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 
GeneralPattern(const GeneralPattern & aOther)32   GeneralPattern(const GeneralPattern& aOther) {}
33 
~GeneralPattern()34   ~GeneralPattern() {
35     if (mPattern) {
36       mPattern->~Pattern();
37     }
38   }
39 
Init(const Pattern & aPattern)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 
InitColorPattern(const DeviceColor & aColor)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 
GetPattern()116   Pattern* GetPattern() { return mPattern; }
117 
GetPattern()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
142