michael@0: /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef MOZILLA_GFX_TOOLS_H_
michael@0: #define MOZILLA_GFX_TOOLS_H_
michael@0: 
michael@0: #include "Types.h"
michael@0: #include "Point.h"
michael@0: #include <math.h>
michael@0: #if defined(_MSC_VER) && (_MSC_VER < 1600)
michael@0: #define hypotf _hypotf
michael@0: #endif
michael@0: 
michael@0: namespace mozilla {
michael@0: namespace gfx {
michael@0: 
michael@0: static inline bool
michael@0: IsOperatorBoundByMask(CompositionOp aOp) {
michael@0:   switch (aOp) {
michael@0:   case CompositionOp::OP_IN:
michael@0:   case CompositionOp::OP_OUT:
michael@0:   case CompositionOp::OP_DEST_IN:
michael@0:   case CompositionOp::OP_DEST_ATOP:
michael@0:   case CompositionOp::OP_SOURCE:
michael@0:     return false;
michael@0:   default:
michael@0:     return true;
michael@0:   }
michael@0: }
michael@0: 
michael@0: template <class T>
michael@0: struct ClassStorage
michael@0: {
michael@0:   char bytes[sizeof(T)];
michael@0: 
michael@0:   const T *addr() const { return (const T *)bytes; }
michael@0:   T *addr() { return (T *)(void *)bytes; }
michael@0: };
michael@0: 
michael@0: static inline bool
michael@0: FuzzyEqual(Float aA, Float aB, Float aErr)
michael@0: {
michael@0:   if ((aA + aErr >= aB) && (aA - aErr <= aB)) {
michael@0:     return true;
michael@0:   }
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: static inline void
michael@0: NudgeToInteger(float *aVal)
michael@0: {
michael@0:   float r = floorf(*aVal + 0.5f);
michael@0:   // The error threshold should be proportional to the rounded value. This
michael@0:   // bounds the relative error introduced by the nudge operation. However,
michael@0:   // when the rounded value is 0, the error threshold can't be proportional
michael@0:   // to the rounded value (we'd never round), so we just choose the same
michael@0:   // threshold as for a rounded value of 1.
michael@0:   if (FuzzyEqual(r, *aVal, r == 0.0f ? 1e-6f : fabs(r*1e-6f))) {
michael@0:     *aVal = r;
michael@0:   }
michael@0: }
michael@0: 
michael@0: static inline Float
michael@0: Distance(Point aA, Point aB)
michael@0: {
michael@0:   return hypotf(aB.x - aA.x, aB.y - aA.y);
michael@0: }
michael@0: 
michael@0: static inline int
michael@0: BytesPerPixel(SurfaceFormat aFormat)
michael@0: {
michael@0:   switch (aFormat) {
michael@0:   case SurfaceFormat::A8:
michael@0:     return 1;
michael@0:   case SurfaceFormat::R5G6B5:
michael@0:     return 2;
michael@0:   default:
michael@0:     return 4;
michael@0:   }
michael@0: }
michael@0: 
michael@0: template<typename T, int alignment = 16>
michael@0: struct AlignedArray
michael@0: {
michael@0:   AlignedArray()
michael@0:     : mStorage(nullptr)
michael@0:     , mPtr(nullptr)
michael@0:   {
michael@0:   }
michael@0: 
michael@0:   MOZ_ALWAYS_INLINE AlignedArray(size_t aSize)
michael@0:     : mStorage(nullptr)
michael@0:   {
michael@0:     Realloc(aSize);
michael@0:   }
michael@0: 
michael@0:   MOZ_ALWAYS_INLINE ~AlignedArray()
michael@0:   {
michael@0:     delete [] mStorage;
michael@0:   }
michael@0: 
michael@0:   void Dealloc()
michael@0:   {
michael@0:     delete [] mStorage;
michael@0:     mStorage = mPtr = nullptr;
michael@0:   }
michael@0: 
michael@0:   MOZ_ALWAYS_INLINE void Realloc(size_t aSize)
michael@0:   {
michael@0:     delete [] mStorage;
michael@0:     mStorage = new (std::nothrow) T[aSize + (alignment - 1)];
michael@0:     if (uintptr_t(mStorage) % alignment) {
michael@0:       // Our storage does not start at a <alignment>-byte boundary. Make sure mData does!
michael@0:       mPtr = (T*)(uintptr_t(mStorage) +
michael@0:         (alignment - (uintptr_t(mStorage) % alignment)));
michael@0:     } else {
michael@0:       mPtr = mStorage;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   MOZ_ALWAYS_INLINE operator T*()
michael@0:   {
michael@0:     return mPtr;
michael@0:   }
michael@0: 
michael@0:   T *mStorage;
michael@0:   T *mPtr;
michael@0: };
michael@0: 
michael@0: template<int alignment>
michael@0: int32_t GetAlignedStride(int32_t aStride)
michael@0: {
michael@0:   if (aStride % alignment) {
michael@0:     return aStride + (alignment - (aStride % alignment));
michael@0:   }
michael@0: 
michael@0:   return aStride;
michael@0: }
michael@0: 
michael@0: }
michael@0: }
michael@0: 
michael@0: #endif /* MOZILLA_GFX_TOOLS_H_ */