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// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_HARFBUZZ_FONT_DATA_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_HARFBUZZ_FONT_DATA_H_
#include <hb-cplusplus.hh>
#include "base/check_op.h"
#include "third_party/blink/renderer/platform/fonts/font_platform_data.h"
#include "third_party/blink/renderer/platform/fonts/opentype/open_type_vertical_data.h"
#include "third_party/blink/renderer/platform/fonts/shaping/harfbuzz_face.h"
#include "third_party/skia/include/core/SkFont.h"
struct hb_font_t;
namespace blink {
const unsigned kInvalidFallbackMetricsValue = static_cast<unsigned>(-1);
// The HarfBuzzFontData struct carries user-pointer data for
// |hb_font_t| callback functions/operations. It contains metrics and OpenType
// layout information related to a font scaled to a particular size.
struct HarfBuzzFontData final : public GarbageCollected<HarfBuzzFontData> {
public:
explicit HarfBuzzFontData(hb_font_t* unscaled_font)
: unscaled_font_(hb::unique_ptr<hb_font_t>(unscaled_font)),
vertical_data_(nullptr),
range_set_(nullptr) {}
HarfBuzzFontData(const HarfBuzzFontData&) = delete;
HarfBuzzFontData& operator=(const HarfBuzzFontData&) = delete;
void Trace(Visitor* visitor) const {
visitor->Trace(vertical_data_);
visitor->Trace(range_set_);
}
// The vertical origin and vertical advance functions in HarfBuzzFace require
// the ascent and height metrics as fallback in case no specific vertical
// layout information is found from the font.
void UpdateFallbackMetricsAndScale(
const FontPlatformData& platform_data,
HarfBuzzFace::VerticalLayoutCallbacks vertical_layout) {
float ascent = 0;
float descent = 0;
font_ = platform_data.CreateSkFont();
if (vertical_layout == HarfBuzzFace::kPrepareForVerticalLayout)
[[unlikely]] {
FontMetrics::AscentDescentWithHacks(ascent, descent, platform_data,
font_);
ascent_fallback_ = ascent;
// Simulate the rounding that FontMetrics does so far for returning the
// integer Height()
height_fallback_ = lroundf(ascent) + lroundf(descent);
int units_per_em =
platform_data.GetHarfBuzzFace()->UnitsPerEmFromHeadTable();
if (!units_per_em) {
DLOG(ERROR)
<< "Units per EM is 0 for font used in vertical writing mode.";
}
size_per_unit_ = platform_data.size() / (units_per_em ? units_per_em : 1);
} else {
ascent_fallback_ = kInvalidFallbackMetricsValue;
height_fallback_ = kInvalidFallbackMetricsValue;
size_per_unit_ = kInvalidFallbackMetricsValue;
}
}
OpenTypeVerticalData* VerticalData() {
if (!vertical_data_) {
DCHECK_NE(ascent_fallback_, kInvalidFallbackMetricsValue);
DCHECK_NE(height_fallback_, kInvalidFallbackMetricsValue);
DCHECK_NE(size_per_unit_, kInvalidFallbackMetricsValue);
vertical_data_ =
MakeGarbageCollected<OpenTypeVerticalData>(font_.refTypeface());
}
vertical_data_->SetScaleAndFallbackMetrics(size_per_unit_, ascent_fallback_,
height_fallback_);
return vertical_data_.Get();
}
const hb::unique_ptr<hb_font_t> unscaled_font_;
SkFont font_;
// Capture these scaled fallback metrics from FontPlatformData so that a
// OpenTypeVerticalData object can be constructed from them when needed.
float size_per_unit_;
float ascent_fallback_;
float height_fallback_;
enum class SpaceGlyphInOpenTypeTables { kUnknown, kPresent, kNotPresent };
SpaceGlyphInOpenTypeTables space_in_gpos_ =
SpaceGlyphInOpenTypeTables::kUnknown;
SpaceGlyphInOpenTypeTables space_in_gsub_ =
SpaceGlyphInOpenTypeTables::kUnknown;
Member<OpenTypeVerticalData> vertical_data_;
Member<const UnicodeRangeSet> range_set_;
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_HARFBUZZ_FONT_DATA_H_
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