third_party/txt/src/minikin/FontFamily.cpp

/*
 * Copyright (C) 2013 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#define LOG_TAG "Minikin"

#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#include <log/log.h>
#include <utils/JenkinsHash.h>

#include <hb-ot.h>
#include <hb.h>

#include <minikin/CmapCoverage.h>
#include <minikin/FontFamily.h>
#include <minikin/MinikinFont.h>
#include "FontLanguage.h"
#include "FontLanguageListCache.h"
#include "FontUtils.h"
#include "HbFontCache.h"
#include "MinikinInternal.h"

using std::vector;

namespace minikin {

FontStyle::FontStyle(int variant, int weight, bool italic)
    : FontStyle(FontLanguageListCache::kEmptyListId, variant, weight, italic) {}

FontStyle::FontStyle(uint32_t languageListId,
                     int variant,
                     int weight,
                     bool italic)
    : bits(pack(variant, weight, italic)), mLanguageListId(languageListId) {}

android::hash_t FontStyle::hash() const {
  uint32_t hash = android::JenkinsHashMix(0, bits);
  hash = android::JenkinsHashMix(hash, mLanguageListId);
  return android::JenkinsHashWhiten(hash);
}

// static
uint32_t FontStyle::registerLanguageList(const std::string& languages) {
  std::scoped_lock _l(gMinikinLock);
  return FontLanguageListCache::getId(languages);
}

// static
uint32_t FontStyle::pack(int variant, int weight, bool italic) {
  return (weight & kWeightMask) | (italic ? kItalicMask : 0) |
         (variant << kVariantShift);
}

Font::Font(const std::shared_ptr<MinikinFont>& typeface, FontStyle style)
    : typeface(typeface), style(style) {}

Font::Font(std::shared_ptr<MinikinFont>&& typeface, FontStyle style)
    : typeface(typeface), style(style) {}

std::unordered_set<AxisTag> Font::getSupportedAxesLocked() const {
  const uint32_t fvarTag = MinikinFont::MakeTag('f', 'v', 'a', 'r');
  HbBlob fvarTable(getFontTable(typeface.get(), fvarTag));
  if (fvarTable.size() == 0) {
    return std::unordered_set<AxisTag>();
  }

  std::unordered_set<AxisTag> supportedAxes;
  analyzeAxes(fvarTable.get(), fvarTable.size(), &supportedAxes);
  return supportedAxes;
}

Font::Font(Font&& o) {
  typeface = std::move(o.typeface);
  style = o.style;
  o.typeface = nullptr;
}

Font::Font(const Font& o) {
  typeface = o.typeface;
  style = o.style;
}

// static
FontFamily::FontFamily(std::vector<Font>&& fonts)
    : FontFamily(0 /* variant */, std::move(fonts)) {}

FontFamily::FontFamily(int variant, std::vector<Font>&& fonts)
    : FontFamily(FontLanguageListCache::kEmptyListId,
                 variant,
                 std::move(fonts)) {}

FontFamily::FontFamily(uint32_t langId, int variant, std::vector<Font>&& fonts)
    : mLangId(langId),
      mVariant(variant),
      mFonts(std::move(fonts)),
      mHasVSTable(false) {
  computeCoverage();
}

bool FontFamily::analyzeStyle(const std::shared_ptr<MinikinFont>& typeface,
                              int* weight,
                              bool* italic) {
  std::scoped_lock _l(gMinikinLock);
  const uint32_t os2Tag = MinikinFont::MakeTag('O', 'S', '/', '2');
  HbBlob os2Table(getFontTable(typeface.get(), os2Tag));
  if (os2Table.get() == nullptr)
    return false;
  return ::minikin::analyzeStyle(os2Table.get(), os2Table.size(), weight,
                                 italic);
}

// Compute a matching metric between two styles - 0 is an exact match
static int computeMatch(FontStyle style1, FontStyle style2) {
  if (style1 == style2)
    return 0;
  int score = abs(style1.getWeight() - style2.getWeight());
  if (style1.getItalic() != style2.getItalic()) {
    score += 2;
  }
  return score;
}

static FontFakery computeFakery(FontStyle wanted, FontStyle actual) {
  // If desired weight is semibold or darker, and 2 or more grades
  // higher than actual (for example, medium 500 -> bold 700), then
  // select fake bold.
  int wantedWeight = wanted.getWeight();
  bool isFakeBold =
      wantedWeight >= 6 && (wantedWeight - actual.getWeight()) >= 2;
  bool isFakeItalic = wanted.getItalic() && !actual.getItalic();
  return FontFakery(isFakeBold, isFakeItalic);
}

FakedFont FontFamily::getClosestMatch(FontStyle style) const {
  const Font* bestFont = nullptr;
  int bestMatch = 0;
  for (size_t i = 0; i < mFonts.size(); i++) {
    const Font& font = mFonts[i];
    int match = computeMatch(font.style, style);
    if (i == 0 || match < bestMatch) {
      bestFont = &font;
      bestMatch = match;
    }
  }
  if (bestFont != nullptr) {
    return FakedFont{bestFont->typeface.get(),
                     computeFakery(style, bestFont->style)};
  }
  return FakedFont{nullptr, FontFakery()};
}

bool FontFamily::isColorEmojiFamily() const {
  const FontLanguages& languageList = FontLanguageListCache::getById(mLangId);
  for (size_t i = 0; i < languageList.size(); ++i) {
    if (languageList[i].getEmojiStyle() == FontLanguage::EMSTYLE_EMOJI) {
      return true;
    }
  }
  return false;
}

void FontFamily::computeCoverage() {
  std::scoped_lock _l(gMinikinLock);
  const FontStyle defaultStyle;
  const MinikinFont* typeface = getClosestMatch(defaultStyle).font;
  const uint32_t cmapTag = MinikinFont::MakeTag('c', 'm', 'a', 'p');
  HbBlob cmapTable(getFontTable(typeface, cmapTag));
  if (cmapTable.get() == nullptr) {
    ALOGE("Could not get cmap table size!\n");
    return;
  }
  mCoverage = CmapCoverage::getCoverage(cmapTable.get(), cmapTable.size(),
                                        &mHasVSTable);

  for (size_t i = 0; i < mFonts.size(); ++i) {
    std::unordered_set<AxisTag> supportedAxes =
        mFonts[i].getSupportedAxesLocked();
    mSupportedAxes.insert(supportedAxes.begin(), supportedAxes.end());
  }
}

bool FontFamily::hasGlyph(uint32_t codepoint,
                          uint32_t variationSelector) const {
  assertMinikinLocked();
  if (variationSelector != 0 && !mHasVSTable) {
    // Early exit if the variation selector is specified but the font doesn't
    // have a cmap format 14 subtable.
    return false;
  }

  const FontStyle defaultStyle;
  hb_font_t* font = getHbFontLocked(getClosestMatch(defaultStyle).font);
  uint32_t unusedGlyph;
  bool result =
      hb_font_get_glyph(font, codepoint, variationSelector, &unusedGlyph);
  hb_font_destroy(font);
  return result;
}

std::shared_ptr<FontFamily> FontFamily::createFamilyWithVariation(
    const std::vector<FontVariation>& variations) const {
  if (variations.empty() || mSupportedAxes.empty()) {
    return nullptr;
  }

  bool hasSupportedAxis = false;
  for (const FontVariation& variation : variations) {
    if (mSupportedAxes.find(variation.axisTag) != mSupportedAxes.end()) {
      hasSupportedAxis = true;
      break;
    }
  }
  if (!hasSupportedAxis) {
    // None of variation axes are suppored by this family.
    return nullptr;
  }

  std::vector<Font> fonts;
  for (const Font& font : mFonts) {
    bool supportedVariations = false;
    std::scoped_lock _l(gMinikinLock);
    std::unordered_set<AxisTag> supportedAxes = font.getSupportedAxesLocked();
    if (!supportedAxes.empty()) {
      for (const FontVariation& variation : variations) {
        if (supportedAxes.find(variation.axisTag) != supportedAxes.end()) {
          supportedVariations = true;
          break;
        }
      }
    }
    std::shared_ptr<MinikinFont> minikinFont;
    if (supportedVariations) {
      minikinFont = font.typeface->createFontWithVariation(variations);
    }
    if (minikinFont == nullptr) {
      minikinFont = font.typeface;
    }
    fonts.push_back(Font(std::move(minikinFont), font.style));
  }

  return std::shared_ptr<FontFamily>(
      new FontFamily(mLangId, mVariant, std::move(fonts)));
}

}  // namespace minikin