示例#1
0
// return root node.
static sk_sp<SkPDFDict> generate_page_tree(SkTArray<sk_sp<SkPDFDict>>* pages) {
    // PDF wants a tree describing all the pages in the document.  We arbitrary
    // choose 8 (kNodeSize) as the number of allowed children.  The internal
    // nodes have type "Pages" with an array of children, a parent pointer, and
    // the number of leaves below the node as "Count."  The leaves are passed
    // into the method, have type "Page" and need a parent pointer. This method
    // builds the tree bottom up, skipping internal nodes that would have only
    // one child.
    static const int kNodeSize = 8;

    // curNodes takes a reference to its items, which it passes to pageTree.
    int totalPageCount = pages->count();
    SkTArray<sk_sp<SkPDFDict>> curNodes;
    curNodes.swap(pages);

    // nextRoundNodes passes its references to nodes on to curNodes.
    int treeCapacity = kNodeSize;
    do {
        SkTArray<sk_sp<SkPDFDict>> nextRoundNodes;
        for (int i = 0; i < curNodes.count(); ) {
            if (i > 0 && i + 1 == curNodes.count()) {
                SkASSERT(curNodes[i]);
                nextRoundNodes.emplace_back(std::move(curNodes[i]));
                break;
            }

            auto newNode = sk_make_sp<SkPDFDict>("Pages");
            auto kids = sk_make_sp<SkPDFArray>();
            kids->reserve(kNodeSize);

            int count = 0;
            for (; i < curNodes.count() && count < kNodeSize; i++, count++) {
                SkASSERT(curNodes[i]);
                curNodes[i]->insertObjRef("Parent", newNode);
                kids->appendObjRef(std::move(curNodes[i]));
            }

            // treeCapacity is the number of leaf nodes possible for the
            // current set of subtrees being generated. (i.e. 8, 64, 512, ...).
            // It is hard to count the number of leaf nodes in the current
            // subtree. However, by construction, we know that unless it's the
            // last subtree for the current depth, the leaf count will be
            // treeCapacity, otherwise it's what ever is left over after
            // consuming treeCapacity chunks.
            int pageCount = treeCapacity;
            if (i == curNodes.count()) {
                pageCount = ((totalPageCount - 1) % treeCapacity) + 1;
            }
            newNode->insertInt("Count", pageCount);
            newNode->insertObject("Kids", std::move(kids));
            nextRoundNodes.emplace_back(std::move(newNode));
        }
        SkDEBUGCODE( for (const auto& n : curNodes) { SkASSERT(!n); } );

        curNodes.swap(&nextRoundNodes);
        nextRoundNodes.reset();
        treeCapacity *= kNodeSize;
    } while (curNodes.count() > 1);
示例#2
0
void SkPDFType0Font::getFontSubset(SkPDFCanon* canon) {
    const SkAdvancedTypefaceMetrics* metricsPtr =
        SkPDFFont::GetMetrics(this->typeface(), canon);
    SkASSERT(metricsPtr);
    if (!metricsPtr) { return; }
    const SkAdvancedTypefaceMetrics& metrics = *metricsPtr;
    SkASSERT(can_embed(metrics));
    SkAdvancedTypefaceMetrics::FontType type = this->getType();
    SkTypeface* face = this->typeface();
    SkASSERT(face);

    auto descriptor = sk_make_sp<SkPDFDict>("FontDescriptor");
    uint16_t emSize = SkToU16(this->typeface()->getUnitsPerEm());
    add_common_font_descriptor_entries(descriptor.get(), metrics, emSize , 0);

    int ttcIndex;
    std::unique_ptr<SkStreamAsset> fontAsset(face->openStream(&ttcIndex));
    size_t fontSize = fontAsset ? fontAsset->getLength() : 0;
    if (0 == fontSize) {
        SkDebugf("Error: (SkTypeface)(%p)::openStream() returned "
                 "empty stream (%p) when identified as kType1CID_Font "
                 "or kTrueType_Font.\n", face, fontAsset.get());
    } else {
        switch (type) {
            case SkAdvancedTypefaceMetrics::kTrueType_Font: {
                #ifdef SK_PDF_USE_SFNTLY
                if (!SkToBool(metrics.fFlags &
                              SkAdvancedTypefaceMetrics::kNotSubsettable_FontFlag)) {
                    sk_sp<SkPDFStream> subsetStream = get_subset_font_stream(
                            std::move(fontAsset), this->glyphUsage(),
                            metrics.fFontName.c_str(), ttcIndex);
                    if (subsetStream) {
                        descriptor->insertObjRef("FontFile2", std::move(subsetStream));
                        break;
                    }
                    // If subsetting fails, fall back to original font data.
                    fontAsset.reset(face->openStream(&ttcIndex));
                    SkASSERT(fontAsset);
                    SkASSERT(fontAsset->getLength() == fontSize);
                    if (!fontAsset || fontAsset->getLength() == 0) { break; }
                }
                #endif  // SK_PDF_USE_SFNTLY
                auto fontStream = sk_make_sp<SkPDFSharedStream>(std::move(fontAsset));
                fontStream->dict()->insertInt("Length1", fontSize);
                descriptor->insertObjRef("FontFile2", std::move(fontStream));
                break;
            }
            case SkAdvancedTypefaceMetrics::kType1CID_Font: {
                auto fontStream = sk_make_sp<SkPDFSharedStream>(std::move(fontAsset));
                fontStream->dict()->insertName("Subtype", "CIDFontType0C");
                descriptor->insertObjRef("FontFile3", std::move(fontStream));
                break;
            }
            default:
                SkASSERT(false);
        }
    }

    auto newCIDFont = sk_make_sp<SkPDFDict>("Font");
    newCIDFont->insertObjRef("FontDescriptor", std::move(descriptor));
    newCIDFont->insertName("BaseFont", metrics.fPostScriptName);

    switch (type) {
        case SkAdvancedTypefaceMetrics::kType1CID_Font:
            newCIDFont->insertName("Subtype", "CIDFontType0");
            break;
        case SkAdvancedTypefaceMetrics::kTrueType_Font:
            newCIDFont->insertName("Subtype", "CIDFontType2");
            newCIDFont->insertName("CIDToGIDMap", "Identity");
            break;
        default:
            SkASSERT(false);
    }
    auto sysInfo = sk_make_sp<SkPDFDict>();
    sysInfo->insertString("Registry", "Adobe");
    sysInfo->insertString("Ordering", "Identity");
    sysInfo->insertInt("Supplement", 0);
    newCIDFont->insertObject("CIDSystemInfo", std::move(sysInfo));

    int16_t defaultWidth = 0;
    {
        int emSize;
        auto glyphCache = SkPDFFont::MakeVectorCache(face, &emSize);
        sk_sp<SkPDFArray> widths = SkPDFMakeCIDGlyphWidthsArray(
                glyphCache.get(), &this->glyphUsage(), SkToS16(emSize), &defaultWidth);
        if (widths && widths->size() > 0) {
            newCIDFont->insertObject("W", std::move(widths));
        }
        newCIDFont->insertScalar(
                "DW", scaleFromFontUnits(defaultWidth, SkToS16(emSize)));
    }

    ////////////////////////////////////////////////////////////////////////////

    this->insertName("Subtype", "Type0");
    this->insertName("BaseFont", metrics.fPostScriptName);
    this->insertName("Encoding", "Identity-H");
    auto descendantFonts = sk_make_sp<SkPDFArray>();
    descendantFonts->appendObjRef(std::move(newCIDFont));
    this->insertObject("DescendantFonts", std::move(descendantFonts));

    if (metrics.fGlyphToUnicode.count() > 0) {
        this->insertObjRef("ToUnicode",
                           SkPDFMakeToUnicodeCmap(metrics.fGlyphToUnicode,
                                                  &this->glyphUsage(),
                                                  multiByteGlyphs(),
                                                  firstGlyphID(),
                                                  lastGlyphID()));
    }
    SkDEBUGCODE(fPopulated = true);
    return;
}