layout/generic/nsTextRunTransformations.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef NSTEXTRUNTRANSFORMATIONS_H_
   8 #define NSTEXTRUNTRANSFORMATIONS_H_
   9
  10 #include "mozilla/Attributes.h"
  11 #include "mozilla/MemoryReporting.h"
  12 #include "mozilla/UniquePtr.h"
  13 #include "gfxTextRun.h"
  14 #include "mozilla/ComputedStyle.h"
  15 #include "nsPresContext.h"
  16 #include "nsStyleStruct.h"
  17
  18 class nsTransformedTextRun;
  19
  20 struct nsTransformedCharStyle final {
  21   NS_INLINE_DECL_REFCOUNTING(nsTransformedCharStyle)
  22
  23   explicit nsTransformedCharStyle(mozilla::ComputedStyle* aStyle,
  24                                   nsPresContext* aPresContext)
  25       : mFont(aStyle->StyleFont()->mFont),
  26         mLanguage(aStyle->StyleFont()->mLanguage),
  27         mPresContext(aPresContext),
  28         mTextTransform(aStyle->StyleText()->mTextTransform),
  29         mMathVariant(aStyle->StyleFont()->mMathVariant),
  30         mExplicitLanguage(aStyle->StyleFont()->mExplicitLanguage) {}
  31
  32   nsFont mFont;
  33   RefPtr<nsAtom> mLanguage;
  34   RefPtr<nsPresContext> mPresContext;
  35   mozilla::StyleTextTransform mTextTransform;
  36   mozilla::StyleMathVariant mMathVariant;
  37   bool mExplicitLanguage;
  38   bool mForceNonFullWidth = false;
  39   bool mMaskPassword = false;
  40
  41  private:
  42   ~nsTransformedCharStyle() = default;
  43   nsTransformedCharStyle(const nsTransformedCharStyle& aOther) = delete;
  44   nsTransformedCharStyle& operator=(const nsTransformedCharStyle& aOther) =
  45       delete;
  46 };
  47
  48 class nsTransformingTextRunFactory {
  49  public:
  50   virtual ~nsTransformingTextRunFactory() = default;
  51
  52   // Default 8-bit path just transforms to Unicode and takes that path
  53   already_AddRefed<nsTransformedTextRun> MakeTextRun(
  54       const uint8_t* aString, uint32_t aLength,
  55       const gfxFontGroup::Parameters* aParams, gfxFontGroup* aFontGroup,
  56       mozilla::gfx::ShapedTextFlags aFlags, nsTextFrameUtils::Flags aFlags2,
  57       nsTArray<RefPtr<nsTransformedCharStyle>>&& aStyles, bool aOwnsFactory);
  58
  59   already_AddRefed<nsTransformedTextRun> MakeTextRun(
  60       const char16_t* aString, uint32_t aLength,
  61       const gfxFontGroup::Parameters* aParams, gfxFontGroup* aFontGroup,
  62       mozilla::gfx::ShapedTextFlags aFlags, nsTextFrameUtils::Flags aFlags2,
  63       nsTArray<RefPtr<nsTransformedCharStyle>>&& aStyles, bool aOwnsFactory);
  64
  65   virtual void RebuildTextRun(nsTransformedTextRun* aTextRun,
  66                               mozilla::gfx::DrawTarget* aRefDrawTarget,
  67                               gfxMissingFontRecorder* aMFR) = 0;
  68 };
  69
  70 /**
  71  * Builds textruns that transform the text in some way (e.g., capitalize)
  72  * and then render the text using some other textrun implementation.
  73  * This factory also supports "text-security" transforms that convert all
  74  * characters to a single symbol.
  75  */
  76 class nsCaseTransformTextRunFactory : public nsTransformingTextRunFactory {
  77  public:
  78   // We could add an optimization here so that when there is no inner
  79   // factory, no title-case conversion, and no upper-casing of SZLIG, we
  80   // override MakeTextRun (after making it virtual in the superclass) and have
  81   // it just convert the string to uppercase or lowercase and create the textrun
  82   // via the fontgroup.
  83
  84   // Takes ownership of aInnerTransformTextRunFactory
  85   nsCaseTransformTextRunFactory(mozilla::UniquePtr<nsTransformingTextRunFactory>
  86                                     aInnerTransformingTextRunFactory,
  87                                 bool aAllUppercase, char16_t aMaskChar)
  88       : mInnerTransformingTextRunFactory(
  89             std::move(aInnerTransformingTextRunFactory)),
  90         mAllUppercase(aAllUppercase),
  91         mMaskChar(aMaskChar) {}
  92
  93   virtual void RebuildTextRun(nsTransformedTextRun* aTextRun,
  94                               mozilla::gfx::DrawTarget* aRefDrawTarget,
  95                               gfxMissingFontRecorder* aMFR) override;
  96
  97   // Perform a transformation on the given string, writing the result into
  98   // aConvertedString. If aGlobalTransform is passed, the transform is global
  99   // and aLanguage is used to determine any language-specific behavior;
 100   // otherwise, an nsTransformedTextRun should be passed in as aTextRun and its
 101   // styles will be used to determine the transform(s) to be applied.
 102   // If such an input textrun is provided, then its line-breaks and styles
 103   // will be copied to the output arrays, which must also be provided by
 104   // the caller. For the global transform usage (no input textrun), these are
 105   // ignored.
 106   // If aMaskChar is non-zero, it is used as a "masking" character to replace
 107   // all characters in the text (for -webkit-text-security).
 108   // If aCaseTransformsOnly is true, then only the upper/lower/capitalize
 109   // transformations are performed; full-width and full-size-kana are ignored.
 110   // If `aTextRun` is not nullptr and characters which are styled with setting
 111   // `nsTransformedCharStyle::mMaskPassword` to true, they are replaced with
 112   // password mask characters and are not transformed (i.e., won't be added
 113   // or merged for the specified transform).  However, unmasked characters
 114   // whose `nsTransformedCharStyle::mMaskPassword` is set to false are
 115   // transformed normally.
 116   // Note that "masking" behavior may be triggered either by
 117   // -webkit-text-security, resulting in a non-zero aMaskChar being passed,
 118   // or by <input type=password>, which results in the editor code setting
 119   // nsTransformedCharStyle::mMaskPassword. (The latter mechanism enables the
 120   // editor to temporarily reveal the just-entered character during typing,
 121   // whereas simply setting aMaskChar would unconditionally mask all the text.)
 122   static bool TransformString(
 123       const nsAString& aString, nsString& aConvertedString,
 124       const mozilla::Maybe<mozilla::StyleTextTransform>& aGlobalTransform,
 125       char16_t aMaskChar, bool aCaseTransformsOnly, const nsAtom* aLanguage,
 126       nsTArray<bool>& aCharsToMergeArray, nsTArray<bool>& aDeletedCharsArray,
 127       const nsTransformedTextRun* aTextRun = nullptr,
 128       uint32_t aOffsetInTextRun = 0,
 129       nsTArray<uint8_t>* aCanBreakBeforeArray = nullptr,
 130       nsTArray<RefPtr<nsTransformedCharStyle>>* aStyleArray = nullptr);
 131
 132  protected:
 133   mozilla::UniquePtr<nsTransformingTextRunFactory>
 134       mInnerTransformingTextRunFactory;
 135   bool mAllUppercase;
 136   char16_t mMaskChar;
 137 };
 138
 139 /**
 140  * So that we can reshape as necessary, we store enough information
 141  * to fully rebuild the textrun contents.
 142  */
 143 class nsTransformedTextRun final : public gfxTextRun {
 144  public:
 145   static already_AddRefed<nsTransformedTextRun> Create(
 146       const gfxTextRunFactory::Parameters* aParams,
 147       nsTransformingTextRunFactory* aFactory, gfxFontGroup* aFontGroup,
 148       const char16_t* aString, uint32_t aLength,
 149       const mozilla::gfx::ShapedTextFlags aFlags,
 150       const nsTextFrameUtils::Flags aFlags2,
 151       nsTArray<RefPtr<nsTransformedCharStyle>>&& aStyles, bool aOwnsFactory);
 152
 153   ~nsTransformedTextRun() {
 154     if (mOwnsFactory) {
 155       delete mFactory;
 156     }
 157   }
 158
 159   void SetCapitalization(uint32_t aStart, uint32_t aLength,
 160                          bool* aCapitalization);
 161   virtual bool SetPotentialLineBreaks(Range aRange,
 162                                       const uint8_t* aBreakBefore) override;
 163   /**
 164    * Called after SetCapitalization and SetPotentialLineBreaks
 165    * are done and before we request any data from the textrun. Also always
 166    * called after a Create.
 167    */
 168   void FinishSettingProperties(mozilla::gfx::DrawTarget* aRefDrawTarget,
 169                                gfxMissingFontRecorder* aMFR) {
 170     if (mNeedsRebuild) {
 171       mNeedsRebuild = false;
 172       mFactory->RebuildTextRun(this, aRefDrawTarget, aMFR);
 173     }
 174   }
 175
 176   // override the gfxTextRun impls to account for additional members here
 177   virtual size_t SizeOfExcludingThis(
 178       mozilla::MallocSizeOf aMallocSizeOf) override;
 179   virtual size_t SizeOfIncludingThis(
 180       mozilla::MallocSizeOf aMallocSizeOf) override;
 181
 182   nsTransformingTextRunFactory* mFactory;
 183   nsTArray<RefPtr<nsTransformedCharStyle>> mStyles;
 184   nsTArray<bool> mCapitalize;
 185   nsString mString;
 186   bool mOwnsFactory;
 187   bool mNeedsRebuild;
 188
 189  private:
 190   nsTransformedTextRun(const gfxTextRunFactory::Parameters* aParams,
 191                        nsTransformingTextRunFactory* aFactory,
 192                        gfxFontGroup* aFontGroup, const char16_t* aString,
 193                        uint32_t aLength,
 194                        const mozilla::gfx::ShapedTextFlags aFlags,
 195                        const nsTextFrameUtils::Flags aFlags2,
 196                        nsTArray<RefPtr<nsTransformedCharStyle>>&& aStyles,
 197                        bool aOwnsFactory)
 198       : gfxTextRun(aParams, aLength, aFontGroup, aFlags, aFlags2),
 199         mFactory(aFactory),
 200         mStyles(std::move(aStyles)),
 201         mString(aString, aLength),
 202         mOwnsFactory(aOwnsFactory),
 203         mNeedsRebuild(true) {
 204     mCharacterGlyphs = reinterpret_cast<CompressedGlyph*>(this + 1);
 205   }
 206 };
 207
 208 /**
 209  * Copy a given textrun, but merge certain characters into a single logical
 210  * character. Glyphs for a character are added to the glyph list for the
 211  * previous character and then the merged character is eliminated. Visually the
 212  * results are identical.
 213  *
 214  * This is used for text-transform:uppercase when we encounter a SZLIG,
 215  * whose uppercase form is "SS", or other ligature or precomposed form
 216  * that expands to multiple codepoints during case transformation,
 217  * and for Greek text when combining diacritics have been deleted.
 218  *
 219  * This function is unable to merge characters when they occur in different
 220  * glyph runs. This only happens in tricky edge cases where a character was
 221  * decomposed by case-mapping (e.g. there's no precomposed uppercase version
 222  * of an accented lowercase letter), and then font-matching caused the
 223  * diacritics to be assigned to a different font than the base character.
 224  * In this situation, the diacritic(s) get discarded, which is less than
 225  * ideal, but they probably weren't going to render very well anyway.
 226  * Bug 543200 will improve this by making font-matching operate on entire
 227  * clusters instead of individual codepoints.
 228  *
 229  * For simplicity, this produces a textrun containing all DetailedGlyphs,
 230  * no simple glyphs. So don't call it unless you really have merging to do.
 231  *
 232  * @param aCharsToMerge when aCharsToMerge[i] is true, this character in aSrc
 233  * is merged into the previous character
 234  *
 235  * @param aDeletedChars when aDeletedChars[i] is true, the character at this
 236  * position in aDest was deleted (has no corresponding char in aSrc)
 237  */
 238 void MergeCharactersInTextRun(gfxTextRun* aDest, gfxTextRun* aSrc,
 239                               const bool* aCharsToMerge,
 240                               const bool* aDeletedChars);
 241
 242 gfxTextRunFactory::Parameters GetParametersForInner(
 243     nsTransformedTextRun* aTextRun, mozilla::gfx::ShapedTextFlags* aFlags,
 244     mozilla::gfx::DrawTarget* aRefDrawTarget);
 245
 246 #endif /*NSTEXTRUNTRANSFORMATIONS_H_*/