flutter_flutter/sky/engine/platform/fonts/SimpleFontData.h

/*
 * This file is part of the internal font implementation.
 *
 * Copyright (C) 2006, 2008, 2010 Apple Inc. All rights reserved.
 * Copyright (C) 2007-2008 Torch Mobile, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#ifndef SKY_ENGINE_PLATFORM_FONTS_SIMPLEFONTDATA_H_
#define SKY_ENGINE_PLATFORM_FONTS_SIMPLEFONTDATA_H_

#include "flutter/sky/engine/platform/PlatformExport.h"
#include "flutter/sky/engine/platform/fonts/CustomFontData.h"
#include "flutter/sky/engine/platform/fonts/FontBaseline.h"
#include "flutter/sky/engine/platform/fonts/FontData.h"
#include "flutter/sky/engine/platform/fonts/FontMetrics.h"
#include "flutter/sky/engine/platform/fonts/FontPlatformData.h"
#include "flutter/sky/engine/platform/fonts/GlyphMetricsMap.h"
#include "flutter/sky/engine/platform/fonts/GlyphPageTreeNode.h"
#include "flutter/sky/engine/platform/fonts/TypesettingFeatures.h"
#include "flutter/sky/engine/platform/fonts/opentype/OpenTypeVerticalData.h"
#include "flutter/sky/engine/platform/geometry/FloatRect.h"
#include "flutter/sky/engine/wtf/OwnPtr.h"
#include "flutter/sky/engine/wtf/PassOwnPtr.h"
#include "flutter/sky/engine/wtf/text/StringHash.h"

namespace blink {

class FontDescription;

enum FontDataVariant {
  AutoVariant,
  NormalVariant,
  SmallCapsVariant,
  EmphasisMarkVariant,
  BrokenIdeographVariant
};
enum Pitch { UnknownPitch, FixedPitch, VariablePitch };

class PLATFORM_EXPORT SimpleFontData : public FontData {
 public:
  // Used to create platform fonts.
  static PassRefPtr<SimpleFontData> create(
      const FontPlatformData& platformData,
      PassRefPtr<CustomFontData> customData = nullptr,
      bool isTextOrientationFallback = false) {
    return adoptRef(new SimpleFontData(platformData, customData,
                                       isTextOrientationFallback));
  }

  // Used to create SVG Fonts.
  static PassRefPtr<SimpleFontData> create(
      PassRefPtr<CustomFontData> customData,
      float fontSize,
      bool syntheticBold,
      bool syntheticItalic) {
    return adoptRef(new SimpleFontData(customData, fontSize, syntheticBold,
                                       syntheticItalic));
  }

  virtual ~SimpleFontData();

  static const SimpleFontData* systemFallback() {
    return reinterpret_cast<const SimpleFontData*>(-1);
  }

  const FontPlatformData& platformData() const { return m_platformData; }
#if ENABLE(OPENTYPE_VERTICAL)
  const OpenTypeVerticalData* verticalData() const {
    return m_verticalData.get();
  }
#endif

  PassRefPtr<SimpleFontData> smallCapsFontData(const FontDescription&) const;
  PassRefPtr<SimpleFontData> emphasisMarkFontData(const FontDescription&) const;
  PassRefPtr<SimpleFontData> brokenIdeographFontData() const;

  PassRefPtr<SimpleFontData> variantFontData(const FontDescription& description,
                                             FontDataVariant variant) const {
    switch (variant) {
      case SmallCapsVariant:
        return smallCapsFontData(description);
      case EmphasisMarkVariant:
        return emphasisMarkFontData(description);
      case BrokenIdeographVariant:
        return brokenIdeographFontData();
      case AutoVariant:
      case NormalVariant:
        break;
    }
    ASSERT_NOT_REACHED();
    return const_cast<SimpleFontData*>(this);
  }

  PassRefPtr<SimpleFontData> verticalRightOrientationFontData() const;
  PassRefPtr<SimpleFontData> uprightOrientationFontData() const;

  bool hasVerticalGlyphs() const { return m_hasVerticalGlyphs; }
  bool isTextOrientationFallback() const { return m_isTextOrientationFallback; }

  FontMetrics& fontMetrics() { return m_fontMetrics; }
  const FontMetrics& fontMetrics() const { return m_fontMetrics; }
  float sizePerUnit() const {
    return platformData().size() /
           (fontMetrics().unitsPerEm() ? fontMetrics().unitsPerEm() : 1);
  }

  float maxCharWidth() const { return m_maxCharWidth; }
  void setMaxCharWidth(float maxCharWidth) { m_maxCharWidth = maxCharWidth; }

  float avgCharWidth() const { return m_avgCharWidth; }
  void setAvgCharWidth(float avgCharWidth) { m_avgCharWidth = avgCharWidth; }

  FloatRect boundsForGlyph(Glyph) const;
  float widthForGlyph(Glyph glyph) const;
  FloatRect platformBoundsForGlyph(Glyph) const;
  float platformWidthForGlyph(Glyph) const;

  float spaceWidth() const { return m_spaceWidth; }
  void setSpaceWidth(float spaceWidth) { m_spaceWidth = spaceWidth; }

  Glyph spaceGlyph() const { return m_spaceGlyph; }
  void setSpaceGlyph(Glyph spaceGlyph) { m_spaceGlyph = spaceGlyph; }
  Glyph zeroWidthSpaceGlyph() const { return m_zeroWidthSpaceGlyph; }
  void setZeroWidthSpaceGlyph(Glyph spaceGlyph) {
    m_zeroWidthSpaceGlyph = spaceGlyph;
  }
  bool isZeroWidthSpaceGlyph(Glyph glyph) const {
    return glyph == m_zeroWidthSpaceGlyph && glyph;
  }
  Glyph zeroGlyph() const { return m_zeroGlyph; }
  void setZeroGlyph(Glyph zeroGlyph) { m_zeroGlyph = zeroGlyph; }

  virtual const SimpleFontData* fontDataForCharacter(UChar32) const override;

  Glyph glyphForCharacter(UChar32) const;

  void determinePitch();
  Pitch pitch() const {
    return m_treatAsFixedPitch ? FixedPitch : VariablePitch;
  }

  bool isSVGFont() const {
    return m_customFontData && m_customFontData->isSVGFont();
  }
  virtual bool isCustomFont() const override { return m_customFontData; }
  virtual bool isLoading() const override {
    return m_customFontData ? m_customFontData->isLoading() : false;
  }
  virtual bool isLoadingFallback() const override {
    return m_customFontData ? m_customFontData->isLoadingFallback() : false;
  }
  virtual bool isSegmented() const override;
  virtual bool shouldSkipDrawing() const override {
    return m_customFontData && m_customFontData->shouldSkipDrawing();
  }

  const GlyphData& missingGlyphData() const { return m_missingGlyphData; }
  void setMissingGlyphData(const GlyphData& glyphData) {
    m_missingGlyphData = glyphData;
  }

#ifndef NDEBUG
  virtual String description() const override;
#endif

  bool canRenderCombiningCharacterSequence(const UChar*, size_t) const;

  PassRefPtr<CustomFontData> customFontData() const { return m_customFontData; }

  // Implemented by the platform.
  virtual bool fillGlyphPage(GlyphPage* pageToFill,
                             unsigned offset,
                             unsigned length,
                             UChar* buffer,
                             unsigned bufferLength) const;

 protected:
  SimpleFontData(const FontPlatformData&,
                 PassRefPtr<CustomFontData> customData,
                 bool isTextOrientationFallback = false);

  SimpleFontData(PassRefPtr<CustomFontData> customData,
                 float fontSize,
                 bool syntheticBold,
                 bool syntheticItalic);

 private:
  void platformInit();
  void platformGlyphInit();
  void platformCharWidthInit();
  void platformDestroy();

  void initCharWidths();

  PassRefPtr<SimpleFontData> createScaledFontData(const FontDescription&,
                                                  float scaleFactor) const;
  PassRefPtr<SimpleFontData> platformCreateScaledFontData(
      const FontDescription&,
      float scaleFactor) const;

  FontMetrics m_fontMetrics;
  float m_maxCharWidth;
  float m_avgCharWidth;

  FontPlatformData m_platformData;

  mutable OwnPtr<GlyphMetricsMap<FloatRect>> m_glyphToBoundsMap;
  mutable GlyphMetricsMap<float> m_glyphToWidthMap;

  bool m_treatAsFixedPitch;

  bool m_isTextOrientationFallback;
  bool m_isBrokenIdeographFallback;
#if ENABLE(OPENTYPE_VERTICAL)
  RefPtr<OpenTypeVerticalData> m_verticalData;
#endif
  bool m_hasVerticalGlyphs;

  Glyph m_spaceGlyph;
  float m_spaceWidth;
  Glyph m_zeroGlyph;

  Glyph m_zeroWidthSpaceGlyph;

  GlyphData m_missingGlyphData;

  struct DerivedFontData {
    static PassOwnPtr<DerivedFontData> create(bool forCustomFont);
    ~DerivedFontData();

    bool forCustomFont;
    RefPtr<SimpleFontData> smallCaps;
    RefPtr<SimpleFontData> emphasisMark;
    RefPtr<SimpleFontData> brokenIdeograph;
    RefPtr<SimpleFontData> verticalRightOrientation;
    RefPtr<SimpleFontData> uprightOrientation;

   private:
    DerivedFontData(bool custom) : forCustomFont(custom) {}
  };

  mutable OwnPtr<DerivedFontData> m_derivedFontData;

  RefPtr<CustomFontData> m_customFontData;

  mutable OwnPtr<HashMap<String, bool>> m_combiningCharacterSequenceSupport;
};

ALWAYS_INLINE FloatRect SimpleFontData::boundsForGlyph(Glyph glyph) const {
  if (isZeroWidthSpaceGlyph(glyph))
    return FloatRect();

  FloatRect bounds;
  if (m_glyphToBoundsMap) {
    bounds = m_glyphToBoundsMap->metricsForGlyph(glyph);
    if (bounds.width() != cGlyphSizeUnknown)
      return bounds;
  }

  bounds = platformBoundsForGlyph(glyph);
  if (!m_glyphToBoundsMap)
    m_glyphToBoundsMap = adoptPtr(new GlyphMetricsMap<FloatRect>);
  m_glyphToBoundsMap->setMetricsForGlyph(glyph, bounds);
  return bounds;
}

ALWAYS_INLINE float SimpleFontData::widthForGlyph(Glyph glyph) const {
  if (isZeroWidthSpaceGlyph(glyph))
    return 0;

  float width = m_glyphToWidthMap.metricsForGlyph(glyph);
  if (width != cGlyphSizeUnknown)
    return width;

#if ENABLE(OPENTYPE_VERTICAL)
  if (m_verticalData)
    width = m_verticalData->advanceHeight(this, glyph);
  else
#endif
    width = platformWidthForGlyph(glyph);

  m_glyphToWidthMap.setMetricsForGlyph(glyph, width);
  return width;
}

DEFINE_FONT_DATA_TYPE_CASTS(SimpleFontData, false);

}  // namespace blink
#endif  // SKY_ENGINE_PLATFORM_FONTS_SIMPLEFONTDATA_H_