gecko-dev/gfx/2d/Tools.h
2012-11-07 09:29:54 +01:00

146 lines
2.9 KiB
C++

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef MOZILLA_GFX_TOOLS_H_
#define MOZILLA_GFX_TOOLS_H_
#include "Types.h"
#include "Point.h"
#include <math.h>
#if defined(_MSC_VER) && (_MSC_VER < 1600)
#define hypotf _hypotf
#endif
namespace mozilla {
namespace gfx {
static inline bool
IsOperatorBoundByMask(CompositionOp aOp) {
switch (aOp) {
case OP_IN:
case OP_OUT:
case OP_DEST_IN:
case OP_DEST_ATOP:
case OP_SOURCE:
return false;
default:
return true;
}
}
template <class T>
struct ClassStorage
{
char bytes[sizeof(T)];
const T *addr() const { return (const T *)bytes; }
T *addr() { return (T *)(void *)bytes; }
};
static inline bool
FuzzyEqual(Float aA, Float aB, Float aErr)
{
if ((aA + aErr >= aB) && (aA - aErr <= aB)) {
return true;
}
return false;
}
static inline void
NudgeToInteger(float *aVal)
{
float r = floorf(*aVal + 0.5f);
// The error threshold should be proportional to the rounded value. This
// bounds the relative error introduced by the nudge operation. However,
// when the rounded value is 0, the error threshold can't be proportional
// to the rounded value (we'd never round), so we just choose the same
// threshold as for a rounded value of 1.
if (FuzzyEqual(r, *aVal, r == 0.0f ? 1e-6f : fabs(r*1e-6f))) {
*aVal = r;
}
}
static inline Float
Distance(Point aA, Point aB)
{
return hypotf(aB.x - aA.x, aB.y - aA.y);
}
static inline int
BytesPerPixel(SurfaceFormat aFormat)
{
switch (aFormat) {
case FORMAT_A8:
return 1;
case FORMAT_R5G6B5:
return 2;
default:
return 4;
}
}
template<typename T, int alignment = 16>
struct AlignedArray
{
AlignedArray()
: mStorage(nullptr)
, mPtr(nullptr)
{
}
MOZ_ALWAYS_INLINE AlignedArray(size_t aSize)
: mStorage(nullptr)
{
Realloc(aSize);
}
MOZ_ALWAYS_INLINE ~AlignedArray()
{
delete [] mStorage;
}
void Dealloc()
{
delete [] mStorage;
mStorage = mPtr = nullptr;
}
MOZ_ALWAYS_INLINE void Realloc(size_t aSize)
{
delete [] mStorage;
mStorage = new T[aSize + (alignment - 1)];
if (uintptr_t(mStorage) % alignment) {
// Our storage does not start at a <alignment>-byte boundary. Make sure mData does!
mPtr = (uint32_t*)(uintptr_t(mStorage) +
(alignment - (uintptr_t(mStorage) % alignment)));
} else {
mPtr = mStorage;
}
}
MOZ_ALWAYS_INLINE operator T*()
{
return mPtr;
}
T *mStorage;
T *mPtr;
};
template<int alignment>
int32_t GetAlignedStride(int32_t aStride)
{
if (aStride % alignment) {
return aStride + (alignment - (aStride % alignment));
}
return aStride;
}
}
}
#endif /* MOZILLA_GFX_TOOLS_H_ */