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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 resourceObjects The resource objects used on the page are added
44      *                         to this array.  This gives the caller a chance
45      *                         to deduplicate resources across pages.
46      */
47     void finalizePage(SkPDFCatalog* catalog, bool firstPage,
48                       SkTDArray<SkPDFObject*>* resourceObjects);
49 
50     /** Determine the size of the page content and store to the catalog
51      *  the offsets of all nonresource-indirect objects that make up the page
52      *  content.  This must be called before emitPage(), but after finalizePage.
53      *  @param catalog    The catalog to add the object offsets to.
54      *  @param fileOffset The file offset where the page content will be
55      *                    emitted.
56      */
57     off_t getPageSize(SkPDFCatalog* catalog, off_t fileOffset);
58 
59     /** Output the page content to the passed stream.
60      *  @param stream     The writable output stream to send the content to.
61      *  @param catalog    The active object catalog.
62      */
63     void emitPage(SkWStream* stream, SkPDFCatalog* catalog);
64 
65     /** Generate a page tree for the passed vector of pages.  New objects are
66      *  added to the catalog.  The pageTree vector is populated with all of
67      *  the 'Pages' dictionaries as well as the 'Page' objects.  Page trees
68      *  have both parent and children links, creating reference cycles, so
69      *  it must be torn down explicitly.  The first page is not added to
70      *  the pageTree dictionary array so the caller can handle it specially.
71      *  @param pages      The ordered vector of page objects.
72      *  @param catalog    The catalog to add new objects into.
73      *  @param pageTree   An output vector with all of the internal and leaf
74      *                    nodes of the pageTree.
75      *  @param rootNode   An output parameter set to the root node.
76      */
77     static void GeneratePageTree(const SkTDArray<SkPDFPage*>& pages,
78                                  SkPDFCatalog* catalog,
79                                  SkTDArray<SkPDFDict*>* pageTree,
80                                  SkPDFDict** rootNode);
81 
82     /** Get the fonts used on this page.
83      */
84     SK_API const SkTDArray<SkPDFFont*>& getFontResources() const;
85 
86     /** Returns a SkPDFGlyphSetMap which represents glyph usage of every font
87      *  that shows on this page.
88      */
89     const SkPDFGlyphSetMap& getFontGlyphUsage() const;
90 
91 private:
92     // Multiple pages may reference the content.
93     SkRefPtr<SkPDFDevice> fDevice;
94 
95     // Once the content is finalized, put it into a stream for output.
96     SkRefPtr<SkPDFStream> fContentStream;
97 };
98 
99 #endif
100