gfx/2d/BaseMargin.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 MOZILLA_GFX_BASEMARGIN_H_
   8 #define MOZILLA_GFX_BASEMARGIN_H_
   9
  10 #include <ostream>
  11
  12 #include "Types.h"
  13
  14 namespace mozilla {
  15
  16 /**
  17  * Sides represents a set of physical sides.
  18  */
  19 struct Sides final {
  20   Sides() : mBits(SideBits::eNone) {}
  21   explicit Sides(SideBits aSideBits) {
  22     MOZ_ASSERT((aSideBits & ~SideBits::eAll) == SideBits::eNone,
  23                "illegal side bits");
  24     mBits = aSideBits;
  25   }
  26   bool IsEmpty() const { return mBits == SideBits::eNone; }
  27   bool Top() const { return (mBits & SideBits::eTop) == SideBits::eTop; }
  28   bool Right() const { return (mBits & SideBits::eRight) == SideBits::eRight; }
  29   bool Bottom() const {
  30     return (mBits & SideBits::eBottom) == SideBits::eBottom;
  31   }
  32   bool Left() const { return (mBits & SideBits::eLeft) == SideBits::eLeft; }
  33   bool Contains(SideBits aSideBits) const {
  34     MOZ_ASSERT(!(aSideBits & ~SideBits::eAll), "illegal side bits");
  35     return (mBits & aSideBits) == aSideBits;
  36   }
  37   Sides operator|(Sides aOther) const {
  38     return Sides(SideBits(mBits | aOther.mBits));
  39   }
  40   Sides operator|(SideBits aSideBits) const { return *this | Sides(aSideBits); }
  41   Sides& operator|=(Sides aOther) {
  42     mBits |= aOther.mBits;
  43     return *this;
  44   }
  45   Sides& operator|=(SideBits aSideBits) { return *this |= Sides(aSideBits); }
  46   bool operator==(Sides aOther) const { return mBits == aOther.mBits; }
  47   bool operator!=(Sides aOther) const { return !(*this == aOther); }
  48
  49  private:
  50   SideBits mBits;
  51 };
  52
  53 namespace gfx {
  54
  55 /**
  56  * Do not use this class directly. Subclass it, pass that subclass as the
  57  * Sub parameter, and only use that subclass.
  58  */
  59 template <class T, class Sub>
  60 struct BaseMargin {
  61   typedef mozilla::Side SideT;  // because we have a method named Side
  62
  63   // Do not change the layout of these members; the Side() methods below
  64   // depend on this order.
  65   T top, right, bottom, left;
  66
  67   // Constructors
  68   BaseMargin() : top(0), right(0), bottom(0), left(0) {}
  69   BaseMargin(T aTop, T aRight, T aBottom, T aLeft)
  70       : top(aTop), right(aRight), bottom(aBottom), left(aLeft) {}
  71
  72   void SizeTo(T aTop, T aRight, T aBottom, T aLeft) {
  73     top = aTop;
  74     right = aRight;
  75     bottom = aBottom;
  76     left = aLeft;
  77   }
  78
  79   T LeftRight() const { return left + right; }
  80   T TopBottom() const { return top + bottom; }
  81
  82   T& Side(SideT aSide) {
  83     // This is ugly!
  84     return *(&top + int(aSide));
  85   }
  86   T Side(SideT aSide) const {
  87     // This is ugly!
  88     return *(&top + int(aSide));
  89   }
  90
  91   Sub& ApplySkipSides(Sides aSkipSides) {
  92     if (aSkipSides.Top()) {
  93       top = 0;
  94     }
  95     if (aSkipSides.Right()) {
  96       right = 0;
  97     }
  98     if (aSkipSides.Bottom()) {
  99       bottom = 0;
 100     }
 101     if (aSkipSides.Left()) {
 102       left = 0;
 103     }
 104     return *static_cast<Sub*>(this);
 105   }
 106
 107   // Overloaded operators. Note that '=' isn't defined so we'll get the
 108   // compiler generated default assignment operator
 109   bool operator==(const Sub& aMargin) const {
 110     return top == aMargin.top && right == aMargin.right &&
 111            bottom == aMargin.bottom && left == aMargin.left;
 112   }
 113   bool operator!=(const Sub& aMargin) const { return !(*this == aMargin); }
 114   Sub operator+(const Sub& aMargin) const {
 115     return Sub(top + aMargin.top, right + aMargin.right,
 116                bottom + aMargin.bottom, left + aMargin.left);
 117   }
 118   Sub operator-(const Sub& aMargin) const {
 119     return Sub(top - aMargin.top, right - aMargin.right,
 120                bottom - aMargin.bottom, left - aMargin.left);
 121   }
 122   Sub& operator+=(const Sub& aMargin) {
 123     top += aMargin.top;
 124     right += aMargin.right;
 125     bottom += aMargin.bottom;
 126     left += aMargin.left;
 127     return *static_cast<Sub*>(this);
 128   }
 129
 130   friend std::ostream& operator<<(std::ostream& aStream,
 131                                   const BaseMargin& aMargin) {
 132     return aStream << '(' << aMargin.top << ',' << aMargin.right << ','
 133                    << aMargin.bottom << ',' << aMargin.left << ')';
 134   }
 135 };
 136
 137 }  // namespace gfx
 138 }  // namespace mozilla
 139
 140 #endif /* MOZILLA_GFX_BASEMARGIN_H_ */