/src/mupdf/source/pdf/pdf-page.c

Source
// Copyright (C) 2004-2026 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 "pdf-annot-imp.h"

#include <stdlib.h>
#include <string.h>
#include <limits.h>

static void pdf_adjust_page_labels(fz_context *ctx, pdf_document *doc, int index, int adjust);

void
pdf_set_page_tree_cache(fz_context *ctx, pdf_document *doc, int enabled)
{
  if (enabled)
  {
    doc->use_page_tree_map = 1;
  }
  else
  {
    pdf_drop_page_tree_internal(ctx, doc);
    doc->use_page_tree_map = 0;
  }
}

int
pdf_count_pages(fz_context *ctx, pdf_document *doc)
{
  int pages;
  if (doc->is_fdf)
    return 0;
  /* FIXME: We should reset linear_page_count to 0 when editing starts
   * (or when linear loading ends) */
  if (doc->linear_page_count != 0)
    pages = doc->linear_page_count;
  else
    pages = pdf_to_int(ctx, pdf_dict_getp(ctx, pdf_trailer(ctx, doc), "Root/Pages/Count"));
  if (pages < 0)
    fz_throw(ctx, FZ_ERROR_FORMAT, "Invalid number of pages");
  /* set an upper bound to cope with malicious /Count entries; as there
   * can't possibly be more pages than objects in the file! */
  if (pages >= pdf_xref_len(ctx, doc))
    fz_throw(ctx, FZ_ERROR_FORMAT, "Invalid number of pages");
  return pages;
}

int pdf_count_pages_imp(fz_context *ctx, fz_document *doc, int chapter)
{
  return pdf_count_pages(ctx, (pdf_document*)doc);
}

static int
pdf_load_page_tree_imp(fz_context *ctx, pdf_document *doc, pdf_obj *node, int idx, pdf_cycle_list *cycle_up)
{
  pdf_cycle_list cycle;
  pdf_obj *type = pdf_dict_get(ctx, node, PDF_NAME(Type));
  if (pdf_name_eq(ctx, type, PDF_NAME(Pages)))
  {
    pdf_obj *kids = pdf_dict_get(ctx, node, PDF_NAME(Kids));
    int i, n = pdf_array_len(ctx, kids);
    if (pdf_cycle(ctx, &cycle, cycle_up, node))
      fz_throw(ctx, FZ_ERROR_FORMAT, "cycle in page tree");
    for (i = 0; i < n; ++i)
      idx = pdf_load_page_tree_imp(ctx, doc, pdf_array_get(ctx, kids, i), idx, &cycle);
  }
  else if (pdf_name_eq(ctx, type, PDF_NAME(Page)))
  {
    if (idx >= doc->map_page_count)
      fz_throw(ctx, FZ_ERROR_FORMAT, "too many kids in page tree");
    doc->rev_page_map[idx].page = idx;
    doc->rev_page_map[idx].object = pdf_to_num(ctx, node);
    doc->fwd_page_map[idx] = pdf_keep_obj(ctx, node);
    ++idx;
  }
  else
  {
    fz_throw(ctx, FZ_ERROR_FORMAT, "non-page object in page tree");
  }
  return idx;
}

static int
cmp_rev_page_map(const void *va, const void *vb)
{
  const pdf_rev_page_map *a = va;
  const pdf_rev_page_map *b = vb;
  return a->object - b->object;
}

void
pdf_load_page_tree(fz_context *ctx, pdf_document *doc)
{
  /* Noop now. */
}

void
pdf_drop_page_tree_internal(fz_context *ctx, pdf_document *doc)
{
  int i;
  fz_free(ctx, doc->rev_page_map);
  doc->rev_page_map = NULL;
  if (doc->fwd_page_map)
    for (i = 0; i < doc->map_page_count; i++)
      pdf_drop_obj(ctx, doc->fwd_page_map[i]);
  fz_free(ctx, doc->fwd_page_map);
  doc->fwd_page_map = NULL;
  doc->map_page_count = 0;
}

static void
pdf_load_page_tree_internal(fz_context *ctx, pdf_document *doc)
{
  int in_op = 0;

  fz_var(in_op);

  /* Check we're not already loaded. */
  if (doc->fwd_page_map != NULL)
    return;

  /* At this point we're trusting that only 1 thread should be doing
   * stuff that hits the document at a time. */
  fz_try(ctx)
  {
    int idx;

    doc->map_page_count = pdf_count_pages(ctx, doc);
    while (1)
    {
      doc->rev_page_map = Memento_label(fz_calloc(ctx, doc->map_page_count, sizeof(pdf_rev_page_map)), "pdf_rev_page_map");
      doc->fwd_page_map = Memento_label(fz_calloc(ctx, doc->map_page_count, sizeof(pdf_obj *)), "pdf_fwd_page_map");
      idx = pdf_load_page_tree_imp(ctx, doc, pdf_dict_getp(ctx, pdf_trailer(ctx, doc), "Root/Pages"), 0, NULL);
      if (idx < doc->map_page_count)
      {
        /* The document claims more pages that it has. Fix that. */
        fz_warn(ctx, "Document claims to have %d pages, but only has %d.", doc->map_page_count, idx);
        /* This put drops the page tree! */
        pdf_begin_implicit_operation(ctx, doc);
        in_op = 1;
        pdf_dict_putp_drop(ctx, pdf_trailer(ctx, doc), "Root/Pages/Count", pdf_new_int(ctx, idx));
        doc->map_page_count = idx;
        pdf_end_operation(ctx, doc);
        in_op = 0;
        continue;
      }
      break;
    }
    if (doc->map_page_count > 0)
      qsort(doc->rev_page_map, doc->map_page_count, sizeof *doc->rev_page_map, cmp_rev_page_map);
  }
  fz_catch(ctx)
  {
    if (in_op)
      pdf_abandon_operation(ctx, doc);
    pdf_drop_page_tree_internal(ctx, doc);
    fz_rethrow(ctx);
  }
}

void
pdf_drop_page_tree(fz_context *ctx, pdf_document *doc)
{
  /* Historical entry point. Now does nothing. We drop 'just in time'. */
}

static pdf_obj *
pdf_lookup_page_loc_imp(fz_context *ctx, pdf_document *doc, pdf_obj *node, int *skip, pdf_obj **parentp, int *indexp)
{
  pdf_mark_list mark_list;
  pdf_obj *kids;
  pdf_obj *hit = NULL;
  int i, len;

  pdf_mark_list_init(ctx, &mark_list);

  fz_try(ctx)
  {
    do
    {
      kids = pdf_dict_get(ctx, node, PDF_NAME(Kids));
      len = pdf_array_len(ctx, kids);

      if (len == 0)
        fz_throw(ctx, FZ_ERROR_FORMAT, "malformed page tree");

      if (pdf_mark_list_push(ctx, &mark_list, node))
        fz_throw(ctx, FZ_ERROR_FORMAT, "cycle in page tree");

      for (i = 0; i < len; i++)
      {
        pdf_obj *kid = pdf_array_get(ctx, kids, i);
        pdf_obj *type = pdf_dict_get(ctx, kid, PDF_NAME(Type));
        if (type ? pdf_name_eq(ctx, type, PDF_NAME(Pages)) : pdf_dict_get(ctx, kid, PDF_NAME(Kids)) && !pdf_dict_get(ctx, kid, PDF_NAME(MediaBox)))
        {
          int count = pdf_dict_get_int(ctx, kid, PDF_NAME(Count));
          if (*skip < count)
          {
            node = kid;
            break;
          }
          else
          {
            *skip -= count;
          }
        }
        else
        {
          if (type ? !pdf_name_eq(ctx, type, PDF_NAME(Page)) : !pdf_dict_get(ctx, kid, PDF_NAME(MediaBox)))
            fz_warn(ctx, "non-page object in page tree (%s)", pdf_to_name(ctx, type));
          if (*skip == 0)
          {
            if (parentp) *parentp = node;
            if (indexp) *indexp = i;
            hit = kid;
            break;
          }
          else
          {
            (*skip)--;
          }
        }
      }
    }
    /* If i < len && hit != NULL the desired page was found in the
    Kids array, done. If i < len && hit == NULL the found page tree
    node contains a Kids array that contains the desired page, loop
    back to top to extract it. When i == len the Kids array has been
    exhausted without finding the desired page, give up.
    */
    while (hit == NULL && i < len);
  }
  fz_always(ctx)
  {
    pdf_mark_list_free(ctx, &mark_list);
  }
  fz_catch(ctx)
  {
    fz_rethrow(ctx);
  }

  return hit;
}

pdf_obj *
pdf_lookup_page_loc(fz_context *ctx, pdf_document *doc, int needle, pdf_obj **parentp, int *indexp)
{
  pdf_obj *root = pdf_dict_get(ctx, pdf_trailer(ctx, doc), PDF_NAME(Root));
  pdf_obj *node = pdf_dict_get(ctx, root, PDF_NAME(Pages));
  int skip = needle;
  pdf_obj *hit;

  if (!node)
    fz_throw(ctx, FZ_ERROR_FORMAT, "cannot find page tree");

  hit = pdf_lookup_page_loc_imp(ctx, doc, node, &skip, parentp, indexp);
  if (!hit)
    fz_throw(ctx, FZ_ERROR_FORMAT, "cannot find page %d in page tree", needle+1);
  return hit;
}

pdf_obj *
pdf_lookup_page_obj(fz_context *ctx, pdf_document *doc, int needle)
{
  if (doc->fwd_page_map == NULL && doc->use_page_tree_map)
  {
    fz_try(ctx)
      pdf_load_page_tree_internal(ctx, doc);
    fz_catch(ctx)
    {
      doc->use_page_tree_map = 0;
      fz_rethrow_if(ctx, FZ_ERROR_SYSTEM);
      fz_report_error(ctx);
      fz_warn(ctx, "Page tree load failed. Falling back to slow lookup");
    }
  }

  if (doc->fwd_page_map)
  {
    if (needle < 0 || needle >= doc->map_page_count)
      fz_throw(ctx, FZ_ERROR_FORMAT, "cannot find page %d in page tree", needle+1);
    if (doc->fwd_page_map[needle] != NULL)
      return doc->fwd_page_map[needle];
  }

  return pdf_lookup_page_loc(ctx, doc, needle, NULL, NULL);
}

static int
pdf_count_pages_before_kid(fz_context *ctx, pdf_document *doc, pdf_obj *parent, int kid_num)
{
  pdf_obj *kids = pdf_dict_get(ctx, parent, PDF_NAME(Kids));
  int i, total = 0, len = pdf_array_len(ctx, kids);
  for (i = 0; i < len; i++)
  {
    pdf_obj *kid = pdf_array_get(ctx, kids, i);
    if (pdf_to_num(ctx, kid) == kid_num)
      return total;
    if (pdf_name_eq(ctx, pdf_dict_get(ctx, kid, PDF_NAME(Type)), PDF_NAME(Pages)))
    {
      pdf_obj *count = pdf_dict_get(ctx, kid, PDF_NAME(Count));
      int n = pdf_to_int(ctx, count);
      if (!pdf_is_int(ctx, count) || n < 0 || INT_MAX - total <= n)
        fz_throw(ctx, FZ_ERROR_FORMAT, "illegal or missing count in pages tree");
      total += n;
    }
    else
      total++;
  }
  return -1; // the page we're looking for is not in the page tree (it has been deleted)
}

static int
pdf_lookup_page_number_slow(fz_context *ctx, pdf_document *doc, pdf_obj *node)
{
  pdf_mark_list mark_list;
  int needle = pdf_to_num(ctx, node);
  int total = 0;
  int n;
  pdf_obj *parent;

  if (!pdf_name_eq(ctx, pdf_dict_get(ctx, node, PDF_NAME(Type)), PDF_NAME(Page)))
  {
    fz_warn(ctx, "invalid page object");
    return -1;
  }

  pdf_mark_list_init(ctx, &mark_list);
  parent = pdf_dict_get(ctx, node, PDF_NAME(Parent));
  fz_try(ctx)
  {
    while (pdf_is_dict(ctx, parent))
    {
      if (pdf_mark_list_push(ctx, &mark_list, parent))
        fz_throw(ctx, FZ_ERROR_FORMAT, "cycle in page tree (parents)");
      n = pdf_count_pages_before_kid(ctx, doc, parent, needle);

      // Page was not found in page tree!
      if (n < 0)
      {
        total = -1;
        break;
      }
      if (INT_MAX - total <= n)
        fz_throw(ctx, FZ_ERROR_FORMAT, "illegal or missing count in pages tree");

      total += n;
      needle = pdf_to_num(ctx, parent);
      parent = pdf_dict_get(ctx, parent, PDF_NAME(Parent));
    }
  }
  fz_always(ctx)
    pdf_mark_list_free(ctx, &mark_list);
  fz_catch(ctx)
    fz_rethrow(ctx);

  return total;
}

static int
pdf_lookup_page_number_fast(fz_context *ctx, pdf_document *doc, int needle)
{
  int l = 0;
  int r = doc->map_page_count - 1;
  while (l <= r)
  {
    int m = (l + r) >> 1;
    int c = needle - doc->rev_page_map[m].object;
    if (c < 0)
      r = m - 1;
    else if (c > 0)
      l = m + 1;
    else
      return doc->rev_page_map[m].page;
  }
  return -1;
}

int
pdf_lookup_page_number(fz_context *ctx, pdf_document *doc, pdf_obj *page)
{
  if (doc->rev_page_map == NULL && doc->use_page_tree_map)
  {
    fz_try(ctx)
      pdf_load_page_tree_internal(ctx, doc);
    fz_catch(ctx)
    {
      doc->use_page_tree_map = 0;
      fz_report_error(ctx);
      fz_warn(ctx, "Page tree load failed. Falling back to slow lookup.");
    }
  }

  if (doc->rev_page_map)
    return pdf_lookup_page_number_fast(ctx, doc, pdf_to_num(ctx, page));
  else
    return pdf_lookup_page_number_slow(ctx, doc, page);
}

static void
pdf_flatten_inheritable_page_item(fz_context *ctx, pdf_obj *page, pdf_obj *key)
{
  pdf_obj *val = pdf_dict_get_inheritable(ctx, page, key);
  if (val)
    pdf_dict_put(ctx, page, key, val);
}

void
pdf_flatten_inheritable_page_items(fz_context *ctx, pdf_obj *page)
{
  pdf_flatten_inheritable_page_item(ctx, page, PDF_NAME(MediaBox));
  pdf_flatten_inheritable_page_item(ctx, page, PDF_NAME(CropBox));
  pdf_flatten_inheritable_page_item(ctx, page, PDF_NAME(Rotate));
  pdf_flatten_inheritable_page_item(ctx, page, PDF_NAME(Resources));
}

/* We need to know whether to install a page-level transparency group */

/*
 * Object memo flags - allows us to secretly remember "a memo" (a bool) in an
 * object, and to read back whether there was a memo, and if so, what it was.
 */
enum
{
  PDF_FLAGS_MEMO_BM = 0,
  PDF_FLAGS_MEMO_OP = 1
};

static int pdf_resources_use_blending(fz_context *ctx, pdf_obj *rdb, pdf_cycle_list *cycle_up);

static int
pdf_extgstate_uses_blending(fz_context *ctx, pdf_obj *dict)
{
  pdf_obj *obj = pdf_dict_get(ctx, dict, PDF_NAME(BM));
  if (obj && !pdf_name_eq(ctx, obj, PDF_NAME(Normal)))
    return 1;
  return 0;
}

int
pdf_pattern_uses_blending(fz_context *ctx, pdf_obj *dict, pdf_cycle_list *cycle_up)
{
  pdf_obj *obj;
  pdf_cycle_list cycle;
  if (pdf_cycle(ctx, &cycle, cycle_up, dict))
    return 0;
  obj = pdf_dict_get(ctx, dict, PDF_NAME(Resources));
  if (pdf_resources_use_blending(ctx, obj, &cycle))
    return 1;
  obj = pdf_dict_get(ctx, dict, PDF_NAME(ExtGState));
  return pdf_extgstate_uses_blending(ctx, obj);
}

static int
pdf_xobject_uses_blending(fz_context *ctx, pdf_obj *dict, pdf_cycle_list *cycle_up)
{
  pdf_obj *obj = pdf_dict_get(ctx, dict, PDF_NAME(Resources));
  pdf_cycle_list cycle;
  if (pdf_cycle(ctx, &cycle, cycle_up, dict))
    return 0;
  if (pdf_name_eq(ctx, pdf_dict_getp(ctx, dict, "Group/S"), PDF_NAME(Transparency)))
    return 1;
  if (pdf_name_eq(ctx, pdf_dict_get(ctx, dict, PDF_NAME(Subtype)), PDF_NAME(Image)) &&
    pdf_dict_get(ctx, dict, PDF_NAME(SMask)) != NULL)
    return 1;
  return pdf_resources_use_blending(ctx, obj, &cycle);
}

static int
pdf_resources_use_blending(fz_context *ctx, pdf_obj *rdb, pdf_cycle_list *cycle_up)
{
  pdf_cycle_list cycle;
  pdf_obj *obj;
  int i, n, useBM = 0;

  if (!rdb)
    return 0;

  /* Have we been here before and remembered an answer? */
  if (pdf_obj_memo(ctx, rdb, PDF_FLAGS_MEMO_BM, &useBM))
    return useBM;

  /* stop on cyclic resource dependencies */
  if (pdf_cycle(ctx, &cycle, cycle_up, rdb))
    return 0;

  obj = pdf_dict_get(ctx, rdb, PDF_NAME(ExtGState));
  n = pdf_dict_len(ctx, obj);
  for (i = 0; i < n; i++)
    if (pdf_extgstate_uses_blending(ctx, pdf_dict_get_val(ctx, obj, i)))
      goto found;

  obj = pdf_dict_get(ctx, rdb, PDF_NAME(Pattern));
  n = pdf_dict_len(ctx, obj);
  for (i = 0; i < n; i++)
    if (pdf_pattern_uses_blending(ctx, pdf_dict_get_val(ctx, obj, i), &cycle))
      goto found;

  obj = pdf_dict_get(ctx, rdb, PDF_NAME(XObject));
  n = pdf_dict_len(ctx, obj);
  for (i = 0; i < n; i++)
    if (pdf_xobject_uses_blending(ctx, pdf_dict_get_val(ctx, obj, i), &cycle))
      goto found;
  if (0)
  {
found:
    useBM = 1;
  }

  pdf_set_obj_memo(ctx, rdb, PDF_FLAGS_MEMO_BM, useBM);
  return useBM;
}

static int pdf_resources_use_overprint(fz_context *ctx, pdf_obj *rdb, pdf_cycle_list *cycle_up);

static int
pdf_extgstate_uses_overprint(fz_context *ctx, pdf_obj *dict)
{
  pdf_obj *obj = pdf_dict_get(ctx, dict, PDF_NAME(OP));
  if (obj && pdf_to_bool(ctx, obj))
    return 1;
  return 0;
}

static int
pdf_pattern_uses_overprint(fz_context *ctx, pdf_obj *dict, pdf_cycle_list *cycle_up)
{
  pdf_obj *obj;
  pdf_cycle_list cycle;
  if (pdf_cycle(ctx, &cycle, cycle_up, dict))
    return 0;
  obj = pdf_dict_get(ctx, dict, PDF_NAME(Resources));
  if (pdf_resources_use_overprint(ctx, obj, &cycle))
    return 1;
  obj = pdf_dict_get(ctx, dict, PDF_NAME(ExtGState));
  return pdf_extgstate_uses_overprint(ctx, obj);
}

static int
pdf_xobject_uses_overprint(fz_context *ctx, pdf_obj *dict, pdf_cycle_list *cycle_up)
{
  pdf_obj *obj = pdf_dict_get(ctx, dict, PDF_NAME(Resources));
  pdf_cycle_list cycle;
  if (pdf_cycle(ctx, &cycle, cycle_up, dict))
    return 0;
  return pdf_resources_use_overprint(ctx, obj, &cycle);
}

static int
pdf_resources_use_overprint(fz_context *ctx, pdf_obj *rdb, pdf_cycle_list *cycle_up)
{
  pdf_cycle_list cycle;
  pdf_obj *obj;
  int i, n, useOP = 0;

  if (!rdb)
    return 0;

  /* Have we been here before and remembered an answer? */
  if (pdf_obj_memo(ctx, rdb, PDF_FLAGS_MEMO_OP, &useOP))
    return useOP;

  /* stop on cyclic resource dependencies */
  if (pdf_cycle(ctx, &cycle, cycle_up, rdb))
    return 0;

  obj = pdf_dict_get(ctx, rdb, PDF_NAME(ExtGState));
  n = pdf_dict_len(ctx, obj);
  for (i = 0; i < n; i++)
    if (pdf_extgstate_uses_overprint(ctx, pdf_dict_get_val(ctx, obj, i)))
      goto found;

  obj = pdf_dict_get(ctx, rdb, PDF_NAME(Pattern));
  n = pdf_dict_len(ctx, obj);
  for (i = 0; i < n; i++)
    if (pdf_pattern_uses_overprint(ctx, pdf_dict_get_val(ctx, obj, i), &cycle))
      goto found;

  obj = pdf_dict_get(ctx, rdb, PDF_NAME(XObject));
  n = pdf_dict_len(ctx, obj);
  for (i = 0; i < n; i++)
    if (pdf_xobject_uses_overprint(ctx, pdf_dict_get_val(ctx, obj, i), &cycle))
      goto found;
  if (0)
  {
found:
    useOP = 1;
  }

  pdf_set_obj_memo(ctx, rdb, PDF_FLAGS_MEMO_OP, useOP);
  return useOP;
}

fz_transition *
pdf_page_presentation(fz_context *ctx, pdf_page *page, fz_transition *transition, float *duration)
{
  pdf_obj *obj, *transdict;

  *duration = pdf_dict_get_real(ctx, page->obj, PDF_NAME(Dur));

  transdict = pdf_dict_get(ctx, page->obj, PDF_NAME(Trans));
  if (!transdict)
    return NULL;

  obj = pdf_dict_get(ctx, transdict, PDF_NAME(D));

  transition->duration = pdf_to_real_default(ctx, obj, 1);

  transition->vertical = !pdf_name_eq(ctx, pdf_dict_get(ctx, transdict, PDF_NAME(Dm)), PDF_NAME(H));
  transition->outwards = !pdf_name_eq(ctx, pdf_dict_get(ctx, transdict, PDF_NAME(M)), PDF_NAME(I));
  /* FIXME: If 'Di' is None, it should be handled differently, but
   * this only affects Fly, and we don't implement that currently. */
  transition->direction = (pdf_dict_get_int(ctx, transdict, PDF_NAME(Di)));
  /* FIXME: Read SS for Fly when we implement it */
  /* FIXME: Read B for Fly when we implement it */

  obj = pdf_dict_get(ctx, transdict, PDF_NAME(S));
  if (pdf_name_eq(ctx, obj, PDF_NAME(Split)))
    transition->type = FZ_TRANSITION_SPLIT;
  else if (pdf_name_eq(ctx, obj, PDF_NAME(Blinds)))
    transition->type = FZ_TRANSITION_BLINDS;
  else if (pdf_name_eq(ctx, obj, PDF_NAME(Box)))
    transition->type = FZ_TRANSITION_BOX;
  else if (pdf_name_eq(ctx, obj, PDF_NAME(Wipe)))
    transition->type = FZ_TRANSITION_WIPE;
  else if (pdf_name_eq(ctx, obj, PDF_NAME(Dissolve)))
    transition->type = FZ_TRANSITION_DISSOLVE;
  else if (pdf_name_eq(ctx, obj, PDF_NAME(Glitter)))
    transition->type = FZ_TRANSITION_GLITTER;
  else if (pdf_name_eq(ctx, obj, PDF_NAME(Fly)))
    transition->type = FZ_TRANSITION_FLY;
  else if (pdf_name_eq(ctx, obj, PDF_NAME(Push)))
    transition->type = FZ_TRANSITION_PUSH;
  else if (pdf_name_eq(ctx, obj, PDF_NAME(Cover)))
    transition->type = FZ_TRANSITION_COVER;
  else if (pdf_name_eq(ctx, obj, PDF_NAME(Uncover)))
    transition->type = FZ_TRANSITION_UNCOVER;
  else if (pdf_name_eq(ctx, obj, PDF_NAME(Fade)))
    transition->type = FZ_TRANSITION_FADE;
  else
    transition->type = FZ_TRANSITION_NONE;

  return transition;
}

fz_rect
pdf_bound_page(fz_context *ctx, pdf_page *page, fz_box_type box)
{
  fz_matrix page_ctm;
  fz_rect rect;
  pdf_page_transform_box(ctx, page, &rect, &page_ctm, box);
  return fz_transform_rect(rect, page_ctm);
}

static fz_rect
pdf_bound_page_imp(fz_context *ctx, fz_page *page, fz_box_type box)
{
  return pdf_bound_page(ctx, (pdf_page*)page, box);
}

void
pdf_set_page_box(fz_context *ctx, pdf_page *page, fz_box_type box, fz_rect rect)
{
  fz_matrix page_ctm, inv_page_ctm;
  fz_rect page_rect;
  pdf_page_transform_box(ctx, page, NULL, &page_ctm, box);
  inv_page_ctm = fz_invert_matrix(page_ctm);
  page_rect = fz_transform_rect(rect, inv_page_ctm);

  switch (box)
  {
  case FZ_MEDIA_BOX:
    pdf_dict_put_rect(ctx, page->obj, PDF_NAME(MediaBox), page_rect);
    break;
  case FZ_CROP_BOX:
    pdf_dict_put_rect(ctx, page->obj, PDF_NAME(CropBox), page_rect);
    break;
  case FZ_BLEED_BOX:
    pdf_dict_put_rect(ctx, page->obj, PDF_NAME(BleedBox), page_rect);
    break;
  case FZ_TRIM_BOX:
    pdf_dict_put_rect(ctx, page->obj, PDF_NAME(TrimBox), page_rect);
    break;
  case FZ_ART_BOX:
    pdf_dict_put_rect(ctx, page->obj, PDF_NAME(ArtBox), page_rect);
    break;
  case FZ_UNKNOWN_BOX:
    fz_throw(ctx, FZ_ERROR_UNSUPPORTED, "unknown page box type: %d", box);
  }
}

fz_link *
pdf_load_links(fz_context *ctx, pdf_page *page)
{
  return fz_keep_link(ctx, page->links);
}

static fz_link *
pdf_load_links_imp(fz_context *ctx, fz_page *page)
{
  return pdf_load_links(ctx, (pdf_page*)page);
}

pdf_obj *
pdf_page_resources(fz_context *ctx, pdf_page *page)
{
  return pdf_dict_get_inheritable(ctx, page->obj, PDF_NAME(Resources));
}

pdf_obj *
pdf_page_contents(fz_context *ctx, pdf_page *page)
{
  return pdf_dict_get(ctx, page->obj, PDF_NAME(Contents));
}

pdf_obj *
pdf_page_group(fz_context *ctx, pdf_page *page)
{
  return pdf_dict_get(ctx, page->obj, PDF_NAME(Group));
}

void
pdf_page_obj_transform_box(fz_context *ctx, pdf_obj *pageobj, fz_rect *outbox, fz_matrix *page_ctm, fz_box_type box)
{
  pdf_obj *obj;
  fz_rect usedbox, tempbox, cropbox, mediabox;
  float userunit = 1;
  int rotate;

  if (!outbox)
    outbox = &tempbox;

  userunit = pdf_dict_get_real_default(ctx, pageobj, PDF_NAME(UserUnit), 1);

  obj = pdf_dict_get_inheritable(ctx, pageobj, PDF_NAME(MediaBox));
  mediabox = pdf_to_rect(ctx, obj);

  obj = NULL;
  if (box == FZ_ART_BOX)
    obj = pdf_dict_get_inheritable(ctx, pageobj, PDF_NAME(ArtBox));
  if (box == FZ_TRIM_BOX)
    obj = pdf_dict_get_inheritable(ctx, pageobj, PDF_NAME(TrimBox));
  if (box == FZ_BLEED_BOX)
    obj = pdf_dict_get_inheritable(ctx, pageobj, PDF_NAME(BleedBox));
  if (box == FZ_CROP_BOX || !obj)
    obj = pdf_dict_get_inheritable(ctx, pageobj, PDF_NAME(CropBox));
  if (box == FZ_MEDIA_BOX || !obj)
    usedbox = mediabox;
  else
  {
    // never use a box larger than fits the paper (mediabox)
    usedbox = fz_intersect_rect(mediabox, pdf_to_rect(ctx, obj));
  }

  if (fz_is_empty_rect(usedbox))
    usedbox = fz_make_rect(0, 0, 612, 792);
  usedbox.x0 = fz_min(usedbox.x0, usedbox.x1);
  usedbox.y0 = fz_min(usedbox.y0, usedbox.y1);
  usedbox.x1 = fz_max(usedbox.x0, usedbox.x1);
  usedbox.y1 = fz_max(usedbox.y0, usedbox.y1);
  if (usedbox.x1 - usedbox.x0 < 1 || usedbox.y1 - usedbox.y0 < 1)
    usedbox = fz_unit_rect;

  *outbox = usedbox;

  /* Snap page rotation to 0, 90, 180 or 270 */
  rotate = pdf_dict_get_inheritable_int(ctx, pageobj, PDF_NAME(Rotate));
  if (rotate < 0)
    rotate = 360 - ((-rotate) % 360);
  if (rotate >= 360)
    rotate = rotate % 360;
  rotate = 90*((rotate + 45)/90);
  if (rotate >= 360)
    rotate = 0;

  /* Compute transform from fitz' page space (upper left page origin, y descending, 72 dpi)
   * to PDF user space (arbitrary page origin, y ascending, UserUnit dpi). */

  /* Make left-handed and scale by UserUnit */
  *page_ctm = fz_scale(userunit, -userunit);

  /* Rotate */
  *page_ctm = fz_pre_rotate(*page_ctm, -rotate);

  /* Always use CropBox to set origin to top left */
  obj = pdf_dict_get_inheritable(ctx, pageobj, PDF_NAME(CropBox));
  if (!pdf_is_array(ctx, obj))
    obj = pdf_dict_get_inheritable(ctx, pageobj, PDF_NAME(MediaBox));
  cropbox = pdf_to_rect(ctx, obj);
  cropbox = fz_intersect_rect(cropbox, mediabox);
  if (fz_is_empty_rect(cropbox))
    cropbox = fz_make_rect(0, 0, 612, 792);
  cropbox.x0 = fz_min(cropbox.x0, cropbox.x1);
  cropbox.y0 = fz_min(cropbox.y0, cropbox.y1);
  cropbox.x1 = fz_max(cropbox.x0, cropbox.x1);
  cropbox.y1 = fz_max(cropbox.y0, cropbox.y1);
  if (cropbox.x1 - cropbox.x0 < 1 || cropbox.y1 - cropbox.y0 < 1)
    cropbox = fz_unit_rect;

  /* Translate page origin of CropBox to 0,0 */
  cropbox = fz_transform_rect(cropbox, *page_ctm);
  *page_ctm = fz_concat(*page_ctm, fz_translate(-cropbox.x0, -cropbox.y0));
}

void
pdf_page_obj_transform(fz_context *ctx, pdf_obj *pageobj, fz_rect *page_cropbox, fz_matrix *page_ctm)
{
  pdf_page_obj_transform_box(ctx, pageobj, page_cropbox, page_ctm, FZ_CROP_BOX);
}

void
pdf_page_transform_box(fz_context *ctx, pdf_page *page, fz_rect *page_cropbox, fz_matrix *page_ctm, fz_box_type box)
{
  pdf_page_obj_transform_box(ctx, page->obj, page_cropbox, page_ctm, box);
}

void
pdf_page_transform(fz_context *ctx, pdf_page *page, fz_rect *cropbox, fz_matrix *ctm)
{
  pdf_page_transform_box(ctx, page, cropbox, ctm, FZ_CROP_BOX);
}

static void
find_seps(fz_context *ctx, fz_separations **seps, pdf_obj *obj, pdf_mark_list *clearme)
{
  int i, n;
  pdf_obj *nameobj, *cols;

  if (!obj)
    return;

  // Already seen this ColorSpace...
  if (pdf_mark_list_push(ctx, clearme, obj))
    return;

  nameobj = pdf_array_get(ctx, obj, 0);
  if (pdf_name_eq(ctx, nameobj, PDF_NAME(Separation)))
  {
    fz_colorspace *cs;
    const char *name = pdf_array_get_name(ctx, obj, 1);

    /* Skip 'special' colorants. */
    if (!strcmp(name, "Black") ||
      !strcmp(name, "Cyan") ||
      !strcmp(name, "Magenta") ||
      !strcmp(name, "Yellow") ||
      !strcmp(name, "All") ||
      !strcmp(name, "None"))
      return;

    n = fz_count_separations(ctx, *seps);
    for (i = 0; i < n; i++)
    {
      if (!strcmp(name, fz_separation_name(ctx, *seps, i)))
        return; /* Got that one already */
    }

    fz_try(ctx)
      cs = pdf_load_colorspace(ctx, obj);
    fz_catch(ctx)
    {
      fz_rethrow_if(ctx, FZ_ERROR_TRYLATER);
      fz_rethrow_if(ctx, FZ_ERROR_SYSTEM);
      fz_report_error(ctx);
      return; /* ignore broken colorspace */
    }
    fz_try(ctx)
    {
      if (!*seps)
        *seps = fz_new_separations(ctx, 0);
      fz_add_separation(ctx, *seps, name, cs, 0);
    }
    fz_always(ctx)
      fz_drop_colorspace(ctx, cs);
    fz_catch(ctx)
      fz_rethrow(ctx);
  }
  else if (pdf_name_eq(ctx, nameobj, PDF_NAME(Indexed)))
  {
    find_seps(ctx, seps, pdf_array_get(ctx, obj, 1), clearme);
  }
  else if (pdf_name_eq(ctx, nameobj, PDF_NAME(DeviceN)))
  {
    /* If the separation colorants exists for this DeviceN color space
     * add those prior to our search for DeviceN color */
    cols = pdf_dict_get(ctx, pdf_array_get(ctx, obj, 4), PDF_NAME(Colorants));
    n = pdf_dict_len(ctx, cols);
    for (i = 0; i < n; i++)
      find_seps(ctx, seps, pdf_dict_get_val(ctx, cols, i), clearme);
  }
}

static void
find_devn(fz_context *ctx, fz_separations **seps, pdf_obj *obj, pdf_mark_list *clearme)
{
  int i, j, n, m;
  pdf_obj *arr;
  pdf_obj *nameobj = pdf_array_get(ctx, obj, 0);

  if (!obj)
    return;

  // Already seen this ColorSpace...
  if (pdf_mark_list_push(ctx, clearme, obj))
    return;

  if (!pdf_name_eq(ctx, nameobj, PDF_NAME(DeviceN)))
    return;

  arr = pdf_array_get(ctx, obj, 1);
  m = pdf_array_len(ctx, arr);
  for (j = 0; j < m; j++)
  {
    fz_colorspace *cs;
    const char *name = pdf_array_get_name(ctx, arr, j);

    /* Skip 'special' colorants. */
    if (!strcmp(name, "Black") ||
      !strcmp(name, "Cyan") ||
      !strcmp(name, "Magenta") ||
      !strcmp(name, "Yellow") ||
      !strcmp(name, "All") ||
      !strcmp(name, "None"))
      continue;

    n = fz_count_separations(ctx, *seps);
    for (i = 0; i < n; i++)
    {
      if (!strcmp(name, fz_separation_name(ctx, *seps, i)))
        break; /* Got that one already */
    }

    if (i == n)
    {
      fz_try(ctx)
        cs = pdf_load_colorspace(ctx, obj);
      fz_catch(ctx)
      {
        fz_rethrow_if(ctx, FZ_ERROR_TRYLATER);
        fz_rethrow_if(ctx, FZ_ERROR_SYSTEM);
        fz_report_error(ctx);
        continue; /* ignore broken colorspace */
      }
      fz_try(ctx)
      {
        if (!*seps)
          *seps = fz_new_separations(ctx, 0);
        fz_add_separation(ctx, *seps, name, cs, j);
      }
      fz_always(ctx)
        fz_drop_colorspace(ctx, cs);
      fz_catch(ctx)
        fz_rethrow(ctx);
    }
  }
}

typedef void (res_finder_fn)(fz_context *ctx, fz_separations **seps, pdf_obj *obj, pdf_mark_list *clearme);

static void
scan_page_seps(fz_context *ctx, pdf_obj *res, fz_separations **seps, res_finder_fn *fn, pdf_mark_list *clearme)
{
  pdf_obj *dict;
  pdf_obj *obj;
  int i, n;

  if (!res)
    return;

  // Already seen this Resources...
  if (pdf_mark_list_push(ctx, clearme, res))
    return;

  dict = pdf_dict_get(ctx, res, PDF_NAME(ColorSpace));
  n = pdf_dict_len(ctx, dict);
  for (i = 0; i < n; i++)
  {
    obj = pdf_dict_get_val(ctx, dict, i);
    fn(ctx, seps, obj, clearme);
  }

  dict = pdf_dict_get(ctx, res, PDF_NAME(Shading));
  n = pdf_dict_len(ctx, dict);
  for (i = 0; i < n; i++)
  {
    obj = pdf_dict_get_val(ctx, dict, i);
    fn(ctx, seps, pdf_dict_get(ctx, obj, PDF_NAME(ColorSpace)), clearme);
  }

  dict = pdf_dict_get(ctx, res, PDF_NAME(Pattern));
  n = pdf_dict_len(ctx, dict);
  for (i = 0; i < n; i++)
  {
    pdf_obj *obj2;
    obj = pdf_dict_get_val(ctx, dict, i);
    obj2 = pdf_dict_get(ctx, obj, PDF_NAME(Shading));
    fn(ctx, seps, pdf_dict_get(ctx, obj2, PDF_NAME(ColorSpace)), clearme);
  }

  dict = pdf_dict_get(ctx, res, PDF_NAME(XObject));
  n = pdf_dict_len(ctx, dict);
  for (i = 0; i < n; i++)
  {
    obj = pdf_dict_get_val(ctx, dict, i);
    // Already seen this XObject...
    if (!pdf_mark_list_push(ctx, clearme, obj))
    {
      fn(ctx, seps, pdf_dict_get(ctx, obj, PDF_NAME(ColorSpace)), clearme);
      /* Recurse on XObject forms. */
      scan_page_seps(ctx, pdf_dict_get(ctx, obj, PDF_NAME(Resources)), seps, fn, clearme);
    }
  }
}

fz_separations *
pdf_page_separations(fz_context *ctx, pdf_page *page)
{
  pdf_obj *res = pdf_page_resources(ctx, page);
  pdf_mark_list clearme;
  fz_separations *seps = NULL;

  pdf_mark_list_init(ctx, &clearme);
  fz_try(ctx)
  {
    /* Run through and look for separations first. This is
     * because separations are simplest to deal with, and
     * because DeviceN may be implemented on top of separations.
     */
    scan_page_seps(ctx, res, &seps, find_seps, &clearme);
  }
  fz_always(ctx)
    pdf_mark_list_free(ctx, &clearme);
  fz_catch(ctx)
  {
    fz_drop_separations(ctx, seps);
    fz_rethrow(ctx);
  }

  pdf_mark_list_init(ctx, &clearme);
  fz_try(ctx)
  {
    /* Now run through again, and look for DeviceNs. These may
     * have spot colors in that aren't defined in terms of
     * separations. */
    scan_page_seps(ctx, res, &seps, find_devn, &clearme);
  }
  fz_always(ctx)
    pdf_mark_list_free(ctx, &clearme);
  fz_catch(ctx)
  {
    fz_drop_separations(ctx, seps);
    fz_rethrow(ctx);
  }

  return seps;
}

int
pdf_page_uses_overprint(fz_context *ctx, pdf_page *page)
{
  return page ? page->overprint : 0;
}

static void
pdf_drop_page_imp(fz_context *ctx, fz_page *page_)
{
  pdf_page *page = (pdf_page*)page_;
  pdf_annot *widget;
  pdf_annot *annot;
  pdf_link *link;

  link = (pdf_link *) page->links;
  while (link)
  {
    link->page = NULL;
    link = (pdf_link *) link->super.next;
  }
  fz_drop_link(ctx, page->links);
  page->links = NULL;

  annot = page->annots;
  while (annot)
  {
    annot->page = NULL;
    annot = annot->next;
  }
  pdf_drop_annots(ctx, page->annots);
  page->annots = NULL;

  widget = page->widgets;
  while (widget)
  {
    widget->page = NULL;
    widget = widget->next;
  }
  pdf_drop_widgets(ctx, page->widgets);
  page->widgets = NULL;
  pdf_drop_obj(ctx, page->obj);
  page->obj = NULL;
  page->doc = NULL;
}

static void pdf_run_page_contents_imp(fz_context *ctx, fz_page *page, fz_device *dev, fz_matrix ctm, fz_cookie *cookie)
{
  pdf_run_page_contents(ctx, (pdf_page*)page, dev, ctm, cookie);
}

static void pdf_run_page_annots_imp(fz_context *ctx, fz_page *page, fz_device *dev, fz_matrix ctm, fz_cookie *cookie)
{
  pdf_run_page_annots(ctx, (pdf_page*)page, dev, ctm, cookie);
}

static void pdf_run_page_widgets_imp(fz_context *ctx, fz_page *page, fz_device *dev, fz_matrix ctm, fz_cookie *cookie)
{
  pdf_run_page_widgets(ctx, (pdf_page*)page, dev, ctm, cookie);
}

static fz_transition * pdf_page_presentation_imp(fz_context *ctx, fz_page *page, fz_transition *transition, float *duration)
{
  return pdf_page_presentation(ctx, (pdf_page*)page, transition, duration);
}

static fz_separations * pdf_page_separations_imp(fz_context *ctx, fz_page *page)
{
  return pdf_page_separations(ctx, (pdf_page*)page);
}

static int pdf_page_uses_overprint_imp(fz_context *ctx, fz_page *page)
{
  return pdf_page_uses_overprint(ctx, (pdf_page*)page);
}

static fz_link * pdf_create_link_imp(fz_context *ctx, fz_page *page, fz_rect bbox, const char *uri)
{
  return pdf_create_link(ctx, (pdf_page*)page, bbox, uri);
}

static void pdf_delete_link_imp(fz_context *ctx, fz_page *page, fz_link *link)
{
  pdf_delete_link(ctx, (pdf_page*)page, link);
}

static pdf_page *
pdf_new_page(fz_context *ctx, pdf_document *doc)
{
  pdf_page *page = fz_new_derived_page(ctx, pdf_page, (fz_document*) doc);

  page->doc = doc; /* typecast alias for page->super.doc */

  page->super.drop_page = pdf_drop_page_imp;
  page->super.load_links = pdf_load_links_imp;
  page->super.bound_page = pdf_bound_page_imp;
  page->super.run_page_contents = pdf_run_page_contents_imp;
  page->super.run_page_annots = pdf_run_page_annots_imp;
  page->super.run_page_widgets = pdf_run_page_widgets_imp;
  page->super.page_presentation = pdf_page_presentation_imp;
  page->super.separations = pdf_page_separations_imp;
  page->super.overprint = pdf_page_uses_overprint_imp;
  page->super.create_link = pdf_create_link_imp;
  page->super.delete_link = pdf_delete_link_imp;

  page->obj = NULL;

  page->transparency = 0;
  page->links = NULL;
  page->annots = NULL;
  page->annot_tailp = &page->annots;
  page->widgets = NULL;
  page->widget_tailp = &page->widgets;

  return page;
}

static void
pdf_load_default_colorspaces_imp(fz_context *ctx, fz_default_colorspaces *default_cs, pdf_obj *obj)
{
  pdf_obj *cs_obj;

  /* The spec says to ignore any colors we can't understand */

  cs_obj = pdf_dict_get(ctx, obj, PDF_NAME(DefaultGray));
  if (cs_obj)
  {
    fz_try(ctx)
    {
      fz_colorspace *cs = pdf_load_colorspace(ctx, cs_obj);
      fz_set_default_gray(ctx, default_cs, cs);
      fz_drop_colorspace(ctx, cs);
    }
    fz_catch(ctx)
    {
      fz_rethrow_if(ctx, FZ_ERROR_TRYLATER);
      fz_rethrow_if(ctx, FZ_ERROR_SYSTEM);
      fz_report_error(ctx);
    }
  }

  cs_obj = pdf_dict_get(ctx, obj, PDF_NAME(DefaultRGB));
  if (cs_obj)
  {
    fz_try(ctx)
    {
      fz_colorspace *cs = pdf_load_colorspace(ctx, cs_obj);
      fz_set_default_rgb(ctx, default_cs, cs);
      fz_drop_colorspace(ctx, cs);
    }
    fz_catch(ctx)
    {
      fz_rethrow_if(ctx, FZ_ERROR_TRYLATER);
      fz_rethrow_if(ctx, FZ_ERROR_SYSTEM);
      fz_report_error(ctx);
    }
  }

  cs_obj = pdf_dict_get(ctx, obj, PDF_NAME(DefaultCMYK));
  if (cs_obj)
  {
    fz_try(ctx)
    {
      fz_colorspace *cs = pdf_load_colorspace(ctx, cs_obj);
      fz_set_default_cmyk(ctx, default_cs, cs);
      fz_drop_colorspace(ctx, cs);
    }
    fz_catch(ctx)
    {
      fz_rethrow_if(ctx, FZ_ERROR_TRYLATER);
      fz_rethrow_if(ctx, FZ_ERROR_SYSTEM);
      fz_report_error(ctx);
    }
  }
}

fz_default_colorspaces *
pdf_load_default_colorspaces(fz_context *ctx, pdf_document *doc, pdf_page *page)
{
  pdf_obj *res;
  pdf_obj *obj;
  fz_default_colorspaces *default_cs;
  fz_colorspace *oi;

  default_cs = fz_new_default_colorspaces(ctx);

  fz_try(ctx)
  {
    res = pdf_page_resources(ctx, page);
    obj = pdf_dict_get(ctx, res, PDF_NAME(ColorSpace));
    if (obj)
      pdf_load_default_colorspaces_imp(ctx, default_cs, obj);

    oi = pdf_document_output_intent(ctx, doc);
    if (oi)
      fz_set_default_output_intent(ctx, default_cs, oi);
  }
  fz_catch(ctx)
  {
    if (fz_caught(ctx) != FZ_ERROR_TRYLATER)
    {
      fz_drop_default_colorspaces(ctx, default_cs);
      fz_rethrow(ctx);
    }
    fz_ignore_error(ctx);
    page->super.incomplete = 1;
  }

  return default_cs;
}

fz_default_colorspaces *
pdf_update_default_colorspaces(fz_context *ctx, fz_default_colorspaces *old_cs, pdf_obj *res)
{
  pdf_obj *obj;
  fz_default_colorspaces *new_cs;

  obj = pdf_dict_get(ctx, res, PDF_NAME(ColorSpace));
  if (!obj)
    return fz_keep_default_colorspaces(ctx, old_cs);

  new_cs = fz_clone_default_colorspaces(ctx, old_cs);
  fz_try(ctx)
    pdf_load_default_colorspaces_imp(ctx, new_cs, obj);
  fz_catch(ctx)
  {
    fz_drop_default_colorspaces(ctx, new_cs);
    fz_rethrow(ctx);
  }

  return new_cs;
}

void pdf_nuke_page(fz_context *ctx, pdf_page *page)
{
  pdf_nuke_links(ctx, page);
  pdf_nuke_annots(ctx, page);
  pdf_drop_obj(ctx, page->obj);
  page->obj = NULL;
  page->super.in_doc = 0;
}

void pdf_sync_page(fz_context *ctx, pdf_page *page)
{
  pdf_sync_links(ctx, page);
  pdf_sync_annots(ctx, page);
}

void pdf_sync_open_pages(fz_context *ctx, pdf_document *doc)
{
  fz_page *page, *next;
  pdf_page *ppage;
  int number;

  for (page = doc->super.open; page != NULL; page = next)
  {
    next = page->next;
    if (page->doc == NULL)
      continue;
    ppage = (pdf_page*)page;
    number = pdf_lookup_page_number(ctx, doc, ppage->obj);
    if (number < 0)
    {
      pdf_nuke_page(ctx, ppage);
      if (next)
        next->prev = page->prev;
      if (page->prev)
        *page->prev = page->next;
    }
    else
    {
      pdf_sync_page(ctx, ppage);
      page->number = number;
    }
  }
}

pdf_page *
pdf_load_page(fz_context *ctx, pdf_document *doc, int number)
{
  return (pdf_page*)fz_load_page(ctx, (fz_document*)doc, number);
}

int
pdf_page_has_transparency(fz_context *ctx, pdf_page *page)
{
  return page->transparency;
}

fz_page *
pdf_load_page_imp(fz_context *ctx, fz_document *doc_, int chapter, int number)
{
  pdf_document *doc = (pdf_document*)doc_;
  pdf_page *page;
  pdf_annot *annot;
  pdf_obj *pageobj, *obj;

  if (doc->is_fdf)
    fz_throw(ctx, FZ_ERROR_FORMAT, "FDF documents have no pages");

  if (chapter != 0)
    fz_throw(ctx, FZ_ERROR_ARGUMENT, "invalid chapter number: %d", chapter);

  if (number < 0 || number >= pdf_count_pages(ctx, doc))
    fz_throw(ctx, FZ_ERROR_ARGUMENT, "invalid page number: %d", number);

  if (doc->file_reading_linearly)
  {
    pageobj = pdf_progressive_advance(ctx, doc, number);
    if (pageobj == NULL)
      fz_throw(ctx, FZ_ERROR_TRYLATER, "page %d not available yet", number);
  }
  else
    pageobj = pdf_lookup_page_obj(ctx, doc, number);

  page = pdf_new_page(ctx, doc);
  page->obj = pdf_keep_obj(ctx, pageobj);

  /* Pre-load annotations and links */
  fz_try(ctx)
  {
    obj = pdf_dict_get(ctx, pageobj, PDF_NAME(Annots));
    if (obj)
    {
      fz_rect page_cropbox;
      fz_matrix page_ctm;
      pdf_page_transform(ctx, page, &page_cropbox, &page_ctm);
      page->links = pdf_load_link_annots(ctx, doc, page, obj, number, page_ctm);
      pdf_load_annots(ctx, page);
    }
  }
  fz_catch(ctx)
  {
    if (fz_caught(ctx) != FZ_ERROR_TRYLATER)
    {
      fz_drop_page(ctx, &page->super);
      fz_rethrow(ctx);
    }
    fz_ignore_error(ctx);
    page->super.incomplete = 1;
    fz_drop_link(ctx, page->links);
    page->links = NULL;
  }

  /* Scan for transparency and overprint */
  fz_try(ctx)
  {
    pdf_obj *resources = pdf_page_resources(ctx, page);
    if (pdf_name_eq(ctx, pdf_dict_getp(ctx, pageobj, "Group/S"), PDF_NAME(Transparency)))
      page->transparency = 1;
    else if (pdf_resources_use_blending(ctx, resources, NULL))
      page->transparency = 1;
    if (pdf_resources_use_overprint(ctx, resources, NULL))
      page->overprint = 1;
    for (annot = page->annots; annot && !page->transparency; annot = annot->next)
    {
      fz_try(ctx)
      {
        pdf_obj *ap;
        pdf_obj *res;
        pdf_annot_push_local_xref(ctx, annot);
        ap = pdf_annot_ap(ctx, annot);
        if (!ap)
          break;
        res = pdf_xobject_resources(ctx, ap);
        if (pdf_resources_use_blending(ctx, res, NULL))
          page->transparency = 1;
        if (pdf_resources_use_overprint(ctx, pdf_xobject_resources(ctx, res), NULL))
          page->overprint = 1;
      }
      fz_always(ctx)
        pdf_annot_pop_local_xref(ctx, annot);
      fz_catch(ctx)
        fz_rethrow(ctx);
    }
    for (annot = page->widgets; annot && !page->transparency; annot = annot->next)
    {
      fz_try(ctx)
      {
        pdf_obj *ap;
        pdf_obj *res;
        pdf_annot_push_local_xref(ctx, annot);
        ap = pdf_annot_ap(ctx, annot);
        if (!ap)
          break;
        res = pdf_xobject_resources(ctx, ap);
        if (pdf_resources_use_blending(ctx, res, NULL))
          page->transparency = 1;
        if (pdf_resources_use_overprint(ctx, pdf_xobject_resources(ctx, res), NULL))
          page->overprint = 1;
      }
      fz_always(ctx)
        pdf_annot_pop_local_xref(ctx, annot);
      fz_catch(ctx)
        fz_rethrow(ctx);
    }
  }
  fz_catch(ctx)
  {
    if (fz_caught(ctx) != FZ_ERROR_TRYLATER)
    {
      fz_drop_page(ctx, &page->super);
      fz_rethrow(ctx);
    }
    fz_ignore_error(ctx);
    page->super.incomplete = 1;
  }

  return (fz_page*)page;
}

void
pdf_delete_page(fz_context *ctx, pdf_document *doc, int at)
{
  pdf_obj *parent, *kids;
  int i;

  pdf_begin_operation(ctx, doc, "Delete page");
  fz_try(ctx)
  {
    pdf_lookup_page_loc(ctx, doc, at, &parent, &i);
    kids = pdf_dict_get(ctx, parent, PDF_NAME(Kids));
    pdf_array_delete(ctx, kids, i);

    while (parent)
    {
      int count = pdf_dict_get_int(ctx, parent, PDF_NAME(Count));
      pdf_dict_put_int(ctx, parent, PDF_NAME(Count), count - 1);
      parent = pdf_dict_get(ctx, parent, PDF_NAME(Parent));
    }

    /* Adjust page labels */
    pdf_adjust_page_labels(ctx, doc, at, -1);
    pdf_end_operation(ctx, doc);
  }
  fz_catch(ctx)
  {
    pdf_abandon_operation(ctx, doc);
    pdf_sync_open_pages(ctx, doc);
    fz_rethrow(ctx);
  }

  pdf_sync_open_pages(ctx, doc);
}

void
pdf_delete_page_range(fz_context *ctx, pdf_document *doc, int start, int end)
{
  int count = pdf_count_pages(ctx, doc);
  if (end < 0)
    end = count;
  start = fz_clampi(start, 0, count);
  end = fz_clampi(end, 0, count);
  while (start < end)
  {
    pdf_delete_page(ctx, doc, start);
    end--;
  }
}

pdf_obj *
pdf_add_page(fz_context *ctx, pdf_document *doc, fz_rect mediabox, int rotate, pdf_obj *resources, fz_buffer *contents)
{
  pdf_obj *page_obj = NULL;
  pdf_obj *page_ref = NULL;

  fz_var(page_obj);
  fz_var(page_ref);

  pdf_begin_operation(ctx, doc, "Add page");

  fz_try(ctx)
  {
    page_obj = pdf_new_dict(ctx, doc, 5);

    pdf_dict_put(ctx, page_obj, PDF_NAME(Type), PDF_NAME(Page));
    pdf_dict_put_rect(ctx, page_obj, PDF_NAME(MediaBox), mediabox);
    pdf_dict_put_int(ctx, page_obj, PDF_NAME(Rotate), rotate);

    if (pdf_is_indirect(ctx, resources))
      pdf_dict_put(ctx, page_obj, PDF_NAME(Resources), resources);
    else if (pdf_is_dict(ctx, resources))
      pdf_dict_put_drop(ctx, page_obj, PDF_NAME(Resources), pdf_add_object(ctx, doc, resources));
    else
      pdf_dict_put_dict(ctx, page_obj, PDF_NAME(Resources), 1);

    if (contents && contents->len > 0)
      pdf_dict_put_drop(ctx, page_obj, PDF_NAME(Contents), pdf_add_stream(ctx, doc, contents, NULL, 0));
    page_ref = pdf_add_object_drop(ctx, doc, page_obj);
    pdf_end_operation(ctx, doc);
  }
  fz_catch(ctx)
  {
    pdf_drop_obj(ctx, page_obj);
    pdf_abandon_operation(ctx, doc);
    fz_rethrow(ctx);
  }
  return page_ref;
}

void
pdf_insert_page(fz_context *ctx, pdf_document *doc, int at, pdf_obj *page_ref)
{
  int count = pdf_count_pages(ctx, doc);
  pdf_obj *parent, *kids;
  int i;

  if (at < 0)
    at = count;
  if (at == INT_MAX)
    at = count;
  if (at > count)
    fz_throw(ctx, FZ_ERROR_ARGUMENT, "cannot insert page beyond end of page tree");

  pdf_begin_operation(ctx, doc, "Insert page");

  fz_try(ctx)
  {
    if (count == 0)
    {
      pdf_obj *root = pdf_dict_get(ctx, pdf_trailer(ctx, doc), PDF_NAME(Root));
      parent = pdf_dict_get(ctx, root, PDF_NAME(Pages));
      if (!parent)
        fz_throw(ctx, FZ_ERROR_FORMAT, "cannot find page tree");
      kids = pdf_dict_get(ctx, parent, PDF_NAME(Kids));
      if (!kids)
        fz_throw(ctx, FZ_ERROR_FORMAT, "malformed page tree");
      pdf_array_insert(ctx, kids, page_ref, 0);
    }
    else if (at == count)
    {
      /* append after last page */
      pdf_lookup_page_loc(ctx, doc, count - 1, &parent, &i);
      kids = pdf_dict_get(ctx, parent, PDF_NAME(Kids));
      pdf_array_insert(ctx, kids, page_ref, i + 1);
    }
    else
    {
      /* insert before found page */
      pdf_lookup_page_loc(ctx, doc, at, &parent, &i);
      kids = pdf_dict_get(ctx, parent, PDF_NAME(Kids));
      pdf_array_insert(ctx, kids, page_ref, i);
    }

    pdf_dict_put(ctx, page_ref, PDF_NAME(Parent), parent);

    /* Adjust page counts */
    while (parent)
    {
      count = pdf_dict_get_int(ctx, parent, PDF_NAME(Count));
      pdf_dict_put_int(ctx, parent, PDF_NAME(Count), count + 1);
      parent = pdf_dict_get(ctx, parent, PDF_NAME(Parent));
    }

    /* Adjust page labels */
    pdf_adjust_page_labels(ctx, doc, at, 1);
    pdf_end_operation(ctx, doc);
  }
  fz_catch(ctx)
  {
    pdf_abandon_operation(ctx, doc);
    pdf_sync_open_pages(ctx, doc);
    fz_rethrow(ctx);
  }
  pdf_sync_open_pages(ctx, doc);
}

/*
 * Page Labels
 */

struct page_label_range {
  int offset;
  pdf_obj *label;
  int nums_ix;
  pdf_obj *nums;
};

static void
pdf_lookup_page_label_imp(fz_context *ctx, pdf_obj *node, int index, struct page_label_range *range)
{
  pdf_obj *kids = pdf_dict_get(ctx, node, PDF_NAME(Kids));
  pdf_obj *nums = pdf_dict_get(ctx, node, PDF_NAME(Nums));
  int i;

  if (pdf_is_array(ctx, kids))
  {
    for (i = 0; i < pdf_array_len(ctx, kids); ++i)
    {
      pdf_obj *kid = pdf_array_get(ctx, kids, i);
      pdf_lookup_page_label_imp(ctx, kid, index, range);
    }
  }

  if (pdf_is_array(ctx, nums))
  {
    for (i = 0; i < pdf_array_len(ctx, nums); i += 2)
    {
      int k = pdf_array_get_int(ctx, nums, i);
      if (k <= index)
      {
        range->offset = k;
        range->label = pdf_array_get(ctx, nums, i + 1);
        range->nums_ix = i;
        range->nums = nums;
      }
      else
      {
        /* stop looking if we've already passed the index */
        return;
      }
    }
  }
}

static struct page_label_range
pdf_lookup_page_label(fz_context *ctx, pdf_document *doc, int index)
{
  pdf_obj *root = pdf_dict_get(ctx, pdf_trailer(ctx, doc), PDF_NAME(Root));
  pdf_obj *labels = pdf_dict_get(ctx, root, PDF_NAME(PageLabels));
  pdf_obj *nums = pdf_dict_get(ctx, labels, PDF_NAME(Nums));
  struct page_label_range range = { 0, NULL, 0, nums };
  pdf_lookup_page_label_imp(ctx, labels, index, &range);
  return range;
}

static void
pdf_flatten_page_label_tree_imp(fz_context *ctx, pdf_obj *node, pdf_obj *new_nums)
{
  pdf_obj *kids = pdf_dict_get(ctx, node, PDF_NAME(Kids));
  pdf_obj *nums = pdf_dict_get(ctx, node, PDF_NAME(Nums));
  int i;

  if (pdf_is_array(ctx, kids))
  {
    for (i = 0; i < pdf_array_len(ctx, kids); ++i)
    {
      pdf_obj *kid = pdf_array_get(ctx, kids, i);
      pdf_flatten_page_label_tree_imp(ctx, kid, new_nums);
    }
  }

  if (pdf_is_array(ctx, nums))
  {
    for (i = 0; i < pdf_array_len(ctx, nums); i += 2)
    {
      pdf_array_push(ctx, new_nums, pdf_array_get(ctx, nums, i));
      pdf_array_push(ctx, new_nums, pdf_array_get(ctx, nums, i + 1));
    }
  }
}

static void
pdf_flatten_page_label_tree(fz_context *ctx, pdf_document *doc)
{
  pdf_obj *root = pdf_dict_get(ctx, pdf_trailer(ctx, doc), PDF_NAME(Root));
  pdf_obj *labels = pdf_dict_get(ctx, root, PDF_NAME(PageLabels));
  pdf_obj *nums = pdf_dict_get(ctx, labels, PDF_NAME(Nums));

  // Already flat...
  if (pdf_is_array(ctx, nums) && pdf_array_len(ctx, nums) >= 2)
    return;

  nums = pdf_new_array(ctx, doc, 8);
  fz_try(ctx)
  {
    if (!labels)
      labels = pdf_dict_put_dict(ctx, root, PDF_NAME(PageLabels), 1);

    pdf_flatten_page_label_tree_imp(ctx, labels, nums);

    pdf_dict_del(ctx, labels, PDF_NAME(Kids));
    pdf_dict_del(ctx, labels, PDF_NAME(Limits));
    pdf_dict_put(ctx, labels, PDF_NAME(Nums), nums);

    /* No Page Label tree found - insert one with default values */
    if (pdf_array_len(ctx, nums) == 0)
    {
      pdf_obj *obj;
      pdf_array_push_int(ctx, nums, 0);
      obj = pdf_array_push_dict(ctx, nums, 1);
      pdf_dict_put(ctx, obj, PDF_NAME(S), PDF_NAME(D));
    }
  }
  fz_always(ctx)
    pdf_drop_obj(ctx, nums);
  fz_catch(ctx)
    fz_rethrow(ctx);
}

static pdf_obj *
pdf_create_page_label(fz_context *ctx, pdf_document *doc, pdf_page_label_style style, const char *prefix, int start)
{
  pdf_obj *obj = pdf_new_dict(ctx, doc, 3);
  fz_try(ctx)
  {
    switch (style)
    {
    default:
    case PDF_PAGE_LABEL_NONE:
      break;
    case PDF_PAGE_LABEL_DECIMAL:
      pdf_dict_put(ctx, obj, PDF_NAME(S), PDF_NAME(D));
      break;
    case PDF_PAGE_LABEL_ROMAN_UC:
      pdf_dict_put(ctx, obj, PDF_NAME(S), PDF_NAME(R));
      break;
    case PDF_PAGE_LABEL_ROMAN_LC:
      pdf_dict_put(ctx, obj, PDF_NAME(S), PDF_NAME(r));
      break;
    case PDF_PAGE_LABEL_ALPHA_UC:
      pdf_dict_put(ctx, obj, PDF_NAME(S), PDF_NAME(A));
      break;
    case PDF_PAGE_LABEL_ALPHA_LC:
      pdf_dict_put(ctx, obj, PDF_NAME(S), PDF_NAME(a));
      break;
    }
    if (prefix && strlen(prefix) > 0)
      pdf_dict_put_text_string(ctx, obj, PDF_NAME(P), prefix);
    if (start > 1)
      pdf_dict_put_int(ctx, obj, PDF_NAME(St), start);
  }
  fz_catch(ctx)
  {
    pdf_drop_obj(ctx, obj);
    fz_rethrow(ctx);
  }
  return obj;
}

static void
pdf_adjust_page_labels(fz_context *ctx, pdf_document *doc, int index, int adjust)
{
  pdf_obj *root = pdf_dict_get(ctx, pdf_trailer(ctx, doc), PDF_NAME(Root));
  pdf_obj *labels = pdf_dict_get(ctx, root, PDF_NAME(PageLabels));

  // Skip the adjustment step if there are no page labels.
  // Exception: If we would adjust the label for page 0, we must create one!
  // Exception: If the document only has one page!
  if (labels || (adjust > 0 && index == 0 && pdf_count_pages(ctx, doc) > 1))
  {
    struct page_label_range range;
    int i;

    // Ensure we have a flat page label tree with at least one entry.
    pdf_flatten_page_label_tree(ctx, doc);

    // Find page label affecting the page that triggered adjustment
    range = pdf_lookup_page_label(ctx, doc, index);

    // Shift all page labels on and after the inserted index
    if (adjust > 0)
    {
      if (range.offset == index)
        i = range.nums_ix;
      else
        i = range.nums_ix + 2;
    }

    // Shift all page labels after the removed index
    else
    {
      i = range.nums_ix + 2;
    }


    // Increase/decrease the indices in the name tree
    for (; i < pdf_array_len(ctx, range.nums); i += 2)
      pdf_array_put_int(ctx, range.nums, i, pdf_array_get_int(ctx, range.nums, i) + adjust);

    // TODO: delete page labels that have no effect (zero range)

    // Make sure the number tree always has an entry for page 0
    if (adjust > 0 && index == 0)
    {
      pdf_array_insert_drop(ctx, range.nums, pdf_new_int(ctx, index), 0);
      pdf_array_insert_drop(ctx, range.nums, pdf_create_page_label(ctx, doc, PDF_PAGE_LABEL_DECIMAL, NULL, 1), 1);
    }
  }
}

void
pdf_set_page_labels(fz_context *ctx, pdf_document *doc,
  int index,
  pdf_page_label_style style, const char *prefix, int start)
{
  struct page_label_range range;

  pdf_begin_operation(ctx, doc, "Set page label");
  fz_try(ctx)
  {
    // Ensure we have a flat page label tree with at least one entry.
    pdf_flatten_page_label_tree(ctx, doc);

    range = pdf_lookup_page_label(ctx, doc, index);

    if (range.offset == index)
    {
      // Replace label
      pdf_array_put_drop(ctx, range.nums,
        range.nums_ix + 1,
        pdf_create_page_label(ctx, doc, style, prefix, start));
    }
    else
    {
      // Insert new label
      pdf_array_insert_drop(ctx, range.nums,
        pdf_new_int(ctx, index),
        range.nums_ix + 2);
      pdf_array_insert_drop(ctx, range.nums,
        pdf_create_page_label(ctx, doc, style, prefix, start),
        range.nums_ix + 3);
    }
    pdf_end_operation(ctx, doc);
  }
  fz_catch(ctx)
  {
    pdf_abandon_operation(ctx, doc);
    fz_rethrow(ctx);
  }
}

void
pdf_delete_page_labels(fz_context *ctx, pdf_document *doc, int index)
{
  struct page_label_range range;

  if (index == 0)
  {
    pdf_set_page_labels(ctx, doc, 0, PDF_PAGE_LABEL_DECIMAL, NULL, 1);
    return;
  }

  pdf_begin_operation(ctx, doc, "Delete page label");
  fz_try(ctx)
  {
    // Ensure we have a flat page label tree with at least one entry.
    pdf_flatten_page_label_tree(ctx, doc);

    range = pdf_lookup_page_label(ctx, doc, index);

    if (range.offset == index)
    {
      // Delete label
      pdf_array_delete(ctx, range.nums, range.nums_ix);
      pdf_array_delete(ctx, range.nums, range.nums_ix);
    }
    pdf_end_operation(ctx, doc);
  }
  fz_catch(ctx)
  {
    pdf_abandon_operation(ctx, doc);
    fz_rethrow(ctx);
  }
}

static const char *roman_uc[3][10] = {
  { "", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX" },
  { "", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC" },
  { "", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM" },
};

static const char *roman_lc[3][10] = {
  { "", "i", "ii", "iii", "iv", "v", "vi", "vii", "viii", "ix" },
  { "", "x", "xx", "xxx", "xl", "l", "lx", "lxx", "lxxx", "xc" },
  { "", "c", "cc", "ccc", "cd", "d", "dc", "dcc", "dccc", "cm" },
};

static void pdf_format_roman_page_label(char *buf, int size, int n, const char *sym[3][10], const char *sym_m)
{
  int I = n % 10;
  int X = (n / 10) % 10;
  int C = (n / 100) % 10;
  int M = (n / 1000);

  fz_strlcpy(buf, "", size);
  while (M--)
    fz_strlcat(buf, sym_m, size);
  fz_strlcat(buf, sym[2][C], size);
  fz_strlcat(buf, sym[1][X], size);
  fz_strlcat(buf, sym[0][I], size);
}

static void pdf_format_alpha_page_label(char *buf, int size, int n, int alpha)
{
  int reps = (n - 1) / 26 + 1;
  if (reps > size - 1)
    reps = size - 1;
  memset(buf, (n - 1) % 26 + alpha, reps);
  buf[reps] = '\0';
}

static void
pdf_format_page_label(fz_context *ctx, int index, pdf_obj *dict, char *buf, size_t size)
{
  pdf_obj *style = pdf_dict_get(ctx, dict, PDF_NAME(S));
  const char *prefix = pdf_dict_get_text_string(ctx, dict, PDF_NAME(P));
  int start = pdf_dict_get_int(ctx, dict, PDF_NAME(St));
  size_t n;

  // St must be >= 1; default is 1.
  if (start < 1)
    start = 1;

  // Add prefix (optional; may be empty)
  fz_strlcpy(buf, prefix, size);
  n = strlen(buf);
  buf += n;
  size -= n;

  // Append number using style (optional)
  if (style == PDF_NAME(D))
    fz_snprintf(buf, size, "%d", index + start);
  else if (style == PDF_NAME(R))
    pdf_format_roman_page_label(buf, (int)size, index + start, roman_uc, "M");
  else if (style == PDF_NAME(r))
    pdf_format_roman_page_label(buf, (int)size, index + start, roman_lc, "m");
  else if (style == PDF_NAME(A))
    pdf_format_alpha_page_label(buf, (int)size, index + start, 'A');
  else if (style == PDF_NAME(a))
    pdf_format_alpha_page_label(buf, (int)size, index + start, 'a');
}

void
pdf_page_label(fz_context *ctx, pdf_document *doc, int index, char *buf, size_t size)
{
  struct page_label_range range = pdf_lookup_page_label(ctx, doc, index);
  if (range.label)
    pdf_format_page_label(ctx, index - range.offset, range.label, buf, size);
  else
    fz_snprintf(buf, size, "%d", index + 1);
}

void
pdf_page_label_imp(fz_context *ctx, fz_document *doc, int chapter, int page, char *buf, size_t size)
{
  pdf_page_label(ctx, pdf_document_from_fz_document(ctx, doc), page, buf, size);
}

pdf_page *
pdf_keep_page(fz_context *ctx, pdf_page *page)
{
  return (pdf_page *) fz_keep_page(ctx, &page->super);
}

void
pdf_drop_page(fz_context *ctx, pdf_page *page)
{
  fz_drop_page(ctx, &page->super);
}

Coverage Report

Created: 2026-05-16 07:03