gfx/2d/PatternHelpers.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_PATTERNHELPERS_H
   8 #define _MOZILLA_GFX_PATTERNHELPERS_H
   9
  10 #include "mozilla/Alignment.h"
  11 #include "mozilla/gfx/2D.h"
  12
  13 namespace mozilla {
  14 namespace gfx {
  15
  16 /**
  17  * This class is used to allow general pattern creation functions to return
  18  * any type of pattern via an out-paramater without allocating a pattern
  19  * instance on the free-store (an instance of this class being created on the
  20  * stack before passing it in to the creation function). Without this class
  21  * writing pattern creation functions would be a pain since Pattern objects are
  22  * not reference counted, making lifetime management of instances created on
  23  * the free-store and returned from a creation function hazardous. Besides
  24  * that, in the case that ColorPattern's are expected to be common, it is
  25  * particularly desirable to avoid the overhead of allocating on the
  26  * free-store.
  27  */
  28 class GeneralPattern final {
  29  public:
  30   explicit GeneralPattern() = default;
  31
  32   GeneralPattern(const GeneralPattern& aOther) {}
  33
  34   ~GeneralPattern() {
  35     if (mPattern) {
  36       mPattern->~Pattern();
  37     }
  38   }
  39
  40   Pattern* Init(const Pattern& aPattern) {
  41     MOZ_ASSERT(!mPattern);
  42     switch (aPattern.GetType()) {
  43       case PatternType::COLOR:
  44         mPattern = new (mColorPattern.addr())
  45             ColorPattern(static_cast<const ColorPattern&>(aPattern));
  46         break;
  47       case PatternType::LINEAR_GRADIENT:
  48         mPattern = new (mLinearGradientPattern.addr()) LinearGradientPattern(
  49             static_cast<const LinearGradientPattern&>(aPattern));
  50         break;
  51       case PatternType::RADIAL_GRADIENT:
  52         mPattern = new (mRadialGradientPattern.addr()) RadialGradientPattern(
  53             static_cast<const RadialGradientPattern&>(aPattern));
  54         break;
  55       case PatternType::CONIC_GRADIENT:
  56         mPattern = new (mConicGradientPattern.addr()) ConicGradientPattern(
  57             static_cast<const ConicGradientPattern&>(aPattern));
  58         break;
  59       case PatternType::SURFACE:
  60         mPattern = new (mSurfacePattern.addr())
  61             SurfacePattern(static_cast<const SurfacePattern&>(aPattern));
  62         break;
  63       default:
  64         MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE("Unknown pattern type");
  65     }
  66     return mPattern;
  67   }
  68
  69   ColorPattern* InitColorPattern(const DeviceColor& aColor) {
  70     MOZ_ASSERT(!mPattern);
  71     mPattern = new (mColorPattern.addr()) ColorPattern(aColor);
  72     return mColorPattern.addr();
  73   }
  74
  75   LinearGradientPattern* InitLinearGradientPattern(
  76       const Point& aBegin, const Point& aEnd,
  77       already_AddRefed<GradientStops> aStops,
  78       const Matrix& aMatrix = Matrix()) {
  79     MOZ_ASSERT(!mPattern);
  80     mPattern = new (mLinearGradientPattern.addr())
  81         LinearGradientPattern(aBegin, aEnd, std::move(aStops), aMatrix);
  82     return mLinearGradientPattern.addr();
  83   }
  84
  85   RadialGradientPattern* InitRadialGradientPattern(
  86       const Point& aCenter1, const Point& aCenter2, Float aRadius1,
  87       Float aRadius2, already_AddRefed<GradientStops> aStops,
  88       const Matrix& aMatrix = Matrix()) {
  89     MOZ_ASSERT(!mPattern);
  90     mPattern = new (mRadialGradientPattern.addr()) RadialGradientPattern(
  91         aCenter1, aCenter2, aRadius1, aRadius2, std::move(aStops), aMatrix);
  92     return mRadialGradientPattern.addr();
  93   }
  94
  95   ConicGradientPattern* InitConicGradientPattern(
  96       const Point& aCenter, Float aAngle, Float aStartOffset, Float aEndOffset,
  97       already_AddRefed<GradientStops> aStops,
  98       const Matrix& aMatrix = Matrix()) {
  99     MOZ_ASSERT(!mPattern);
 100     mPattern = new (mConicGradientPattern.addr()) ConicGradientPattern(
 101         aCenter, aAngle, aStartOffset, aEndOffset, std::move(aStops), aMatrix);
 102     return mConicGradientPattern.addr();
 103   }
 104
 105   SurfacePattern* InitSurfacePattern(
 106       SourceSurface* aSourceSurface, ExtendMode aExtendMode,
 107       const Matrix& aMatrix = Matrix(),
 108       SamplingFilter aSamplingFilter = SamplingFilter::GOOD,
 109       const IntRect& aSamplingRect = IntRect()) {
 110     MOZ_ASSERT(!mPattern);
 111     mPattern = new (mSurfacePattern.addr()) SurfacePattern(
 112         aSourceSurface, aExtendMode, aMatrix, aSamplingFilter, aSamplingRect);
 113     return mSurfacePattern.addr();
 114   }
 115
 116   Pattern* GetPattern() { return mPattern; }
 117
 118   const Pattern* GetPattern() const { return mPattern; }
 119
 120   operator Pattern&() {
 121     if (!mPattern) {
 122       MOZ_CRASH("GFX: GeneralPattern not initialized");
 123     }
 124     return *mPattern;
 125   }
 126
 127  private:
 128   union {
 129     AlignedStorage2<ColorPattern> mColorPattern;
 130     AlignedStorage2<LinearGradientPattern> mLinearGradientPattern;
 131     AlignedStorage2<RadialGradientPattern> mRadialGradientPattern;
 132     AlignedStorage2<ConicGradientPattern> mConicGradientPattern;
 133     AlignedStorage2<SurfacePattern> mSurfacePattern;
 134   };
 135   Pattern* mPattern = nullptr;
 136 };
 137
 138 }  // namespace gfx
 139 }  // namespace mozilla
 140
 141 #endif  //  _MOZILLA_GFX_PATTERNHELPERS_H