font.h

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#ifndef ION_TEXT_FONT_H_
#define ION_TEXT_FONT_H_

#include <string>

#include "ion/base/allocator.h"
#include "ion/base/array2.h"
#include "ion/base/invalid.h"
#include "ion/base/referent.h"
#include "ion/base/stlalloc/allocmap.h"
#include "ion/math/vector.h"
#include "ion/text/layout.h"

namespace ion {
namespace text {

typedef uint32 CharIndex;

class Font;
typedef base::ReferentPtr<Font>::Type FontPtr;

class ION_API Font : public base::Referent {
 public:
  struct GlyphGrid {
    GlyphGrid() : pixels(), is_sdf(false) {}
    GlyphGrid(size_t width, size_t height);

    base::Array2<double> pixels;

    bool IsZeroSize() const;

    bool is_sdf;
  };

  struct FontMetrics {
    FontMetrics() : line_advance_height(0.f) {}

    float line_advance_height;
  };

  const std::string& GetName() const { return name_; }

  size_t GetSizeInPixels() const { return size_in_pixels_; }

  size_t GetSdfPadding() const { return sdf_padding_; }

  const FontMetrics& GetFontMetrics() const { return font_metrics_; }

  const GlyphGrid& GetGlyphGrid(GlyphIndex glyph_index) const;

  void FilterGlyphs(GlyphSet* glyph_set);

  virtual GlyphIndex GetDefaultGlyphForChar(CharIndex char_index) const = 0;

  void AddGlyphsForAsciiCharacterRange(ion::text::CharIndex start,
                                       ion::text::CharIndex finish,
                                       ion::text::GlyphSet* glyphs);

  virtual const Layout BuildLayout(const std::string& text,
                                   const LayoutOptions& options) const = 0;

  void CacheSdfGrids(const GlyphSet& glyph_set);

  virtual void AddFallbackFont(const FontPtr& fallback) = 0;

 protected:
  typedef base::AllocMap<GlyphIndex, GlyphGrid> GlyphMap;

  Font(const std::string& name, size_t size_in_pixels, size_t sdf_padding);

  ~Font() override;

  GlyphGrid* GetMutableGlyphGrid(GlyphIndex glyph_index) const;

  GlyphGrid* GetMutableGlyphGridLocked(GlyphIndex glyph_index) const;

  virtual bool LoadGlyphGrid(GlyphIndex glyph_index,
                             GlyphGrid* glyph_grid) const;

  const GlyphGrid& AddGlyph(GlyphIndex glyph_index,
                            const GlyphGrid& glyph) const;

  void SetFontMetrics(const FontMetrics& metrics);

  bool CacheSdfGrid(GlyphIndex glyph_index,
                    const base::Array2<double>& sdf_pixels);

  const size_t size_in_pixels_;

 private:
  const std::string name_;
  const size_t sdf_padding_;
  FontMetrics font_metrics_;
  mutable GlyphMap glyph_grid_map_;
  mutable port::Mutex mutex_;

  DISALLOW_IMPLICIT_CONSTRUCTORS(Font);
};

}  // namespace text
}  // namespace ion

#endif  // ION_TEXT_FONT_H_