gfx/thebes/gfxFontFeatures.h

   1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2
   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 file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef GFX_FONT_FEATURES_H
   8 #define GFX_FONT_FEATURES_H
   9
  10 #include "nsAtom.h"
  11 #include "nsTHashtable.h"
  12 #include "nsTArray.h"
  13 #include "nsString.h"
  14
  15 // An OpenType feature tag and value pair
  16 struct gfxFontFeature {
  17   uint32_t
  18       mTag;  // see http://www.microsoft.com/typography/otspec/featuretags.htm
  19   uint32_t mValue;  // 0 = off, 1 = on, larger values may be used as parameters
  20                     // to features that select among multiple alternatives
  21 };
  22
  23 inline bool operator<(const gfxFontFeature& a, const gfxFontFeature& b) {
  24   return (a.mTag < b.mTag) || ((a.mTag == b.mTag) && (a.mValue < b.mValue));
  25 }
  26
  27 inline bool operator==(const gfxFontFeature& a, const gfxFontFeature& b) {
  28   return (a.mTag == b.mTag) && (a.mValue == b.mValue);
  29 }
  30
  31 class nsAtom;
  32
  33 class gfxFontFeatureValueSet final {
  34  public:
  35   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(gfxFontFeatureValueSet)
  36
  37   gfxFontFeatureValueSet();
  38
  39   struct ValueList {
  40     ValueList(const nsAString& aName, const nsTArray<uint32_t>& aSelectors)
  41         : name(aName), featureSelectors(aSelectors.Clone()) {}
  42     nsString name;
  43     nsTArray<uint32_t> featureSelectors;
  44   };
  45
  46   struct FeatureValues {
  47     uint32_t alternate;
  48     nsTArray<ValueList> valuelist;
  49   };
  50
  51   mozilla::Span<const uint32_t> GetFontFeatureValuesFor(
  52       const nsACString& aFamily, uint32_t aVariantProperty,
  53       nsAtom* aName) const;
  54
  55   // Appends a new hash entry with given key values and returns a pointer to
  56   // mValues array to fill. This should be filled first.
  57   nsTArray<uint32_t>* AppendFeatureValueHashEntry(const nsACString& aFamily,
  58                                                   nsAtom* aName,
  59                                                   uint32_t aAlternate);
  60
  61  private:
  62   // Private destructor, to discourage deletion outside of Release():
  63   ~gfxFontFeatureValueSet() = default;
  64
  65   struct FeatureValueHashKey {
  66     nsCString mFamily;
  67     uint32_t mPropVal;
  68     RefPtr<nsAtom> mName;
  69
  70     FeatureValueHashKey() : mPropVal(0) {}
  71     FeatureValueHashKey(const nsACString& aFamily, uint32_t aPropVal,
  72                         nsAtom* aName)
  73         : mFamily(aFamily), mPropVal(aPropVal), mName(aName) {}
  74     FeatureValueHashKey(const FeatureValueHashKey& aKey) = default;
  75   };
  76
  77   class FeatureValueHashEntry : public PLDHashEntryHdr {
  78    public:
  79     typedef const FeatureValueHashKey& KeyType;
  80     typedef const FeatureValueHashKey* KeyTypePointer;
  81
  82     explicit FeatureValueHashEntry(KeyTypePointer aKey) {}
  83     FeatureValueHashEntry(FeatureValueHashEntry&& other)
  84         : PLDHashEntryHdr(std::move(other)),
  85           mKey(std::move(other.mKey)),
  86           mValues(std::move(other.mValues)) {
  87       NS_ERROR("Should not be called");
  88     }
  89     ~FeatureValueHashEntry() = default;
  90
  91     bool KeyEquals(const KeyTypePointer aKey) const;
  92     static KeyTypePointer KeyToPointer(KeyType aKey) { return &aKey; }
  93     static PLDHashNumber HashKey(const KeyTypePointer aKey);
  94     enum { ALLOW_MEMMOVE = true };
  95
  96     FeatureValueHashKey mKey;
  97     nsTArray<uint32_t> mValues;
  98   };
  99
 100   nsTHashtable<FeatureValueHashEntry> mFontFeatureValues;
 101 };
 102
 103 #endif