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      1 
      2 /*
      3  * Copyright 2010 The Android Open Source Project
      4  *
      5  * Use of this source code is governed by a BSD-style license that can be
      6  * found in the LICENSE file.
      7  */
      8 
      9 
     10 #ifndef SkPDFPage_DEFINED
     11 #define SkPDFPage_DEFINED
     12 
     13 #include "SkPDFTypes.h"
     14 #include "SkPDFStream.h"
     15 #include "SkRefCnt.h"
     16 #include "SkTDArray.h"
     17 
     18 class SkPDFCatalog;
     19 class SkPDFDevice;
     20 class SkWStream;
     21 
     22 /** \class SkPDFPage
     23 
     24     A SkPDFPage contains meta information about a page, is used in the page
     25     tree and points to the content of the page.
     26 */
     27 class SkPDFPage : public SkPDFDict {
     28 public:
     29     /** Create a PDF page with the passed PDF device.  The device need not
     30      *  have content on it yet.
     31      *  @param content    The page content.
     32      */
     33     explicit SkPDFPage(SkPDFDevice* content);
     34     ~SkPDFPage();
     35 
     36     /** Before a page and its contents can be sized and emitted, it must
     37      *  be finalized.  No changes to the PDFDevice will be honored after
     38      *  finalizePage has been called.  This function adds the page content
     39      *  to the passed catalog, so it must be called for each document
     40      *  that the page is part of.
     41      *  @param catalog         The catalog to add page content objects to.
     42      *  @param firstPage       Indicate if this is the first page of a document.
     43      *  @param newResourceObjects All the resource objects (recursively) used on
     44      *                         the page are added to this array.  This gives
     45      *                         the caller a chance to deduplicate resources
     46      *                         across pages.
     47      *  @param knownResourceObjects  The set of resources to be ignored.
     48      */
     49     void finalizePage(SkPDFCatalog* catalog, bool firstPage,
     50                       const SkTSet<SkPDFObject*>& knownResourceObjects,
     51                       SkTSet<SkPDFObject*>* newResourceObjects);
     52 
     53     /** Add destinations for this page to the supplied dictionary.
     54      *  @param dict       Dictionary to add destinations to.
     55      */
     56     void appendDestinations(SkPDFDict* dict);
     57 
     58     /** Determine the size of the page content and store to the catalog
     59      *  the offsets of all nonresource-indirect objects that make up the page
     60      *  content.  This must be called before emitPage(), but after finalizePage.
     61      *  @param catalog    The catalog to add the object offsets to.
     62      *  @param fileOffset The file offset where the page content will be
     63      *                    emitted.
     64      */
     65     off_t getPageSize(SkPDFCatalog* catalog, off_t fileOffset);
     66 
     67     /** Output the page content to the passed stream.
     68      *  @param stream     The writable output stream to send the content to.
     69      *  @param catalog    The active object catalog.
     70      */
     71     void emitPage(SkWStream* stream, SkPDFCatalog* catalog);
     72 
     73     /** Generate a page tree for the passed vector of pages.  New objects are
     74      *  added to the catalog.  The pageTree vector is populated with all of
     75      *  the 'Pages' dictionaries as well as the 'Page' objects.  Page trees
     76      *  have both parent and children links, creating reference cycles, so
     77      *  it must be torn down explicitly.  The first page is not added to
     78      *  the pageTree dictionary array so the caller can handle it specially.
     79      *  @param pages      The ordered vector of page objects.
     80      *  @param catalog    The catalog to add new objects into.
     81      *  @param pageTree   An output vector with all of the internal and leaf
     82      *                    nodes of the pageTree.
     83      *  @param rootNode   An output parameter set to the root node.
     84      */
     85     static void GeneratePageTree(const SkTDArray<SkPDFPage*>& pages,
     86                                  SkPDFCatalog* catalog,
     87                                  SkTDArray<SkPDFDict*>* pageTree,
     88                                  SkPDFDict** rootNode);
     89 
     90     /** Get the fonts used on this page.
     91      */
     92     const SkTDArray<SkPDFFont*>& getFontResources() const;
     93 
     94     /** Returns a SkPDFGlyphSetMap which represents glyph usage of every font
     95      *  that shows on this page.
     96      */
     97     const SkPDFGlyphSetMap& getFontGlyphUsage() const;
     98 
     99 private:
    100     // Multiple pages may reference the content.
    101     SkAutoTUnref<SkPDFDevice> fDevice;
    102 
    103     // Once the content is finalized, put it into a stream for output.
    104     SkAutoTUnref<SkPDFStream> fContentStream;
    105 };
    106 
    107 #endif
    108