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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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
#include "Blur.h"
#include <algorithm>
#include <math.h>
#include <string.h>
#include "mozilla/CheckedInt.h"
#include "NumericTools.h"
#include "2D.h"
#include "DataSurfaceHelpers.h"
#include "Tools.h"
#ifdef USE_NEON
# include "mozilla/arm.h"
#endif
namespace mozilla {
namespace gfx {
/**
* Helper function to process each row of the box blur.
* It takes care of transposing the data on input or output depending
* on whether we intend a horizontal or vertical blur, and whether we're
* reading from the initial source or writing to the final destination.
* It allows starting or ending anywhere within the row to accomodate
* a skip rect.
*/
template <bool aTransposeInput, bool aTransposeOutput>
static inline void BoxBlurRow(const uint8_t* aInput, uint8_t* aOutput,
int32_t aLeftLobe, int32_t aRightLobe,
int32_t aWidth, int32_t aStride, int32_t aStart,
int32_t aEnd) {
// If the input or output is transposed, then we will move down a row
// for each step, instead of moving over a column. Since these values
// only depend on a template parameter, they will more easily get
// copy-propagated in the non-transposed case, which is why they
// are not passed as parameters.
const int32_t inputStep = aTransposeInput ? aStride : 1;
const int32_t outputStep = aTransposeOutput ? aStride : 1;
// We need to sample aLeftLobe pixels to the left and aRightLobe pixels
// to the right of the current position, then average them. So this is
// the size of the total width of this filter.
const int32_t boxSize = aLeftLobe + aRightLobe + 1;
// Instead of dividing the pixel sum by boxSize to average, we can just
// compute a scale that will normalize the result so that it can be quickly
// shifted into the desired range.
const uint32_t reciprocal = (1 << 24) / boxSize;
// The shift would normally truncate the result, whereas we would rather
// prefer to round the result to the closest increment. By adding 0.5 units
// to the initial sum, we bias the sum so that it will be rounded by the
// truncation instead.
uint32_t alphaSum = (boxSize + 1) / 2;
// We process the row with a moving filter, keeping a sum (alphaSum) of
// boxSize pixels. As we move over a pixel, we need to add on a pixel
// from the right extreme of the window that moved into range, and subtract
// off a pixel from the left extreme of window that moved out of range.
// But first, we need to initialization alphaSum to the contents of
// the window before we can get going. If the window moves out of bounds
// of the row, we clamp each sample to be the closest pixel from within
// row bounds, so the 0th and aWidth-1th pixel.
int32_t initLeft = aStart - aLeftLobe;
if (initLeft < 0) {
// If the left lobe samples before the row, add in clamped samples.
alphaSum += -initLeft * aInput[0];
initLeft = 0;
}
int32_t initRight = aStart + boxSize - aLeftLobe;
if (initRight > aWidth) {
// If the right lobe samples after the row, add in clamped samples.
alphaSum += (initRight - aWidth) * aInput[(aWidth - 1) * inputStep];
initRight = aWidth;
}
// Finally, add in all the valid, non-clamped samples to fill up the
// rest of the window.
const uint8_t* src = &aInput[initLeft * inputStep];
const uint8_t* iterEnd = &aInput[initRight * inputStep];
#define INIT_ITER \
alphaSum += *src; \
src += inputStep;
// We unroll the per-pixel loop here substantially. The amount of work
// done per sample is so small that the cost of a loop condition check
// and a branch can substantially add to or even dominate the performance
// of the loop.
while (src + 16 * inputStep <= iterEnd) {
INIT_ITER;
INIT_ITER;
INIT_ITER;
INIT_ITER;
INIT_ITER;
INIT_ITER;
INIT_ITER;
INIT_ITER;
INIT_ITER;
INIT_ITER;
INIT_ITER;
INIT_ITER;
INIT_ITER;
INIT_ITER;
INIT_ITER;
INIT_ITER;
}
while (src < iterEnd) {
INIT_ITER;
}
// Now we start moving the window over the row. We will be accessing
// pixels form aStart - aLeftLobe up to aEnd + aRightLobe, which may be
// out of bounds of the row. To avoid having to check within the inner
// loops if we are in bound, we instead compute the points at which
// we will move out of bounds of the row on the left side (splitLeft)
// and right side (splitRight).
int32_t splitLeft = std::min(std::max(aLeftLobe, aStart), aEnd);
int32_t splitRight =
std::min(std::max(aWidth - (boxSize - aLeftLobe), aStart), aEnd);
// If the filter window is actually large than the size of the row,
// there will be a middle area of overlap where the leftmost and rightmost
// pixel of the filter will both be outside the row. In this case, we need
// to invert the splits so that splitLeft <= splitRight.
if (boxSize > aWidth) {
std::swap(splitLeft, splitRight);
}
// Process all pixels up to splitLeft that would sample before the start of
// the row. Note that because inputStep and outputStep may not be a const 1
// value, it is more performant to increment pointers here for the source and
// destination rather than use a loop counter, since doing so would entail an
// expensive multiplication that significantly slows down the loop.
uint8_t* dst = &aOutput[aStart * outputStep];
iterEnd = &aOutput[splitLeft * outputStep];
src = &aInput[(aStart + boxSize - aLeftLobe) * inputStep];
uint8_t firstVal = aInput[0];
#define LEFT_ITER \
*dst = (alphaSum * reciprocal) >> 24; \
alphaSum += *src - firstVal; \
dst += outputStep; \
src += inputStep;
while (dst + 16 * outputStep <= iterEnd) {
LEFT_ITER;
LEFT_ITER;
LEFT_ITER;
LEFT_ITER;
LEFT_ITER;
LEFT_ITER;
LEFT_ITER;
LEFT_ITER;
LEFT_ITER;
LEFT_ITER;
LEFT_ITER;
LEFT_ITER;
LEFT_ITER;
LEFT_ITER;
LEFT_ITER;
LEFT_ITER;
}
while (dst < iterEnd) {
LEFT_ITER;
}
// Process all pixels between splitLeft and splitRight.
iterEnd = &aOutput[splitRight * outputStep];
if (boxSize <= aWidth) {
// The filter window is smaller than the row size, so the leftmost and
// rightmost samples are both within row bounds.
src = &aInput[(splitLeft - aLeftLobe) * inputStep];
int32_t boxStep = boxSize * inputStep;
#define CENTER_ITER \
*dst = (alphaSum * reciprocal) >> 24; \
alphaSum += src[boxStep] - *src; \
dst += outputStep; \
src += inputStep;
while (dst + 16 * outputStep <= iterEnd) {
CENTER_ITER;
CENTER_ITER;
CENTER_ITER;
CENTER_ITER;
CENTER_ITER;
CENTER_ITER;
CENTER_ITER;
CENTER_ITER;
CENTER_ITER;
CENTER_ITER;
CENTER_ITER;
CENTER_ITER;
CENTER_ITER;
CENTER_ITER;
CENTER_ITER;
CENTER_ITER;
}
while (dst < iterEnd) {
CENTER_ITER;
}
} else {
// The filter window is larger than the row size, and we're in the area of
// split overlap. So the leftmost and rightmost samples are both out of
// bounds and need to be clamped. We can just precompute the difference here
// consequently.
int32_t firstLastDiff = aInput[(aWidth - 1) * inputStep] - aInput[0];
while (dst < iterEnd) {
*dst = (alphaSum * reciprocal) >> 24;
alphaSum += firstLastDiff;
dst += outputStep;
}
}
// Process all remaining pixels after splitRight that would sample after the
// row end.
iterEnd = &aOutput[aEnd * outputStep];
src = &aInput[(splitRight - aLeftLobe) * inputStep];
uint8_t lastVal = aInput[(aWidth - 1) * inputStep];
#define RIGHT_ITER \
*dst = (alphaSum * reciprocal) >> 24; \
alphaSum += lastVal - *src; \
dst += outputStep; \
src += inputStep;
while (dst + 16 * outputStep <= iterEnd) {
RIGHT_ITER;
RIGHT_ITER;
RIGHT_ITER;
RIGHT_ITER;
RIGHT_ITER;
RIGHT_ITER;
RIGHT_ITER;
RIGHT_ITER;
RIGHT_ITER;
RIGHT_ITER;
RIGHT_ITER;
RIGHT_ITER;
RIGHT_ITER;
RIGHT_ITER;
RIGHT_ITER;
RIGHT_ITER;
}
while (dst < iterEnd) {
RIGHT_ITER;
}
}
/**
* Box blur involves looking at one pixel, and setting its value to the average
* of its neighbouring pixels. This is meant to provide a 3-pass approximation
* of a Gaussian blur.
* @param aTranspose Whether to transpose the buffer when reading and writing
* to it.
* @param aData The buffer to be blurred.
* @param aLobes The number of pixels to blend on the left and right for each of
* 3 passes.
* @param aWidth The number of columns in the buffers.
* @param aRows The number of rows in the buffers.
* @param aStride The stride of the buffer.
*/
template <bool aTranspose>
static void BoxBlur(uint8_t* aData, const int32_t aLobes[3][2], int32_t aWidth,
int32_t aRows, int32_t aStride, IntRect aSkipRect) {
if (aTranspose) {
std::swap(aWidth, aRows);
aSkipRect.Swap();
}
MOZ_ASSERT(aWidth > 0);
// All three passes of the box blur that approximate the Gaussian are done
// on each row in turn, so we only need two temporary row buffers to process
// each row, instead of a full-sized buffer. Data moves from the source to the
// first temporary, from the first temporary to the second, then from the
// second back to the destination. This way is more cache-friendly than
// processing whe whole buffer in each pass and thus yields a nice speedup.
uint8_t* tmpRow = new (std::nothrow) uint8_t[2 * aWidth];
if (!tmpRow) {
return;
}
uint8_t* tmpRow2 = tmpRow + aWidth;
const int32_t stride = aTranspose ? 1 : aStride;
bool skipRectCoversWholeRow =
0 >= aSkipRect.X() && aWidth <= aSkipRect.XMost();
for (int32_t y = 0; y < aRows; y++) {
// Check whether the skip rect intersects this row. If the skip
// rect covers the whole surface in this row, we can avoid
// this row entirely (and any others along the skip rect).
bool inSkipRectY = aSkipRect.ContainsY(y);
if (inSkipRectY && skipRectCoversWholeRow) {
aData += stride * (aSkipRect.YMost() - y);
y = aSkipRect.YMost() - 1;
continue;
}
// Read in data from the source transposed if necessary.
BoxBlurRow<aTranspose, false>(aData, tmpRow, aLobes[0][0], aLobes[0][1],
aWidth, aStride, 0, aWidth);
// For the middle pass, the data is already pre-transposed and does not need
// to be post-transposed yet.
BoxBlurRow<false, false>(tmpRow, tmpRow2, aLobes[1][0], aLobes[1][1],
aWidth, aStride, 0, aWidth);
// Write back data to the destination transposed if necessary too.
// Make sure not to overwrite the skip rect by only outputting to the
// destination before and after the skip rect, if requested.
int32_t skipStart =
inSkipRectY ? std::min(std::max(aSkipRect.X(), 0), aWidth) : aWidth;
int32_t skipEnd = std::max(skipStart, aSkipRect.XMost());
if (skipStart > 0) {
BoxBlurRow<false, aTranspose>(tmpRow2, aData, aLobes[2][0], aLobes[2][1],
aWidth, aStride, 0, skipStart);
}
if (skipEnd < aWidth) {
BoxBlurRow<false, aTranspose>(tmpRow2, aData, aLobes[2][0], aLobes[2][1],
aWidth, aStride, skipEnd, aWidth);
}
aData += stride;
}
delete[] tmpRow;
}
static void ComputeLobes(int32_t aRadius, int32_t aLobes[3][2]) {
int32_t major, minor, final;
* some notes about approximating the Gaussian blur with box-blurs.
* The comments below are in the terminology of that page.
*/
int32_t z = aRadius / 3;
switch (aRadius % 3) {
case 0:
// aRadius = z*3; choose d = 2*z + 1
major = minor = final = z;
break;
case 1:
// aRadius = z*3 + 1
// This is a tricky case since there is no value of d which will
// yield a radius of exactly aRadius. If d is odd, i.e. d=2*k + 1
// for some integer k, then the radius will be 3*k. If d is even,
// i.e. d=2*k, then the radius will be 3*k - 1.
// So we have to choose values that don't match the standard
// algorithm.
major = z + 1;
minor = final = z;
break;
case 2:
// aRadius = z*3 + 2; choose d = 2*z + 2
major = final = z + 1;
minor = z;
break;
default:
// Mathematical impossibility!
MOZ_ASSERT(false);
major = minor = final = 0;
}
MOZ_ASSERT(major + minor + final == aRadius);
aLobes[0][0] = major;
aLobes[0][1] = minor;
aLobes[1][0] = minor;
aLobes[1][1] = major;
aLobes[2][0] = final;
aLobes[2][1] = final;
}
static void SpreadHorizontal(uint8_t* aInput, uint8_t* aOutput, int32_t aRadius,
int32_t aWidth, int32_t aRows, int32_t aStride,
const IntRect& aSkipRect) {
if (aRadius == 0) {
memcpy(aOutput, aInput, aStride * aRows);
return;
}
bool skipRectCoversWholeRow =
0 >= aSkipRect.X() && aWidth <= aSkipRect.XMost();
for (int32_t y = 0; y < aRows; y++) {
// Check whether the skip rect intersects this row. If the skip
// rect covers the whole surface in this row, we can avoid
// this row entirely (and any others along the skip rect).
bool inSkipRectY = aSkipRect.ContainsY(y);
if (inSkipRectY && skipRectCoversWholeRow) {
y = aSkipRect.YMost() - 1;
continue;
}
for (int32_t x = 0; x < aWidth; x++) {
// Check whether we are within the skip rect. If so, go
// to the next point outside the skip rect.
if (inSkipRectY && aSkipRect.ContainsX(x)) {
x = aSkipRect.XMost();
if (x >= aWidth) break;
}
int32_t sMin = std::max(x - aRadius, 0);
int32_t sMax = std::min(x + aRadius, aWidth - 1);
int32_t v = 0;
for (int32_t s = sMin; s <= sMax; ++s) {
v = std::max<int32_t>(v, aInput[aStride * y + s]);
}
aOutput[aStride * y + x] = v;
}
}
}
static void SpreadVertical(uint8_t* aInput, uint8_t* aOutput, int32_t aRadius,
int32_t aWidth, int32_t aRows, int32_t aStride,
const IntRect& aSkipRect) {
if (aRadius == 0) {
memcpy(aOutput, aInput, aStride * aRows);
return;
}
bool skipRectCoversWholeColumn =
0 >= aSkipRect.Y() && aRows <= aSkipRect.YMost();
for (int32_t x = 0; x < aWidth; x++) {
bool inSkipRectX = aSkipRect.ContainsX(x);
if (inSkipRectX && skipRectCoversWholeColumn) {
x = aSkipRect.XMost() - 1;
continue;
}
for (int32_t y = 0; y < aRows; y++) {
// Check whether we are within the skip rect. If so, go
// to the next point outside the skip rect.
if (inSkipRectX && aSkipRect.ContainsY(y)) {
y = aSkipRect.YMost();
if (y >= aRows) break;
}
int32_t sMin = std::max(y - aRadius, 0);
int32_t sMax = std::min(y + aRadius, aRows - 1);
int32_t v = 0;
for (int32_t s = sMin; s <= sMax; ++s) {
v = std::max<int32_t>(v, aInput[aStride * s + x]);
}
aOutput[aStride * y + x] = v;
}
}
}
CheckedInt<int32_t> AlphaBoxBlur::RoundUpToMultipleOf4(int32_t aVal) {
CheckedInt<int32_t> val(aVal);
val += 3;
val /= 4;
val *= 4;
return val;
}
AlphaBoxBlur::AlphaBoxBlur(const Rect& aRect, const IntSize& aSpreadRadius,
const IntSize& aBlurRadius, const Rect* aDirtyRect,
const Rect* aSkipRect)
: mStride(0), mSurfaceAllocationSize(0) {
Init(aRect, aSpreadRadius, aBlurRadius, aDirtyRect, aSkipRect);
}
AlphaBoxBlur::AlphaBoxBlur()
: mStride(0), mSurfaceAllocationSize(0), mHasDirtyRect(false) {}
void AlphaBoxBlur::Init(const Rect& aRect, const IntSize& aSpreadRadius,
const IntSize& aBlurRadius, const Rect* aDirtyRect,
const Rect* aSkipRect) {
mSpreadRadius = aSpreadRadius;
mBlurRadius = aBlurRadius;
Rect rect(aRect);
rect.Inflate(Size(aBlurRadius + aSpreadRadius));
rect.RoundOut();
if (aDirtyRect) {
// If we get passed a dirty rect from layout, we can minimize the
// shadow size and make painting faster.
mHasDirtyRect = true;
mDirtyRect = *aDirtyRect;
Rect requiredBlurArea = mDirtyRect.Intersect(rect);
requiredBlurArea.Inflate(Size(aBlurRadius + aSpreadRadius));
rect = requiredBlurArea.Intersect(rect);
} else {
mHasDirtyRect = false;
}
mRect = TruncatedToInt(rect);
if (mRect.IsEmpty()) {
return;
}
if (aSkipRect) {
// If we get passed a skip rect, we can lower the amount of
// blurring/spreading we need to do. We convert it to IntRect to avoid
// expensive int<->float conversions if we were to use Rect instead.
Rect skipRect = *aSkipRect;
skipRect.Deflate(Size(aBlurRadius + aSpreadRadius));
mSkipRect = RoundedIn(skipRect);
mSkipRect = mSkipRect.Intersect(mRect);
if (mSkipRect.IsEqualInterior(mRect)) {
return;
}
mSkipRect -= mRect.TopLeft();
// Ensure the skip rect is 4-pixel-aligned in the x axis, so that all our
mSkipRect.SetLeftEdge(RoundUpToMultiple(mSkipRect.X(), 4));
mSkipRect.SetRightEdge(RoundDownToMultiple(mSkipRect.XMost(), 4));
if (mSkipRect.IsEmpty()) {
mSkipRect = IntRect();
}
} else {
mSkipRect = IntRect();
}
CheckedInt<int32_t> stride = RoundUpToMultipleOf4(mRect.Width());
if (stride.isValid()) {
mStride = stride.value();
// We need to leave room for an additional 3 bytes for a potential overrun
// in our blurring code.
size_t size = BufferSizeFromStrideAndHeight(mStride, mRect.Height(), 3);
if (size != 0) {
mSurfaceAllocationSize = size;
}
}
}
AlphaBoxBlur::AlphaBoxBlur(const Rect& aRect, int32_t aStride, float aSigmaX,
float aSigmaY)
: mRect(TruncatedToInt(aRect)),
mBlurRadius(CalculateBlurRadius(Point(aSigmaX, aSigmaY))),
mStride(aStride),
mSurfaceAllocationSize(0),
mHasDirtyRect(false) {
IntRect intRect;
if (aRect.ToIntRect(&intRect)) {
size_t minDataSize =
BufferSizeFromStrideAndHeight(intRect.Width(), intRect.Height());
if (minDataSize != 0) {
mSurfaceAllocationSize = minDataSize;
}
}
}
AlphaBoxBlur::~AlphaBoxBlur() = default;
IntSize AlphaBoxBlur::GetSize() const {
IntSize size(mRect.Width(), mRect.Height());
return size;
}
int32_t AlphaBoxBlur::GetStride() const { return mStride; }
IntRect AlphaBoxBlur::GetRect() const { return mRect; }
Rect* AlphaBoxBlur::GetDirtyRect() {
if (mHasDirtyRect) {
return &mDirtyRect;
}
return nullptr;
}
size_t AlphaBoxBlur::GetSurfaceAllocationSize() const {
return mSurfaceAllocationSize;
}
void AlphaBoxBlur::Blur(uint8_t* aData) const {
if (!aData) {
return;
}
// no need to do all this if not blurring or spreading
if (mBlurRadius != IntSize(0, 0) || mSpreadRadius != IntSize(0, 0)) {
int32_t stride = GetStride();
IntSize size = GetSize();
if (mSpreadRadius.width > 0 || mSpreadRadius.height > 0) {
// No need to use CheckedInt here - we have validated it in the
// constructor.
size_t szB = stride * size.height;
uint8_t* tmpData = new (std::nothrow) uint8_t[szB];
if (!tmpData) {
return;
}
memset(tmpData, 0, szB);
SpreadHorizontal(aData, tmpData, mSpreadRadius.width, size.width,
size.height, stride, mSkipRect);
SpreadVertical(tmpData, aData, mSpreadRadius.height, size.width,
size.height, stride, mSkipRect);
delete[] tmpData;
}
int32_t horizontalLobes[3][2];
ComputeLobes(mBlurRadius.width, horizontalLobes);
int32_t verticalLobes[3][2];
ComputeLobes(mBlurRadius.height, verticalLobes);
// We want to allow for some extra space on the left for alignment reasons.
int32_t maxLeftLobe =
RoundUpToMultipleOf4(horizontalLobes[0][0] + 1).value();
IntSize integralImageSize(
size.width + maxLeftLobe + horizontalLobes[1][1],
size.height + verticalLobes[0][0] + verticalLobes[1][1] + 1);
if ((integralImageSize.width * integralImageSize.height) > (1 << 24)) {
// Fallback to old blurring code when the surface is so large it may
// overflow our integral image!
if (mBlurRadius.width > 0) {
BoxBlur<false>(aData, horizontalLobes, size.width, size.height, stride,
mSkipRect);
}
if (mBlurRadius.height > 0) {
BoxBlur<true>(aData, verticalLobes, size.width, size.height, stride,
mSkipRect);
}
} else {
size_t integralImageStride =
GetAlignedStride<16>(integralImageSize.width, 4);
if (integralImageStride == 0) {
return;
}
// We need to leave room for an additional 12 bytes for a maximum overrun
// of 3 pixels in the blurring code.
size_t bufLen = BufferSizeFromStrideAndHeight(
integralImageStride, integralImageSize.height, 12);
if (bufLen == 0) {
return;
}
// bufLen is a byte count, but here we want a multiple of 32-bit ints, so
// we divide by 4.
AlignedArray<uint32_t> integralImage((bufLen / 4) +
((bufLen % 4) ? 1 : 0));
if (!integralImage) {
return;
}
#ifdef USE_SSE2
if (Factory::HasSSE2()) {
BoxBlur_SSE2(aData, horizontalLobes[0][0], horizontalLobes[0][1],
verticalLobes[0][0], verticalLobes[0][1], integralImage,
integralImageStride);
BoxBlur_SSE2(aData, horizontalLobes[1][0], horizontalLobes[1][1],
verticalLobes[1][0], verticalLobes[1][1], integralImage,
integralImageStride);
BoxBlur_SSE2(aData, horizontalLobes[2][0], horizontalLobes[2][1],
verticalLobes[2][0], verticalLobes[2][1], integralImage,
integralImageStride);
} else
#endif
#ifdef USE_NEON
if (mozilla::supports_neon()) {
BoxBlur_NEON(aData, horizontalLobes[0][0], horizontalLobes[0][1],
verticalLobes[0][0], verticalLobes[0][1], integralImage,
integralImageStride);
BoxBlur_NEON(aData, horizontalLobes[1][0], horizontalLobes[1][1],
verticalLobes[1][0], verticalLobes[1][1], integralImage,
integralImageStride);
BoxBlur_NEON(aData, horizontalLobes[2][0], horizontalLobes[2][1],
verticalLobes[2][0], verticalLobes[2][1], integralImage,
integralImageStride);
} else
#endif
{
#ifdef _MIPS_ARCH_LOONGSON3A
BoxBlur_LS3(aData, horizontalLobes[0][0], horizontalLobes[0][1],
verticalLobes[0][0], verticalLobes[0][1], integralImage,
integralImageStride);
BoxBlur_LS3(aData, horizontalLobes[1][0], horizontalLobes[1][1],
verticalLobes[1][0], verticalLobes[1][1], integralImage,
integralImageStride);
BoxBlur_LS3(aData, horizontalLobes[2][0], horizontalLobes[2][1],
verticalLobes[2][0], verticalLobes[2][1], integralImage,
integralImageStride);
#else
BoxBlur_C(aData, horizontalLobes[0][0], horizontalLobes[0][1],
verticalLobes[0][0], verticalLobes[0][1], integralImage,
integralImageStride);
BoxBlur_C(aData, horizontalLobes[1][0], horizontalLobes[1][1],
verticalLobes[1][0], verticalLobes[1][1], integralImage,
integralImageStride);
BoxBlur_C(aData, horizontalLobes[2][0], horizontalLobes[2][1],
verticalLobes[2][0], verticalLobes[2][1], integralImage,
integralImageStride);
#endif
}
}
}
}
MOZ_ALWAYS_INLINE void GenerateIntegralRow(uint32_t* aDest,
const uint8_t* aSource,
uint32_t* aPreviousRow,
const uint32_t& aSourceWidth,
const uint32_t& aLeftInflation,
const uint32_t& aRightInflation) {
uint32_t currentRowSum = 0;
uint32_t pixel = aSource[0];
for (uint32_t x = 0; x < aLeftInflation; x++) {
currentRowSum += pixel;
*aDest++ = currentRowSum + *aPreviousRow++;
}
for (uint32_t x = aLeftInflation; x < (aSourceWidth + aLeftInflation);
x += 4) {
uint32_t alphaValues = *(uint32_t*)(aSource + (x - aLeftInflation));
#if defined WORDS_BIGENDIAN || defined IS_BIG_ENDIAN || defined __BIG_ENDIAN__
currentRowSum += (alphaValues >> 24) & 0xff;
*aDest++ = *aPreviousRow++ + currentRowSum;
currentRowSum += (alphaValues >> 16) & 0xff;
*aDest++ = *aPreviousRow++ + currentRowSum;
currentRowSum += (alphaValues >> 8) & 0xff;
*aDest++ = *aPreviousRow++ + currentRowSum;
currentRowSum += alphaValues & 0xff;
*aDest++ = *aPreviousRow++ + currentRowSum;
#else
currentRowSum += alphaValues & 0xff;
*aDest++ = *aPreviousRow++ + currentRowSum;
alphaValues >>= 8;
currentRowSum += alphaValues & 0xff;
*aDest++ = *aPreviousRow++ + currentRowSum;
alphaValues >>= 8;
currentRowSum += alphaValues & 0xff;
*aDest++ = *aPreviousRow++ + currentRowSum;
alphaValues >>= 8;
currentRowSum += alphaValues & 0xff;
*aDest++ = *aPreviousRow++ + currentRowSum;
#endif
}
pixel = aSource[aSourceWidth - 1];
for (uint32_t x = (aSourceWidth + aLeftInflation);
x < (aSourceWidth + aLeftInflation + aRightInflation); x++) {
currentRowSum += pixel;
*aDest++ = currentRowSum + *aPreviousRow++;
}
}
MOZ_ALWAYS_INLINE void GenerateIntegralImage_C(
int32_t aLeftInflation, int32_t aRightInflation, int32_t aTopInflation,
int32_t aBottomInflation, uint32_t* aIntegralImage,
size_t aIntegralImageStride, uint8_t* aSource, int32_t aSourceStride,
const IntSize& aSize) {
uint32_t stride32bit = aIntegralImageStride / 4;
IntSize integralImageSize(aSize.width + aLeftInflation + aRightInflation,
aSize.height + aTopInflation + aBottomInflation);
memset(aIntegralImage, 0, aIntegralImageStride);
GenerateIntegralRow(aIntegralImage, aSource, aIntegralImage, aSize.width,
aLeftInflation, aRightInflation);
for (int y = 1; y < aTopInflation + 1; y++) {
GenerateIntegralRow(aIntegralImage + (y * stride32bit), aSource,
aIntegralImage + (y - 1) * stride32bit, aSize.width,
aLeftInflation, aRightInflation);
}
for (int y = aTopInflation + 1; y < (aSize.height + aTopInflation); y++) {
GenerateIntegralRow(aIntegralImage + (y * stride32bit),
aSource + aSourceStride * (y - aTopInflation),
aIntegralImage + (y - 1) * stride32bit, aSize.width,
aLeftInflation, aRightInflation);
}
if (aBottomInflation) {
for (int y = (aSize.height + aTopInflation); y < integralImageSize.height;
y++) {
GenerateIntegralRow(aIntegralImage + (y * stride32bit),
aSource + ((aSize.height - 1) * aSourceStride),
aIntegralImage + (y - 1) * stride32bit, aSize.width,
aLeftInflation, aRightInflation);
}
}
}
/**
* Attempt to do an in-place box blur using an integral image.
*/
void AlphaBoxBlur::BoxBlur_C(uint8_t* aData, int32_t aLeftLobe,
int32_t aRightLobe, int32_t aTopLobe,
int32_t aBottomLobe, uint32_t* aIntegralImage,
size_t aIntegralImageStride) const {
IntSize size = GetSize();
MOZ_ASSERT(size.width > 0);
// Our 'left' or 'top' lobe will include the current pixel. i.e. when
// looking at an integral image the value of a pixel at 'x,y' is calculated
// using the value of the integral image values above/below that.
aLeftLobe++;
aTopLobe++;
int32_t boxSize = (aLeftLobe + aRightLobe) * (aTopLobe + aBottomLobe);
MOZ_ASSERT(boxSize > 0);
if (boxSize == 1) {
return;
}
int32_t stride32bit = aIntegralImageStride / 4;
int32_t leftInflation = RoundUpToMultipleOf4(aLeftLobe).value();
GenerateIntegralImage_C(leftInflation, aRightLobe, aTopLobe, aBottomLobe,
aIntegralImage, aIntegralImageStride, aData, mStride,
size);
uint32_t reciprocal = uint32_t((uint64_t(1) << 32) / boxSize);
uint32_t* innerIntegral =
aIntegralImage + (aTopLobe * stride32bit) + leftInflation;
// Storing these locally makes this about 30% faster! Presumably the compiler
// can't be sure we're not altering the member variables in this loop.
IntRect skipRect = mSkipRect;
uint8_t* data = aData;
int32_t stride = mStride;
for (int32_t y = 0; y < size.height; y++) {
// Not using ContainsY(y) because we do not skip y == skipRect.Y()
// although that may not be done on purpose
bool inSkipRectY = y > skipRect.Y() && y < skipRect.YMost();
uint32_t* topLeftBase =
innerIntegral + ((y - aTopLobe) * stride32bit - aLeftLobe);
uint32_t* topRightBase =
innerIntegral + ((y - aTopLobe) * stride32bit + aRightLobe);
uint32_t* bottomRightBase =
innerIntegral + ((y + aBottomLobe) * stride32bit + aRightLobe);
uint32_t* bottomLeftBase =
innerIntegral + ((y + aBottomLobe) * stride32bit - aLeftLobe);
for (int32_t x = 0; x < size.width; x++) {
// Not using ContainsX(x) because we do not skip x == skipRect.X()
// although that may not be done on purpose
if (inSkipRectY && x > skipRect.X() && x < skipRect.XMost()) {
x = skipRect.XMost() - 1;
// Trigger early jump on coming loop iterations, this will be reset
// next line anyway.
inSkipRectY = false;
continue;
}
int32_t topLeft = topLeftBase[x];
int32_t topRight = topRightBase[x];
int32_t bottomRight = bottomRightBase[x];
int32_t bottomLeft = bottomLeftBase[x];
uint32_t value = bottomRight - topRight - bottomLeft;
value += topLeft;
data[stride * y + x] =
(uint64_t(reciprocal) * value + (uint64_t(1) << 31)) >> 32;
}
}
}
/**
* Compute the box blur size (which we're calling the blur radius) from
* the standard deviation.
*
* Much of this, the 3 * sqrt(2 * pi) / 4, is the known value for
* approximating a Gaussian using box blurs. This yields quite a good
* approximation for a Gaussian. Then we multiply this by 1.5 since our
* code wants the radius of the entire triple-box-blur kernel instead of
* the diameter of an individual box blur. For more details, see:
*/
static const Float GAUSSIAN_SCALE_FACTOR =
Float((3 * sqrt(2 * M_PI) / 4) * 1.5);
IntSize AlphaBoxBlur::CalculateBlurRadius(const Point& aStd) {
IntSize size(
static_cast<int32_t>(floor(aStd.x * GAUSSIAN_SCALE_FACTOR + 0.5f)),
static_cast<int32_t>(floor(aStd.y * GAUSSIAN_SCALE_FACTOR + 0.5f)));
return size;
}
Float AlphaBoxBlur::CalculateBlurSigma(int32_t aBlurRadius) {
return aBlurRadius / GAUSSIAN_SCALE_FACTOR;
}
} // namespace gfx
} // namespace mozilla