi_gstate_alloc_cb(gs_memory_t * mem)
{
    pdfi_int_gstate *igs;

    igs = (pdfi_int_gstate *)gs_alloc_bytes(mem, sizeof(pdfi_int_gstate), "pdfi_gstate_alloc");
    if (igs == NULL)
        return NULL;
    memset(igs, 0, sizeof(pdfi_int_gstate));
    return igs;
}

/* Copy the interpreter's part of a graphics state. */
static int
pdfi_gstate_copy_cb(void *to, const void *from)
{
    const pdfi_int_gstate *igs_from = (const pdfi_int_gstate *)from;
    pdfi_int_gstate *igs_to = (pdfi_int_gstate *)to;

    /* Need to free destination contents before overwriting.
     *  On grestore, they might be non-empty.
     */
    if (igs_to != NULL) {
        pdfi_gstate_smask_free(igs_to);
        pdfi_countdown(igs_to->current_font);
        *(pdfi_int_gstate *) igs_to = *igs_from;
        pdfi_countup(igs_to->current_font);
        pdfi_gstate_smask_install(igs_to, igs_from->memory, igs_from->SMask, igs_from->GroupGState);
    }
    return 0;
}

/* Free the interpreter's part of a graphics state. */
static void
pdfi_gstate_free_cb(void *old, gs_memory_t * mem, gs_gstate *pgs)
{
    pdfi_int_gstate *igs = (pdfi_int_gstate *)old;
    if (old == NULL)
        return;
    pdfi_gstate_smask_free(igs);
    pdfi_countdown(igs->current_font);
    /* We need to use the graphics state memory, in case we are running under Ghostscript. */
    gs_free_object(pgs->memory, igs, "pdfi_gstate_free");
}

static const gs_gstate_client_procs pdfi_gstate_procs = {
    pdfi_gstate_alloc_cb,
    pdfi_gstate_copy_cb,
    pdfi_gstate_free_cb,
    NULL, /* copy_for */
};

int
pdfi_gstate_set_client(pdf_context *ctx, gs_gstate *pgs)
{
    pdfi_int_gstate *igs;

    /* We need to use the graphics state memory, in case we are running under Ghostscript. */
    igs = pdfi_gstate_alloc_cb(pgs->memory);
    if (igs == NULL)
        return_error(gs_error_VMerror);
    igs->ctx = ctx;
    gs_gstate_set_client(pgs, igs, &pdfi_gstate_procs, true /* TODO: client_has_pattern_streams ? */);
    return 0;
}

int pdfi_concat(pdf_context *ctx)
{
    int code;
    double Values[6];
    gs_matrix m;

    if (pdfi_count_stack(ctx) < 6) {
        pdfi_clearstack(ctx);
        return_error(gs_error_stackunderflow);
    }

    if (ctx->text.BlockDepth != 0)
        pdfi_set_warning(ctx, 0, NULL, W_PDF_OPINVALIDINTEXT, "pdfi_concat", NULL);

    code = pdfi_destack_reals(ctx, Values, 6);
    if (code < 0)
        return code;

    m.xx = (float)Values[0];
    m.xy = (float)Values[1];
    m.yx = (float)Values[2];
    m.yy = (float)Values[3];
    m.tx = (float)Values[4];
    m.ty = (float)Values[5];

    return gs_concat(ctx->pgs, (const gs_matrix *)&m);
}

int pdfi_op_q(pdf_context *ctx)
{
    int code;

#if DEBUG_GSAVE
    dbgmprintf(ctx->memory, "(doing q)\n"); /* TODO: Spammy, delete me at some point */
#endif
    code = pdfi_gsave(ctx);

    if (code < 0)
        return code;
    else {
        if (ctx->page.has_transparency)
            return gs_push_transparency_state(ctx->pgs);
    }
    return 0;
}

int pdfi_op_Q(pdf_context *ctx)
{
    int code = 0;

#if DEBUG_GSAVE
    dbgmprintf(ctx->memory, "(doing Q)\n"); /* TODO: Spammy, delete me at some point */
#endif
    if (ctx->pgs->level <= ctx->current_stream_save.gsave_level) {
        /* We don't throw an error here, we just ignore it and continue */
        pdfi_set_warning(ctx, 0, NULL, W_PDF_TOOMANYQ, "pdfi_op_Q", (char *)"ignoring Q");
        return 0;
    }
    if (ctx->page.has_transparency) {
        code = gs_pop_transparency_state(ctx->pgs, false);
        if (code < 0)
            return code;
    }

    return pdfi_grestore(ctx);
}

/* We want pdfi_grestore() so we can track and warn of "too many Qs"
 * in the interests of symmetry, we also have pdfi_gsave()
 */
int pdfi_gsave(pdf_context *ctx)
{
    return gs_gsave(ctx->pgs);
}

int pdfi_grestore(pdf_context *ctx)
{
    int code = 0;

    /* Make sure we have encountered as many gsave operations in this
     * stream as grestores. If not, log an error
     */
    if (ctx->pgs->level > ctx->current_stream_save.gsave_level) {
        code = gs_grestore(ctx->pgs);
    } else {
        /* We don't throw an error here, we just ignore it and continue */
        pdfi_set_warning(ctx, 0, NULL, W_PDF_TOOMANYQ, "pdfi_grestore", (char *)"ignoring q");
    }
    return code;
}

int pdfi_gs_setgstate(gs_gstate * pgs, const gs_gstate * pfrom)
{
    int code = 0;

    code = gs_setgstate(pgs, pfrom);
    if (code < 0)
        return code;

    return code;
}

int pdfi_setlinewidth(pdf_context *ctx)
{
    int code;
    double d1;

    if (pdfi_count_stack(ctx) < 1)
        return_error(gs_error_stackunderflow);

    code = pdfi_destack_real(ctx, &d1);
    if (code < 0)
        return code;

    return gs_setlinewidth(ctx->pgs, d1);
}

int pdfi_setlinejoin(pdf_context *ctx)
{
    int code;
    int64_t i;

    if (pdfi_count_stack(ctx) < 1)
        return_error(gs_error_stackunderflow);

    code = pdfi_destack_int(ctx, &i);
    if (code < 0)
        return code;

    return gs_setlinejoin(ctx->pgs, (int)i);
}

int pdfi_setlinecap(pdf_context *ctx)
{
    int code;
    int64_t i;

    if (pdfi_count_stack(ctx) < 1)
        return_error(gs_error_stackunderflow);

    code = pdfi_destack_int(ctx, &i);
    if (code < 0)
        return code;

    return gs_setlinecap(ctx->pgs, i);
}

int pdfi_setflat(pdf_context *ctx)
{
    int code;
    double d1;

    if (pdfi_count_stack(ctx) < 1)
        return_error(gs_error_stackunderflow);

    code = pdfi_destack_real(ctx, &d1);
    if (code < 0)
        return code;

    /* PDF spec says the value is 1-100, with 0 meaning "use the default"
     * But gs code (and now our code) forces the value to be <= 1
     * This matches what Adobe and evince seem to do (see Bug 555657).
     * Apparently mupdf implements this as a no-op, which is essentially
     * what this does now.
     */
    if (d1 > 1.0)
        d1 = 1.0;
    return gs_setflat(ctx->pgs, d1);
}

int pdfi_setdash_impl(pdf_context *ctx, pdf_array *a, double phase_d)
{
    float *dash_array;
    double temp;
    int i, code;

    dash_array = (float *)gs_alloc_bytes(ctx->memory, pdfi_array_size(a) * sizeof (float),
                                         "temporary float array for setdash");
    if (dash_array == NULL)
        return_error(gs_error_VMerror);

    for (i=0;i < pdfi_array_size(a);i++){
        code = pdfi_array_get_number(ctx, a, (uint64_t)i, &temp);
        if (code < 0) {
            gs_free_object(ctx->memory, dash_array, "error in setdash");
            return code;
        }
        dash_array[i] = (float)temp;
    }
    code = gs_setdash(ctx->pgs, dash_array, pdfi_array_size(a), phase_d);
    gs_free_object(ctx->memory, dash_array, "error in setdash");
    return code;
}

int pdfi_setdash(pdf_context *ctx)
{
    pdf_array *a;
    double phase_d;
    int code;

    if (pdfi_count_stack(ctx) < 2) {
        pdfi_clearstack(ctx);
        return_error(gs_error_stackunderflow);
    }

    code = pdfi_destack_real(ctx, &phase_d);
    if (code < 0) {
        pdfi_pop(ctx, 1);
        return code;
    }

    a = (pdf_array *)ctx->stack_top[-1];
    pdfi_countup(a);
    pdfi_pop(ctx, 1);

    if (pdfi_type_of(a) != PDF_ARRAY) {
        pdfi_countdown(a);
        return_error(gs_error_typecheck);
    }

    code = pdfi_setdash_impl(ctx, a, phase_d);
    pdfi_countdown(a);
    return code;
}

int pdfi_setmiterlimit(pdf_context *ctx)
{
    int code;
    double d1;

    if (pdfi_count_stack(ctx) < 1)
        return_error(gs_error_stackunderflow);

    code = pdfi_destack_real(ctx, &d1);
    if (code < 0)
        return code;

    /* PostScript (and therefore the graphics library) impose a minimum
     * value of 1.0 on miter limit. PDF does not specify a minimum, but less
     * than 1 doesn't make a lot of sense. This code brought over from the old
     * PDF interpreter which silently clamped the value to 1.
     */
    if (d1 < 1.0)
        d1 = 1.0;

    return gs_setmiterlimit(ctx->pgs, d1);
}

static int GS_LW(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    double d1;
    int code;

    code = pdfi_dict_get_number(ctx, GS, "LW", &d1);
    if (code < 0)
        return code;

    code = gs_setlinewidth(ctx->pgs, d1);
    return code;
}

static int GS_LC(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    int64_t i;
    int code;

    code = pdfi_dict_get_int(ctx, GS, "LC", &i);
    if (code < 0)
        return code;

    code = gs_setlinecap(ctx->pgs, i);
    return code;
}

static int GS_LJ(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    int64_t i;
    int code;

    code = pdfi_dict_get_int(ctx, GS, "LJ", &i);
    if (code < 0)
        return code;

    code = gs_setlinejoin(ctx->pgs, i);
    return code;
}

static int GS_ML(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    int code;
    double d1;

    code = pdfi_dict_get_number(ctx, GS, "ML", &d1);
    if (code < 0)
        return code;

    code = gs_setmiterlimit(ctx->pgs, d1);
    return code;
}

static int GS_D(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    pdf_array *a, *a1;
    double d;
    int code;

    code = pdfi_dict_get_type(ctx, GS, "D", PDF_ARRAY, (pdf_obj **)&a);
    if (code < 0)
        return code;

    code = pdfi_array_get_type(ctx, a, (int64_t)0, PDF_ARRAY, (pdf_obj **)&a1);
    if (code < 0) {
        pdfi_countdown(a);
        return code;
    }

    code = pdfi_array_get_number(ctx, a, (int64_t)1, &d);
    if (code < 0) {
        pdfi_countdown(a1);
        pdfi_countdown(a);
        return code;
    }

    code = pdfi_setdash_impl(ctx, a1, d);
    pdfi_countdown(a1);
    pdfi_countdown(a);
    return code;
}

static int GS_RI(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    pdf_name *n;
    int code;

    code = pdfi_dict_get_type(ctx, GS, "RI", PDF_NAME, (pdf_obj **)&n);
    if (code < 0)
        return code;

    code = pdfi_setrenderingintent(ctx, n);
    pdfi_countdown(n);
    return code;
}

static int GS_OP(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    bool b;
    int code;
    bool known=false;

    code = pdfi_dict_get_bool(ctx, GS, "OP", &b);
    if (code < 0)
        return code;

    gs_setstrokeoverprint(ctx->pgs, b);

    /* If op not in the dict, then also set it with OP
     * Because that's what gs does pdf_draw.ps/gsparamdict/OP
     */
    code = pdfi_dict_known(ctx, GS, "op", &known);
    if (!known)
        gs_setfilloverprint(ctx->pgs, b);

    return 0;
}

static int GS_op(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    bool b;
    int code;

    code = pdfi_dict_get_bool(ctx, GS, "op", &b);
    if (code < 0)
        return code;

    gs_setfilloverprint(ctx->pgs, b);
    return 0;
}

static int GS_OPM(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    int64_t i;
    int code;

    code = pdfi_dict_get_int(ctx, GS, "OPM", &i);
    if (code < 0)
        return code;

    code = gs_setoverprintmode(ctx->pgs, i);
    return code;
}

static int GS_Font(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    pdf_array *font_array = NULL;
    pdf_dict *font_dict = NULL;
    int code = 0;
    double point_size = 0.0;

    code = pdfi_dict_get_type(ctx, GS, "Font", PDF_ARRAY, (pdf_obj **)&font_array);
    if (code < 0)
        return code;

    if (pdfi_array_size(font_array) != 2)
        return_error(gs_error_rangecheck);

    code = pdfi_array_get(ctx, font_array, 0, (pdf_obj **)&font_dict);
    if (code < 0)
        goto GS_Font_error;

    code = pdfi_array_get_number(ctx, font_array, 1, &point_size);
    if (code < 0)
        goto GS_Font_error;

    code = pdfi_load_dict_font(ctx, stream_dict, page_dict, font_dict, point_size);

GS_Font_error:
    pdfi_countdown(font_array);
    pdfi_countdown(font_dict);
    return code;
}

static int pdfi_set_blackgeneration(pdf_context *ctx, pdf_obj *obj, pdf_dict *page_dict, bool is_BG)
{
    int code = 0, i;
    gs_function_t *pfn;

    switch (pdfi_type_of(obj)) {
        case PDF_NAME:
            if (is_BG) {
                pdfi_set_error(ctx, 0, NULL, E_PDF_BG_ISNAME, "pdfi_set_blackgeneration", "");
                if (ctx->args.pdfstoponerror)
                    code = gs_note_error(gs_error_typecheck);
                else
                    code = 0;
            } else {
                if (pdfi_name_is((const pdf_name *)obj, "Identity"))
                    code = gs_setblackgeneration_remap(ctx->pgs, gs_identity_transfer, false);
                else if (pdfi_name_is((const pdf_name *)obj, "Default")) {
                    code = gs_setblackgeneration_remap(ctx->pgs, ctx->page.DefaultBG.proc, false);
                    memcpy(ctx->pgs->black_generation->values, ctx->page.DefaultBG.values, transfer_map_size * sizeof(frac));
                } else
                    code = gs_note_error(gs_error_rangecheck);
            }
            goto exit;

        case PDF_DICT:
        case PDF_STREAM:
            code = pdfi_build_function(ctx, &pfn, NULL, 1, obj, page_dict);
            if (code < 0)
                return code;

            if (pfn->params.n != 1) {
                pdfi_free_function(ctx, pfn);
                return_error(gs_error_rangecheck);
            }

            gs_setblackgeneration_remap(ctx->pgs, gs_mapped_transfer, false);
            for (i = 0; i < transfer_map_size; i++) {
                float v, f;

                f = (1.0f / (transfer_map_size - 1)) * i;

                code = gs_function_evaluate(pfn, (const float *)&f, &v);
                if (code < 0) {
                    pdfi_free_function(ctx, pfn);
                    return code;
                }

                ctx->pgs->black_generation->values[i] =
                    (v < 0.0 ? float2frac(0.0) :
                     v >= 1.0 ? frac_1 :
                     float2frac(v));
            }
            code = pdfi_free_function(ctx, pfn);
            break;

        default:
            return_error(gs_error_typecheck);
    }
exit:
    return code;
}

static int GS_BG(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    int code;
    pdf_obj *obj = NULL;

    /* If the dictionary also has a BG2, then we must use that */
    code = pdfi_dict_get(ctx, GS, "BG2", &obj);
    if (code == 0) {
        pdfi_countdown(obj);
        return 0;
    }

    code = pdfi_dict_get(ctx, GS, "BG", &obj);
    if (code < 0)
        return code;

    code = pdfi_set_blackgeneration(ctx, obj, page_dict, true);

    pdfi_countdown(obj);

    return code;
}

static int GS_BG2(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    int code;
    pdf_obj *obj = NULL;

    code = pdfi_dict_get(ctx, GS, "BG2", &obj);
    if (code < 0)
        return code;

    code = pdfi_set_blackgeneration(ctx, obj, page_dict, false);

    pdfi_countdown(obj);

    return code;
}

static int pdfi_set_undercolorremoval(pdf_context *ctx, pdf_obj *obj, pdf_dict *page_dict, bool is_UCR)
{
    int code = 0, i;
    gs_function_t *pfn;

    switch (pdfi_type_of(obj)) {
        case PDF_NAME:
            if (is_UCR) {
                pdfi_set_error(ctx, 0, NULL, E_PDF_UCR_ISNAME, "pdfi_set_undercolorremoval", "");
                if (ctx->args.pdfstoponerror)
                    code = gs_note_error(gs_error_typecheck);
                else
                    code = 0;
            } else {
                if (pdfi_name_is((const pdf_name *)obj, "Identity")) {
                    code = gs_setundercolorremoval_remap(ctx->pgs, gs_identity_transfer, false);
                } else if (pdfi_name_is((const pdf_name *)obj, "Default")) {
                    code = gs_setundercolorremoval_remap(ctx->pgs, ctx->page.DefaultUCR.proc, false);
                    memcpy(ctx->pgs->undercolor_removal->values, ctx->page.DefaultUCR.values, transfer_map_size * sizeof(frac));
                } else {
                    code = gs_note_error(gs_error_rangecheck);
                }
            }
            goto exit;

        case PDF_DICT:
        case PDF_STREAM:
            code = pdfi_build_function(ctx, &pfn, NULL, 1, obj, page_dict);
            if (code < 0)
                return code;

            if (pfn->params.n == 1) {
                gs_setundercolorremoval_remap(ctx->pgs, gs_mapped_transfer, false);
                for (i = 0; i < transfer_map_size; i++) {
                    float v, f;

                    f = (1.0f / (transfer_map_size - 1)) * i;

                    code = gs_function_evaluate(pfn, (const float *)&f, &v);
                    if (code < 0) {
                        pdfi_free_function(ctx, pfn);
                        return code;
                    }

                    ctx->pgs->undercolor_removal->values[i] =
                        (v < 0.0 ? float2frac(0.0) :
                         v >= 1.0 ? frac_1 :
                         float2frac(v));
                }
                code = pdfi_free_function(ctx, pfn);
            }
            else {
                (void)pdfi_free_function(ctx, pfn);
                code = gs_note_error(gs_error_rangecheck);
            }
            break;

        default:
            return_error(gs_error_typecheck);
    }
exit:
    return code;
}

static int GS_UCR(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    int code;
    pdf_obj *obj = NULL;

    /* If the dictionary also has a UCR2, then we must use that and ignore the UCR */
    code = pdfi_dict_get(ctx, GS, "UCR2", &obj);
    if (code == 0) {
        pdfi_countdown(obj);
        return 0;
    }

    code = pdfi_dict_get(ctx, GS, "UCR", &obj);
    if (code < 0)
        return code;

    code = pdfi_set_undercolorremoval(ctx, obj, page_dict, true);

    pdfi_countdown(obj);

    return code;
}

static int GS_UCR2(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    int code;
    pdf_obj *obj = NULL;

    code = pdfi_dict_get(ctx, GS, "UCR2", &obj);
    if (code < 0)
        return code;

    code = pdfi_set_undercolorremoval(ctx, obj, page_dict, false);

    pdfi_countdown(obj);

    return code;
}

typedef enum {
    E_IDENTITY,
    E_DEFAULT,
    E_FUNCTION
} pdf_transfer_function_type_e;

/* We use this for both TR and TR2, is_TR is true if this is a TR, in which case we don't want
 * to permit /Default names for fucntions.
 */
static int pdfi_set_all_transfers(pdf_context *ctx, pdf_array *a, pdf_dict *page_dict, bool is_TR)
{
    int code = 0, i, j;
    pdf_obj *o = NULL;
    int proc_types[4];
    gs_mapping_proc map_procs[4];
    gs_function_t *pfn[4];

    memset(pfn, 0x00, 4 * sizeof(gs_function_t *));
    memset(map_procs, 0x00, 4 * sizeof(gs_mapping_proc *));

    /* Two passes, the first one is to find the appropriate transfer procedures
     * and do the majorty of the error checking;
     */
    for (i = 0; i < 4; i++) {
        code = pdfi_array_get(ctx, a, (uint64_t)i, &o);
        if (code < 0)
            goto exit;
        switch (pdfi_type_of(o)) {
            case PDF_NAME:
                if (pdfi_name_is((const pdf_name *)o, "Identity")) {
                    proc_types[i] = E_IDENTITY;
                    map_procs[i] = gs_identity_transfer;
                } else if (!is_TR && pdfi_name_is((const pdf_name *)o, "Default")) {
                    proc_types[i] = E_DEFAULT;
                    map_procs[i] = ctx->page.DefaultTransfers[i].proc;
                } else {
                    pdfi_countdown(o);
                    code = gs_note_error(gs_error_typecheck);
                    goto exit;
                }
                break;
            case PDF_STREAM:
            case PDF_DICT:
                proc_types[i] = E_FUNCTION;
                map_procs[i] = gs_mapped_transfer;
                code = pdfi_build_function(ctx, &pfn[i], NULL, 1, o, page_dict);
                if (code < 0) {
                    pdfi_countdown(o);
                    goto exit;
                }
                if (pfn[i]->params.m != 1 || pfn[i]->params.n != 1) {
                    pdfi_countdown(o);
                    code = gs_note_error(gs_error_rangecheck);
                    goto exit;
                }
                break;
            default:
                pdfi_countdown(o);
                code = gs_note_error(gs_error_typecheck);
                goto exit;
        }
        pdfi_countdown(o);
    }
    code = gs_setcolortransfer_remap(ctx->pgs, map_procs[0], map_procs[1], map_procs[2], map_procs[3], false);
    if (code < 0)
        goto exit;

    /* Second pass is to evaluate and set the transfer maps */
    for (j = 0; j < 4; j++) {
        if (proc_types[j] == E_DEFAULT) {
            switch(j) {
                case 0:
                    memcpy(ctx->pgs->set_transfer.red->values, ctx->page.DefaultTransfers[j].values, transfer_map_size * sizeof(frac));
                    break;
                case 1:
                    memcpy(ctx->pgs->set_transfer.green->values, ctx->page.DefaultTransfers[j].values, transfer_map_size * sizeof(frac));
                    break;
                case 2:
                    memcpy(ctx->pgs->set_transfer.blue->values, ctx->page.DefaultTransfers[j].values, transfer_map_size * sizeof(frac));
                    break;
                case 3:
                    memcpy(ctx->pgs->set_transfer.gray->values, ctx->page.DefaultTransfers[j].values, transfer_map_size * sizeof(frac));
                    break;
            }
        }
        if (proc_types[j] == E_FUNCTION) {
            for (i = 0; i < transfer_map_size; i++) {
                float v, f;
                frac value;

                f = (1.0f / (transfer_map_size - 1)) * i;

                code = gs_function_evaluate(pfn[j], (const float *)&f, &v);
                if (code < 0)
                    goto exit;

                value =
                    (v < 0.0 ? float2frac(0.0) :
                     v >= 1.0 ? frac_1 :
                     float2frac(v));
                switch(j) {
                    case 0:
                        ctx->pgs->set_transfer.red->values[i] = value;
                        break;
                    case 1:
                        ctx->pgs->set_transfer.green->values[i] = value;
                        break;
                    case 2:
                        ctx->pgs->set_transfer.blue->values[i] = value;
                        break;
                    case 3:
                        ctx->pgs->set_transfer.gray->values[i] = value;
                        break;
                }
            }
        }
    }
 exit:
    for (i = 0; i < 4; i++) {
        pdfi_free_function(ctx, pfn[i]);
    }
    return code;
}

static int pdfi_set_gray_transfer(pdf_context *ctx, pdf_obj *tr_obj, pdf_dict *page_dict)
{
    int code = 0, i;
    gs_function_t *pfn;

    if (pdfi_type_of(tr_obj) != PDF_DICT && pdfi_type_of(tr_obj) != PDF_STREAM)
        return_error(gs_error_typecheck);

    code = pdfi_build_function(ctx, &pfn, NULL, 1, tr_obj, page_dict);
    if (code < 0)
        return code;

    if (pfn->params.m != 1 || pfn->params.n != 1) {
        (void)pdfi_free_function(ctx, pfn);
        return_error(gs_error_rangecheck);
    }

    gs_settransfer_remap(ctx->pgs, gs_mapped_transfer, false);
    for (i = 0; i < transfer_map_size; i++) {
        float v, f;

        f = (1.0f / (transfer_map_size - 1)) * i;

        code = gs_function_evaluate(pfn, (const float *)&f, &v);
        if (code < 0) {
            pdfi_free_function(ctx, pfn);
            return code;
        }

        ctx->pgs->set_transfer.gray->values[i] =
            (v < 0.0 ? float2frac(0.0) :
             v >= 1.0 ? frac_1 :
             float2frac(v));
    }
    return pdfi_free_function(ctx, pfn);
}

static int pdfi_set_transfer(pdf_context *ctx, pdf_obj *obj, pdf_dict *page_dict, bool is_TR)
{
    int code = 0;

    if (pdfi_type_of(obj) == PDF_NAME) {
        if (pdfi_name_is((const pdf_name *)obj, "Identity")) {
            code = gs_settransfer_remap(ctx->pgs, gs_identity_transfer, false);
            goto exit;
        } else {
            if (is_TR) {
                pdfi_set_error(ctx, 0, NULL, E_PDF_TR_NAME_NOT_IDENTITY, "pdfi_set_transfer", "");
                if (ctx->args.pdfstoponerror)
                    code = gs_note_error(gs_error_rangecheck);
                else
                    code = 0;
                goto exit;
            } else {
                if (pdfi_name_is((const pdf_name *)obj, "Default")) {
                    code = gs_settransfer_remap(ctx->pgs, ctx->page.DefaultTransfers[3].proc, false);
                    memcpy(ctx->pgs->set_transfer.gray->values, ctx->page.DefaultTransfers[3].values, transfer_map_size * sizeof(frac));
                    goto exit;
                } else {
                    code = gs_note_error(gs_error_rangecheck);
                    goto exit;
                }
            }
        }
    }

    if (pdfi_type_of(obj) == PDF_ARRAY) {
        if (pdfi_array_size((pdf_array *)obj) != 4) {
            code = gs_note_error(gs_error_rangecheck);
            goto exit;
        } else {
            code = pdfi_set_all_transfers(ctx, (pdf_array *)obj, page_dict, false);
        }
    } else
        code = pdfi_set_gray_transfer(ctx, obj, page_dict);

exit:
    return code;
}

static int GS_TR(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    int code;
    pdf_obj *obj = NULL;

    code = pdfi_dict_get(ctx, GS, "TR", &obj);
    if (code < 0)
        return code;

    code = pdfi_set_transfer(ctx, obj, page_dict, true);

    pdfi_countdown(obj);

    return code;
}

static int GS_TR2(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    int code;
    pdf_obj *obj = NULL;
    code = pdfi_dict_get(ctx, GS, "TR2", &obj);
    if (code < 0)
        return code;

    code = pdfi_set_transfer(ctx, obj, page_dict, false);

    pdfi_countdown(obj);

    return code;
}

static const char *spot_functions[] = {
    "{dup mul exch dup mul add 1 exch sub}",        /* SimpleDot */
    "{dup mul exch dup mul add 1 sub}",             /* InvertedSimpleDot */
    "{360 mul sin 2 div exch 360 mul sin 2 div add",/* DoubleDot */
    "360 mul sin 2 div exch 360 mul\
     sin 2 div add neg}",                           /* InvertedDoubleDot */
    "{180 mul cos exch 180 mul cos add 2 div}",     /* CosineDot */
    "{360 mul sin 2 div exch 2 div \
     360 mul sin 2 div add}",                       /* Double */
    "{360 mul sin 2 div exch 2 div \
     360 mul sin 2 div add neg}",                   /* InvertedDouble */
    "{exch pop abs neg}",                           /* Line */
    "{pop}",                                        /* LineX */
    "{exch pop}",                                   /* LineY */
    "{abs exch abs 2 copy add 1.0 le\
     {dup mul exch dup mul add 1 exch sub}\
     {1 sub dup mul exch 1 sub dup mul add 1 sub}\
     ifelse}",                                      /* Round */
    "{abs exch abs 2 copy 3 mul exch 4 mul\
     add 3 sub dup 0 lt\
     {pop dup mul exch 0.75 div dup mul add\
     4 div 1 exch sub}\
     {dup 1 gt\
     {pop 1 exch sub dup mul exch 1 exch sub\
     0.75 div dup mul add 4 div 1 sub}\
     {0.5 exch sub exch pop exch pop}}\
     ifelse}ifelse}}",                              /* Ellipse */
    "{dup mul 0.9 mul exch dup mul add 1 exch sub}",/* EllipseA */
    "{dup mul 0.9 mul exch dup mul add 1 sub}",     /* InvertedEllipseA */
    "{dup 5 mul 8 div mul exch dup mul exch add\
     sqrt 1 exch sub}",                             /* EllipseB */
    "{dup mul exch dup mul 0.9 mul add 1 exch sub}",/* EllipseC */
    "{dup mul exch dup mul 0.9 mul add 1 sub}",     /* InvertedEllipseC */
    "{abs exch abs 2 copy lt {exch} if pop neg}",   /* Square */
    "{abs exch abs 2 copy gt {exch} if pop neg}",   /* Cross */
    "{abs exch abs 0.9 mul add 2 div}",             /* Rhomboid */
    "{abs exch abs 2 copy add 0.75 le\
     {dup mul exch dup mul add 1 exch sub}\
     {2 copy add 1.23 le\
     {0.85 mul add 1 exch sub}\
     {1 sub dup mul exch 1 sub dup mul add 1 sub}\
     ifelse} ifelse}"                               /* Diamond */
};

static const char *spot_table[] = {
    "SimpleDot",
    "InvertedSimpleDot",
    "DoubleDot",
    "InvertedDoubleDot",
    "CosineDot",
    "Double",
    "InvertedDouble",
    "Line",
    "LineX",
    "LineY",
    "Round",
    "Ellipse",
    "EllipseA",
    "InvertedEllipseA",
    "EllipseB",
    "EllipseC",
    "InvertedEllipseC",
    "Square",
    "Cross",
    "Rhomboid",
    "Diamond"
};

/* Dummy spot function */
static float
pdfi_spot1_dummy(double x, double y)
{
    return (x + y) / 2;
}

static int pdfi_evaluate_transfer(pdf_context *ctx, pdf_obj *transfer, pdf_dict *page_dict, gx_transfer_map **pmap)
{
    int t_ix = 0, code = 0;
    float value, out;
    gs_function_t *transfer_fn = NULL;

    rc_alloc_struct_1(*pmap, gx_transfer_map, &st_transfer_map, ctx->memory,
          return_error(gs_error_VMerror),
          "pdfi process_transfer");
    (*pmap)->proc = gs_mapped_transfer;		/* 0 => use closure */
    (*pmap)->closure.proc = NULL;
    (*pmap)->closure.data = NULL;
    (*pmap)->id = gs_next_ids(ctx->memory, 1);

    code = pdfi_build_function(ctx, &transfer_fn, (const float *)NULL, 1, transfer, page_dict);
    if (code >= 0) {
        for (t_ix = 0;t_ix < 256;t_ix++) {
            value = (float)t_ix * 1.0f / 255.0f;
            code = gs_function_evaluate(transfer_fn, (const float *)&value, &out);
            if (code < 0)
                goto error;
            (*pmap)->values[t_ix] =  float2frac(out);
        }
    }
error:
    pdfi_free_function(ctx, transfer_fn);
    return code;
}

static int build_type1_halftone(pdf_context *ctx, pdf_dict *halftone_dict, pdf_dict *page_dict, gx_ht_order *porder, gs_halftone_component *phtc, char *name, int len, int comp_num)
{
    int code, i, j;
    pdf_obj *obj = NULL, *transfer = NULL;
    double f, a;
    float values[2] = {0, 0}, domain[4] = {-1, 1, -1, 1}, out;
    gs_function_t *pfn = NULL;
    gx_ht_order *order = NULL;
    gs_screen_enum *penum = NULL;
    gs_point pt;
    gx_transfer_map *pmap = NULL;
    bool as;

    code = pdfi_dict_get_number(ctx, halftone_dict, "Frequency", &f);
    if (code < 0)
        return code;

    code = pdfi_dict_get_number(ctx, halftone_dict, "Angle", &a);
    if (code < 0)
        return code;

    code = pdfi_dict_get(ctx, halftone_dict, "SpotFunction", &obj);
    if (code < 0)
        return code;

    code = pdfi_dict_get_bool(ctx, halftone_dict, "AccurateScreens", &as);
    if (code == gs_error_undefined)
        as = 0;
    else if (code < 0)
        return code;

    order = (gx_ht_order *)gs_alloc_bytes(ctx->memory, sizeof(gx_ht_order), "build_type1_halftone");
    if (order == NULL) {
        code = gs_note_error(gs_error_VMerror);
        goto error;
    }
    memset(order, 0x00, sizeof(gx_ht_order));

    switch (pdfi_type_of(obj)) {
        case PDF_NAME:
            if (pdfi_name_is((pdf_name *)obj, "Default")) {
                i = 0;
            } else {
                for (i = 0; i < (sizeof(spot_table) / sizeof (char *)); i++) {
                    if (pdfi_name_is((pdf_name *)obj, spot_table[i]))
                        break;
                }
                if (i >= (sizeof(spot_table) / sizeof (char *))) {
                    code = gs_note_error(gs_error_rangecheck);
                    goto error;
                }
            }
            code = pdfi_build_halftone_function(ctx, &pfn, (byte *)spot_functions[i], strlen(spot_functions[i]));
            if (code < 0)
                goto error;
            break;
        case PDF_DICT:
        case PDF_STREAM:
            code = pdfi_build_function(ctx, &pfn, (const float *)domain, 2, obj, page_dict);
            if (code < 0)
                goto error;
            break;
        case PDF_ARRAY:
            for (j = 0; j < pdfi_array_size((pdf_array *)obj); j++) {
                pdf_name *n = NULL;

                code = pdfi_array_get(ctx, (pdf_array *)obj, j, (pdf_obj **)&n);
                if (code < 0)
                    goto error;
                if (pdfi_type_of(n) != PDF_NAME)
                    pdfi_set_error(ctx, 0, NULL, E_PDF_BAD_TYPE, "build_type1_halftone", "Halftone array element is not a name");
                else {
                    for (i = 0; i < (sizeof(spot_table) / sizeof (char *)); i++) {
                        if (pdfi_name_is((pdf_name *)n, spot_table[i])) {
                            pdfi_countdown(n);
                            n = NULL;
                            code = pdfi_build_halftone_function(ctx, &pfn, (byte *)spot_functions[i], strlen(spot_functions[i]));
                            if (code < 0)
                                goto error;
                            break;
                        }
                    }
                    if (i >= (sizeof(spot_table) / sizeof (char *))) {
                        pdfi_countdown(n);
                        n = NULL;
                    } else
                        break;
                }
                pdfi_countdown(n);
            }
            if (j >= pdfi_array_size((pdf_array *)obj)) {
                code = gs_note_error(gs_error_rangecheck);
                goto error;
            }
            break;
        default:
            code = gs_note_error(gs_error_typecheck);
            goto error;
    }

    if (pdfi_dict_knownget(ctx, halftone_dict, "TransferFunction", &transfer) > 0) {
        switch (pdfi_type_of(transfer)) {
            case PDF_NAME:
                /* As far as I can tell, only /Identity is valid as a name, so we can just ignore
                 * names, if it's not Identity it would be an error (which we would ignore) and if
                 * it is, it has no effect. So what's the point ?
                 */
                break;
            case PDF_STREAM:
                pdfi_evaluate_transfer(ctx, transfer, page_dict, &pmap);
                break;
            default:
                /* should be an error, but we can just ignore it */
                pdfi_set_warning(ctx, 0, NULL, W_PDF_TYPECHECK, "build_type1_halftone", NULL);
                break;
        }
    }

    phtc->params.spot.screen.frequency = f;
    phtc->params.spot.screen.angle = a;
    phtc->params.spot.screen.spot_function = pdfi_spot1_dummy;
    phtc->params.spot.transfer = (code > 0 ? (gs_mapping_proc) 0 : gs_mapped_transfer);
    phtc->params.spot.transfer_closure.proc = 0;
    phtc->params.spot.transfer_closure.data = 0;
    phtc->params.spot.accurate_screens = as;
    phtc->type = ht_type_spot;
    code = pdfi_get_name_index(ctx, name, len, (unsigned int *)&phtc->cname);
    if (code < 0)
        goto error;

    if (comp_num == -1)
        phtc->comp_number = gs_cname_to_colorant_number(ctx->pgs, (byte *)name, len, 1);
    else
        phtc->comp_number = comp_num;

    code = gs_screen_order_init_memory(order, ctx->pgs, &phtc->params.spot.screen,
                                       gs_currentaccuratescreens(ctx->memory), ctx->memory);
    if (code < 0)
        goto error;

    penum = gs_screen_enum_alloc(ctx->memory, "build_type1_halftone");
    if (penum == 0) {
        code = gs_error_VMerror;
        goto error;
    }

    code = gs_screen_enum_init_memory(penum, order, ctx->pgs, &phtc->params.spot.screen, ctx->memory);
    if (code < 0)
        goto error;

    do {
        /* Generate x and y, the parameteric variables */
        code = gs_screen_currentpoint(penum, &pt);
        if (code < 0)
            goto error;

        if (code == 1)
            break;

        /* Process sample */
        values[0] = pt.x, values[1] = pt.y;
        code = gs_function_evaluate(pfn, (const float *)&values, &out);
        if (code < 0)
            goto error;

        /* Store the sample */
        code = gs_screen_next(penum, out);
        if (code < 0)
            goto error;

    } while (1);
    code = 0;
    *porder = penum->order;
    (*porder).transfer = pmap;

error:
    pdfi_countdown(transfer);
    pdfi_countdown(obj);
    pdfi_free_function(ctx, pfn);
    if (code < 0 && order != NULL) {
        gs_free_object(ctx->memory, order->bit_data, "build_type1_halftone error");
        gs_free_object(ctx->memory, order->levels, "build_type1_halftone error");
    }
    if (code < 0 && pmap != NULL)
        rc_decrement(pmap, "pdfi process_transfer");
    gs_free_object(ctx->memory, order, "build_type1_halftone");
    gs_free_object(ctx->memory, penum, "build_type1_halftone");
    return code;
}

static int build_type6_halftone(pdf_context *ctx, pdf_stream *halftone_stream, pdf_dict *page_dict,
                                gx_ht_order *porder, gs_halftone_component *phtc, char *name, int len)
{
    int code;
    int64_t w, h, length = 0;
    gs_threshold2_halftone *ptp = &phtc->params.threshold2;
    pdf_dict *halftone_dict = NULL;

    code = pdfi_dict_from_obj(ctx, (pdf_obj *)halftone_stream, &halftone_dict);
    if (code < 0)
        return code;

    ptp->thresholds.data = NULL;
    ptp->thresholds.size = 0;

    code = pdfi_dict_get_int(ctx, halftone_dict, "Width", &w);
    if (code < 0)
        return code;
    ptp->width = w;
    ptp->width2 = 0;

    code = pdfi_dict_get_int(ctx, halftone_dict, "Height", &h);
    if (code < 0)
        return code;
    ptp->height = h;
    ptp->height2 = 0;

    ptp->bytes_per_sample = 1;
    ptp->transfer = 0;
    ptp->transfer_closure.proc = 0;
    ptp->transfer_closure.data = 0;

    code = pdfi_get_name_index(ctx, name, len, (unsigned int *)&phtc->cname);
    if (code < 0)
        goto error;

    phtc->comp_number = gs_cname_to_colorant_number(ctx->pgs, (byte *)name, len, 1);

    length = w * h;
    code = pdfi_stream_to_buffer(ctx, halftone_stream,
                                 (byte **)&ptp->thresholds.data, &length);
    if (code < 0)
        goto error;

    /* Guard against a returned buffer larger than a gs_const_bytestring can hold */
    if (length > max_uint) {
        code = gs_note_error(gs_error_rangecheck);
        goto error;
    }

    ptp->thresholds.size = length;
    phtc->type = ht_type_threshold2;
    return code;

error:
    gs_free_object(ctx->memory, (byte *)ptp->thresholds.data, "build_type6_halftone");
    return code;
}

static int build_type10_halftone(pdf_context *ctx, pdf_stream *halftone_stream, pdf_dict *page_dict, gx_ht_order *porder, gs_halftone_component *phtc, char *name, int len)
{
    int code;
    int64_t w, h, length = 0;
    gs_threshold2_halftone *ptp = &phtc->params.threshold2;
    pdf_dict *halftone_dict = NULL;

    code = pdfi_dict_from_obj(ctx, (pdf_obj *)halftone_stream, &halftone_dict);

    ptp->thresholds.data = NULL;
    ptp->thresholds.size = 0;

    code = pdfi_dict_get_int(ctx, halftone_dict, "Xsquare", &w);
    if (code < 0)
        return code;
    ptp->width = ptp->height = w;

    code = pdfi_dict_get_int(ctx, halftone_dict, "Ysquare", &h);
    if (code < 0)
        return code;
    ptp->width2 = ptp->height2 = h;

    ptp->bytes_per_sample = 1;
    ptp->transfer = 0;
    ptp->transfer_closure.proc = 0;
    ptp->transfer_closure.data = 0;

    code = pdfi_get_name_index(ctx, name, len, (unsigned int *)&phtc->cname);
    if (code < 0)
        goto error;

    phtc->comp_number = gs_cname_to_colorant_number(ctx->pgs, (byte *)name, len, 1);

    length = (w * w) + (h * h);
    code = pdfi_stream_to_buffer(ctx, halftone_stream,
                                 (byte **)&ptp->thresholds.data, &length);
    if (code < 0)
        goto error;

    /* Guard against a returned buffer larger than a gs_const_bytestring can hold */
    if (length > max_uint) {
        code = gs_note_error(gs_error_rangecheck);
        goto error;
    }

    ptp->thresholds.size = length;
    phtc->type = ht_type_threshold2;
    return code;

error:
    gs_free_object(ctx->memory, (byte *)ptp->thresholds.data, "build_type10_halftone");
    return code;
}

static int build_type16_halftone(pdf_context *ctx, pdf_stream *halftone_stream, pdf_dict *page_dict, gx_ht_order *porder, gs_halftone_component *phtc, char *name, int len)
{
    int code;
    int64_t w, h, length = 0;
    gs_threshold2_halftone *ptp = &phtc->params.threshold2;
    pdf_dict *halftone_dict = NULL;

    code = pdfi_dict_from_obj(ctx, (pdf_obj *)halftone_stream, &halftone_dict);
    if (code < 0)
        return code;

    ptp->thresholds.data = NULL;
    ptp->thresholds.size = 0;

    code = pdfi_dict_get_int(ctx, halftone_dict, "Width", &w);
    if (code < 0)
        return code;
    ptp->width = w;

    code = pdfi_dict_get_int(ctx, halftone_dict, "Height", &h);
    if (code < 0)
        return code;
    ptp->height = h;

    w = 0;
    code = pdfi_dict_get_int(ctx, halftone_dict, "Width2", &w);
    if (code < 0 && code != gs_error_undefined)
        return code;
    ptp->width2 = w;

    h = 0;
    code = pdfi_dict_get_int(ctx, halftone_dict, "Height2", &h);
    if (code < 0 && code != gs_error_undefined)
        return code;
    ptp->height2 = h;

    ptp->bytes_per_sample = 2;
    ptp->transfer = 0;
    ptp->transfer_closure.proc = 0;
    ptp->transfer_closure.data = 0;

    code = pdfi_get_name_index(ctx, name, len, (unsigned int *)&phtc->cname);
    if (code < 0)
        goto error;

    phtc->comp_number = gs_cname_to_colorant_number(ctx->pgs, (byte *)name, len, 1);

    if (ptp->width2 != 0 && ptp->height2 != 0) {
        length = ((ptp->width * ptp->height) + (ptp->width2 * ptp->height2)) * 2;
    } else {
        length = (int64_t)ptp->width * (int64_t)ptp->height * 2;
    }

    code = pdfi_stream_to_buffer(ctx, halftone_stream,
                                 (byte **)&ptp->thresholds.data, &length);
    if (code < 0)
        goto error;

    /* Guard against a returned buffer larger than a gs_const_bytestring can hold */
    if (length > max_uint) {
        code = gs_note_error(gs_error_rangecheck);
        goto error;
    }

    ptp->thresholds.size = length;
    phtc->type = ht_type_threshold2;
    return code;

error:
    gs_free_object(ctx->memory, (byte *)ptp->thresholds.data, "build_type16_halftone");
    return code;
}

static void pdfi_free_halftone(gs_memory_t *memory, void *data, client_name_t cname)
{
    int i=0;
    gs_halftone *pht = (gs_halftone *)data;
    gs_halftone_component comp;

    for (i=0;i< pht->params.multiple.num_comp;i++) {
        comp = pht->params.multiple.components[i];
        switch(comp.type) {
            case ht_type_threshold:
                if (comp.params.threshold.thresholds.data != NULL)
                    gs_free_object(memory, (byte *)comp.params.threshold.thresholds.data, "pdfi_free_halftone - thresholds");
                break;
            case ht_type_threshold2:
                if (comp.params.threshold2.thresholds.data != NULL)
                    gs_free_object(memory, (byte *)comp.params.threshold2.thresholds.data, "pdfi_free_halftone - thresholds");
                break;
            default:
                break;
        }
    }
    gs_free_object(memory, pht->params.multiple.components, "pdfi_free_halftone");
    gs_free_object(memory, pht, "pdfi_free_halftone");
}

static int build_type5_halftone(pdf_context *ctx, pdf_dict *halftone_dict, pdf_dict *page_dict, gx_device_halftone *pdht, gs_halftone *pht)
{
    int code, code1, str_len, comp_number;
    int64_t type;
    char *str = NULL;
    bool known = false;
    gs_halftone_component *phtc = NULL, *phtc1;
    gx_ht_order_component *pocs = 0;
    pdf_obj *Key = NULL, *Value = NULL;
    uint64_t index = 0, ix = 0;
    int NumComponents = 0;
    gx_ht_order *porder1 = NULL;
    pdf_dict *subdict = NULL;

    /* The only case involving multiple halftones, we need to enumerate each entry
     * in the dictionary
     */
    /* Type 5 halftone dictionaries are required to have a Default */
    code = pdfi_dict_known(ctx, halftone_dict, "Default", &known);
    if (code < 0)
        return code;
    if (!known) {
        code = gs_note_error(gs_error_undefined);
        return code;
    }

    code = pdfi_loop_detector_mark(ctx);
    if (code < 0)
        goto error;
    code = pdfi_dict_first(ctx, halftone_dict, &Key, &Value, &index);
    code1 = pdfi_loop_detector_cleartomark(ctx);
    if (code < 0)
        goto error;
    if (code1 < 0) {
        code = code1;
        goto error;
    }

    /* First establish the number of components from the halftone which we will use.
     * If the component number is GX_DEVICE_COLOR_MAX_COMPONENTS then its the default,
     * if its < 0 then its not available in the device. Otherwise its a colorant which is
     * being rendered, so we need to set that halftone component. The Default will be
     * stored in the device halftone order rather than in the component array order
     * members.
     */
    do {
        if (pdfi_type_of(Key) != PDF_NAME) {
            code = gs_note_error(gs_error_typecheck);
            goto error;
        }
        if (!pdfi_name_is((const pdf_name *)Key, "HalftoneName") && !pdfi_name_is((const pdf_name *)Key, "HalftoneType") && !pdfi_name_is((const pdf_name *)Key, "Type")) {
            code = pdfi_string_from_name(ctx, (pdf_name *)Key, &str, &str_len);
            if (code < 0)
                goto error;

            comp_number = gs_cname_to_colorant_number(ctx->pgs, (byte *)str, str_len,
                                        ht_type_multiple);
            if (comp_number >= 0)
                NumComponents++;
            gs_free_object(ctx->memory, str, "pdfi_string_from_name");
            str = NULL;
        }

        pdfi_countdown(Key);
        pdfi_countdown(Value);
        Key = Value = NULL;

        code = pdfi_loop_detector_mark(ctx);
        if (code < 0)
            goto error;
        code = pdfi_dict_next(ctx, halftone_dict, &Key, &Value, &index);
        code1 = pdfi_loop_detector_cleartomark(ctx);
        if (code < 0  && code != gs_error_undefined)
            goto error;
        else if (code1 < 0) {
            code = code1;
            goto error;
        }
    } while (code >= 0);

    if (NumComponents == 0) {
        code = gs_note_error(gs_error_syntaxerror);
        goto error;
    }

    pocs = gs_alloc_struct_array(ctx->memory, NumComponents,
                                 gx_ht_order_component,
                                 &st_ht_order_component_element,
                                 "gs_sethalftone");
    if (pocs == NULL)
        goto error;

    memset(pocs, 0x00, NumComponents * sizeof(gx_ht_order_component));
    pdht->components = pocs;
    pdht->num_comp = NumComponents;
    phtc = (gs_halftone_component *)gs_alloc_bytes(ctx->memory, sizeof(gs_halftone_component) * NumComponents, "pdfi_do_halftone");
    if (phtc == 0) {
        code = gs_note_error(gs_error_VMerror);
        goto error;
    }

    code = pdfi_loop_detector_mark(ctx);
    if (code < 0)
        goto error;
    code = pdfi_dict_first(ctx, halftone_dict, &Key, &Value, &index);
    code1 = pdfi_loop_detector_cleartomark(ctx);
    if (code < 0)
        goto error;
    else if (code1 < 0) {
        code = code1;
        goto error;
    }

    /* index 0 in the component array is reserved for the Default, we can't get here without
     * having a /Default, so we just leave room for it and start filing the other inks from
     * index 1.
     */
    ix = 1;
    do {
        if (pdfi_type_of(Key) != PDF_NAME) {
            code = gs_note_error(gs_error_typecheck);
            goto error;
        }
        if (!pdfi_name_is((const pdf_name *)Key, "HalftoneName") && !pdfi_name_is((const pdf_name *)Key, "HalftoneType") && !pdfi_name_is((const pdf_name *)Key, "Type")) {
            if (!pdfi_name_is((const pdf_name *)Key, "HalftoneName") && !pdfi_name_is((const pdf_name *)Key, "HalftoneType") && !pdfi_name_is((const pdf_name *)Key, "Type")) {
                code = pdfi_dict_from_obj(ctx, Value, &subdict);
                if (code < 0)
                    goto error;

                code = pdfi_string_from_name(ctx, (pdf_name *)Key, &str, &str_len);
                if (code < 0)
                    goto error;

                comp_number = gs_cname_to_colorant_number(ctx->pgs, (byte *)str, str_len,
                                            ht_type_multiple);
                if (comp_number >= 0) {
                    /* If comp_number == GX_DEVICE_COLOR_MAX_COMPONENTS then it is the /Default
                     * In that case we want to store it in index 0 of the halftone components array
                     */
                    if (comp_number == GX_DEVICE_COLOR_MAX_COMPONENTS) {
                        phtc[0].comp_number = comp_number;
                        porder1 = &(pdht->components[0].corder);
                        pdht->components[0].comp_number = comp_number;
                        phtc1 = &phtc[0];
                    } else {
                        phtc[ix].comp_number = comp_number;
                        porder1 = &(pdht->components[ix].corder);
                        pdht->components[ix].comp_number = phtc[ix].comp_number;
                        phtc1 = &phtc[ix++];
                    }

                    code = pdfi_dict_get_int(ctx, subdict, "HalftoneType", &type);
                    if (code < 0)
                        goto error;

                    switch(type) {
                        case 1:
                            code = build_type1_halftone(ctx, (pdf_dict *)Value, page_dict, porder1, phtc1, str, str_len, comp_number);
                            if (code < 0)
                                goto error;
                            break;
                        case 6:
                            if (pdfi_type_of(Value) != PDF_STREAM) {
                                code = gs_note_error(gs_error_typecheck);
                                goto error;
                            }
                            code = build_type6_halftone(ctx, (pdf_stream *)Value, page_dict, porder1, phtc1, str, str_len);
                            if (code < 0)
                                goto error;
                            break;
                        case 10:
                            if (pdfi_type_of(Value) != PDF_STREAM) {
                                code = gs_note_error(gs_error_typecheck);
                                goto error;
                            }
                            code = build_type10_halftone(ctx, (pdf_stream *)Value, page_dict, porder1, phtc1, str, str_len);
                            if (code < 0)
                                goto error;
                            break;
                        case 16:
                            if (pdfi_type_of(Value) != PDF_STREAM) {
                                code = gs_note_error(gs_error_typecheck);
                                goto error;
                            }
                            code = build_type16_halftone(ctx, (pdf_stream *)Value, page_dict, porder1, phtc1, str, str_len);
                            if (code < 0)
                                goto error;
                            break;
                        default:
                            code = gs_note_error(gs_error_rangecheck);
                            goto error;
                            break;

                    }
                    gs_free_object(ctx->memory, str, "pdfi_string_from_name");
                    str = NULL;
                } else {
                    gs_free_object(ctx->memory, str, "pdfi_string_from_name");
                    str = NULL;
                }
            }
        }

        pdfi_countdown(Key);
        pdfi_countdown(Value);
        Key = Value = NULL;

        code = pdfi_loop_detector_mark(ctx);
        if (code < 0)
            goto error;
        code = pdfi_dict_next(ctx, halftone_dict, &Key, &Value, &index);
        code1 = pdfi_loop_detector_cleartomark(ctx);
        if (code < 0 && code != gs_error_undefined)
            goto error;
        else if (code1 < 0) {
            code = code1;
            goto error;
        }
    } while (code >= 0);
    code = 0;

    /* If we only had one component, it must be the Default, in which case we
     * do not need the components array. So we can copy the order from the 0th
     * index of the components array (Default is stored at index 0) to the
     * device halftone order, and free the components array.
     */
    pdht->order = pdht->components[0].corder;
    if (ix == 1) {
        gs_free_object(ctx->memory, pocs, "pdfi_build_type5_halftone");
        pdht->components = 0;
        pdht->num_comp = 0;
    } else {
        pdht->components = pocs;
        pdht->num_comp = ix;
    }

    pht->type = ht_type_multiple;
    pht->params.multiple.components = phtc;
    pht->params.multiple.num_comp = NumComponents;
    pht->params.multiple.get_colorname_string = pdfi_separation_name_from_index;

    return 0;

error:
    pdfi_countdown(Key);
    pdfi_countdown(Value);
    gs_free_object(ctx->memory, str, "pdfi_string_from_name");
    gs_free_object(ctx->memory, pocs, "pdfi_build_type5_halftone");
    gs_free_object(ctx->memory, phtc, "pdfi_build_type5_halftone");
    pht->params.multiple.components = NULL;
    pht->params.multiple.num_comp = 0;
    pdht->components = NULL;
    pdht->num_comp = 0;
    return code;
}

static int pdfi_do_halftone(pdf_context *ctx, pdf_obj *halftone_obj, pdf_dict *page_dict)
{
    int code;
    char *str = NULL;
    int64_t type;
    gs_halftone *pht = NULL;
    gx_device_halftone *pdht = NULL;
    gs_halftone_component *phtc = NULL;
    pdf_obj *Key = NULL, *Value = NULL, *transfer = NULL;
    pdf_dict *halftone_dict = NULL;
    gx_transfer_map *pmap = NULL;

    code = pdfi_dict_from_obj(ctx, halftone_obj, &halftone_dict);
    if (code < 0)
        return code;

    code = pdfi_dict_get_int(ctx, halftone_dict, "HalftoneType", &type);
    if (code < 0)
        return code;

    pht = (gs_halftone *)gs_alloc_bytes(ctx->memory, sizeof(gs_halftone), "pdfi_do_halftone");
    if (pht == 0) {
        code = gs_note_error(gs_error_VMerror);
        goto error;
    }
    memset(pht, 0x00, sizeof(gs_halftone));
    pht->rc.memory = ctx->memory;
    pht->rc.free = pdfi_free_halftone;

    pdht = (gx_device_halftone *)gs_alloc_bytes(ctx->memory, sizeof(gx_device_halftone), "pdfi_do_halftone");
    if (pdht == 0) {
        code = gs_note_error(gs_error_VMerror);
        goto error;
    }
    memset(pdht, 0x00, sizeof(gx_device_halftone));
    pdht->num_dev_comp = ctx->pgs->device->color_info.num_components;
    pdht->rc.memory = ctx->memory;

    switch(type) {
        case 1:
            phtc = (gs_halftone_component *)gs_alloc_bytes(ctx->memory, sizeof(gs_halftone_component), "pdfi_do_halftone");
            if (phtc == 0) {
                code = gs_note_error(gs_error_VMerror);
                goto error;
            }

            code = build_type1_halftone(ctx, halftone_dict, page_dict, &pdht->order, phtc, (char *)"Default", 7, -1);
            if (code < 0)
                goto error;

            pht->type = ht_type_multiple;
            pht->params.multiple.components = phtc;
            pht->params.multiple.num_comp = 1;
            pht->params.multiple.get_colorname_string = pdfi_separation_name_from_index;
            code = gx_gstate_dev_ht_install(ctx->pgs, pdht, pht->type, gs_currentdevice_inline(ctx->pgs), HT_OBJTYPE_DEFAULT);
            if (code < 0)
                goto error;

            gx_device_halftone_release(pdht, pdht->rc.memory);
            rc_decrement(ctx->pgs->halftone, "pdfi_do_halftone(halftone)");
            ctx->pgs->halftone = pht;
            rc_increment(ctx->pgs->halftone);
            gx_unset_both_dev_colors(ctx->pgs);
            break;

        case 5:
            code = build_type5_halftone(ctx, halftone_dict, page_dict, pdht, pht);
            if (code < 0)
                goto error;

            code = gx_gstate_dev_ht_install(ctx->pgs, pdht, pht->type, gs_currentdevice_inline(ctx->pgs), HT_OBJTYPE_DEFAULT);
            if (code < 0)
                goto error;

            gx_device_halftone_release(pdht, pdht->rc.memory);
            rc_decrement(ctx->pgs->halftone, "");
            ctx->pgs->halftone = pht;
            rc_increment(ctx->pgs->halftone);
            gx_unset_both_dev_colors(ctx->pgs);
            break;

        case 6:
            if (pdfi_type_of(halftone_obj) != PDF_STREAM)
                return_error(gs_error_typecheck);
            phtc = (gs_halftone_component *)gs_alloc_bytes(ctx->memory, sizeof(gs_halftone_component), "pdfi_do_halftone");
            if (phtc == 0) {
                code = gs_note_error(gs_error_VMerror);
                goto error;
            }

            code = build_type6_halftone(ctx, (pdf_stream *)halftone_obj, page_dict, &pdht->order, phtc, (char *)"Default", 7);
            if (code < 0)
                goto error;

            pht->type = ht_type_multiple;
            pht->params.multiple.components = phtc;
            pht->params.multiple.num_comp = 1;
            pht->params.multiple.get_colorname_string = pdfi_separation_name_from_index;

            code = gs_sethalftone_prepare(ctx->pgs, pht, pdht);

            /* Transfer function pdht->order->transfer */
            if (pdfi_dict_knownget(ctx, ((pdf_stream *)halftone_obj)->stream_dict, "TransferFunction", &transfer) > 0) {
                switch (pdfi_type_of(transfer)) {
                    case PDF_NAME:
                        /* As far as I can tell, only /Identity is valid as a name, so we can just ignore
                         * names, if it's not Identity it would be an error (which we would ignore) and if
                         * it is, it has no effect. So what's the point ?
                         */
                        break;
                    case PDF_STREAM:
                        /* If we get an error here, we can just ignore it, and not apply the transfer */
                        code = pdfi_evaluate_transfer(ctx, transfer, page_dict, &pmap);
                        if (code >= 0) {
                            pdht->order.transfer = pmap;
                        }
                        break;
                    default:
                        /* should be an error, but we can just ignore it */
                        pdfi_set_warning(ctx, 0, NULL, W_PDF_TYPECHECK, "do_halftone", NULL);
                        break;
                }
                pdfi_countdown(transfer);
            }

            code = gx_gstate_dev_ht_install(ctx->pgs, pdht, pht->type, gs_currentdevice_inline(ctx->pgs), HT_OBJTYPE_DEFAULT);
            if (code < 0)
                goto error;

            gx_device_halftone_release(pdht, pdht->rc.memory);
            rc_decrement(ctx->pgs->halftone, "pdfi_do_halftone(halftone)");
            ctx->pgs->halftone = pht;
            rc_increment(ctx->pgs->halftone);
            gx_unset_both_dev_colors(ctx->pgs);
            break;
        case 10:
            if (pdfi_type_of(halftone_obj) != PDF_STREAM)
                return_error(gs_error_typecheck);
            phtc = (gs_halftone_component *)gs_alloc_bytes(ctx->memory, sizeof(gs_halftone_component), "pdfi_do_halftone");
            if (phtc == 0) {
                code = gs_note_error(gs_error_VMerror);
                goto error;
            }

            code = build_type10_halftone(ctx, (pdf_stream *)halftone_obj, page_dict, &pdht->order, phtc, (char *)"Default", 7);
            if (code < 0)
                goto error;

            pht->type = ht_type_multiple;
            pht->params.multiple.components = phtc;
            pht->params.multiple.num_comp = 1;
            pht->params.multiple.get_colorname_string = pdfi_separation_name_from_index;

            code = gs_sethalftone_prepare(ctx->pgs, pht, pdht);

            /* Transfer function pdht->order->transfer */
            if (pdfi_dict_knownget(ctx, ((pdf_stream *)halftone_obj)->stream_dict, "TransferFunction", &transfer) > 0) {
                switch (pdfi_type_of(transfer)) {
                    case PDF_NAME:
                        /* As far as I can tell, only /Identity is valid as a name, so we can just ignore
                         * names, if it's not Identity it would be an error (which we would ignore) and if
                         * it is, it has no effect. So what's the point ?
                         */
                        break;
                    case PDF_STREAM:
                        /* If we get an error here, we can just ignore it, and not apply the transfer */
                        code = pdfi_evaluate_transfer(ctx, transfer, page_dict, &pmap);
                        if (code >= 0) {
                            pdht->order.transfer = pmap;
                        }
                        break;
                    default:
                        /* should be an error, but we can just ignore it */
                        pdfi_set_warning(ctx, 0, NULL, W_PDF_TYPECHECK, "do_halftone", NULL);
                        break;
                }
                pdfi_countdown(transfer);
            }

            code = gx_gstate_dev_ht_install(ctx->pgs, pdht, pht->type, gs_currentdevice_inline(ctx->pgs), HT_OBJTYPE_DEFAULT);
            if (code < 0)
                goto error;

            gx_device_halftone_release(pdht, pdht->rc.memory);
            rc_decrement(ctx->pgs->halftone, "pdfi_do_halftone(halftone)");
            ctx->pgs->halftone = pht;
            rc_increment(ctx->pgs->halftone);
            gx_unset_both_dev_colors(ctx->pgs);
            break;
        case 16:
            if (pdfi_type_of(halftone_obj) != PDF_STREAM)
                return_error(gs_error_typecheck);
            phtc = (gs_halftone_component *)gs_alloc_bytes(ctx->memory, sizeof(gs_halftone_component), "pdfi_do_halftone");
            if (phtc == 0) {
                code = gs_note_error(gs_error_VMerror);
                goto error;
            }

            code = build_type16_halftone(ctx, (pdf_stream *)halftone_obj, page_dict, &pdht->order, phtc, (char *)"Default", 7);
            if (code < 0)
                goto error;

            pht->type = ht_type_multiple;
            pht->params.multiple.components = phtc;
            pht->params.multiple.num_comp = 1;
            pht->params.multiple.get_colorname_string = pdfi_separation_name_from_index;

            code = gs_sethalftone_prepare(ctx->pgs, pht, pdht);

            /* Transfer function pdht->order->transfer */
            if (pdfi_dict_knownget(ctx, ((pdf_stream *)halftone_obj)->stream_dict, "TransferFunction", &transfer) > 0) {
                switch (pdfi_type_of(transfer)) {
                    case PDF_NAME:
                        /* As far as I can tell, only /Identity is valid as a name, so we can just ignore
                         * names, if it's not Identity it would be an error (which we would ignore) and if
                         * it is, it has no effect. So what's the point ?
                         */
                        break;
                    case PDF_STREAM:
                        /* If we get an error here, we can just ignore it, and not apply the transfer */
                        code = pdfi_evaluate_transfer(ctx, transfer, page_dict, &pmap);
                        if (code >= 0) {
                            pdht->order.transfer = pmap;
                        }
                        break;
                    default:
                        /* should be an error, but we can just ignore it */
                        pdfi_set_warning(ctx, 0, NULL, W_PDF_TYPECHECK, "do_halftone", NULL);
                        break;
                }
                pdfi_countdown(transfer);
            }

            code = gx_gstate_dev_ht_install(ctx->pgs, pdht, pht->type, gs_currentdevice_inline(ctx->pgs), HT_OBJTYPE_DEFAULT);
            if (code < 0)
                goto error;

            gx_device_halftone_release(pdht, pdht->rc.memory);
            rc_decrement(ctx->pgs->halftone, "pdfi_do_halftone(halftone)");
            ctx->pgs->halftone = pht;
            rc_increment(ctx->pgs->halftone);
            gx_unset_both_dev_colors(ctx->pgs);
            break;
        default:
            code = gs_note_error(gs_error_rangecheck);
            goto error;
            break;
    }
    gs_free_object(ctx->memory, pdht, "pdfi_do_halftone");
    return 0;

error:
    if (pdht != NULL)
        gx_device_halftone_release(pdht, pdht->rc.memory);
    gs_free_object(ctx->memory, str, "pdfi_string_from_name");
    pdfi_countdown(Key);
    pdfi_countdown(Value);
    gs_free_object(ctx->memory, pht, "pdfi_do_halftone");
    gs_free_object(ctx->memory, phtc, "pdfi_do_halftone");
    gs_free_object(ctx->memory, pdht, "pdfi_do_halftone");
    return code;
}

static int GS_HT(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    int code;
    pdf_obj *obj = NULL;

    code = pdfi_dict_get(ctx, GS, "HT", &obj);
    if (code < 0)
        return code;


    if (pdfi_type_of(obj) == PDF_NAME) {
        if (pdfi_name_is((const pdf_name *)obj, "Default")) {
            goto exit;
        } else {
            code = gs_note_error(gs_error_rangecheck);
            goto exit;
        }
    } else {
        code = pdfi_do_halftone(ctx, obj, page_dict);
    }
    if (code < 0 && !ctx->args.pdfstoponerror) {
        pdfi_set_error(ctx, code, NULL, E_BAD_HALFTONE, "GS_HT", "Halftone will be ignored");
        code = 0;
    }

exit:
    pdfi_countdown(obj);
    return code;
}

static int GS_FL(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    int code;
    double d1;

    code = pdfi_dict_get_number(ctx, GS, "FL", &d1);
    if (code < 0)
        return code;

    code = gs_setflat(ctx->pgs, d1);
    return code;
}

static int GS_SM(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    int code;
    double d1;

    code = pdfi_dict_get_number(ctx, GS, "SM", &d1);
    if (code < 0)
        return code;

    code = gs_setsmoothness(ctx->pgs, d1);
    return code;
}

static int GS_SA(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    bool b;
    int code;

    code = pdfi_dict_get_bool(ctx, GS, "SA", &b);
    if (code < 0)
        return code;

    return gs_setstrokeadjust(ctx->pgs, b);
}

static int GS_BM(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    pdf_name *n;
    int code;
    gs_blend_mode_t mode = 0; /* Start with /Normal */

    code = pdfi_dict_get(ctx, GS, "BM", (pdf_obj **)&n);
    if (code < 0)
        return code;

    if (pdfi_type_of(n) == PDF_ARRAY) {
        int i;
        pdf_array *a = (pdf_array *)n;

        for (i=0;i < pdfi_array_size(a);i++){
            code = pdfi_array_get_type(ctx, a, i, PDF_NAME, (pdf_obj **)&n);
            if (code < 0)
                continue;
            code = pdfi_get_blend_mode(ctx, n, &mode);
            pdfi_countdown(n);
            if (code == 0)
                break;
        }
        pdfi_countdown(a);
        return gs_setblendmode(ctx->pgs, mode);
    }

    if (pdfi_type_of(n) == PDF_NAME) {
        code = pdfi_get_blend_mode(ctx, n, &mode);
        pdfi_countdown(n);
        if (code == 0)
            return gs_setblendmode(ctx->pgs, mode);
        return_error(gs_error_undefined);
    }
    return_error(gs_error_typecheck);
}

static int GS_SMask(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    pdf_obj *o = NULL;
    pdfi_int_gstate *igs = (pdfi_int_gstate *)ctx->pgs->client_data;
    int code;
    bool Processed;

    if (ctx->page.has_transparency == false || ctx->args.notransparency == true)
        return 0;

    code = pdfi_dict_get(ctx, GS, "SMask", (pdf_obj **)&o);
    if (code < 0)
        return code;

    switch (pdfi_type_of(o)) {
        case PDF_NAME:
        {
            pdf_name *n = (pdf_name *)o;

            if (pdfi_name_is(n, "None")) {
                if (igs->SMask) {
                    pdfi_gstate_smask_free(igs);
                    code = pdfi_trans_end_smask_notify(ctx);
                }
                goto exit;
            }
            code = pdfi_find_resource(ctx, (unsigned char *)"ExtGState", n, stream_dict, page_dict, &o);
            pdfi_countdown(n);
            if (code < 0)
                return code;
            break;
        }

        case PDF_DICT:
        {
            code = pdfi_dict_knownget_bool(ctx, (pdf_dict *)o, "Processed", &Processed);
            /* Need to clear the Processed flag in the SMask if another value is set
             * (even if it's the same SMask?)
             * TODO: I think there is a better way to do this that doesn't require sticking this
             * flag in the SMask dictionary.  But for now, let's get correct behavior.
             */
            if (code > 0 && Processed) {
                code = pdfi_dict_put_bool(ctx, (pdf_dict *)o, "Processed", false);
                if (code < 0)
                    return code;
            }
            if (igs->SMask)
                pdfi_gstate_smask_free(igs);
            /* We need to use the graphics state memory, in case we are running under Ghostscript. */
            pdfi_gstate_smask_install(igs, ctx->pgs->memory, (pdf_dict *)o, ctx->pgs);
            break;
        }

        default:
            break;
    }

 exit:
    pdfi_countdown(o);
    return 0;
}

static int GS_CA(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    int code;
    double d1;

    code = pdfi_dict_get_number(ctx, GS, "CA", &d1);
    if (code < 0)
        return code;

    if (d1 > 1.0) {
        pdfi_set_warning(ctx, 0, NULL, W_PDF_CA_OUTOFRANGE, "GS_CA", NULL);
        d1 = 1.0;
    }

    if (d1 < 0.0) {
        pdfi_set_warning(ctx, 0, NULL, W_PDF_CA_OUTOFRANGE, "GS_CA", NULL);
        d1 = 0.0;
    }

    code = gs_setstrokeconstantalpha(ctx->pgs, d1);
    return code;
}

static int GS_ca(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    int code;
    double d1;

    code = pdfi_dict_get_number(ctx, GS, "ca", &d1);
    if (code < 0)
        return code;

    if (d1 > 1.0) {
        pdfi_set_warning(ctx, 0, NULL, W_PDF_CA_OUTOFRANGE, "GS_ca", NULL);
        d1 = 1.0;
    }

    if (d1 < 0.0) {
        pdfi_set_warning(ctx, 0, NULL, W_PDF_CA_OUTOFRANGE, "GS_ca", NULL);
        d1 = 0.0;
    }

    code = gs_setfillconstantalpha(ctx->pgs, d1);
    return code;
}

static int GS_AIS(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    bool b;
    int code;

    code = pdfi_dict_get_bool(ctx, GS, "AIS", &b);
    if (code < 0)
        return code;

    return gs_setalphaisshape(ctx->pgs, b);
}

static int GS_TK(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    bool b;
    int code;

    code = pdfi_dict_get_bool(ctx, GS, "TK", &b);
    if (code < 0)
        return code;

    return gs_settextknockout(ctx->pgs, b);
}

typedef int (*GS_proc)(pdf_context *ctx, pdf_dict *GS, pdf_dict *stream_dict, pdf_dict *page_dict);

typedef struct GS_Func {
    const char *Name;
    GS_proc proc;
} GS_Func_t;

GS_Func_t ExtGStateTable[] = {
    {"LW", GS_LW},
    {"LC", GS_LC},
    {"LJ", GS_LJ},
    {"ML", GS_ML},
    {"D", GS_D},
    {"RI", GS_RI},
    {"OP", GS_OP},
    {"op", GS_op},
    {"OPM", GS_OPM},
    {"Font", GS_Font},
    {"BG", GS_BG},
    {"BG2", GS_BG2},
    {"UCR", GS_UCR},
    {"UCR2", GS_UCR2},
    {"TR", GS_TR},
    {"TR2", GS_TR2},
    {"HT", GS_HT},
    {"FL", GS_FL},
    {"SM", GS_SM},
    {"SA", GS_SA},
    {"BM", GS_BM},
    {"SMask", GS_SMask},
    {"CA", GS_CA},
    {"ca", GS_ca},
    {"AIS", GS_AIS},
    {"TK", GS_TK},
};

/* Set gstate from dictionary
 * NOTE: stream_dict may not be needed and can currently be NULL.
 * If we decide it can't be NULL, check Patterns implementation to refactor it to pass that param.
 */
int pdfi_set_ExtGState(pdf_context *ctx, pdf_dict *stream_dict,
                       pdf_dict *page_dict, pdf_dict *gstate_dict)
{
    int code, i, limit = sizeof(ExtGStateTable) / sizeof (GS_Func_t);
    bool known;

    for (i=0;i < limit; i++) {
        code = pdfi_dict_known(ctx, gstate_dict, ExtGStateTable[i].Name, &known);
        if (code < 0)
            break;
        if (known) {
            code = ExtGStateTable[i].proc(ctx, gstate_dict, NULL, page_dict);
            if (code < 0)
                break;
        }
    }
    return code;
}

int pdfi_setgstate(pdf_context *ctx, pdf_dict *stream_dict, pdf_dict *page_dict)
{
    pdf_name *n = NULL;
    pdf_obj *o = NULL;
    int code=0, code1 = 0;

    code = pdfi_loop_detector_mark(ctx);
    if (code < 0)
        return code;

    if (pdfi_count_stack(ctx) < 1) {
        code = gs_note_error(gs_error_stackunderflow);
        goto setgstate_error;
    }
    n = (pdf_name *)ctx->stack_top[-1];
    pdfi_countup(n);
    pdfi_pop(ctx, 1);

    if (pdfi_type_of(n) != PDF_NAME) {
        code = gs_note_error(gs_error_typecheck);
        goto setgstate_error;
    }

    code = pdfi_find_resource(ctx, (unsigned char *)"ExtGState", n, (pdf_dict *)stream_dict,
                              page_dict, &o);
    if (code < 0)
        goto setgstate_error;

    if (pdfi_type_of(o) != PDF_DICT) {
        code = gs_note_error(gs_error_typecheck);
        goto setgstate_error;
    }

    code = pdfi_set_ExtGState(ctx, stream_dict, page_dict, (pdf_dict *)o);

setgstate_error:
    code1 = pdfi_loop_detector_cleartomark(ctx);
    if (code == 0) code = code1;

    pdfi_countdown(n);
    pdfi_countdown(o);
    return code;
}


int pdfi_free_DefaultQState(pdf_context *ctx)
{
    if (ctx->DefaultQState)
        gs_gstate_free(ctx->DefaultQState);
    ctx->DefaultQState = NULL;
    return 0;
}

int pdfi_set_DefaultQState(pdf_context *ctx, gs_gstate *pgs)
{
    pdfi_free_DefaultQState(ctx);
    /* We need to use the graphics state memory, in case we are running under Ghostscript. */
    ctx->DefaultQState = gs_gstate_copy(pgs, ctx->pgs->memory);
    if (ctx->DefaultQState == NULL)
        return_error(gs_error_VMerror);
    return 0;
}

gs_gstate *pdfi_get_DefaultQState(pdf_context *ctx)
{
    return ctx->DefaultQState;
}

int pdfi_copy_DefaultQState(pdf_context *ctx, gs_gstate **pgs)
{
    /* We need to use the graphics state memory, in case we are running under Ghostscript. */
    *pgs = gs_gstate_copy(ctx->DefaultQState, ctx->pgs->memory);
    if (*pgs == NULL)
        return_error(gs_error_VMerror);
    return 0;
}

int pdfi_restore_DefaultQState(pdf_context *ctx, gs_gstate **pgs)
{
    int code;

    code = pdfi_set_DefaultQState(ctx, *pgs);
    gs_gstate_free(*pgs);
    *pgs = NULL;
    return code;
}