// Copyright (C) 2004-2021 Artifex Software, Inc.

//

// This file is part of MuPDF.

//

// MuPDF is free software: you can redistribute it and/or modify it under the

// terms of the GNU Affero General Public License as published by the Free

// Software Foundation, either version 3 of the License, or (at your option)

// any later version.

//

// MuPDF is distributed in the hope that it will be useful, but WITHOUT ANY

// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

// FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more

// details.

//

// You should have received a copy of the GNU Affero General Public License

// along with MuPDF. If not, see <https://www.gnu.org/licenses/agpl-3.0.en.html>

//

// Alternative licensing terms are available from the licensor.

// For commercial licensing, see <https://www.artifex.com/> or contact

// Artifex Software, Inc., 39 Mesa Street, Suite 108A, San Francisco,

// CA 94129, USA, for further information.

#include "mupdf/fitz.h"

#include <assert.h>

#include <string.h>

#include <limits.h>

#ifdef OCR_DISABLED

/* In non-OCR builds, we need to define this otherwise SWIG Python gets SEGV

when it attempts to import mupdf.py and _mupdf.py. */

const char *fz_pdfocr_write_options_usage = "";

#else

#include "tessocr.h"

const char *fz_pdfocr_write_options_usage =

  "PDFOCR output options:\n"

  "\tcompression=none: No compression (default)\n"

  "\tcompression=flate: Flate compression\n"

  "\tstrip-height=N: Strip height (default 0=fullpage)\n"

  "\tocr-language=<lang>: OCR language (default=eng)\n"

  "\tocr-datadir=<datadir>: OCR data path (default=rely on TESSDATA_PREFIX)\n"

  "\n";

static const char funky_font[] =

"3 0 obj\n<</BaseFont/GlyphLessFont/DescendantFonts[4 0 R]"

"/Encoding/Identity-H/Subtype/Type0/ToUnicode 6 0 R/Type/Font"

">>\nendobj\n";

static const char funky_font2[] =

"4 0 obj\n"

"<</BaseFont/GlyphLessFont/CIDToGIDMap 5 0 R"

"/CIDSystemInfo<</Ordering (Identity)/Registry (Adobe)/Supplement 0>>"

"/FontDescriptor 7 0 R/Subtype/CIDFontType2/Type/Font/DW 500>>"

"\nendobj\n";

static const char funky_font3[] =

"5 0 obj\n<</Length 210/Filter/FlateDecode>>\nstream\n"

"\x78\x9c\xec\xc2\x01\x09\x00\x00\x00\x02\xa0\xfa\x7f\xba\x21\x89"

"\xa6\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"

"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"

"\x80\x7b\x03\x00\x00\xff\xff\xec\xc2\x01\x0d\x00\x00\x00\xc2\x20"

"\xdf\xbf\xb4\x45\x18\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"

"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"

"\x00\x00\x00\x00\x00\xeb\x00\x00\x00\xff\xff\xec\xc2\x01\x0d\x00"

"\x00\x00\xc2\x20\xdf\xbf\xb4\x45\x18\x00\x00\x00\x00\x00\x00\x00"

"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"

"\x00\x00\x00\x00\x00\x00\x00\x00\x00\xeb\x00\x00\x00\xff\xff\xed"

"\xc2\x01\x0d\x00\x00\x00\xc2\x20\xdf\xbf\xb4\x45\x18\x00\x00\x00"

"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"

"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xeb\x00\xff"

"\x00\x10"

"\nendstream\nendobj\n";

static const char funky_font4[] =

"6 0 obj\n<</Length 353>>\nstream\n"

"/CIDInit /ProcSet findresource begin\n"

"12 dict begin\n"

"begincmap\n"

"/CIDSystemInfo\n"

"<<\n"

"  /Registry (Adobe)\n"

"  /Ordering (UCS)\n"

"  /Supplement 0\n"

">> def\n"

"/CMapName /Adobe-Identity-UCS def\n"

"/CMapType 2 def\n"

"1 begincodespacerange\n"

"<0000> <FFFF>\n"

"endcodespacerange\n"

"1 beginbfrange\n"

"<0000> <FFFF> <0000>\n"

"endbfrange\n"

"endcmap\n"

"CMapName currentdict /CMap defineresource pop\n"

"end\n"

"end\n"

"endstream\n"

"endobj\n";

static const char funky_font5[] =

"7 0 obj\n"

"<</Ascent 1000/CapHeight 1000/Descent -1/Flags 5"

"/FontBBox[0 0 500 1000]/FontFile2 8 0 R/FontName/GlyphLessFont"

"/ItalicAngle 0/StemV 80/Type/FontDescriptor>>\nendobj\n";

static const char funky_font6[] =

"8 0 obj\n<</Length 572/Length1 572>>\nstream\n"

"\x00\x01\x00\x00\x00\x0a\x00\x80\x00\x03\x00\x20\x4f\x53\x2f\x32"

"\x56\xde\xc8\x94\x00\x00\x01\x28\x00\x00\x00\x60\x63\x6d\x61\x70"

"\x00\x0a\x00\x34\x00\x00\x01\x90\x00\x00\x00\x1e\x67\x6c\x79\x66"

"\x15\x22\x41\x24\x00\x00\x01\xb8\x00\x00\x00\x18\x68\x65\x61\x64"

"\x0b\x78\xf1\x65\x00\x00\x00\xac\x00\x00\x00\x36\x68\x68\x65\x61"

"\x0c\x02\x04\x02\x00\x00\x00\xe4\x00\x00\x00\x24\x68\x6d\x74\x78"

"\x04\x00\x00\x00\x00\x00\x01\x88\x00\x00\x00\x08\x6c\x6f\x63\x61"

"\x00\x0c\x00\x00\x00\x00\x01\xb0\x00\x00\x00\x06\x6d\x61\x78\x70"

"\x00\x04\x00\x05\x00\x00\x01\x08\x00\x00\x00\x20\x6e\x61\x6d\x65"

"\xf2\xeb\x16\xda\x00\x00\x01\xd0\x00\x00\x00\x4b\x70\x6f\x73\x74"

"\x00\x01\x00\x01\x00\x00\x02\x1c\x00\x00\x00\x20\x00\x01\x00\x00"

"\x00\x01\x00\x00\xb0\x94\x71\x10\x5f\x0f\x3c\xf5\x04\x07\x08\x00"

"\x00\x00\x00\x00\xcf\x9a\xfc\x6e\x00\x00\x00\x00\xd4\xc3\xa7\xf2"

"\x00\x00\x00\x00\x04\x00\x08\x00\x00\x00\x00\x10\x00\x02\x00\x00"

"\x00\x00\x00\x00\x00\x01\x00\x00\x08\x00\xff\xff\x00\x00\x04\x00"

"\x00\x00\x00\x00\x04\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00"

"\x00\x00\x00\x00\x00\x00\x00\x02\x00\x01\x00\x00\x00\x02\x00\x04"

"\x00\x01\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00"

"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x03\x00\x00\x01\x90\x00\x05"

"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"

"\x00\x00\x00\x00\x00\x00\x00\x00\x05\x00\x01\x00\x01\x00\x00\x00"

"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"

"\x00\x00\x47\x4f\x4f\x47\x00\x40\x00\x00\x00\x00\x00\x01\xff\xff"

"\x00\x00\x00\x01\x00\x01\x80\x00\x00\x00\x00\x00\x00\x00\x00\x00"

"\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00"

"\x00\x00\x00\x02\x00\x01\x00\x00\x00\x00\x00\x14\x00\x03\x00\x00"

"\x00\x00\x00\x14\x00\x06\x00\x0a\x00\x00\x00\x00\x00\x00\x00\x00"

"\x00\x00\x00\x00\x00\x0c\x00\x00\x00\x01\x00\x00\x00\x00\x04\x00"

"\x08\x00\x00\x03\x00\x00\x31\x21\x11\x21\x04\x00\xfc\x00\x08\x00"

"\x00\x00\x00\x03\x00\x2a\x00\x00\x00\x03\x00\x00\x00\x05\x00\x16"

"\x00\x00\x00\x01\x00\x00\x00\x00\x00\x05\x00\x0b\x00\x16\x00\x03"

"\x00\x01\x04\x09\x00\x05\x00\x16\x00\x00\x00\x56\x00\x65\x00\x72"

"\x00\x73\x00\x69\x00\x6f\x00\x6e\x00\x20\x00\x31\x00\x2e\x00\x30"

"\x56\x65\x72\x73\x69\x6f\x6e\x20\x31\x2e\x30\x00\x00\x01\x00\x00"

"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00"

"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"

"\nendstream\nendobj\n";

#endif

fz_pdfocr_options *

fz_parse_pdfocr_options(fz_context *ctx, fz_pdfocr_options *opts, const char *args)

{

#ifdef OCR_DISABLED

  fz_throw(ctx, FZ_ERROR_GENERIC, "No OCR support in this build");

#else

  const char *val;

  memset(opts, 0, sizeof *opts);

  if (fz_has_option(ctx, args, "compression", &val))

  {

    if (fz_option_eq(val, "none"))

      opts->compress = 0;

    else if (fz_option_eq(val, "flate"))

      opts->compress = 1;

    else

      fz_throw(ctx, FZ_ERROR_GENERIC, "Unsupported PDFOCR compression %s (none, or flate only)", val);

  }

  if (fz_has_option(ctx, args, "strip-height", &val))

  {

    int i = fz_atoi(val);

    if (i <= 0)

      fz_throw(ctx, FZ_ERROR_GENERIC, "Unsupported PDFOCR strip height %d (suggest 0)", i);

    opts->strip_height = i;

  }

  if (fz_has_option(ctx, args, "ocr-language", &val))

  {

    fz_copy_option(ctx, val, opts->language, nelem(opts->language));

  }

  if (fz_has_option(ctx, args, "ocr-datadir", &val))

  {

    fz_copy_option(ctx, val, opts->datadir, nelem(opts->datadir));

  }

  return opts;

#endif

}

void

fz_write_pixmap_as_pdfocr(fz_context *ctx, fz_output *out, const fz_pixmap *pixmap, const fz_pdfocr_options *pdfocr)

{

#ifdef OCR_DISABLED

  fz_throw(ctx, FZ_ERROR_GENERIC, "No OCR support in this build");

#else

  fz_band_writer *writer;

  if (!pixmap || !out)

    return;

  writer = fz_new_pdfocr_band_writer(ctx, out, pdfocr);

  fz_try(ctx)

  {

    fz_write_header(ctx, writer, pixmap->w, pixmap->h, pixmap->n, pixmap->alpha, pixmap->xres, pixmap->yres, 0, pixmap->colorspace, pixmap->seps);

    fz_write_band(ctx, writer, pixmap->stride, pixmap->h, pixmap->samples);

    fz_close_band_writer(ctx, writer);

  }

  fz_always(ctx)

    fz_drop_band_writer(ctx, writer);

  fz_catch(ctx)

    fz_rethrow(ctx);

#endif

}

#ifndef OCR_DISABLED

typedef struct pdfocr_band_writer_s

{

  fz_band_writer super;

  fz_pdfocr_options options;

  int obj_num;

  int xref_max;

  int64_t *xref;

  int pages;

  int page_max;

  int *page_obj;

  unsigned char *stripbuf;

  unsigned char *compbuf;

  size_t complen;

  void *tessapi;

  fz_pixmap *ocrbitmap;

  fz_pdfocr_progress_fn *progress;

  void *progress_arg;

} pdfocr_band_writer;

static int

new_obj(fz_context *ctx, pdfocr_band_writer *writer)

{

  int64_t pos = fz_tell_output(ctx, writer->super.out);

  if (writer->obj_num >= writer->xref_max)

  {

    int new_max = writer->xref_max * 2;

    if (new_max < writer->obj_num + 8)

      new_max = writer->obj_num + 8;

    writer->xref = fz_realloc_array(ctx, writer->xref, new_max, int64_t);

    writer->xref_max = new_max;

  }

  writer->xref[writer->obj_num] = pos;

  return writer->obj_num++;

}

static void

pdfocr_write_header(fz_context *ctx, fz_band_writer *writer_, fz_colorspace *cs)

{

  pdfocr_band_writer *writer = (pdfocr_band_writer *)writer_;

  fz_output *out = writer->super.out;

  int w = writer->super.w;

  int h = writer->super.h;

  int n = writer->super.n;

  int s = writer->super.s;

  int a = writer->super.alpha;

  int xres = writer->super.xres;

  int yres = writer->super.yres;

  int sh = writer->options.strip_height;

  int strips;

  int i;

  if (sh == 0)

    sh = h;

  assert(sh != 0 && "pdfocr_write_header() should not be given zero height input.");

  strips = (h + sh-1)/sh;

  if (a != 0)

    fz_throw(ctx, FZ_ERROR_GENERIC, "PDFOCR cannot write alpha channel");

  if (s != 0)

    fz_throw(ctx, FZ_ERROR_GENERIC, "PDFOCR cannot write spot colors");

  if (n != 3 && n != 1)

    fz_throw(ctx, FZ_ERROR_GENERIC, "PDFOCR expected to be Grayscale or RGB");

  fz_free(ctx, writer->stripbuf);

  writer->stripbuf = NULL;

  fz_free(ctx, writer->compbuf);

  writer->compbuf = NULL;

  fz_drop_pixmap(ctx, writer->ocrbitmap);

  writer->ocrbitmap = NULL;

  writer->stripbuf = Memento_label(fz_malloc(ctx, (size_t)w * sh * n), "pdfocr_stripbuf");

  writer->complen = fz_deflate_bound(ctx, (size_t)w * sh * n);

  writer->compbuf = Memento_label(fz_malloc(ctx, writer->complen), "pdfocr_compbuf");

  /* Always round the width of ocrbitmap up to a multiple of 4. */

  writer->ocrbitmap = fz_new_pixmap(ctx, NULL, (w+3)&~3, h, NULL, 0);

  fz_set_pixmap_resolution(ctx, writer->ocrbitmap, xres, yres);

  /* Send the file header on the first page */

  if (writer->pages == 0)

  {

    fz_write_string(ctx, out, "%PDF-1.4\n%PDFOCR-1.0\n");

    if (writer->xref_max < 9)

    {

      int new_max = 9;

      writer->xref = fz_realloc_array(ctx, writer->xref, new_max, int64_t);

      writer->xref_max = new_max;

    }

    writer->xref[3] = fz_tell_output(ctx, out);

    fz_write_data(ctx, out, funky_font,  sizeof(funky_font)-1);

    writer->xref[4] = fz_tell_output(ctx, out);

    fz_write_data(ctx, out, funky_font2, sizeof(funky_font2)-1);

    writer->xref[5] = fz_tell_output(ctx, out);

    fz_write_data(ctx, out, funky_font3, sizeof(funky_font3)-1);

    writer->xref[6] = fz_tell_output(ctx, out);

    fz_write_data(ctx, out, funky_font4, sizeof(funky_font4)-1);

    writer->xref[7] = fz_tell_output(ctx, out);

    fz_write_data(ctx, out, funky_font5, sizeof(funky_font5)-1);

    writer->xref[8] = fz_tell_output(ctx, out);

    fz_write_data(ctx, out, funky_font6, sizeof(funky_font6)-1);

  }

  if (writer->page_max <= writer->pages)

  {

    int new_max = writer->page_max * 2;

    if (new_max == 0)

      new_max = writer->pages + 8;

    writer->page_obj = fz_realloc_array(ctx, writer->page_obj, new_max, int);

    writer->page_max = new_max;

  }

  writer->page_obj[writer->pages] = writer->obj_num;

  writer->pages++;

  /* Send the Page Object */

  fz_write_printf(ctx, out, "%d 0 obj\n<</Type/Page/Parent 2 0 R/Resources<</XObject<<", new_obj(ctx, writer));

  for (i = 0; i < strips; i++)

    fz_write_printf(ctx, out, "/I%d %d 0 R", i, writer->obj_num + i);

  fz_write_printf(ctx, out, ">>/Font<</F0 3 0 R>>>>/MediaBox[0 0 %g %g]/Contents %d 0 R>>\nendobj\n",

    w * 72.0f / xres, h * 72.0f / yres, writer->obj_num + strips);

}

static void

flush_strip(fz_context *ctx, pdfocr_band_writer *writer, int fill)

{

  unsigned char *data = writer->stripbuf;

  fz_output *out = writer->super.out;

  int w = writer->super.w;

  int n = writer->super.n;

  size_t len = (size_t)w*n*fill;

  /* Buffer is full, compress it and write it. */

  if (writer->options.compress)

  {

    size_t destLen = writer->complen;

    fz_deflate(ctx, writer->compbuf, &destLen, data, len, FZ_DEFLATE_DEFAULT);

    len = destLen;

    data = writer->compbuf;

  }

  fz_write_printf(ctx, out, "%d 0 obj\n<</Width %d/ColorSpace/Device%s/Height %d%s/Subtype/Image",

    new_obj(ctx, writer), w, n == 1 ? "Gray" : "RGB", fill, writer->options.compress ? "/Filter/FlateDecode" : "");

  fz_write_printf(ctx, out, "/Length %zd/Type/XObject/BitsPerComponent 8>>\nstream\n", len);

  fz_write_data(ctx, out, data, len);

  fz_write_string(ctx, out, "\nendstream\nendobj\n");

}

static void

pdfocr_write_band(fz_context *ctx, fz_band_writer *writer_, int stride, int band_start, int band_height, const unsigned char *sp)

{

  pdfocr_band_writer *writer = (pdfocr_band_writer *)writer_;

  fz_output *out = writer->super.out;

  int w = writer->super.w;

  int h = writer->super.h;

  int n = writer->super.n;

  int sh = writer->options.strip_height;

  int line;

  unsigned char *d = writer->ocrbitmap->samples;

  if (!out)

    return;

  if (sh == 0)

    sh = h;

  for (line = 0; line < band_height; line++)

  {

    int dstline = (band_start+line) % sh;

    memcpy(writer->stripbuf + (size_t)w*n*dstline,

         sp + (size_t)line * w * n,

         (size_t)w * n);

    if (dstline+1 == sh)

      flush_strip(ctx, writer, dstline+1);

  }

  if (band_start + band_height == h && h % sh != 0)

    flush_strip(ctx, writer, h % sh);

  /* Copy strip to ocrbitmap, converting if required. */

  d += band_start*w;

  if (n == 1)

  {

    int y;

    for (y = band_height; y > 0; y--)

    {

      memcpy(d, sp, w);

      if (writer->ocrbitmap->w - w)

        memset(d + w, 0, writer->ocrbitmap->w - w);

      d += writer->ocrbitmap->w;

    }

  }

  else

  {

    int x, y;

    for (y = band_height; y > 0; y--)

    {

      for (x = w; x > 0; x--)

      {

        *d++ = (sp[0] + 2*sp[1] + sp[2] + 2)>>2;

        sp += 3;

      }

      for (x = writer->ocrbitmap->w - w; x > 0; x--)

        *d++ = 0;

    }

  }

}

enum

{

  WORD_CONTAINS_L2R = 1,

  WORD_CONTAINS_R2L = 2,

  WORD_CONTAINS_T2B = 4,

  WORD_CONTAINS_B2T = 8

};

typedef struct word_t

{

  struct word_t *next;

  float bbox[4];

  int dirn;

  int len;

  int chars[1];

} word_t;

typedef struct

{

  fz_buffer *buf;

  pdfocr_band_writer *writer;

  /* We collate the current word into the following fields: */

  int word_max;

  int word_len;

  int *word_chars;

  float word_bbox[4];

  int word_dirn;

  int word_prev_char_bbox[4];

  /* When we finish a word, we try to add it to the line. If the

   * word fits onto the end of the existing line, great. If not,

   * we flush the entire line, and start a new one just with the

   * new word. This enables us to output a whole line at once,

   * which is beneficial to avoid jittering the font sizes

   * up/down, which looks bad when we try to select text in the

   * produced PDF. */

  word_t *line;

  word_t **line_tail;

  float line_bbox[4];

  int line_dirn;

  float cur_size;

  float cur_scale;

  float tx, ty;

} char_callback_data_t;

static void

flush_words(fz_context *ctx, char_callback_data_t *cb)

{

  float size;

  if (cb->line == NULL)

    return;

  if ((cb->line_dirn & (WORD_CONTAINS_T2B | WORD_CONTAINS_B2T)) != 0)

  {

    /* Vertical line */

  }

  else

  {

    /* Horizontal line */

    size = cb->line_bbox[3] - cb->line_bbox[1];

    if (size != 0 && size != cb->cur_size)

    {

      fz_append_printf(ctx, cb->buf, "/F0 %g Tf\n", size);

      cb->cur_size = size;

    }

    /* Guard against division by 0. This makes no difference to the

     * actual calculation as if size is 0, word->bbox[2] == word->bbox[0]

     * too. */

    if (size == 0)

      size = 1;

  }

  while (cb->line)

  {

    word_t *word = cb->line;

    float x, y;

    int i, len = word->len;

    float scale;

    if ((cb->line_dirn & (WORD_CONTAINS_T2B | WORD_CONTAINS_B2T)) != 0)

    {

      /* Contains vertical text. */

      size = (word->bbox[3] - word->bbox[1]) / len;

      if (size == 0)

        size = 1;

      if (size != cb->cur_size)

      {

        fz_append_printf(ctx, cb->buf, "/F0 %g Tf\n", size);

        cb->cur_size = size;

      }

      /* Set the scale so that our glyphs fill the line bbox. */

      scale = (cb->line_bbox[2] - cb->line_bbox[0]) / size * 200;

      if (scale != 0)

      {

        float letter_height = (word->bbox[3] - word->bbox[1]) / len;

        if (scale != cb->cur_scale)

        {

          fz_append_printf(ctx, cb->buf, "%d Tz\n", (int)scale);

          cb->cur_scale = scale;

        }

        for (i = 0; i < len; i++)

        {

          x = word->bbox[0];

          y = word->bbox[1] + letter_height * i;

          fz_append_printf(ctx, cb->buf, "%g %g Td\n", x-cb->tx, y-cb->ty);

          cb->tx = x;

          cb->ty = y;

          fz_append_printf(ctx, cb->buf, "<%04x>Tj\n", word->chars[i]);

        }

      }

    }

    else

    {

      scale = (word->bbox[2] - word->bbox[0]) / size / len * 200;

      if (scale != 0)

      {

        if (scale != cb->cur_scale)

        {

          fz_append_printf(ctx, cb->buf, "%d Tz\n", (int)scale);

          cb->cur_scale = scale;

        }

        if ((word->dirn & (WORD_CONTAINS_R2L | WORD_CONTAINS_L2R)) == WORD_CONTAINS_R2L)

        {

          /* Purely R2L text */

          x = word->bbox[0];

          y = cb->line_bbox[1];

          fz_append_printf(ctx, cb->buf, "%g %g Td\n", x-cb->tx, y-cb->ty);

          cb->tx = x;

          cb->ty = y;

          /* Tesseract has sent us R2L text in R2L order (i.e. in Logical order).

           * We want to output it in that same logical order, but PDF operators

           * all move the point as if outputting L2R. We can either reverse the

           * order of chars (bad, because of cut/paste) or we can perform

           * gymnastics with the position. We opt for the latter. */

          fz_append_printf(ctx, cb->buf, "[");

          for (i = 0; i < len; i++)

          {

            if (i == 0)

            {

              if (len > 1)

                fz_append_printf(ctx, cb->buf, "%d", -500*(len-1));

            }

            else

              fz_append_printf(ctx, cb->buf, "%d", 1000);

            fz_append_printf(ctx, cb->buf, "<%04x>", word->chars[i]);

          }

          fz_append_printf(ctx, cb->buf, "]TJ\n");

        }

        else

        {

          /* L2R (or mixed) text */

          x = word->bbox[0];

          y = cb->line_bbox[1];

          fz_append_printf(ctx, cb->buf, "%g %g Td\n", x-cb->tx, y-cb->ty);

          cb->tx = x;

          cb->ty = y;

          fz_append_printf(ctx, cb->buf, "<");

          for (i = 0; i < len; i++)

            fz_append_printf(ctx, cb->buf, "%04x", word->chars[i]);

          fz_append_printf(ctx, cb->buf, ">Tj\n");

        }

      }

    }

    cb->line = word->next;

    fz_free(ctx, word);

  }

  cb->line_tail = &cb->line;

  cb->line = NULL;

  cb->line_dirn = 0;

}

static void

queue_word(fz_context *ctx, char_callback_data_t *cb)

{

  word_t *word;

  int line_is_v, line_is_h, word_is_v, word_is_h;

  if (cb->word_len == 0)

    return;

  word = fz_malloc(ctx, sizeof(*word) + (cb->word_len-1)*sizeof(int));

  word->next = NULL;

  word->len = cb->word_len;

  memcpy(word->bbox, cb->word_bbox, 4*sizeof(float));

  memcpy(word->chars, cb->word_chars, cb->word_len * sizeof(int));

  cb->word_len = 0;

  line_is_v = !!(cb->line_dirn & (WORD_CONTAINS_B2T | WORD_CONTAINS_T2B));

  word_is_v = !!(cb->word_dirn & (WORD_CONTAINS_B2T | WORD_CONTAINS_T2B));

  line_is_h = !!(cb->line_dirn & (WORD_CONTAINS_L2R | WORD_CONTAINS_R2L));

  word_is_h = !!(cb->word_dirn & (WORD_CONTAINS_L2R | WORD_CONTAINS_R2L));

  word->dirn = cb->word_dirn;

  cb->word_dirn = 0;

  /* Can we put the new word onto the end of the existing line? */

  if (cb->line != NULL &&

    !line_is_v && !word_is_v &&

    word->bbox[1] <= cb->line_bbox[3] &&

    word->bbox[3] >= cb->line_bbox[1] &&

    (word->bbox[0] >= cb->line_bbox[2] || word->bbox[2] <= cb->line_bbox[0]))

  {

    /* Can append (horizontal motion). */

    if (word->bbox[0] < cb->line_bbox[0])

      cb->line_bbox[0] = word->bbox[0];

    if (word->bbox[1] < cb->line_bbox[1])

      cb->line_bbox[1] = word->bbox[1];

    if (word->bbox[2] > cb->line_bbox[2])

      cb->line_bbox[2] = word->bbox[2];

    if (word->bbox[3] > cb->line_bbox[3])

      cb->line_bbox[3] = word->bbox[3];

  }

  else if (cb->line != NULL &&

    !line_is_h && !word_is_h &&

    word->bbox[0] <= cb->line_bbox[2] &&

    word->bbox[2] >= cb->line_bbox[0] &&

    (word->bbox[1] >= cb->line_bbox[3] || word->bbox[3] <= cb->line_bbox[1]))

  {

    /* Can append (vertical motion). */

    if (!word_is_v)

      word->dirn |= WORD_CONTAINS_T2B;

    if (word->bbox[0] < cb->line_bbox[0])

      cb->line_bbox[0] = word->bbox[0];

    if (word->bbox[1] < cb->line_bbox[1])

      cb->line_bbox[1] = word->bbox[1];

    if (word->bbox[2] > cb->line_bbox[2])

      cb->line_bbox[2] = word->bbox[2];

    if (word->bbox[3] > cb->line_bbox[3])

      cb->line_bbox[3] = word->bbox[3];

  }

  else

  {

    fz_try(ctx)

      flush_words(ctx, cb);

    fz_catch(ctx)

    {

      fz_free(ctx, word);

      fz_rethrow(ctx);

    }

    memcpy(cb->line_bbox, word->bbox, 4*sizeof(float));

  }

  *cb->line_tail = word;

  cb->line_tail = &word->next;

  cb->line_dirn |= word->dirn;

}

static void

char_callback(fz_context *ctx, void *arg, int unicode,

    const char *font_name,

    const int *line_bbox, const int *word_bbox,

    const int *char_bbox, int pointsize)

{

  char_callback_data_t *cb = (char_callback_data_t *)arg;

  pdfocr_band_writer *writer = cb->writer;

  float bbox[4];

  bbox[0] = word_bbox[0] * 72.0f / cb->writer->ocrbitmap->xres;

  bbox[3] = (writer->ocrbitmap->h - 1 - word_bbox[1]) * 72.0f / cb->writer->ocrbitmap->yres;

  bbox[2] = word_bbox[2] * 72.0f / cb->writer->ocrbitmap->yres;

  bbox[1] = (writer->ocrbitmap->h - 1 - word_bbox[3]) * 72.0f / cb->writer->ocrbitmap->yres;

  if (bbox[0] != cb->word_bbox[0] ||

    bbox[1] != cb->word_bbox[1] ||

    bbox[2] != cb->word_bbox[2] ||

    bbox[3] != cb->word_bbox[3])

  {

    queue_word(ctx, cb);

    memcpy(cb->word_bbox, bbox, 4 * sizeof(float));

  }

  if (cb->word_len == 0)

  {

    cb->word_dirn = 0;

    memcpy(cb->word_prev_char_bbox, char_bbox, 4 * sizeof(int));

  }

  else

  {

    int ox = cb->word_prev_char_bbox[0] + cb->word_prev_char_bbox[2];

    int oy = cb->word_prev_char_bbox[1] + cb->word_prev_char_bbox[3];

    int x = char_bbox[0] + char_bbox[2] - ox;

    int y = char_bbox[1] + char_bbox[3] - oy;

    int ax = x < 0 ? -x : x;

    int ay = y < 0 ? -y : y;

    if (ax > ay)

    {

      if (x > 0)

        cb->word_dirn |= WORD_CONTAINS_L2R;

      else if (x < 0)

        cb->word_dirn |= WORD_CONTAINS_R2L;

    }

    else if (ay < ax)

    {

      if (y > 0)

        cb->word_dirn |= WORD_CONTAINS_T2B;

      else if (y < 0)

        cb->word_dirn |= WORD_CONTAINS_B2T;

    }

  }

  if (cb->word_max == cb->word_len)

  {

    int newmax = cb->word_max * 2;

    if (newmax == 0)

      newmax = 16;

    cb->word_chars = fz_realloc_array(ctx, cb->word_chars, newmax, int);

    cb->word_max = newmax;

  }

  cb->word_chars[cb->word_len++] = unicode;

}

static int

pdfocr_progress(fz_context *ctx, void *arg, int prog)

{

  char_callback_data_t *cb = (char_callback_data_t *)arg;

  pdfocr_band_writer *writer = cb->writer;

  if (writer->progress == NULL)

    return 0;

  return writer->progress(ctx, writer->progress_arg, writer->pages - 1, prog);

}

static void

pdfocr_write_trailer(fz_context *ctx, fz_band_writer *writer_)

{

  pdfocr_band_writer *writer = (pdfocr_band_writer *)writer_;

  fz_output *out = writer->super.out;

  int w = writer->super.w;

  int h = writer->super.h;

  int xres = writer->super.xres;

  int yres = writer->super.yres;

  int sh = writer->options.strip_height;

  int strips;

  int i;

  size_t len;

  unsigned char *data;

  fz_buffer *buf = NULL;

  char_callback_data_t cb = { NULL };

  if (sh == 0)

    sh = h;

  strips = (h + sh-1)/sh;

  /* Send the Page contents */

  /* We need the length to this, so write to a buffer first */

  fz_var(buf);

  fz_var(cb);

  fz_try(ctx)

  {

    cb.writer = writer;

    cb.buf = buf = fz_new_buffer(ctx, 0);

    cb.line_tail = &cb.line;

    cb.word_dirn = 0;

    cb.line_dirn = 0;

    fz_append_printf(ctx, buf, "q\n%g 0 0 %g 0 0 cm\n", 72.0f/xres, 72.0f/yres);

    for (i = 0; i < strips; i++)

    {

      int at = h - (i+1)*sh;

      int this_sh = sh;

      if (at < 0)

      {

        this_sh += at;

        at = 0;

      }

      fz_append_printf(ctx, buf, "/P <</MCID 0>> BDC\nq\n%d 0 0 %d 0 %d cm\n/I%d Do\nQ\n",

        w, this_sh, at, i);

    }

    fz_append_printf(ctx, buf, "Q\nBT\n3 Tr\n");

    ocr_recognise(ctx, writer->tessapi, writer->ocrbitmap, char_callback, pdfocr_progress, &cb);

    queue_word(ctx, &cb);

    flush_words(ctx, &cb);

    fz_append_printf(ctx, buf, "ET\n");

    len = fz_buffer_storage(ctx, buf, &data);

    fz_write_printf(ctx, out, "%d 0 obj\n<</Length %zd>>\nstream\n", new_obj(ctx, writer), len);

    fz_write_data(ctx, out, data, len);

    fz_drop_buffer(ctx, buf);

    buf = NULL;

    fz_write_string(ctx, out, "\nendstream\nendobj\n");

  }

  fz_always(ctx)

  {

    fz_free(ctx, cb.word_chars);

  }

  fz_catch(ctx)

  {

    fz_drop_buffer(ctx, buf);

    fz_rethrow(ctx);

  }

}

static void

pdfocr_close_band_writer(fz_context *ctx, fz_band_writer *writer_)

{

  pdfocr_band_writer *writer = (pdfocr_band_writer *)writer_;

  fz_output *out = writer->super.out;

  int i;

  /* We actually do the trailer writing in the close */

  if (writer->xref_max > 2)

  {

    int64_t t_pos;

    /* Catalog */

    writer->xref[1] = fz_tell_output(ctx, out);

    fz_write_printf(ctx, out, "1 0 obj\n<</Type/Catalog/Pages 2 0 R>>\nendobj\n");

    /* Page table */

    writer->xref[2] = fz_tell_output(ctx, out);

    fz_write_printf(ctx, out, "2 0 obj\n<</Count %d/Kids[", writer->pages);

    for (i = 0; i < writer->pages; i++)

    {

      if (i > 0)

        fz_write_byte(ctx, out, ' ');

      fz_write_printf(ctx, out, "%d 0 R", writer->page_obj[i]);

    }

    fz_write_string(ctx, out, "]/Type/Pages>>\nendobj\n");

    /* Xref */

    t_pos = fz_tell_output(ctx, out);

    fz_write_printf(ctx, out, "xref\n0 %d\n0000000000 65535 f \n", writer->obj_num);

    for (i = 1; i < writer->obj_num; i++)

      fz_write_printf(ctx, out, "%010ld 00000 n \n", writer->xref[i]);

    fz_write_printf(ctx, out, "trailer\n<</Size %d/Root 1 0 R>>\nstartxref\n%ld\n%%%%EOF\n", writer->obj_num, t_pos);

  }

}

static void

pdfocr_drop_band_writer(fz_context *ctx, fz_band_writer *writer_)

{

  pdfocr_band_writer *writer = (pdfocr_band_writer *)writer_;

  fz_free(ctx, writer->stripbuf);

  fz_free(ctx, writer->compbuf);

  fz_free(ctx, writer->page_obj);

  fz_free(ctx, writer->xref);

  fz_drop_pixmap(ctx, writer->ocrbitmap);

  ocr_fin(ctx, writer->tessapi);

}

#endif

fz_band_writer *fz_new_pdfocr_band_writer(fz_context *ctx, fz_output *out, const fz_pdfocr_options *options)

{

#ifdef OCR_DISABLED

  fz_throw(ctx, FZ_ERROR_GENERIC, "No OCR support in this build");

#else

  pdfocr_band_writer *writer = fz_new_band_writer(ctx, pdfocr_band_writer, out);

  writer->super.header = pdfocr_write_header;

  writer->super.band = pdfocr_write_band;

  writer->super.trailer = pdfocr_write_trailer;

  writer->super.close = pdfocr_close_band_writer;

  writer->super.drop = pdfocr_drop_band_writer;

  if (options)

    writer->options = *options;

  else

    memset(&writer->options, 0, sizeof(writer->options));

  /* Objects:

   *  1 reserved for catalog

   *  2 for pages tree

   *  3 font

   *  4 cidfont

   *  5 cid to gid map

   *  6 tounicode

   *  7 font descriptor

   *  8 font file

   */

  writer->obj_num = 9;

  fz_try(ctx)

  {

    writer->tessapi = ocr_init(ctx, writer->options.language, writer->options.datadir);

  }

  fz_catch(ctx)

  {

    fz_drop_band_writer(ctx, &writer->super);

    fz_throw(ctx, FZ_ERROR_GENERIC, "OCR initialisation failed");

  }

  return &writer->super;

#endif

}

void

fz_pdfocr_band_writer_set_progress(fz_context *ctx, fz_band_writer *writer_, fz_pdfocr_progress_fn *progress, void *progress_arg)

{

#ifdef OCR_DISABLED

  fz_throw(ctx, FZ_ERROR_GENERIC, "No OCR support in this build");

#else

  pdfocr_band_writer *writer = (pdfocr_band_writer *)writer_;

  if (writer == NULL)

    return;

  if (writer->super.header != pdfocr_write_header)

    fz_throw(ctx, FZ_ERROR_GENERIC, "Not a pdfocr band writer!");

  writer->progress = progress;

  writer->progress_arg = progress_arg;

#endif

}

void

fz_save_pixmap_as_pdfocr(fz_context *ctx, fz_pixmap *pixmap, char *filename, int append, const fz_pdfocr_options *pdfocr)

{

#ifdef OCR_DISABLED

  fz_throw(ctx, FZ_ERROR_GENERIC, "No OCR support in this build");

#else

  fz_output *out = fz_new_output_with_path(ctx, filename, append);

  fz_try(ctx)

  {

    fz_write_pixmap_as_pdfocr(ctx, out, pixmap, pdfocr);

    fz_close_output(ctx, out);

  }

  fz_always(ctx)

    fz_drop_output(ctx, out);

  fz_catch(ctx)

    fz_rethrow(ctx);

#endif

}

/* High-level document writer interface */

#ifndef OCR_DISABLED

typedef struct

{

  fz_document_writer super;

  fz_draw_options draw;

  fz_pdfocr_options pdfocr;

  fz_pixmap *pixmap;

  fz_band_writer *bander;

  fz_output *out;

  int pagenum;

} fz_pdfocr_writer;

static fz_device *

pdfocr_begin_page(fz_context *ctx, fz_document_writer *wri_, fz_rect mediabox)

{

  fz_pdfocr_writer *wri = (fz_pdfocr_writer*)wri_;

  return fz_new_draw_device_with_options(ctx, &wri->draw, mediabox, &wri->pixmap);

}

static void

pdfocr_end_page(fz_context *ctx, fz_document_writer *wri_, fz_device *dev)

{

  fz_pdfocr_writer *wri = (fz_pdfocr_writer*)wri_;

  fz_pixmap *pix = wri->pixmap;

  fz_try(ctx)

  {

    fz_close_device(ctx, dev);

    fz_write_header(ctx, wri->bander, pix->w, pix->h, pix->n, pix->alpha, pix->xres, pix->yres, wri->pagenum++, pix->colorspace, pix->seps);

    fz_write_band(ctx, wri->bander, pix->stride, pix->h, pix->samples);

  }

  fz_always(ctx)

  {

    fz_drop_device(ctx, dev);

    fz_drop_pixmap(ctx, pix);

    wri->pixmap = NULL;

  }

  fz_catch(ctx)

    fz_rethrow(ctx);

}

static void

pdfocr_close_writer(fz_context *ctx, fz_document_writer *wri_)

{

  fz_pdfocr_writer *wri = (fz_pdfocr_writer*)wri_;

  fz_close_band_writer(ctx, wri->bander);

  fz_close_output(ctx, wri->out);

}

static void

pdfocr_drop_writer(fz_context *ctx, fz_document_writer *wri_)

{

  fz_pdfocr_writer *wri = (fz_pdfocr_writer*)wri_;

  fz_drop_pixmap(ctx, wri->pixmap);

  fz_drop_band_writer(ctx, wri->bander);

  fz_drop_output(ctx, wri->out);

}

#endif

fz_document_writer *

fz_new_pdfocr_writer_with_output(fz_context *ctx, fz_output *out, const char *options)

{

#ifdef OCR_DISABLED

  fz_throw(ctx, FZ_ERROR_GENERIC, "No OCR support in this build");

#else

  fz_pdfocr_writer *wri = NULL;

  fz_var(wri);

  fz_try(ctx)

  {

    wri = fz_new_derived_document_writer(ctx, fz_pdfocr_writer, pdfocr_begin_page, pdfocr_end_page, pdfocr_close_writer, pdfocr_drop_writer);

    fz_parse_draw_options(ctx, &wri->draw, options);

    fz_parse_pdfocr_options(ctx, &wri->pdfocr, options);

    wri->out = out;

    wri->bander = fz_new_pdfocr_band_writer(ctx, wri->out, &wri->pdfocr);

  }

  fz_catch(ctx)

  {

    fz_drop_output(ctx, out);

    fz_free(ctx, wri);

    fz_rethrow(ctx);

  }

  return (fz_document_writer*)wri;

#endif

}

fz_document_writer *

fz_new_pdfocr_writer(fz_context *ctx, const char *path, const char *options)

{

#ifdef OCR_DISABLED

  fz_throw(ctx, FZ_ERROR_GENERIC, "No OCR support in this build");

#else

  fz_output *out = fz_new_output_with_path(ctx, path ? path : "out.pdfocr", 0);

  return fz_new_pdfocr_writer_with_output(ctx, out, options);

#endif

}

void

fz_pdfocr_writer_set_progress(fz_context *ctx, fz_document_writer *writer, fz_pdfocr_progress_fn *progress, void *progress_arg)

{

#ifdef OCR_DISABLED

  fz_throw(ctx, FZ_ERROR_GENERIC, "No OCR support in this build");

#else

  fz_pdfocr_writer *wri = (fz_pdfocr_writer *)writer;

  if (!writer)

    return;

  if (writer->begin_page != pdfocr_begin_page)

    fz_throw(ctx, FZ_ERROR_GENERIC, "Not a pdfocr writer!");

  fz_pdfocr_band_writer_set_progress(ctx, wri->bander, progress, progress_arg);

#endif

}