src/pdf/SkPDFSubsetFont.cpp

// Copyright 2018 Google LLC.
// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.

#include "SkPDFSubsetFont.h"

#if defined(SK_PDF_USE_SFNTLY)

#if defined(SK_USING_THIRD_PARTY_ICU)
#include "SkLoadICU.h"
#endif

#include "sample/chromium/font_subsetter.h"
#include <vector>

sk_sp<SkData> SkPDFSubsetFont(sk_sp<SkData> fontData,
                              const SkPDFGlyphUse& glyphUsage,
                              const char* fontName,
                              int ttcIndex) {
#if defined(SK_USING_THIRD_PARTY_ICU)
    if (!SkLoadICU()) {
        return nullptr;
    }
#endif
    // Generate glyph id array in format needed by sfntly.
    // TODO(halcanary): sfntly should take a more compact format.
    std::vector<unsigned> subset;
    if (!glyphUsage.has(0)) {
        subset.push_back(0);  // Always include glyph 0.
    }
    glyphUsage.getSetValues([&subset](unsigned v) { subset.push_back(v); });

    unsigned char* subsetFont{nullptr};
#if defined(SK_BUILD_FOR_GOOGLE3)
    // TODO(halcanary): update SK_BUILD_FOR_GOOGLE3 to newest version of Sfntly.
    (void)ttcIndex;
    int subsetFontSize = SfntlyWrapper::SubsetFont(fontName,
                                                   fontData->bytes(),
                                                   fontData->size(),
                                                   subset.data(),
                                                   subset.size(),
                                                   &subsetFont);
#else
    (void)fontName;
    int subsetFontSize = SfntlyWrapper::SubsetFont(ttcIndex,
                                                   fontData->bytes(),
                                                   fontData->size(),
                                                   subset.data(),
                                                   subset.size(),
                                                   &subsetFont);
#endif
    SkASSERT(subsetFontSize > 0 || subsetFont == nullptr);
    if (subsetFontSize < 1 || subsetFont == nullptr) {
        return nullptr;
    }
    return SkData::MakeWithProc(subsetFont, subsetFontSize,
                                [](const void* p, void*) { delete[] (unsigned char*)p; },
                                nullptr);
}
#endif