layout/style/nsCSSValue.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 /* representation of simple property values within CSS declarations */
   8
   9 #ifndef nsCSSValue_h___
  10 #define nsCSSValue_h___
  11
  12 #include "mozilla/Attributes.h"
  13 #include "mozilla/CORSMode.h"
  14 #include "mozilla/EnumTypeTraits.h"
  15 #include "mozilla/MemoryReporting.h"
  16 #include "mozilla/ServoBindingTypes.h"
  17 #include "mozilla/URLExtraData.h"
  18 #include "mozilla/UniquePtr.h"
  19
  20 #include "nsCoord.h"
  21 #include "nsTArray.h"
  22
  23 #include <type_traits>
  24
  25 // XXX Avoid including this here by moving function bodies to the cpp file
  26 #include "mozilla/FloatingPoint.h"
  27
  28 class imgRequestProxy;
  29 class nsAtom;
  30 class nsIContent;
  31
  32 class nsIPrincipal;
  33 class nsIURI;
  34 class nsPresContext;
  35 template <class T>
  36 class nsPtrHashKey;
  37 struct RawServoCssUrlData;
  38
  39 namespace mozilla {
  40 class CSSStyleSheet;
  41 }  // namespace mozilla
  42
  43 // Forward declaration copied here since ServoBindings.h #includes nsCSSValue.h.
  44 extern "C" {
  45 mozilla::URLExtraData* Servo_CssUrlData_GetExtraData(const RawServoCssUrlData*);
  46 bool Servo_CssUrlData_IsLocalRef(const RawServoCssUrlData* url);
  47 }
  48
  49 enum nsCSSUnit : uint32_t {
  50   eCSSUnit_Null = 0,  // (n/a) null unit, value is not specified
  51
  52   eCSSUnit_Percent = 100,  // (1.0 == 100%) value is percentage of
  53                            // something
  54   eCSSUnit_Number = 101,   // value is numeric (usually multiplier,
  55                            // different behavior than percent)
  56
  57   // Font relative measure
  58   eCSSUnit_EM = 800,           // == current font size
  59   eCSSUnit_XHeight = 801,      // distance from top of lower case x to
  60                                // baseline
  61   eCSSUnit_Char = 802,         // number of characters, used for width with
  62                                // monospace font
  63   eCSSUnit_RootEM = 803,       // == root element font size
  64   eCSSUnit_Ideographic = 804,  // == CJK water ideograph width
  65   eCSSUnit_CapHeight = 805,    // == Capital letter height
  66
  67   // Screen relative measure
  68   eCSSUnit_Point = 900,       // 4/3 of a CSS pixel
  69   eCSSUnit_Inch = 901,        // 96 CSS pixels
  70   eCSSUnit_Millimeter = 902,  // 96/25.4 CSS pixels
  71   eCSSUnit_Centimeter = 903,  // 96/2.54 CSS pixels
  72   eCSSUnit_Pica = 904,        // 12 points == 16 CSS pixls
  73   eCSSUnit_Quarter = 905,     // 96/101.6 CSS pixels
  74   eCSSUnit_Pixel = 906,       // CSS pixel unit
  75
  76   // Viewport percentage lengths
  77   eCSSUnit_VW = 950,
  78   eCSSUnit_VH = 951,
  79   eCSSUnit_VMin = 952,
  80   eCSSUnit_VMax = 953,
  81 };
  82
  83 struct nsCSSValuePair;
  84 struct nsCSSValuePair_heap;
  85 struct nsCSSValueList;
  86 struct nsCSSValueList_heap;
  87 struct nsCSSValueSharedList;
  88 struct nsCSSValuePairList;
  89 struct nsCSSValuePairList_heap;
  90
  91 class nsCSSValue {
  92  public:
  93   explicit nsCSSValue() : mUnit(eCSSUnit_Null) {}
  94
  95   nsCSSValue(float aValue, nsCSSUnit aUnit);
  96   nsCSSValue(const nsCSSValue& aCopy);
  97   nsCSSValue(nsCSSValue&& aOther) : mUnit(aOther.mUnit), mValue(aOther.mValue) {
  98     aOther.mUnit = eCSSUnit_Null;
  99   }
 100
 101   nsCSSValue& operator=(const nsCSSValue& aCopy);
 102   nsCSSValue& operator=(nsCSSValue&& aCopy);
 103   bool operator==(const nsCSSValue& aOther) const;
 104
 105   bool operator!=(const nsCSSValue& aOther) const { return !(*this == aOther); }
 106
 107   nsCSSUnit GetUnit() const { return mUnit; }
 108   bool IsLengthUnit() const {
 109     return eCSSUnit_EM <= mUnit && mUnit <= eCSSUnit_Pixel;
 110   }
 111   /**
 112    * A "pixel" length unit is a some multiple of CSS pixels.
 113    */
 114   static bool IsPixelLengthUnit(nsCSSUnit aUnit) {
 115     return eCSSUnit_Point <= aUnit && aUnit <= eCSSUnit_Pixel;
 116   }
 117   bool IsPixelLengthUnit() const { return IsPixelLengthUnit(mUnit); }
 118   static bool IsPercentLengthUnit(nsCSSUnit aUnit) {
 119     return aUnit == eCSSUnit_Percent;
 120   }
 121   static bool IsFloatUnit(nsCSSUnit aUnit) { return eCSSUnit_Number <= aUnit; }
 122
 123   float GetPercentValue() const {
 124     MOZ_ASSERT(mUnit == eCSSUnit_Percent, "not a percent value");
 125     return mValue;
 126   }
 127
 128   float GetFloatValue() const {
 129     MOZ_ASSERT(eCSSUnit_Number <= mUnit, "not a float value");
 130     MOZ_ASSERT(!std::isnan(mValue));
 131     return mValue;
 132   }
 133
 134   nscoord GetPixelLength() const;
 135
 136   void Reset() { mUnit = eCSSUnit_Null; }
 137   ~nsCSSValue() { Reset(); }
 138
 139  public:
 140   void SetPercentValue(float aValue);
 141   void SetFloatValue(float aValue, nsCSSUnit aUnit);
 142
 143  protected:
 144   nsCSSUnit mUnit;
 145   float mValue;
 146 };
 147
 148 #endif /* nsCSSValue_h___ */