layout/generic/nsTextRunTransformations.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef NSTEXTRUNTRANSFORMATIONS_H_
   7 #define NSTEXTRUNTRANSFORMATIONS_H_
   8
   9 #include "mozilla/Attributes.h"
  10 #include "mozilla/MemoryReporting.h"
  11 #include "gfxTextRun.h"
  12 #include "nsStyleContext.h"
  13
  14 class nsTransformedTextRun;
  15
  16 class nsTransformingTextRunFactory {
  17 public:
  18   virtual ~nsTransformingTextRunFactory() {}
  19
  20   // Default 8-bit path just transforms to Unicode and takes that path
  21   nsTransformedTextRun* MakeTextRun(const uint8_t* aString, uint32_t aLength,
  22                                     const gfxFontGroup::Parameters* aParams,
  23                                     gfxFontGroup* aFontGroup, uint32_t aFlags,
  24                                     nsStyleContext** aStyles,
  25                                     bool aOwnsFactory);
  26   nsTransformedTextRun* MakeTextRun(const char16_t* aString, uint32_t aLength,
  27                                     const gfxFontGroup::Parameters* aParams,
  28                                     gfxFontGroup* aFontGroup, uint32_t aFlags,
  29                                     nsStyleContext** aStyles,
  30                                     bool aOwnsFactory);
  31
  32   virtual void RebuildTextRun(nsTransformedTextRun* aTextRun,
  33                               gfxContext* aRefContext,
  34                               gfxMissingFontRecorder* aMFR) = 0;
  35 };
  36
  37 /**
  38  * Builds textruns that transform the text in some way (e.g., capitalize)
  39  * and then render the text using some other textrun implementation.
  40  */
  41 class nsCaseTransformTextRunFactory : public nsTransformingTextRunFactory {
  42 public:
  43   // We could add an optimization here so that when there is no inner
  44   // factory, no title-case conversion, and no upper-casing of SZLIG, we override
  45   // MakeTextRun (after making it virtual in the superclass) and have it
  46   // just convert the string to uppercase or lowercase and create the textrun
  47   // via the fontgroup.
  48
  49   // Takes ownership of aInnerTransformTextRunFactory
  50   explicit nsCaseTransformTextRunFactory(nsTransformingTextRunFactory* aInnerTransformingTextRunFactory,
  51                                          bool aAllUppercase = false)
  52     : mInnerTransformingTextRunFactory(aInnerTransformingTextRunFactory),
  53       mAllUppercase(aAllUppercase) {}
  54
  55   virtual void RebuildTextRun(nsTransformedTextRun* aTextRun,
  56                               gfxContext* aRefContext,
  57                               gfxMissingFontRecorder* aMFR) MOZ_OVERRIDE;
  58
  59   // Perform a transformation on the given string, writing the result into
  60   // aConvertedString. If aAllUppercase is true, the transform is (global)
  61   // upper-casing, and aLanguage is used to determine any language-specific
  62   // behavior; otherwise, an nsTransformedTextRun should be passed in
  63   // as aTextRun and its styles will be used to determine the transform(s)
  64   // to be applied.
  65   // If such an input textrun is provided, then its line-breaks and styles
  66   // will be copied to the output arrays, which must also be provided by
  67   // the caller. For the global upper-casing usage (no input textrun),
  68   // these are ignored.
  69   static bool TransformString(const nsAString& aString,
  70                               nsString& aConvertedString,
  71                               bool aAllUppercase,
  72                               const nsIAtom* aLanguage,
  73                               nsTArray<bool>& aCharsToMergeArray,
  74                               nsTArray<bool>& aDeletedCharsArray,
  75                               nsTransformedTextRun* aTextRun = nullptr,
  76                               nsTArray<uint8_t>* aCanBreakBeforeArray = nullptr,
  77                               nsTArray<nsStyleContext*>* aStyleArray = nullptr);
  78
  79 protected:
  80   nsAutoPtr<nsTransformingTextRunFactory> mInnerTransformingTextRunFactory;
  81   bool                                    mAllUppercase;
  82 };
  83
  84 /**
  85  * So that we can reshape as necessary, we store enough information
  86  * to fully rebuild the textrun contents.
  87  */
  88 class nsTransformedTextRun MOZ_FINAL : public gfxTextRun {
  89 public:
  90   static nsTransformedTextRun *Create(const gfxTextRunFactory::Parameters* aParams,
  91                                       nsTransformingTextRunFactory* aFactory,
  92                                       gfxFontGroup* aFontGroup,
  93                                       const char16_t* aString, uint32_t aLength,
  94                                       const uint32_t aFlags, nsStyleContext** aStyles,
  95                                       bool aOwnsFactory);
  96
  97   ~nsTransformedTextRun() {
  98     if (mOwnsFactory) {
  99       delete mFactory;
 100     }
 101   }
 102
 103   void SetCapitalization(uint32_t aStart, uint32_t aLength,
 104                          bool* aCapitalization,
 105                          gfxContext* aRefContext);
 106   virtual bool SetPotentialLineBreaks(uint32_t aStart, uint32_t aLength,
 107                                         uint8_t* aBreakBefore,
 108                                         gfxContext* aRefContext);
 109   /**
 110    * Called after SetCapitalization and SetPotentialLineBreaks
 111    * are done and before we request any data from the textrun. Also always
 112    * called after a Create.
 113    */
 114   void FinishSettingProperties(gfxContext* aRefContext,
 115                                gfxMissingFontRecorder* aMFR)
 116   {
 117     if (mNeedsRebuild) {
 118       mNeedsRebuild = false;
 119       mFactory->RebuildTextRun(this, aRefContext, aMFR);
 120     }
 121   }
 122
 123   // override the gfxTextRun impls to account for additional members here
 124   virtual size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) MOZ_MUST_OVERRIDE;
 125   virtual size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) MOZ_MUST_OVERRIDE;
 126
 127   nsTransformingTextRunFactory       *mFactory;
 128   nsTArray<nsRefPtr<nsStyleContext> > mStyles;
 129   nsTArray<bool>                      mCapitalize;
 130   nsString                            mString;
 131   bool                                mOwnsFactory;
 132   bool                                mNeedsRebuild;
 133
 134 private:
 135   nsTransformedTextRun(const gfxTextRunFactory::Parameters* aParams,
 136                        nsTransformingTextRunFactory* aFactory,
 137                        gfxFontGroup* aFontGroup,
 138                        const char16_t* aString, uint32_t aLength,
 139                        const uint32_t aFlags, nsStyleContext** aStyles,
 140                        bool aOwnsFactory)
 141     : gfxTextRun(aParams, aLength, aFontGroup, aFlags),
 142       mFactory(aFactory), mString(aString, aLength),
 143       mOwnsFactory(aOwnsFactory), mNeedsRebuild(true)
 144   {
 145     mCharacterGlyphs = reinterpret_cast<CompressedGlyph*>(this + 1);
 146
 147     uint32_t i;
 148     for (i = 0; i < aLength; ++i) {
 149       mStyles.AppendElement(aStyles[i]);
 150     }
 151   }
 152 };
 153
 154 /**
 155  * Copy a given textrun, but merge certain characters into a single logical
 156  * character. Glyphs for a character are added to the glyph list for the previous
 157  * character and then the merged character is eliminated. Visually the results
 158  * are identical.
 159  *
 160  * This is used for text-transform:uppercase when we encounter a SZLIG,
 161  * whose uppercase form is "SS", or other ligature or precomposed form
 162  * that expands to multiple codepoints during case transformation,
 163  * and for Greek text when combining diacritics have been deleted.
 164  *
 165  * This function is unable to merge characters when they occur in different
 166  * glyph runs. This only happens in tricky edge cases where a character was
 167  * decomposed by case-mapping (e.g. there's no precomposed uppercase version
 168  * of an accented lowercase letter), and then font-matching caused the
 169  * diacritics to be assigned to a different font than the base character.
 170  * In this situation, the diacritic(s) get discarded, which is less than
 171  * ideal, but they probably weren't going to render very well anyway.
 172  * Bug 543200 will improve this by making font-matching operate on entire
 173  * clusters instead of individual codepoints.
 174  *
 175  * For simplicity, this produces a textrun containing all DetailedGlyphs,
 176  * no simple glyphs. So don't call it unless you really have merging to do.
 177  *
 178  * @param aCharsToMerge when aCharsToMerge[i] is true, this character in aSrc
 179  * is merged into the previous character
 180  *
 181  * @param aDeletedChars when aDeletedChars[i] is true, the character at this
 182  * position in aDest was deleted (has no corresponding char in aSrc)
 183  */
 184 void
 185 MergeCharactersInTextRun(gfxTextRun* aDest, gfxTextRun* aSrc,
 186                          const bool* aCharsToMerge, const bool* aDeletedChars);
 187
 188 gfxTextRunFactory::Parameters
 189 GetParametersForInner(nsTransformedTextRun* aTextRun, uint32_t* aFlags,
 190                       gfxContext* aRefContext);
 191
 192
 193 #endif /*NSTEXTRUNTRANSFORMATIONS_H_*/