third_party/blink/renderer/platform/fonts/font_description.h

/*
 * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
 *           (C) 2000 Antti Koivisto (koivisto@kde.org)
 *           (C) 2000 Dirk Mueller (mueller@kde.org)
 * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights
 * reserved.
 * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
 *
 * 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 THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_FONT_DESCRIPTION_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_FONT_DESCRIPTION_H_

#include <unicode/uscript.h>

#include "base/memory/scoped_refptr.h"
#include "third_party/blink/renderer/platform/font_family_names.h"
#include "third_party/blink/renderer/platform/fonts/font_cache_key.h"
#include "third_party/blink/renderer/platform/fonts/font_family.h"
#include "third_party/blink/renderer/platform/fonts/font_orientation.h"
#include "third_party/blink/renderer/platform/fonts/font_selection_types.h"
#include "third_party/blink/renderer/platform/fonts/font_smoothing_mode.h"
#include "third_party/blink/renderer/platform/fonts/font_variant_east_asian.h"
#include "third_party/blink/renderer/platform/fonts/font_variant_numeric.h"
#include "third_party/blink/renderer/platform/fonts/font_width_variant.h"
#include "third_party/blink/renderer/platform/fonts/opentype/font_settings.h"
#include "third_party/blink/renderer/platform/fonts/text_rendering_mode.h"
#include "third_party/blink/renderer/platform/fonts/typesetting_features.h"
#include "third_party/blink/renderer/platform/text/layout_locale.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
#include "third_party/blink/renderer/platform/wtf/math_extras.h"
#include "third_party/skia/include/core/SkFontStyle.h"

namespace blink {

const float kFontSizeAdjustNone = -1;
typedef struct { uint32_t parts[2]; } FieldsAsUnsignedType;

class PLATFORM_EXPORT FontDescription {
  USING_FAST_MALLOC(FontDescription);

 public:
  enum GenericFamilyType {
    kNoFamily,
    kStandardFamily,
    kSerifFamily,
    kSansSerifFamily,
    kMonospaceFamily,
    kCursiveFamily,
    kFantasyFamily,
    kPictographFamily
  };
  static String ToString(GenericFamilyType);

  enum Kerning { kAutoKerning, kNormalKerning, kNoneKerning };
  static String ToString(Kerning);

  enum LigaturesState {
    kNormalLigaturesState,
    kDisabledLigaturesState,
    kEnabledLigaturesState
  };
  static String ToString(LigaturesState);

  enum FontVariantCaps {
    kCapsNormal,
    kSmallCaps,
    kAllSmallCaps,
    kPetiteCaps,
    kAllPetiteCaps,
    kUnicase,
    kTitlingCaps
  };
  static String ToString(FontVariantCaps);

  FontDescription();
  FontDescription(const FontDescription&);

  FontDescription& operator=(const FontDescription&);

  bool operator==(const FontDescription&) const;
  bool operator!=(const FontDescription& other) const {
    return !(*this == other);
  }

  struct VariantLigatures {
    STACK_ALLOCATED();

   public:
    VariantLigatures(LigaturesState state = kNormalLigaturesState)
        : common(state),
          discretionary(state),
          historical(state),
          contextual(state) {}

    String ToString() const;

    unsigned common : 2;
    unsigned discretionary : 2;
    unsigned historical : 2;
    unsigned contextual : 2;
  };

  struct Size {
    STACK_ALLOCATED();

   public:
    Size(unsigned keyword, float value, bool is_absolute)
        : keyword(keyword), is_absolute(is_absolute), value(value) {}

    String ToString() const;

    unsigned keyword : 4;      // FontDescription::KeywordSize
    unsigned is_absolute : 1;  // FontDescription::IsAbsoluteSize
    float value;               // FontDescription::SpecifiedSize
  };

  struct FamilyDescription {
    STACK_ALLOCATED();

   public:
    FamilyDescription(GenericFamilyType generic_family)
        : generic_family(generic_family) {}
    FamilyDescription(GenericFamilyType generic_family,
                      const FontFamily& family)
        : generic_family(generic_family), family(family) {}

    String ToString() const;

    GenericFamilyType generic_family;
    FontFamily family;
  };

  const FontFamily& Family() const { return family_list_; }
  FamilyDescription GetFamilyDescription() const {
    return FamilyDescription(GenericFamily(), Family());
  }
  FontFamily& FirstFamily() { return family_list_; }
  Size GetSize() const {
    return Size(KeywordSize(), SpecifiedSize(), IsAbsoluteSize());
  }
  float SpecifiedSize() const { return specified_size_; }
  float ComputedSize() const { return computed_size_; }
  float AdjustedSize() const { return adjusted_size_; }
  float SizeAdjust() const { return size_adjust_; }
  bool HasSizeAdjust() const { return size_adjust_ != kFontSizeAdjustNone; }
  int ComputedPixelSize() const { return int(computed_size_ + 0.5f); }
  FontVariantCaps VariantCaps() const {
    return static_cast<FontVariantCaps>(fields_.variant_caps_);
  }
  bool IsAbsoluteSize() const { return fields_.is_absolute_size_; }
  FontSelectionValue Weight() const { return font_selection_request_.weight; }
  FontSelectionValue Style() const { return font_selection_request_.slope; }
  FontSelectionValue Stretch() const { return font_selection_request_.width; }
  static FontSelectionValue LighterWeight(FontSelectionValue);
  static FontSelectionValue BolderWeight(FontSelectionValue);
  static Size LargerSize(const Size&);
  static Size SmallerSize(const Size&);
  GenericFamilyType GenericFamily() const {
    return static_cast<GenericFamilyType>(fields_.generic_family_);
  }

  // only use fixed default size when there is only one font family, and that
  // family is "monospace"
  bool IsMonospace() const {
    return GenericFamily() == kMonospaceFamily && !Family().Next() &&
           Family().Family() == font_family_names::kWebkitMonospace;
  }
  Kerning GetKerning() const { return static_cast<Kerning>(fields_.kerning_); }
  FontVariantEastAsian VariantEastAsian() const {
    return FontVariantEastAsian::InitializeFromUnsigned(
        fields_.variant_east_asian_);
  }
  VariantLigatures GetVariantLigatures() const;
  FontVariantNumeric VariantNumeric() const {
    return FontVariantNumeric::InitializeFromUnsigned(fields_.variant_numeric_);
  }
  LigaturesState CommonLigaturesState() const {
    return static_cast<LigaturesState>(fields_.common_ligatures_state_);
  }
  LigaturesState DiscretionaryLigaturesState() const {
    return static_cast<LigaturesState>(fields_.discretionary_ligatures_state_);
  }
  LigaturesState HistoricalLigaturesState() const {
    return static_cast<LigaturesState>(fields_.historical_ligatures_state_);
  }
  LigaturesState ContextualLigaturesState() const {
    return static_cast<LigaturesState>(fields_.contextual_ligatures_state_);
  }
  unsigned KeywordSize() const { return fields_.keyword_size_; }
  FontSmoothingMode FontSmoothing() const {
    return static_cast<FontSmoothingMode>(fields_.font_smoothing_);
  }
  TextRenderingMode TextRendering() const {
    return static_cast<TextRenderingMode>(fields_.text_rendering_);
  }
  const LayoutLocale* Locale() const { return locale_.get(); }
  const LayoutLocale& LocaleOrDefault() const {
    return LayoutLocale::ValueOrDefault(locale_.get());
  }
  UScriptCode GetScript() const { return LocaleOrDefault().GetScript(); }
  bool IsSyntheticBold() const { return fields_.synthetic_bold_; }
  bool IsSyntheticItalic() const { return fields_.synthetic_italic_; }
  bool UseSubpixelPositioning() const {
    return fields_.subpixel_text_position_;
  }

  FontSelectionRequest GetFontSelectionRequest() const;
  float WordSpacing() const { return word_spacing_; }
  float LetterSpacing() const { return letter_spacing_; }
  FontOrientation Orientation() const {
    return static_cast<FontOrientation>(fields_.orientation_);
  }
  bool IsVerticalAnyUpright() const {
    return blink::IsVerticalAnyUpright(Orientation());
  }
  bool IsVerticalNonCJKUpright() const {
    return blink::IsVerticalNonCJKUpright(Orientation());
  }
  bool IsVerticalUpright(UChar32 character) const {
    return blink::IsVerticalUpright(Orientation(), character);
  }
  bool IsVerticalBaseline() const {
    return blink::IsVerticalBaseline(Orientation());
  }
  FontWidthVariant WidthVariant() const {
    return static_cast<FontWidthVariant>(fields_.width_variant_);
  }
  FontFeatureSettings* FeatureSettings() const {
    return feature_settings_.get();
  }
  FontVariationSettings* VariationSettings() const {
    return variation_settings_.get();
  }

  float EffectiveFontSize()
      const;  // Returns either the computedSize or the computedPixelSize
  FontCacheKey CacheKey(
      const FontFaceCreationParams&,
      bool is_unique_match,
      const FontSelectionRequest& = FontSelectionRequest()) const;

  void SetFamily(const FontFamily& family) { family_list_ = family; }
  void SetComputedSize(float s) { computed_size_ = clampTo<float>(s); }
  void SetSpecifiedSize(float s) { specified_size_ = clampTo<float>(s); }
  void SetAdjustedSize(float s) { adjusted_size_ = clampTo<float>(s); }
  void SetSizeAdjust(float aspect) { size_adjust_ = clampTo<float>(aspect); }

  void SetStyle(FontSelectionValue i) { font_selection_request_.slope = i; }
  void SetWeight(FontSelectionValue w) { font_selection_request_.weight = w; }
  void SetStretch(FontSelectionValue s) { font_selection_request_.width = s; }

  void SetVariantCaps(FontVariantCaps);
  void SetVariantEastAsian(const FontVariantEastAsian);
  void SetVariantLigatures(const VariantLigatures&);
  void SetVariantNumeric(const FontVariantNumeric&);
  void SetIsAbsoluteSize(bool s) { fields_.is_absolute_size_ = s; }

  void SetGenericFamily(GenericFamilyType generic_family) {
    fields_.generic_family_ = generic_family;
  }
  void SetKerning(Kerning kerning) {
    fields_.kerning_ = kerning;
    UpdateTypesettingFeatures();
  }
  void SetKeywordSize(unsigned s) { fields_.keyword_size_ = s; }
  void SetFontSmoothing(FontSmoothingMode smoothing) {
    fields_.font_smoothing_ = smoothing;
  }
  void SetTextRendering(TextRenderingMode rendering) {
    fields_.text_rendering_ = rendering;
    UpdateTypesettingFeatures();
  }
  void SetOrientation(FontOrientation orientation) {
    fields_.orientation_ = static_cast<unsigned>(orientation);
  }
  void SetWidthVariant(FontWidthVariant width_variant) {
    fields_.width_variant_ = width_variant;
  }
  void SetLocale(scoped_refptr<const LayoutLocale> locale) {
    locale_ = std::move(locale);
  }
  void SetSyntheticBold(bool synthetic_bold) {
    fields_.synthetic_bold_ = synthetic_bold;
  }
  void SetSyntheticItalic(bool synthetic_italic) {
    fields_.synthetic_italic_ = synthetic_italic;
  }
  void SetFeatureSettings(scoped_refptr<FontFeatureSettings> settings) {
    feature_settings_ = std::move(settings);
  }
  void SetVariationSettings(scoped_refptr<FontVariationSettings> settings) {
    variation_settings_ = std::move(settings);
  }
  void SetWordSpacing(float s) { word_spacing_ = s; }
  void SetLetterSpacing(float s) {
    letter_spacing_ = s;
    UpdateTypesettingFeatures();
  }

  TypesettingFeatures GetTypesettingFeatures() const {
    return static_cast<TypesettingFeatures>(fields_.typesetting_features_);
  }

  static void SetSubpixelPositioning(bool b) {
    use_subpixel_text_positioning_ = b;
  }
  static bool SubpixelPositioning() { return use_subpixel_text_positioning_; }

  void SetSubpixelAscentDescent(bool sp) const {
    fields_.subpixel_ascent_descent_ = sp;
  }

  bool SubpixelAscentDescent() const {
    return fields_.subpixel_ascent_descent_;
  }

  static void SetDefaultTypesettingFeatures(TypesettingFeatures);
  static TypesettingFeatures DefaultTypesettingFeatures();

  unsigned StyleHashWithoutFamilyList() const;
  // TODO(drott): We should not expose internal structure here, but rather
  // introduce a hash function here.
  unsigned BitmapFields() const { return fields_as_unsigned_.parts[0]; }
  unsigned AuxiliaryBitmapFields() const {
    return fields_as_unsigned_.parts[1];
  }

  SkFontStyle SkiaFontStyle() const;

  int MinimumPrefixWidthToHyphenate() const;

  String ToString() const;

 private:
  FontFamily family_list_;  // The list of font families to be used.
  scoped_refptr<FontFeatureSettings> feature_settings_;
  scoped_refptr<FontVariationSettings> variation_settings_;
  scoped_refptr<const LayoutLocale> locale_;

  void UpdateTypesettingFeatures();

  // Specified CSS value. Independent of rendering issues such as integer
  // rounding, minimum font sizes, and zooming.
  float specified_size_;
  // Computed size adjusted for the minimum font size and the zoom factor.
  float computed_size_;

  // (Given aspect value / aspect value of a font family) * specifiedSize.
  // This value is adjusted for the minimum font size and the zoom factor
  // as well as a computed size is.
  float adjusted_size_;

  // Given aspect value, i.e. font-size-adjust.
  float size_adjust_;

  float letter_spacing_;
  float word_spacing_;

  // Covers stretch, style, weight.
  FontSelectionRequest font_selection_request_;

  struct BitFields {
    DISALLOW_NEW();

    String ToString() const;

    unsigned orientation_ : kFontOrientationBitCount;

    unsigned width_variant_ : 2;  // FontWidthVariant

    unsigned variant_caps_ : 3;  // FontVariantCaps
    unsigned
        is_absolute_size_ : 1;  // Whether or not CSS specified an explicit size
    // (logical sizes like "medium" don't count).
    unsigned generic_family_ : 3;  // GenericFamilyType

    unsigned kerning_ : 2;  // Kerning

    unsigned common_ligatures_state_ : 2;
    unsigned discretionary_ligatures_state_ : 2;
    unsigned historical_ligatures_state_ : 2;
    unsigned contextual_ligatures_state_ : 2;

    // We cache whether or not a font is currently represented by a CSS keyword
    // (e.g., medium).  If so, then we can accurately translate across different
    // generic families to adjust for different preference settings (e.g., 13px
    // monospace vs. 16px everything else).  Sizes are 1-8 (like the HTML size
    // values for <font>).
    unsigned keyword_size_ : 4;

    unsigned font_smoothing_ : 2;  // FontSmoothingMode
    unsigned text_rendering_ : 2;  // TextRenderingMode
    unsigned synthetic_bold_ : 1;
    unsigned synthetic_italic_ : 1;
    unsigned subpixel_text_position_ : 1;
    unsigned typesetting_features_ : 3;
    unsigned variant_numeric_ : 8;
    unsigned variant_east_asian_ : 6;
    mutable unsigned subpixel_ascent_descent_ : 1;
  };

  static_assert(sizeof(BitFields) == sizeof(FieldsAsUnsignedType),
                "Mapped bitfield datatypes must have identical size.");
  union {
    BitFields fields_;
    FieldsAsUnsignedType fields_as_unsigned_;
  };

  static TypesettingFeatures default_typesetting_features_;

  static bool use_subpixel_text_positioning_;
};

}  // namespace blink

#endif