chromium/src/third_party/blink/renderer/platform/fonts/shaping/harfbuzz_shaper.h

/*
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#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_HARFBUZZ_SHAPER_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_HARFBUZZ_SHAPER_H_

#include "third_party/blink/renderer/platform/fonts/shaping/run_segmenter.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 RangeData;
struct BufferSlice;

class PLATFORM_EXPORT HarfBuzzShaper final {
  DISALLOW_NEW();

 public:
  HarfBuzzShaper(const String& text) : text_(text) {}

  // 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.
  scoped_refptr<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.
  scoped_refptr<ShapeResult> Shape(
      const Font*,
      TextDirection,
      unsigned start,
      unsigned end,
      const Vector<RunSegmenter::RunSegmenterRange>&) const;

  // Shape a single range. Start and end positions defined by the range.
  scoped_refptr<ShapeResult> Shape(const Font*,
                                   TextDirection,
                                   unsigned start,
                                   unsigned end,
                                   const RunSegmenter::RunSegmenterRange) 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.
  scoped_refptr<ShapeResult> Shape(const Font*, TextDirection) const;

  const String& GetText() const { return text_; }
  unsigned TextLength() const { return text_.length(); }

  ~HarfBuzzShaper() = default;

 private:
  // 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(RangeData*,
                    const RunSegmenter::RunSegmenterRange&,
                    ShapeResult*) const;

  void ExtractShapeResults(RangeData*,
                           bool& font_cycle_queued,
                           const ReshapeQueueItem&,
                           const SimpleFontData*,
                           UScriptCode,
                           CanvasRotationInVertical,
                           bool is_last_font,
                           ShapeResult*) const;

  bool CollectFallbackHintChars(const Deque<ReshapeQueueItem>&,
                                bool needs_hint_list,
                                Vector<UChar32>& hint) const;

  void CommitGlyphs(RangeData*,
                    const SimpleFontData* current_font,
                    UScriptCode current_run_script,
                    CanvasRotationInVertical,
                    bool is_last_font,
                    const BufferSlice&,
                    ShapeResult*) const;

  const String text_;
};

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_HARFBUZZ_SHAPER_H_