src/third_party/skia/src/pdf/SkPDFPage.cpp

   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 #include "SkPDFCatalog.h"
  11 #include "SkPDFDevice.h"
  12 #include "SkPDFPage.h"
  13 #include "SkPDFResourceDict.h"
  14 #include "SkStream.h"
  15
  16 SkPDFPage::SkPDFPage(SkPDFDevice* content)
  17     : SkPDFDict("Page"),
  18       fDevice(content) {
  19   SkSafeRef(content);
  20 }
  21
  22 SkPDFPage::~SkPDFPage() {}
  23
  24 void SkPDFPage::finalizePage(SkPDFCatalog* catalog, bool firstPage,
  25                              const SkTSet<SkPDFObject*>& knownResourceObjects,
  26                              SkTSet<SkPDFObject*>* newResourceObjects) {
  27     SkPDFResourceDict* resourceDict = fDevice->getResourceDict();
  28     if (fContentStream.get() == NULL) {
  29         insert("Resources", resourceDict);
  30         SkSafeUnref(this->insert("MediaBox", fDevice->copyMediaBox()));
  31         if (!SkToBool(catalog->getDocumentFlags() &
  32                       SkPDFDocument::kNoLinks_Flags)) {
  33             SkPDFArray* annots = fDevice->getAnnotations();
  34             if (annots && annots->size() > 0) {
  35                 insert("Annots", annots);
  36             }
  37         }
  38
  39         SkAutoTUnref<SkStream> content(fDevice->content());
  40         fContentStream.reset(new SkPDFStream(content.get()));
  41         insert("Contents", new SkPDFObjRef(fContentStream.get()))->unref();
  42     }
  43     catalog->addObject(fContentStream.get(), firstPage);
  44     resourceDict->getReferencedResources(knownResourceObjects,
  45                                          newResourceObjects,
  46                                          true);
  47 }
  48
  49 off_t SkPDFPage::getPageSize(SkPDFCatalog* catalog, off_t fileOffset) {
  50     SkASSERT(fContentStream.get() != NULL);
  51     catalog->setFileOffset(fContentStream.get(), fileOffset);
  52     return fContentStream->getOutputSize(catalog, true);
  53 }
  54
  55 void SkPDFPage::emitPage(SkWStream* stream, SkPDFCatalog* catalog) {
  56     SkASSERT(fContentStream.get() != NULL);
  57     fContentStream->emitObject(stream, catalog, true);
  58 }
  59
  60 // static
  61 void SkPDFPage::GeneratePageTree(const SkTDArray<SkPDFPage*>& pages,
  62                                  SkPDFCatalog* catalog,
  63                                  SkTDArray<SkPDFDict*>* pageTree,
  64                                  SkPDFDict** rootNode) {
  65     // PDF wants a tree describing all the pages in the document.  We arbitrary
  66     // choose 8 (kNodeSize) as the number of allowed children.  The internal
  67     // nodes have type "Pages" with an array of children, a parent pointer, and
  68     // the number of leaves below the node as "Count."  The leaves are passed
  69     // into the method, have type "Page" and need a parent pointer. This method
  70     // builds the tree bottom up, skipping internal nodes that would have only
  71     // one child.
  72     static const int kNodeSize = 8;
  73
  74     SkAutoTUnref<SkPDFName> kidsName(new SkPDFName("Kids"));
  75     SkAutoTUnref<SkPDFName> countName(new SkPDFName("Count"));
  76     SkAutoTUnref<SkPDFName> parentName(new SkPDFName("Parent"));
  77
  78     // curNodes takes a reference to its items, which it passes to pageTree.
  79     SkTDArray<SkPDFDict*> curNodes;
  80     curNodes.setReserve(pages.count());
  81     for (int i = 0; i < pages.count(); i++) {
  82         SkSafeRef(pages[i]);
  83         curNodes.push(pages[i]);
  84     }
  85
  86     // nextRoundNodes passes its references to nodes on to curNodes.
  87     SkTDArray<SkPDFDict*> nextRoundNodes;
  88     nextRoundNodes.setReserve((pages.count() + kNodeSize - 1)/kNodeSize);
  89
  90     int treeCapacity = kNodeSize;
  91     do {
  92         for (int i = 0; i < curNodes.count(); ) {
  93             if (i > 0 && i + 1 == curNodes.count()) {
  94                 nextRoundNodes.push(curNodes[i]);
  95                 break;
  96             }
  97
  98             SkPDFDict* newNode = new SkPDFDict("Pages");
  99             SkAutoTUnref<SkPDFObjRef> newNodeRef(new SkPDFObjRef(newNode));
 100
 101             SkAutoTUnref<SkPDFArray> kids(new SkPDFArray);
 102             kids->reserve(kNodeSize);
 103
 104             int count = 0;
 105             for (; i < curNodes.count() && count < kNodeSize; i++, count++) {
 106                 curNodes[i]->insert(parentName.get(), newNodeRef.get());
 107                 kids->append(new SkPDFObjRef(curNodes[i]))->unref();
 108
 109                 // TODO(vandebo): put the objects in strict access order.
 110                 // Probably doesn't matter because they are so small.
 111                 if (curNodes[i] != pages[0]) {
 112                     pageTree->push(curNodes[i]);  // Transfer reference.
 113                     catalog->addObject(curNodes[i], false);
 114                 } else {
 115                     SkSafeUnref(curNodes[i]);
 116                     catalog->addObject(curNodes[i], true);
 117                 }
 118             }
 119
 120             // treeCapacity is the number of leaf nodes possible for the
 121             // current set of subtrees being generated. (i.e. 8, 64, 512, ...).
 122             // It is hard to count the number of leaf nodes in the current
 123             // subtree. However, by construction, we know that unless it's the
 124             // last subtree for the current depth, the leaf count will be
 125             // treeCapacity, otherwise it's what ever is left over after
 126             // consuming treeCapacity chunks.
 127             int pageCount = treeCapacity;
 128             if (i == curNodes.count()) {
 129                 pageCount = ((pages.count() - 1) % treeCapacity) + 1;
 130             }
 131             newNode->insert(countName.get(), new SkPDFInt(pageCount))->unref();
 132             newNode->insert(kidsName.get(), kids.get());
 133             nextRoundNodes.push(newNode);  // Transfer reference.
 134         }
 135
 136         curNodes = nextRoundNodes;
 137         nextRoundNodes.rewind();
 138         treeCapacity *= kNodeSize;
 139     } while (curNodes.count() > 1);
 140
 141     pageTree->push(curNodes[0]);  // Transfer reference.
 142     catalog->addObject(curNodes[0], false);
 143     if (rootNode) {
 144         *rootNode = curNodes[0];
 145     }
 146 }
 147
 148 const SkTDArray<SkPDFFont*>& SkPDFPage::getFontResources() const {
 149     return fDevice->getFontResources();
 150 }
 151
 152 const SkPDFGlyphSetMap& SkPDFPage::getFontGlyphUsage() const {
 153     return fDevice->getFontGlyphUsage();
 154 }
 155
 156 void SkPDFPage::appendDestinations(SkPDFDict* dict) {
 157     fDevice->appendDestinations(dict, this);
 158 }