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/*
* Copyright (C) 2012 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_HARFBUZZ_SHAPER_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_HARFBUZZ_SHAPER_H_
#include "base/functional/callback.h"
#include "third_party/blink/renderer/platform/fonts/font_fallback_iterator.h"
#include "third_party/blink/renderer/platform/fonts/shaping/run_segmenter.h"
#include "third_party/blink/renderer/platform/fonts/shaping/shape_options.h"
#include "third_party/blink/renderer/platform/fonts/shaping/shape_result.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
#include "third_party/blink/renderer/platform/wtf/text/wtf_string.h"
#include "third_party/blink/renderer/platform/wtf/vector.h"
namespace blink {
class Font;
class SimpleFontData;
class HarfBuzzShaper;
struct ReshapeQueueItem;
struct RangeContext;
struct BufferSlice;
class PLATFORM_EXPORT HarfBuzzShaper final {
DISALLOW_NEW();
using EmojiMetricsCallback =
base::RepeatingCallback<void(unsigned, unsigned)>;
public:
// The optional emoji_metrics_callback argument is a mock metrics reporting
// function used during tests. Otherwise successful and unsuccessful emoji
// clusters are reported per Document / WorkerGlobalContext to
// FontMatchingMetrics.
explicit HarfBuzzShaper(
String text,
EmojiMetricsCallback emoji_metrics_callback = EmojiMetricsCallback())
: text_(std::move(text)),
emoji_metrics_reporter_for_testing_(emoji_metrics_callback) {}
// Shape a range, defined by the start and end parameters, of the string
// supplied to the constructor.
// The start and end positions should represent boundaries where a break may
// occur, such as at the beginning or end of lines or at element boundaries.
// If given arbitrary positions the results are not guaranteed to be correct.
// May be called multiple times; font and direction may vary between calls.
ShapeResult* Shape(const Font*,
TextDirection,
unsigned start,
unsigned end) const;
// Shape a range that has already been pre-segmented. Start and end positions
// must match the positions defined by the ranges and must be at valid break
// positions.
ShapeResult* Shape(const Font*,
TextDirection,
unsigned start,
unsigned end,
const Vector<RunSegmenter::RunSegmenterRange>&,
ShapeOptions = ShapeOptions()) const;
// Shape a single range. Start and end positions defined by the range.
ShapeResult* Shape(const Font*,
TextDirection,
unsigned start,
unsigned end,
const RunSegmenter::RunSegmenterRange,
ShapeOptions = ShapeOptions()) const;
// Shape the entire string with a single font and direction.
// Equivalent to calling the range version with a start offset of zero and an
// end offset equal to the length.
ShapeResult* Shape(const Font*, TextDirection) const;
const String& GetText() const { return text_; }
unsigned TextLength() const { return text_.length(); }
// This function is between `Shape` and `SimpleFontData::GlyphForCharacter`.
//
// Unlike `Shape`, it works only for one `SimpleFontData`, not `Font`, without
// cascading nor fallback. Missing glyphs are reported as `.notdef` (0). Also
// it's a lot less expensive than `Shape`.
//
// Unlike `SimpleFontData::GlyphForCharacter`, it shapes, taking locale,
// script, and OpenType features into account.
struct GlyphData {
unsigned cluster;
Glyph glyph;
gfx::PointF advance;
gfx::PointF offset;
};
using GlyphDataList = Vector<GlyphData, 16>;
void GetGlyphData(const SimpleFontData& font_data,
const LayoutLocale& locale,
UScriptCode script,
bool is_horizontal,
GlyphDataList& glyphs);
enum FallbackFontStage {
// There were no unshaped variation sequences found, so we don't need to
// perform second fallback fonts list pass.
kIntermediate,
kLast,
// Found unshaped variation sequences and we are on the first fallback pass,
// so we are including variation selectors during shaping.
kIntermediateWithVS,
kLastWithVS,
// Found unshaped variation sequences and we are on the second and last
// fallback pass, so we are ignoring variation selectors during shaping.
kIntermediateIgnoreVS,
kLastIgnoreVS
};
~HarfBuzzShaper() = default;
private:
using HintCharList = FontFallbackIterator::HintCharList;
// Shapes a single seqment, as identified by the RunSegmenterRange parameter,
// one or more times taking font fallback into account. The start and end
// parameters are for the entire text run, not the segment, and are used to
// determine pre- and post-context for shaping.
void ShapeSegment(RangeContext*,
const RunSegmenter::RunSegmenterRange&,
ShapeResult*) const;
void ExtractShapeResults(RangeContext*,
bool& font_cycle_queued,
const ReshapeQueueItem&,
const SimpleFontData*,
UScriptCode,
CanvasRotationInVertical,
FallbackFontStage& fallback_stage,
ShapeResult*) const;
bool CollectFallbackHintChars(const Deque<ReshapeQueueItem>&,
bool needs_hint_list,
HintCharList& hint) const;
void CommitGlyphs(RangeContext*,
const SimpleFontData* current_font,
UScriptCode current_run_script,
CanvasRotationInVertical,
FallbackFontStage fallback_stage,
const BufferSlice&,
ShapeResult*) const;
void CheckTextLen(unsigned start, unsigned length) const;
void CheckTextEnd(unsigned start, unsigned end) const;
const String text_;
EmojiMetricsCallback emoji_metrics_reporter_for_testing_;
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_HARFBUZZ_SHAPER_H_
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