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/*
* Copyright (C) 2021 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 "minikin/Font.h"
#include <hb-ot.h>
#include <hb.h>
#include <log/log.h>
#include <vector>
#include "FontUtils.h"
#include "LocaleListCache.h"
#include "MinikinInternal.h"
#include "minikin/HbUtils.h"
#include "minikin/MinikinFont.h"
#include "minikin/MinikinFontFactory.h"
namespace minikin {
std::shared_ptr<Font> Font::Builder::build() {
if (mIsWeightSet && mIsSlantSet) {
// No need to read OS/2 header of the font file.
return std::shared_ptr<Font>(new Font(std::move(mTypeface), FontStyle(mWeight, mSlant),
prepareFont(mTypeface), mLocaleListId));
}
HbFontUniquePtr font = prepareFont(mTypeface);
FontStyle styleFromFont = analyzeStyle(font);
if (!mIsWeightSet) {
mWeight = styleFromFont.weight();
}
if (!mIsSlantSet) {
mSlant = styleFromFont.slant();
}
return std::shared_ptr<Font>(new Font(std::move(mTypeface), FontStyle(mWeight, mSlant),
std::move(font), mLocaleListId));
}
Font::Font(BufferReader* reader) : mExternalRefsHolder(nullptr), mTypefaceMetadataReader(nullptr) {
mStyle = FontStyle(reader);
mLocaleListId = LocaleListCache::readFrom(reader);
mTypefaceMetadataReader = *reader;
MinikinFontFactory::getInstance().skip(reader);
}
void Font::writeTo(BufferWriter* writer) const {
mStyle.writeTo(writer);
LocaleListCache::writeTo(writer, mLocaleListId);
MinikinFontFactory::getInstance().write(writer, typeface().get());
}
Font::Font(Font&& o) noexcept
: mStyle(o.mStyle),
mLocaleListId(o.mLocaleListId),
mTypefaceMetadataReader(o.mTypefaceMetadataReader) {
mExternalRefsHolder.store(o.mExternalRefsHolder.exchange(nullptr));
}
Font& Font::operator=(Font&& o) noexcept {
resetExternalRefs(o.mExternalRefsHolder.exchange(nullptr));
mStyle = o.mStyle;
mLocaleListId = o.mLocaleListId;
mTypefaceMetadataReader = o.mTypefaceMetadataReader;
return *this;
}
Font::~Font() {
resetExternalRefs(nullptr);
}
void Font::resetExternalRefs(ExternalRefs* refs) {
ExternalRefs* oldRefs = mExternalRefsHolder.exchange(refs);
if (oldRefs != nullptr) {
delete oldRefs;
}
}
const std::shared_ptr<MinikinFont>& Font::typeface() const {
return getExternalRefs()->mTypeface;
}
const HbFontUniquePtr& Font::baseFont() const {
return getExternalRefs()->mBaseFont;
}
const Font::ExternalRefs* Font::getExternalRefs() const {
// Thread safety note: getExternalRefs() is thread-safe.
// getExternalRefs() returns the first ExternalRefs set to mExternalRefsHolder.
// When multiple threads called getExternalRefs() at the same time and
// mExternalRefsHolder is not set, multiple ExternalRefs may be created,
// but only one ExternalRefs will be set to mExternalRefsHolder and
// others will be deleted.
Font::ExternalRefs* externalRefs = mExternalRefsHolder.load();
if (externalRefs) return externalRefs;
// mExternalRefsHolder is null. Try creating an ExternalRefs.
std::shared_ptr<MinikinFont> typeface =
MinikinFontFactory::getInstance().create(mTypefaceMetadataReader);
HbFontUniquePtr font = prepareFont(typeface);
Font::ExternalRefs* newExternalRefs =
new Font::ExternalRefs(std::move(typeface), std::move(font));
// Set the new ExternalRefs to mExternalRefsHolder if it is still null.
Font::ExternalRefs* expected = nullptr;
if (mExternalRefsHolder.compare_exchange_strong(expected, newExternalRefs)) {
return newExternalRefs;
} else {
// Another thread has already created and set an ExternalRefs.
// Delete ours and use theirs instead.
delete newExternalRefs;
// compare_exchange_strong writes the stored value into 'expected'
// when comparison fails.
return expected;
}
}
// static
HbFontUniquePtr Font::prepareFont(const std::shared_ptr<MinikinFont>& typeface) {
const char* buf = reinterpret_cast<const char*>(typeface->GetFontData());
size_t size = typeface->GetFontSize();
uint32_t ttcIndex = typeface->GetFontIndex();
HbBlobUniquePtr blob(hb_blob_create(buf, size, HB_MEMORY_MODE_READONLY, nullptr, nullptr));
HbFaceUniquePtr face(hb_face_create(blob.get(), ttcIndex));
HbFontUniquePtr parent(hb_font_create(face.get()));
hb_ot_font_set_funcs(parent.get());
uint32_t upem = hb_face_get_upem(face.get());
hb_font_set_scale(parent.get(), upem, upem);
HbFontUniquePtr font(hb_font_create_sub_font(parent.get()));
std::vector<hb_variation_t> variations;
variations.reserve(typeface->GetAxes().size());
for (const FontVariation& variation : typeface->GetAxes()) {
variations.push_back({variation.axisTag, variation.value});
}
hb_font_set_variations(font.get(), variations.data(), variations.size());
return font;
}
// static
FontStyle Font::analyzeStyle(const HbFontUniquePtr& font) {
HbBlob os2Table(font, MinikinFont::MakeTag('O', 'S', '/', '2'));
if (!os2Table) {
return FontStyle();
}
int weight;
bool italic;
if (!::minikin::analyzeStyle(os2Table.get(), os2Table.size(), &weight, &italic)) {
return FontStyle();
}
// TODO: Update weight/italic based on fvar value.
return FontStyle(static_cast<uint16_t>(weight), static_cast<FontStyle::Slant>(italic));
}
std::unordered_set<AxisTag> Font::getSupportedAxes() const {
HbBlob fvarTable(baseFont(), MinikinFont::MakeTag('f', 'v', 'a', 'r'));
if (!fvarTable) {
return std::unordered_set<AxisTag>();
}
std::unordered_set<AxisTag> supportedAxes;
analyzeAxes(fvarTable.get(), fvarTable.size(), &supportedAxes);
return supportedAxes;
}
} // namespace minikin
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