path: root/src/pdf/SkPDFFont.cpp

/*
 * Copyright 2011 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "SkData.h"
#include "SkGlyphCache.h"
#include "SkPaint.h"
#include "SkPDFCanon.h"
#include "SkPDFConvertType1FontStream.h"
#include "SkPDFDevice.h"
#include "SkPDFMakeToUnicodeCmap.h"
#include "SkPDFFont.h"
#include "SkPDFUtils.h"
#include "SkRefCnt.h"
#include "SkScalar.h"
#include "SkStream.h"
#include "SkTypefacePriv.h"
#include "SkTypes.h"
#include "SkUtils.h"

#if defined (SK_SFNTLY_SUBSETTER)
    #if defined (GOOGLE3)
        // #including #defines doesn't work with this build system.
        #include "typography/font/sfntly/src/sample/chromium/font_subsetter.h"
    #else
        #include SK_SFNTLY_SUBSETTER
    #endif
#endif

namespace {

// PDF's notion of symbolic vs non-symbolic is related to the character set, not
// symbols vs. characters.  Rarely is a font the right character set to call it
// non-symbolic, so always call it symbolic.  (PDF 1.4 spec, section 5.7.1)
static const int kPdfSymbolic = 4;

struct AdvanceMetric {
    enum MetricType {
        kDefault,  // Default advance: fAdvance.count = 1
        kRange,    // Advances for a range: fAdvance.count = fEndID-fStartID
        kRun       // fStartID-fEndID have same advance: fAdvance.count = 1
    };
    MetricType fType;
    uint16_t fStartId;
    uint16_t fEndId;
    SkTDArray<int16_t> fAdvance;
    AdvanceMetric(uint16_t startId) : fStartId(startId) {}
    AdvanceMetric(AdvanceMetric&&) = default;
    AdvanceMetric& operator=(AdvanceMetric&& other) = default;
    AdvanceMetric(const AdvanceMetric&) = delete;
    AdvanceMetric& operator=(const AdvanceMetric&) = delete;
};

class SkPDFType0Font final : public SkPDFFont {
public:
    SkPDFType0Font(const SkAdvancedTypefaceMetrics* info,
                   SkTypeface* typeface);
    virtual ~SkPDFType0Font();
    bool multiByteGlyphs() const override { return true; }
    SkPDFFont* getFontSubset(const SkPDFGlyphSet* usage) override;
#ifdef SK_DEBUG
    void emitObject(SkWStream*,
                    const SkPDFObjNumMap&,
                    const SkPDFSubstituteMap&) const override;
#endif

private:
#ifdef SK_DEBUG
    bool fPopulated;
#endif
    bool populate(const SkPDFGlyphSet* subset);
    typedef SkPDFDict INHERITED;
};

class SkPDFCIDFont final : public SkPDFFont {
public:
    SkPDFCIDFont(const SkAdvancedTypefaceMetrics* info,
                 SkTypeface* typeface,
                 const SkPDFGlyphSet* subset);
    virtual ~SkPDFCIDFont();
    bool multiByteGlyphs() const override { return true; }

private:
    bool populate(const SkPDFGlyphSet* subset);
    bool addFontDescriptor(int16_t defaultWidth,
                           const SkTDArray<uint32_t>* subset);
};

class SkPDFType1Font final : public SkPDFFont {
public:
    SkPDFType1Font(const SkAdvancedTypefaceMetrics* info,
                   SkTypeface* typeface,
                   uint16_t glyphID,
                   SkPDFDict* relatedFontDescriptor);
    virtual ~SkPDFType1Font();
    bool multiByteGlyphs() const override { return false; }

private:
    bool populate(int16_t glyphID);
    bool addFontDescriptor(int16_t defaultWidth);
};

class SkPDFType3Font final : public SkPDFFont {
public:
    SkPDFType3Font(const SkAdvancedTypefaceMetrics* info,
                   SkTypeface* typeface,
                   uint16_t glyphID);
    virtual ~SkPDFType3Font();
    bool multiByteGlyphs() const override { return false; }

private:
    bool populate(uint16_t glyphID);
};

///////////////////////////////////////////////////////////////////////////////
// File-Local Functions
///////////////////////////////////////////////////////////////////////////////

const int16_t kInvalidAdvance = SK_MinS16;
const int16_t kDontCareAdvance = SK_MinS16 + 1;

static void stripUninterestingTrailingAdvancesFromRange(
        AdvanceMetric* range) {
    SkASSERT(range);

    int expectedAdvanceCount = range->fEndId - range->fStartId + 1;
    if (range->fAdvance.count() < expectedAdvanceCount) {
        return;
    }

    for (int i = expectedAdvanceCount - 1; i >= 0; --i) {
        if (range->fAdvance[i] != kDontCareAdvance &&
            range->fAdvance[i] != kInvalidAdvance &&
            range->fAdvance[i] != 0) {
            range->fEndId = range->fStartId + i;
            break;
        }
    }
}

static void zeroWildcardsInRange(AdvanceMetric* range) {
    SkASSERT(range);
    if (range->fType != AdvanceMetric::kRange) {
        return;
    }
    SkASSERT(range->fAdvance.count() == range->fEndId - range->fStartId + 1);

    // Zero out wildcards.
    for (int i = 0; i < range->fAdvance.count(); ++i) {
        if (range->fAdvance[i] == kDontCareAdvance) {
            range->fAdvance[i] = 0;
        }
    }
}

static void FinishRange(
        AdvanceMetric* range,
        int endId,
        AdvanceMetric::MetricType type) {
    range->fEndId = endId;
    range->fType = type;
    stripUninterestingTrailingAdvancesFromRange(range);
    int newLength;
    if (type == AdvanceMetric::kRange) {
        newLength = range->fEndId - range->fStartId + 1;
    } else {
        if (range->fEndId == range->fStartId) {
            range->fType = AdvanceMetric::kRange;
        }
        newLength = 1;
    }
    SkASSERT(range->fAdvance.count() >= newLength);
    range->fAdvance.setCount(newLength);
    zeroWildcardsInRange(range);
}


/** Retrieve advance data for glyphs. Used by the PDF backend.
    @param num_glyphs    Total number of glyphs in the given font.
    @param glyphIDs      For per-glyph info, specify subset of the
                         font by giving glyph ids.  Each integer
                         represents a glyph id.  Passing nullptr
                         means all glyphs in the font.
    @param glyphIDsCount Number of elements in subsetGlyphIds.
                         Ignored if glyphIDs is nullptr.
*/
// TODO(halcanary): this function is complex enough to need its logic
// tested with unit tests.  On the other hand, I want to do another
// round of re-factoring before figuring out how to mock this.
// TODO(halcanary): this function should be combined with
// composeAdvanceData() so that we don't need to produce a linked list
// of intermediate values.  Or we could make the intermediate value
// something other than a linked list.
static void get_glyph_widths(SkSinglyLinkedList<AdvanceMetric>* glyphWidths,
                             int num_glyphs,
                             const uint32_t* subsetGlyphIDs,
                             uint32_t subsetGlyphIDsLength,
                             SkGlyphCache* glyphCache) {
    // Assuming that on average, the ASCII representation of an advance plus
    // a space is 8 characters and the ASCII representation of a glyph id is 3
    // characters, then the following cut offs for using different range types
    // apply:
    // The cost of stopping and starting the range is 7 characers
    //  a. Removing 4 0's or don't care's is a win
    // The cost of stopping and starting the range plus a run is 22
    // characters
    //  b. Removing 3 repeating advances is a win
    //  c. Removing 2 repeating advances and 3 don't cares is a win
    // When not currently in a range the cost of a run over a range is 16
    // characaters, so:
    //  d. Removing a leading 0/don't cares is a win because it is omitted
    //  e. Removing 2 repeating advances is a win

    AdvanceMetric* prevRange = nullptr;
    int16_t lastAdvance = kInvalidAdvance;
    int repeatedAdvances = 0;
    int wildCardsInRun = 0;
    int trailingWildCards = 0;
    uint32_t subsetIndex = 0;

    // Limit the loop count to glyph id ranges provided.
    int firstIndex = 0;
    int lastIndex = num_glyphs;
    if (subsetGlyphIDs) {
        firstIndex = static_cast<int>(subsetGlyphIDs[0]);
        lastIndex =
                static_cast<int>(subsetGlyphIDs[subsetGlyphIDsLength - 1]) + 1;
    }
    AdvanceMetric curRange(firstIndex);

    for (int gId = firstIndex; gId <= lastIndex; gId++) {
        int16_t advance = kInvalidAdvance;
        if (gId < lastIndex) {
            // Get glyph id only when subset is nullptr, or the id is in subset.
            SkASSERT(!subsetGlyphIDs || (subsetIndex < subsetGlyphIDsLength &&
                    static_cast<uint32_t>(gId) <= subsetGlyphIDs[subsetIndex]));
            if (!subsetGlyphIDs ||
                (subsetIndex < subsetGlyphIDsLength &&
                 static_cast<uint32_t>(gId) == subsetGlyphIDs[subsetIndex])) {
                advance = (int16_t)glyphCache->getGlyphIDAdvance(gId).fAdvanceX;
                ++subsetIndex;
            } else {
                advance = kDontCareAdvance;
            }
        }
        if (advance == lastAdvance) {
            repeatedAdvances++;
            trailingWildCards = 0;
        } else if (advance == kDontCareAdvance) {
            wildCardsInRun++;
            trailingWildCards++;
        } else if (curRange.fAdvance.count() ==
                   repeatedAdvances + 1 + wildCardsInRun) {  // All in run.
            if (lastAdvance == 0) {
                curRange.fStartId = gId;  // reset
                curRange.fAdvance.setCount(0);
                trailingWildCards = 0;
            } else if (repeatedAdvances + 1 >= 2 || trailingWildCards >= 4) {
                FinishRange(&curRange, gId - 1, AdvanceMetric::kRun);
                prevRange = glyphWidths->emplace_back(std::move(curRange));
                curRange = AdvanceMetric(gId);
                trailingWildCards = 0;
            }
            repeatedAdvances = 0;
            wildCardsInRun = trailingWildCards;
            trailingWildCards = 0;
        } else {
            if (lastAdvance == 0 &&
                    repeatedAdvances + 1 + wildCardsInRun >= 4) {
                FinishRange(&curRange,
                            gId - repeatedAdvances - wildCardsInRun - 2,
                            AdvanceMetric::kRange);
                prevRange = glyphWidths->emplace_back(std::move(curRange));
                curRange = AdvanceMetric(gId);
                trailingWildCards = 0;
            } else if (trailingWildCards >= 4 && repeatedAdvances + 1 < 2) {
                FinishRange(&curRange, gId - trailingWildCards - 1,
                            AdvanceMetric::kRange);
                prevRange = glyphWidths->emplace_back(std::move(curRange));
                curRange = AdvanceMetric(gId);
                trailingWildCards = 0;
            } else if (lastAdvance != 0 &&
                       (repeatedAdvances + 1 >= 3 ||
                        (repeatedAdvances + 1 >= 2 && wildCardsInRun >= 3))) {
                FinishRange(&curRange,
                            gId - repeatedAdvances - wildCardsInRun - 2,
                            AdvanceMetric::kRange);
                (void)glyphWidths->emplace_back(std::move(curRange));
                curRange =
                        AdvanceMetric(gId - repeatedAdvances - wildCardsInRun - 1);
                curRange.fAdvance.append(1, &lastAdvance);
                FinishRange(&curRange, gId - 1, AdvanceMetric::kRun);
                prevRange = glyphWidths->emplace_back(std::move(curRange));
                curRange = AdvanceMetric(gId);
                trailingWildCards = 0;
            }
            repeatedAdvances = 0;
            wildCardsInRun = trailingWildCards;
            trailingWildCards = 0;
        }
        curRange.fAdvance.append(1, &advance);
        if (advance != kDontCareAdvance) {
            lastAdvance = advance;
        }
    }
    if (curRange.fStartId == lastIndex) {
        if (!prevRange) {
            glyphWidths->reset();
            return;  // https://crbug.com/567031
        }
    } else {
        FinishRange(&curRange, lastIndex - 1, AdvanceMetric::kRange);
        glyphWidths->emplace_back(std::move(curRange));
    }
}

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


// scale from em-units to base-1000, returning as a SkScalar
SkScalar from_font_units(SkScalar scaled, uint16_t emSize) {
    if (emSize == 1000) {
        return scaled;
    } else {
        return SkScalarMulDiv(scaled, 1000, emSize);
    }
}

SkScalar scaleFromFontUnits(int16_t val, uint16_t emSize) {
    return from_font_units(SkIntToScalar(val), emSize);
}


void setGlyphWidthAndBoundingBox(SkScalar width, SkIRect box,
                                 SkWStream* content) {
    // Specify width and bounding box for the glyph.
    SkPDFUtils::AppendScalar(width, content);
    content->writeText(" 0 ");
    content->writeDecAsText(box.fLeft);
    content->writeText(" ");
    content->writeDecAsText(box.fTop);
    content->writeText(" ");
    content->writeDecAsText(box.fRight);
    content->writeText(" ");
    content->writeDecAsText(box.fBottom);
    content->writeText(" d1\n");
}

static sk_sp<SkPDFArray> makeFontBBox(SkIRect glyphBBox, uint16_t emSize) {
    auto bbox = sk_make_sp<SkPDFArray>();
    bbox->reserve(4);
    bbox->appendScalar(scaleFromFontUnits(glyphBBox.fLeft, emSize));
    bbox->appendScalar(scaleFromFontUnits(glyphBBox.fBottom, emSize));
    bbox->appendScalar(scaleFromFontUnits(glyphBBox.fRight, emSize));
    bbox->appendScalar(scaleFromFontUnits(glyphBBox.fTop, emSize));
    return bbox;
}

sk_sp<SkPDFArray> composeAdvanceData(
        const SkSinglyLinkedList<AdvanceMetric>& advanceInfo,
        uint16_t emSize,
        int16_t* defaultAdvance) {
    auto result = sk_make_sp<SkPDFArray>();
    for (const AdvanceMetric& range : advanceInfo) {
        switch (range.fType) {
            case AdvanceMetric::kDefault: {
                SkASSERT(range.fAdvance.count() == 1);
                *defaultAdvance = range.fAdvance[0];
                break;
            }
            case AdvanceMetric::kRange: {
                auto advanceArray = sk_make_sp<SkPDFArray>();
                for (int j = 0; j < range.fAdvance.count(); j++)
                    advanceArray->appendScalar(
                            scaleFromFontUnits(range.fAdvance[j], emSize));
                result->appendInt(range.fStartId);
                result->appendObject(std::move(advanceArray));
                break;
            }
            case AdvanceMetric::kRun: {
                SkASSERT(range.fAdvance.count() == 1);
                result->appendInt(range.fStartId);
                result->appendInt(range.fEndId);
                result->appendScalar(
                        scaleFromFontUnits(range.fAdvance[0], emSize));
                break;
            }
        }
    }
    return result;
}

}  // namespace


///////////////////////////////////////////////////////////////////////////////
// class SkPDFGlyphSet
///////////////////////////////////////////////////////////////////////////////

SkPDFGlyphSet::SkPDFGlyphSet() : fBitSet(SK_MaxU16 + 1) {
}

void SkPDFGlyphSet::set(const uint16_t* glyphIDs, int numGlyphs) {
    for (int i = 0; i < numGlyphs; ++i) {
        fBitSet.setBit(glyphIDs[i], true);
    }
}

bool SkPDFGlyphSet::has(uint16_t glyphID) const {
    return fBitSet.isBitSet(glyphID);
}

void SkPDFGlyphSet::exportTo(SkTDArray<unsigned int>* glyphIDs) const {
    fBitSet.exportTo(glyphIDs);
}

///////////////////////////////////////////////////////////////////////////////
// class SkPDFGlyphSetMap
///////////////////////////////////////////////////////////////////////////////

SkPDFGlyphSetMap::SkPDFGlyphSetMap() {}

SkPDFGlyphSetMap::~SkPDFGlyphSetMap() {
    fMap.reset();
}

void SkPDFGlyphSetMap::noteGlyphUsage(SkPDFFont* font, const uint16_t* glyphIDs,
                                      int numGlyphs) {
    SkPDFGlyphSet* subset = getGlyphSetForFont(font);
    if (subset) {
        subset->set(glyphIDs, numGlyphs);
    }
}

SkPDFGlyphSet* SkPDFGlyphSetMap::getGlyphSetForFont(SkPDFFont* font) {
    int index = fMap.count();
    for (int i = 0; i < index; ++i) {
        if (fMap[i].fFont == font) {
            return &fMap[i].fGlyphSet;
        }
    }
    FontGlyphSetPair& pair = fMap.push_back();
    pair.fFont = font;
    return &pair.fGlyphSet;
}

///////////////////////////////////////////////////////////////////////////////
// class SkPDFFont
///////////////////////////////////////////////////////////////////////////////

/* Font subset design: It would be nice to be able to subset fonts
 * (particularly type 3 fonts), but it's a lot of work and not a priority.
 *
 * Resources are canonicalized and uniqueified by pointer so there has to be
 * some additional state indicating which subset of the font is used.  It
 * must be maintained at the page granularity and then combined at the document
 * granularity. a) change SkPDFFont to fill in its state on demand, kind of
 * like SkPDFGraphicState.  b) maintain a per font glyph usage class in each
 * page/pdf device. c) in the document, retrieve the per font glyph usage
 * from each page and combine it and ask for a resource with that subset.
 */

SkPDFFont::~SkPDFFont() {}

SkTypeface* SkPDFFont::typeface() {
    return fTypeface.get();
}

SkAdvancedTypefaceMetrics::FontType SkPDFFont::getType() {
    return fFontType;
}

bool SkPDFFont::canEmbed() const {
    if (!fFontInfo.get()) {
        SkASSERT(fFontType == SkAdvancedTypefaceMetrics::kOther_Font);
        return true;
    }
    return (fFontInfo->fFlags &
            SkAdvancedTypefaceMetrics::kNotEmbeddable_FontFlag) == 0;
}

bool SkPDFFont::canSubset() const {
    if (!fFontInfo.get()) {
        SkASSERT(fFontType == SkAdvancedTypefaceMetrics::kOther_Font);
        return true;
    }
    return (fFontInfo->fFlags &
            SkAdvancedTypefaceMetrics::kNotSubsettable_FontFlag) == 0;
}

bool SkPDFFont::hasGlyph(uint16_t id) {
    return (id >= fFirstGlyphID && id <= fLastGlyphID) || id == 0;
}

int SkPDFFont::glyphsToPDFFontEncoding(uint16_t* glyphIDs, int numGlyphs) {
    // A font with multibyte glyphs will support all glyph IDs in a single font.
    if (this->multiByteGlyphs()) {
        return numGlyphs;
    }

    for (int i = 0; i < numGlyphs; i++) {
        if (glyphIDs[i] == 0) {
            continue;
        }
        if (glyphIDs[i] < fFirstGlyphID || glyphIDs[i] > fLastGlyphID) {
            return i;
        }
        glyphIDs[i] -= (fFirstGlyphID - 1);
    }

    return numGlyphs;
}

// static
SkPDFFont* SkPDFFont::GetFontResource(SkPDFCanon* canon,
                                      SkTypeface* typeface,
                                      uint16_t glyphID) {
    SkASSERT(canon);
    SkAutoResolveDefaultTypeface autoResolve(typeface);
    typeface = autoResolve.get();
    const uint32_t fontID = typeface->uniqueID();

    SkPDFFont* relatedFont;
    if (SkPDFFont* pdfFont = canon->findFont(fontID, glyphID, &relatedFont)) {
        return SkRef(pdfFont);
    }

    sk_sp<const SkAdvancedTypefaceMetrics> fontMetrics;
    SkPDFDict* relatedFontDescriptor = nullptr;
    if (relatedFont) {
        fontMetrics.reset(SkSafeRef(relatedFont->fontInfo()));
        relatedFontDescriptor = relatedFont->getFontDescriptor();

        // This only is to catch callers who pass invalid glyph ids.
        // If glyph id is invalid, then we will create duplicate entries
        // for TrueType fonts.
        SkAdvancedTypefaceMetrics::FontType fontType =
            fontMetrics.get() ? fontMetrics.get()->fType :
                                SkAdvancedTypefaceMetrics::kOther_Font;

        if (fontType == SkAdvancedTypefaceMetrics::kType1CID_Font ||
            fontType == SkAdvancedTypefaceMetrics::kTrueType_Font) {
            return SkRef(relatedFont);
        }
    } else {
        SkTypeface::PerGlyphInfo info =
            SkTBitOr(SkTypeface::kGlyphNames_PerGlyphInfo,
                     SkTypeface::kToUnicode_PerGlyphInfo);
        fontMetrics.reset(
            typeface->getAdvancedTypefaceMetrics(info, nullptr, 0));
    }

    SkPDFFont* font = SkPDFFont::Create(canon, fontMetrics.get(), typeface,
                                        glyphID, relatedFontDescriptor);
    canon->addFont(font, fontID, font->fFirstGlyphID);
    return font;
}

SkPDFFont* SkPDFFont::getFontSubset(const SkPDFGlyphSet*) {
    return nullptr;  // Default: no support.
}

SkPDFFont::SkPDFFont(const SkAdvancedTypefaceMetrics* info,
                     SkTypeface* typeface,
                     SkPDFDict* relatedFontDescriptor)
    : SkPDFDict("Font")
    , fTypeface(ref_or_default(typeface))
    , fFirstGlyphID(1)
    , fLastGlyphID(info ? info->fLastGlyphID : 0)
    , fFontInfo(SkSafeRef(info))
    , fDescriptor(SkSafeRef(relatedFontDescriptor)) {
    if (info == nullptr ||
            info->fFlags & SkAdvancedTypefaceMetrics::kMultiMaster_FontFlag) {
        fFontType = SkAdvancedTypefaceMetrics::kOther_Font;
    } else {
        fFontType = info->fType;
    }
}

// static
SkPDFFont* SkPDFFont::Create(SkPDFCanon* canon,
                             const SkAdvancedTypefaceMetrics* info,
                             SkTypeface* typeface,
                             uint16_t glyphID,
                             SkPDFDict* relatedFontDescriptor) {
    SkAdvancedTypefaceMetrics::FontType type =
        info ? info->fType : SkAdvancedTypefaceMetrics::kOther_Font;

    if (info && (info->fFlags & SkAdvancedTypefaceMetrics::kMultiMaster_FontFlag)) {
        return new SkPDFType3Font(info, typeface, glyphID);
    }
    if (type == SkAdvancedTypefaceMetrics::kType1CID_Font ||
        type == SkAdvancedTypefaceMetrics::kTrueType_Font) {
        SkASSERT(relatedFontDescriptor == nullptr);
        return new SkPDFType0Font(info, typeface);
    }
    if (type == SkAdvancedTypefaceMetrics::kType1_Font) {
        return new SkPDFType1Font(info, typeface, glyphID, relatedFontDescriptor);
    }

    SkASSERT(type == SkAdvancedTypefaceMetrics::kCFF_Font ||
             type == SkAdvancedTypefaceMetrics::kOther_Font);

    return new SkPDFType3Font(info, typeface, glyphID);
}

const SkAdvancedTypefaceMetrics* SkPDFFont::fontInfo() {
    return fFontInfo.get();
}

void SkPDFFont::setFontInfo(const SkAdvancedTypefaceMetrics* info) {
    if (info == nullptr || info == fFontInfo.get()) {
        return;
    }
    fFontInfo.reset(info);
    SkSafeRef(info);
}

uint16_t SkPDFFont::firstGlyphID() const {
    return fFirstGlyphID;
}

uint16_t SkPDFFont::lastGlyphID() const {
    return fLastGlyphID;
}

void SkPDFFont::setLastGlyphID(uint16_t glyphID) {
    fLastGlyphID = glyphID;
}

SkPDFDict* SkPDFFont::getFontDescriptor() {
    return fDescriptor.get();
}

void SkPDFFont::setFontDescriptor(SkPDFDict* descriptor) {
    fDescriptor.reset(descriptor);
    SkSafeRef(descriptor);
}

bool SkPDFFont::addCommonFontDescriptorEntries(int16_t defaultWidth) {
    if (fDescriptor.get() == nullptr) {
        return false;
    }

    const uint16_t emSize = fFontInfo->fEmSize;

    fDescriptor->insertName("FontName", fFontInfo->fFontName);
    fDescriptor->insertInt("Flags", fFontInfo->fStyle | kPdfSymbolic);
    fDescriptor->insertScalar("Ascent",
            scaleFromFontUnits(fFontInfo->fAscent, emSize));
    fDescriptor->insertScalar("Descent",
            scaleFromFontUnits(fFontInfo->fDescent, emSize));
    fDescriptor->insertScalar("StemV",
            scaleFromFontUnits(fFontInfo->fStemV, emSize));

    fDescriptor->insertScalar("CapHeight",
            scaleFromFontUnits(fFontInfo->fCapHeight, emSize));
    fDescriptor->insertInt("ItalicAngle", fFontInfo->fItalicAngle);
    fDescriptor->insertObject(
            "FontBBox", makeFontBBox(fFontInfo->fBBox, fFontInfo->fEmSize));

    if (defaultWidth > 0) {
        fDescriptor->insertScalar("MissingWidth",
                scaleFromFontUnits(defaultWidth, emSize));
    }
    return true;
}

void SkPDFFont::adjustGlyphRangeForSingleByteEncoding(uint16_t glyphID) {
    // Single byte glyph encoding supports a max of 255 glyphs.
    fFirstGlyphID = glyphID - (glyphID - 1) % 255;
    if (fLastGlyphID > fFirstGlyphID + 255 - 1) {
        fLastGlyphID = fFirstGlyphID + 255 - 1;
    }
}

void SkPDFFont::populateToUnicodeTable(const SkPDFGlyphSet* subset) {
    if (fFontInfo == nullptr || fFontInfo->fGlyphToUnicode.begin() == nullptr) {
        return;
    }
    this->insertObjRef("ToUnicode",
                       SkPDFMakeToUnicodeCmap(fFontInfo->fGlyphToUnicode,
                                              subset,
                                              multiByteGlyphs(),
                                              firstGlyphID(),
                                              lastGlyphID()));
}

///////////////////////////////////////////////////////////////////////////////
// class SkPDFType0Font
///////////////////////////////////////////////////////////////////////////////

SkPDFType0Font::SkPDFType0Font(const SkAdvancedTypefaceMetrics* info, SkTypeface* typeface)
    : SkPDFFont(info, typeface, nullptr) {
    SkDEBUGCODE(fPopulated = false);
    if (!canSubset()) {
        this->populate(nullptr);
    }
}

SkPDFType0Font::~SkPDFType0Font() {}

SkPDFFont* SkPDFType0Font::getFontSubset(const SkPDFGlyphSet* subset) {
    if (!canSubset()) {
        return nullptr;
    }
    SkPDFType0Font* newSubset = new SkPDFType0Font(fontInfo(), typeface());
    newSubset->populate(subset);
    return newSubset;
}

#ifdef SK_DEBUG
void SkPDFType0Font::emitObject(SkWStream* stream,
                                const SkPDFObjNumMap& objNumMap,
                                const SkPDFSubstituteMap& substitutes) const {
    SkASSERT(fPopulated);
    return INHERITED::emitObject(stream, objNumMap, substitutes);
}
#endif

bool SkPDFType0Font::populate(const SkPDFGlyphSet* subset) {
    insertName("Subtype", "Type0");
    insertName("BaseFont", fontInfo()->fFontName);
    insertName("Encoding", "Identity-H");

    sk_sp<SkPDFCIDFont> newCIDFont(
            new SkPDFCIDFont(fontInfo(), typeface(), subset));
    auto descendantFonts = sk_make_sp<SkPDFArray>();
    descendantFonts->appendObjRef(std::move(newCIDFont));
    this->insertObject("DescendantFonts", std::move(descendantFonts));

    this->populateToUnicodeTable(subset);

    SkDEBUGCODE(fPopulated = true);
    return true;
}

///////////////////////////////////////////////////////////////////////////////
// class SkPDFCIDFont
///////////////////////////////////////////////////////////////////////////////

SkPDFCIDFont::SkPDFCIDFont(const SkAdvancedTypefaceMetrics* info,
                           SkTypeface* typeface,
                           const SkPDFGlyphSet* subset)
    : SkPDFFont(info, typeface, nullptr) {
    this->populate(subset);
}

SkPDFCIDFont::~SkPDFCIDFont() {}

#ifdef SK_SFNTLY_SUBSETTER
// if possible, make no copy.
static sk_sp<SkData> stream_to_data(std::unique_ptr<SkStreamAsset> stream) {
    SkASSERT(stream);
    (void)stream->rewind();
    SkASSERT(stream->hasLength());
    size_t size = stream->getLength();
    if (const void* base = stream->getMemoryBase()) {
        SkData::ReleaseProc proc =
            [](const void*, void* ctx) { delete (SkStream*)ctx; };
        return SkData::MakeWithProc(base, size, proc, stream.release());
    }
    return SkData::MakeFromStream(stream.get(), size);
}

static sk_sp<SkPDFObject> get_subset_font_stream(
        std::unique_ptr<SkStreamAsset> fontAsset,
        const SkTDArray<uint32_t>& subset,
        const char* fontName) {
    // sfntly requires unsigned int* to be passed in,
    // as far as we know, unsigned int is equivalent
    // to uint32_t on all platforms.
    static_assert(sizeof(unsigned) == sizeof(uint32_t), "");

    // TODO(halcanary): Use ttcIndex, not fontName.

    unsigned char* subsetFont{nullptr};
    int subsetFontSize{0};
    {
        sk_sp<SkData> fontData(stream_to_data(std::move(fontAsset)));
        subsetFontSize =
            SfntlyWrapper::SubsetFont(fontName,
                                      fontData->bytes(),
                                      fontData->size(),
                                      subset.begin(),
                                      subset.count(),
                                      &subsetFont);
    }
    SkASSERT(subsetFontSize > 0 || subsetFont == nullptr);
    if (subsetFontSize < 1) {
        return nullptr;
    }
    SkASSERT(subsetFont != nullptr);
    auto subsetStream = sk_make_sp<SkPDFStream>(
            SkData::MakeWithProc(
                    subsetFont, subsetFontSize,
                    [](const void* p, void*) { delete[] (unsigned char*)p; },
                    nullptr));
    subsetStream->dict()->insertInt("Length1", subsetFontSize);
    return subsetStream;
}
#endif  // SK_SFNTLY_SUBSETTER

bool SkPDFCIDFont::addFontDescriptor(int16_t defaultWidth,
                                     const SkTDArray<uint32_t>* subset) {
    auto descriptor = sk_make_sp<SkPDFDict>("FontDescriptor");
    setFontDescriptor(descriptor.get());
    if (!addCommonFontDescriptorEntries(defaultWidth)) {
        this->insertObjRef("FontDescriptor", std::move(descriptor));
        return false;
    }
    SkASSERT(this->canEmbed());

    switch (getType()) {
        case SkAdvancedTypefaceMetrics::kTrueType_Font: {
            int ttcIndex;
            std::unique_ptr<SkStreamAsset> fontAsset(
                    this->typeface()->openStream(&ttcIndex));
            SkASSERT(fontAsset);
            if (!fontAsset) {
                return false;
            }
            size_t fontSize = fontAsset->getLength();
            SkASSERT(fontSize > 0);
            if (fontSize == 0) {
                return false;
            }

            #ifdef SK_SFNTLY_SUBSETTER
            if (this->canSubset() && subset) {
                sk_sp<SkPDFObject> subsetStream = get_subset_font_stream(
                        std::move(fontAsset), *subset, fontInfo()->fFontName.c_str());
                if (subsetStream) {
                    descriptor->insertObjRef("FontFile2", std::move(subsetStream));
                    break;
                }
                // If subsetting fails, fall back to original font data.
                fontAsset.reset(this->typeface()->openStream(&ttcIndex));
            }
            #endif  // SK_SFNTLY_SUBSETTER
            auto fontStream = sk_make_sp<SkPDFSharedStream>(std::move(fontAsset));
            fontStream->dict()->insertInt("Length1", fontSize);
            descriptor->insertObjRef("FontFile2", std::move(fontStream));
            break;
        }
        case SkAdvancedTypefaceMetrics::kCFF_Font:
        case SkAdvancedTypefaceMetrics::kType1CID_Font: {
            std::unique_ptr<SkStreamAsset> fontData(
                    this->typeface()->openStream(nullptr));
            SkASSERT(fontData);
            SkASSERT(fontData->getLength() > 0);
            if (!fontData || 0 == fontData->getLength()) {
                return false;
            }
            auto fontStream = sk_make_sp<SkPDFSharedStream>(std::move(fontData));
            if (getType() == SkAdvancedTypefaceMetrics::kCFF_Font) {
                fontStream->dict()->insertName("Subtype", "Type1C");
            } else {
                fontStream->dict()->insertName("Subtype", "CIDFontType0c");
            }
            descriptor->insertObjRef("FontFile3", std::move(fontStream));
            break;
        }
        default:
            SkASSERT(false);
    }
    this->insertObjRef("FontDescriptor", std::move(descriptor));
    return true;
}

void set_glyph_widths(SkTypeface* tf,
                      const SkTDArray<uint32_t>* glyphIDs,
                      SkSinglyLinkedList<AdvanceMetric>* dst) {
    SkPaint tmpPaint;
    tmpPaint.setHinting(SkPaint::kNo_Hinting);
    tmpPaint.setTypeface(sk_ref_sp(tf));
    tmpPaint.setTextSize((SkScalar)tf->getUnitsPerEm());
    SkAutoGlyphCache autoGlyphCache(tmpPaint, nullptr, nullptr);
    if (!glyphIDs || glyphIDs->isEmpty()) {
        get_glyph_widths(dst, tf->countGlyphs(), nullptr, 0, autoGlyphCache.get());
    } else {
        get_glyph_widths(dst, tf->countGlyphs(), glyphIDs->begin(),
                         glyphIDs->count(), autoGlyphCache.get());
    }
}

sk_sp<const SkAdvancedTypefaceMetrics> SkPDFFont::GetFontMetricsWithGlyphNames(
        SkTypeface* typeface, uint32_t* glyphs, uint32_t glyphsCount) {
    return sk_sp<const SkAdvancedTypefaceMetrics>(
            typeface->getAdvancedTypefaceMetrics(
                    SkTypeface::kGlyphNames_PerGlyphInfo, glyphs, glyphsCount));
}

sk_sp<const SkAdvancedTypefaceMetrics> SkPDFFont::GetFontMetricsWithToUnicode(
        SkTypeface* typeface, uint32_t* glyphs, uint32_t glyphsCount) {
    return sk_sp<const SkAdvancedTypefaceMetrics>(
            typeface->getAdvancedTypefaceMetrics(
                    SkTypeface::kToUnicode_PerGlyphInfo, glyphs, glyphsCount));
}

bool SkPDFCIDFont::populate(const SkPDFGlyphSet* subset) {
    // Generate new font metrics with advance info for true type fonts.
    // Generate glyph id array.
    SkTDArray<uint32_t> glyphIDs;
    if (subset) {
        if (!subset->has(0)) {
            glyphIDs.push(0);  // Always include glyph 0.
        }
        subset->exportTo(&glyphIDs);
    }
    if (fontInfo()->fType == SkAdvancedTypefaceMetrics::kTrueType_Font) {
        uint32_t* glyphs = (glyphIDs.count() == 0) ? nullptr : glyphIDs.begin();
        uint32_t glyphsCount = glyphs ? glyphIDs.count() : 0;
        sk_sp<const SkAdvancedTypefaceMetrics> fontMetrics =
            SkPDFFont::GetFontMetricsWithGlyphNames(this->typeface(), glyphs, glyphsCount);
        this->setFontInfo(fontMetrics.get());
        this->addFontDescriptor(0, &glyphIDs);
    } else {
        // Other CID fonts
        addFontDescriptor(0, nullptr);
    }

    insertName("BaseFont", fontInfo()->fFontName);

    if (getType() == SkAdvancedTypefaceMetrics::kType1CID_Font) {
        insertName("Subtype", "CIDFontType0");
    } else if (getType() == SkAdvancedTypefaceMetrics::kTrueType_Font) {
        insertName("Subtype", "CIDFontType2");
        insertName("CIDToGIDMap", "Identity");
    } else {
        SkASSERT(false);
    }

    auto sysInfo = sk_make_sp<SkPDFDict>();
    sysInfo->insertString("Registry", "Adobe");
    sysInfo->insertString("Ordering", "Identity");
    sysInfo->insertInt("Supplement", 0);
    this->insertObject("CIDSystemInfo", std::move(sysInfo));

    SkSinglyLinkedList<AdvanceMetric> tmpMetrics;
    set_glyph_widths(this->typeface(), &glyphIDs, &tmpMetrics);
    int16_t defaultWidth = 0;
    uint16_t emSize = (uint16_t)this->fontInfo()->fEmSize;
    sk_sp<SkPDFArray> widths = composeAdvanceData(tmpMetrics, emSize, &defaultWidth);
    if (widths->size()) {
        this->insertObject("W", std::move(widths));
    }

    this->insertScalar(
            "DW", scaleFromFontUnits(defaultWidth, emSize));
    return true;
}

///////////////////////////////////////////////////////////////////////////////
// class SkPDFType1Font
///////////////////////////////////////////////////////////////////////////////

SkPDFType1Font::SkPDFType1Font(const SkAdvancedTypefaceMetrics* info,
                               SkTypeface* typeface,
                               uint16_t glyphID,
                               SkPDFDict* relatedFontDescriptor)
    : SkPDFFont(info, typeface, relatedFontDescriptor) {
    this->populate(glyphID);
}

SkPDFType1Font::~SkPDFType1Font() {}

bool SkPDFType1Font::addFontDescriptor(int16_t defaultWidth) {
    if (SkPDFDict* descriptor = getFontDescriptor()) {
        this->insertObjRef("FontDescriptor",
                           sk_ref_sp(descriptor));
        return true;
    }

    auto descriptor = sk_make_sp<SkPDFDict>("FontDescriptor");
    setFontDescriptor(descriptor.get());

    int ttcIndex;
    size_t header SK_INIT_TO_AVOID_WARNING;
    size_t data SK_INIT_TO_AVOID_WARNING;
    size_t trailer SK_INIT_TO_AVOID_WARNING;
    std::unique_ptr<SkStreamAsset> rawFontData(typeface()->openStream(&ttcIndex));
    sk_sp<SkData> fontData = SkPDFConvertType1FontStream(std::move(rawFontData),
                                                         &header, &data, &trailer);
    if (!fontData) {
        return false;
    }
    SkASSERT(this->canEmbed());
    auto fontStream = sk_make_sp<SkPDFStream>(std::move(fontData));
    fontStream->dict()->insertInt("Length1", header);
    fontStream->dict()->insertInt("Length2", data);
    fontStream->dict()->insertInt("Length3", trailer);
    descriptor->insertObjRef("FontFile", std::move(fontStream));

    this->insertObjRef("FontDescriptor", std::move(descriptor));

    return addCommonFontDescriptorEntries(defaultWidth);
}

bool SkPDFType1Font::populate(int16_t glyphID) {
    this->insertName("Subtype", "Type1");
    this->insertName("BaseFont", fontInfo()->fFontName);
    adjustGlyphRangeForSingleByteEncoding(glyphID);
    SkGlyphID firstGlyphID = this->firstGlyphID();
    SkGlyphID lastGlyphID = this->lastGlyphID();

    // glyphCount not including glyph 0
    unsigned glyphCount = 1 + lastGlyphID - firstGlyphID;
    SkASSERT(glyphCount > 0 && glyphCount <= 255);
    this->insertInt("FirstChar", (size_t)0);
    this->insertInt("LastChar", (size_t)glyphCount);
    {
        SkPaint tmpPaint;
        tmpPaint.setHinting(SkPaint::kNo_Hinting);
        tmpPaint.setTypeface(sk_ref_sp(this->typeface()));
        tmpPaint.setTextSize((SkScalar)this->typeface()->getUnitsPerEm());
        SkAutoGlyphCache glyphCache(tmpPaint, nullptr, nullptr);
        auto widths = sk_make_sp<SkPDFArray>();
        SkScalar advance = glyphCache->getGlyphIDAdvance(0).fAdvanceX;
        const uint16_t emSize = this->fontInfo()->fEmSize;
        widths->appendScalar(from_font_units(advance, emSize));
        for (unsigned gID = firstGlyphID; gID <= lastGlyphID; gID++) {
            advance = glyphCache->getGlyphIDAdvance(gID).fAdvanceX;
            widths->appendScalar(from_font_units(advance, emSize));
        }
        this->insertObject("Widths", std::move(widths));
    }
    if (!addFontDescriptor(0)) {
        return false;
    }
    auto encDiffs = sk_make_sp<SkPDFArray>();
    encDiffs->reserve(lastGlyphID - firstGlyphID + 3);
    encDiffs->appendInt(0);
    const SkTArray<SkString>& glyphNames = this->fontInfo()->fGlyphNames;
    SkASSERT(glyphNames.count() > lastGlyphID);
    encDiffs->appendName(glyphNames[0].c_str());
    const SkString unknown("UNKNOWN");
    for (int gID = firstGlyphID; gID <= lastGlyphID; gID++) {
        const bool valid = gID < glyphNames.count() && !glyphNames[gID].isEmpty();
        const SkString& name = valid ? glyphNames[gID] : unknown;
        encDiffs->appendName(name);
    }

    auto encoding = sk_make_sp<SkPDFDict>("Encoding");
    encoding->insertObject("Differences", std::move(encDiffs));
    this->insertObject("Encoding", std::move(encoding));
    return true;
}

///////////////////////////////////////////////////////////////////////////////
// class SkPDFType3Font
///////////////////////////////////////////////////////////////////////////////

SkPDFType3Font::SkPDFType3Font(const SkAdvancedTypefaceMetrics* info,
                               SkTypeface* typeface,
                               uint16_t glyphID)
    : SkPDFFont(info, typeface, nullptr) {
    this->populate(glyphID);
}

SkPDFType3Font::~SkPDFType3Font() {}

bool SkPDFType3Font::populate(uint16_t glyphID) {
    SkPaint paint;
    paint.setTypeface(sk_ref_sp(this->typeface()));
    paint.setTextSize(1000);
    const SkSurfaceProps props(0, kUnknown_SkPixelGeometry);
    SkAutoGlyphCache autoCache(paint, &props, nullptr);
    SkGlyphCache* cache = autoCache.getCache();
    // If fLastGlyphID isn't set (because there is not fFontInfo), look it up.
    if (lastGlyphID() == 0) {
        setLastGlyphID(cache->getGlyphCount() - 1);
    }

    adjustGlyphRangeForSingleByteEncoding(glyphID);

    insertName("Subtype", "Type3");
    // Flip about the x-axis and scale by 1/1000.
    SkMatrix fontMatrix;
    fontMatrix.setScale(SkScalarInvert(1000), -SkScalarInvert(1000));
    this->insertObject("FontMatrix", SkPDFUtils::MatrixToArray(fontMatrix));

    auto charProcs = sk_make_sp<SkPDFDict>();
    auto encoding = sk_make_sp<SkPDFDict>("Encoding");

    auto encDiffs = sk_make_sp<SkPDFArray>();
    encDiffs->reserve(lastGlyphID() - firstGlyphID() + 2);
    encDiffs->appendInt(1);

    auto widthArray = sk_make_sp<SkPDFArray>();

    SkIRect bbox = SkIRect::MakeEmpty();
    for (int gID = firstGlyphID(); gID <= lastGlyphID(); gID++) {
        SkString characterName;
        characterName.printf("gid%d", gID);
        encDiffs->appendName(characterName.c_str());

        const SkGlyph& glyph = cache->getGlyphIDMetrics(gID);
        widthArray->appendScalar(SkFloatToScalar(glyph.fAdvanceX));
        SkIRect glyphBBox = SkIRect::MakeXYWH(glyph.fLeft, glyph.fTop,
                                              glyph.fWidth, glyph.fHeight);
        bbox.join(glyphBBox);

        SkDynamicMemoryWStream content;
        setGlyphWidthAndBoundingBox(SkFloatToScalar(glyph.fAdvanceX), glyphBBox,
                                    &content);
        const SkPath* path = cache->findPath(glyph);
        if (path) {
            SkPDFUtils::EmitPath(*path, paint.getStyle(), &content);
            SkPDFUtils::PaintPath(paint.getStyle(), path->getFillType(),
                                  &content);
        }
        charProcs->insertObjRef(
                characterName, sk_make_sp<SkPDFStream>(
                        std::unique_ptr<SkStreamAsset>(content.detachAsStream())));
    }

    encoding->insertObject("Differences", std::move(encDiffs));

    this->insertObject("CharProcs", std::move(charProcs));
    this->insertObject("Encoding", std::move(encoding));

    this->insertObject("FontBBox", makeFontBBox(bbox, 1000));
    this->insertInt("FirstChar", 1);
    this->insertInt("LastChar", lastGlyphID() - firstGlyphID() + 1);
    this->insertObject("Widths", std::move(widthArray));
    this->insertName("CIDToGIDMap", "Identity");

    this->populateToUnicodeTable(nullptr);
    return true;
}

SkPDFFont::Match SkPDFFont::IsMatch(SkPDFFont* existingFont,
                                    uint32_t existingFontID,
                                    uint16_t existingGlyphID,
                                    uint32_t searchFontID,
                                    uint16_t searchGlyphID) {
    if (existingFontID != searchFontID) {
        return SkPDFFont::kNot_Match;
    }
    if (existingGlyphID == 0 || searchGlyphID == 0) {
        return SkPDFFont::kExact_Match;
    }
    if (existingFont != nullptr) {
        return (existingFont->fFirstGlyphID <= searchGlyphID &&
                searchGlyphID <= existingFont->fLastGlyphID)
                       ? SkPDFFont::kExact_Match
                       : SkPDFFont::kRelated_Match;
    }
    return (existingGlyphID == searchGlyphID) ? SkPDFFont::kExact_Match
                                              : SkPDFFont::kRelated_Match;
}

//  Since getAdvancedTypefaceMetrics is expensive, cache the result.
bool SkPDFFont::CanEmbedTypeface(SkTypeface* typeface, SkPDFCanon* canon) {
    SkAutoResolveDefaultTypeface face(typeface);
    uint32_t id = face->uniqueID();
    if (bool* value = canon->fCanEmbedTypeface.find(id)) {
        return *value;
    }
    bool canEmbed = true;
    sk_sp<const SkAdvancedTypefaceMetrics> fontMetrics(
            face->getAdvancedTypefaceMetrics(
                    SkTypeface::kNo_PerGlyphInfo, nullptr, 0));
    if (fontMetrics) {
        canEmbed = !SkToBool(
                fontMetrics->fFlags &
                SkAdvancedTypefaceMetrics::kNotEmbeddable_FontFlag);
    }
    return *canon->fCanEmbedTypeface.set(id, canEmbed);
}

void SkPDFFont::drop() {
    fTypeface = nullptr;
    fFontInfo = nullptr;
    fDescriptor = nullptr;
    this->SkPDFDict::drop();
}